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href="command-line-options.html#red-primary">&#x2011;red&#x2011;primary</a> <span class='bull'></span> <a href="command-line-options.html#regard-warnings">&#x2011;regard&#x2011;warnings</a> <span class='bull'></span> <a href="command-line-options.html#region">&#x2011;region</a> <span class='bull'></span> <a href="command-line-options.html#remap">&#x2011;remap</a> <span class='bull'></span> <a href="command-line-options.html#remote">&#x2011;remote</a> <span class='bull'></span> <a href="command-line-options.html#render">&#x2011;render</a> <span class='bull'></span> <a href="command-line-options.html#repage">&#x2011;repage</a> <span class='bull'></span> <a href="command-line-options.html#resample">&#x2011;resample</a> <span class='bull'></span> <a href="command-line-options.html#resize">&#x2011;resize</a> <span class='bull'></span> <a href="command-line-options.html#respect-parentheses">&#x2011;respect&#x2011;parentheses</a> <span class='bull'></span> <a href="command-line-options.html#reverse">&#x2011;reverse</a> <span class='bull'></span> <a href="command-line-options.html#roll">&#x2011;roll</a> <span class='bull'></span> <a href="command-line-options.html#rotate">&#x2011;rotate</a> <span class='bull'></span> <a href="command-line-options.html#sample">&#x2011;sample</a> <span class='bull'></span> <a href="command-line-options.html#sampling-factor">&#x2011;sampling&#x2011;factor</a> <span class='bull'></span> <a href="command-line-options.html#scale">&#x2011;scale</a> <span class='bull'></span> <a href="command-line-options.html#scene">&#x2011;scene</a> <span class='bull'></span> <a href="command-line-options.html#screen">&#x2011;screen</a> <span class='bull'></span> <a href="command-line-options.html#seed">&#x2011;seed</a> <span class='bull'></span> <a href="command-line-options.html#segment">&#x2011;segment</a> <span class='bull'></span> <a href="command-line-options.html#selective-blur">&#x2011;selective&#x2011;blur</a> <span class='bull'></span> <a href="command-line-options.html#separate">&#x2011;separate</a> <span class='bull'></span> <a href="command-line-options.html#sepia-tone">&#x2011;sepia&#x2011;tone</a> <span class='bull'></span> <a href="command-line-options.html#set">&#x2011;set</a> <span class='bull'></span> <a href="command-line-options.html#shade">&#x2011;shade</a> <span class='bull'></span> <a href="command-line-options.html#shadow">&#x2011;shadow</a> <span class='bull'></span> <a href="command-line-options.html#shared-memory">&#x2011;shared&#x2011;memory</a> <span class='bull'></span> <a href="command-line-options.html#sharpen">&#x2011;sharpen</a> <span class='bull'></span> <a href="command-line-options.html#shave">&#x2011;shave</a> <span class='bull'></span> <a href="command-line-options.html#shear">&#x2011;shear</a> <span class='bull'></span> <a href="command-line-options.html#sigmoidal-contrast">&#x2011;sigmoidal&#x2011;contrast</a> <span class='bull'></span> <a href="command-line-options.html#silent">&#x2011;silent</a> <span class='bull'></span> <a href="command-line-options.html#similarity-threshold">&#x2011;similarity&#x2011;threshold</a> <span class='bull'></span> <a href="command-line-options.html#size">&#x2011;size</a> <span class='bull'></span> <a href="command-line-options.html#sketch">&#x2011;sketch</a> <span class='bull'></span> <a href="command-line-options.html#smush">&#x2011;smush</a> <span class='bull'></span> <a href="command-line-options.html#snaps">&#x2011;snaps</a> <span class='bull'></span> <a href="command-line-options.html#solarize">&#x2011;solarize</a> <span class='bull'></span> <a href="command-line-options.html#sparse-color">&#x2011;sparse&#x2011;color</a> <span class='bull'></span> <a href="command-line-options.html#splice">&#x2011;splice</a> <span class='bull'></span> <a href="command-line-options.html#spread">&#x2011;spread</a> <span class='bull'></span> <a href="command-line-options.html#statistic">&#x2011;statistic</a> <span class='bull'></span> <a href="command-line-options.html#stegano">&#x2011;stegano</a> <span class='bull'></span> <a href="command-line-options.html#stereo">&#x2011;stereo</a> <span class='bull'></span> <a href="command-line-options.html#stretch">&#x2011;stretch</a> <span class='bull'></span> <a href="command-line-options.html#strip">&#x2011;strip</a> <span class='bull'></span> <a href="command-line-options.html#stroke">&#x2011;stroke</a> <span class='bull'></span> <a href="command-line-options.html#strokewidth">&#x2011;strokewidth</a> <span class='bull'></span> <a href="command-line-options.html#style">&#x2011;style</a> <span class='bull'></span> <a href="command-line-options.html#subimage-search">&#x2011;subimage&#x2011;search</a> <span class='bull'></span> <a href="command-line-options.html#swap">&#x2011;swap</a> <span class='bull'></span> <a href="command-line-options.html#swirl">&#x2011;swirl</a> <span class='bull'></span> <a href="command-line-options.html#synchronize">&#x2011;synchronize</a> <span class='bull'></span> <a href="command-line-options.html#taint">&#x2011;taint</a> <span class='bull'></span> <a href="command-line-options.html#text-font">&#x2011;text&#x2011;font</a> <span class='bull'></span> <a href="command-line-options.html#texture">&#x2011;texture</a> <span class='bull'></span> <a href="command-line-options.html#threshold">&#x2011;threshold</a> <span class='bull'></span> <a href="command-line-options.html#thumbnail">&#x2011;thumbnail</a> <span class='bull'></span> <a href="command-line-options.html#tile">&#x2011;tile</a> <span class='bull'></span> <a href="command-line-options.html#tile-offset">&#x2011;tile&#x2011;offset</a> <span class='bull'></span> <a href="command-line-options.html#tint">&#x2011;tint</a> <span class='bull'></span> <a href="command-line-options.html#title">&#x2011;title</a> <span class='bull'></span> <a href="command-line-options.html#transform">&#x2011;transform</a> <span class='bull'></span> <a href="command-line-options.html#transparent">&#x2011;transparent</a> <span class='bull'></span> <a href="command-line-options.html#transparent-color">&#x2011;transparent&#x2011;color</a> <span class='bull'></span> <a href="command-line-options.html#transpose">&#x2011;transpose</a> <span class='bull'></span> <a href="command-line-options.html#transverse">&#x2011;transverse</a> <span class='bull'></span> <a href="command-line-options.html#treedepth">&#x2011;treedepth</a> <span class='bull'></span> <a href="command-line-options.html#trim">&#x2011;trim</a> <span class='bull'></span> <a href="command-line-options.html#type">&#x2011;type</a> <span class='bull'></span> <a href="command-line-options.html#undercolor">&#x2011;undercolor</a> <span class='bull'></span> <a href="command-line-options.html#unique-colors">&#x2011;unique&#x2011;colors</a> <span class='bull'></span> <a href="command-line-options.html#units">&#x2011;units</a> <span class='bull'></span> <a href="command-line-options.html#unsharp">&#x2011;unsharp</a> <span class='bull'></span> <a href="command-line-options.html#update">&#x2011;update</a> <span class='bull'></span> <a href="command-line-options.html#verbose">&#x2011;verbose</a> <span class='bull'></span> <a href="command-line-options.html#version">&#x2011;version</a> <span class='bull'></span> <a href="command-line-options.html#view">&#x2011;view</a> <span class='bull'></span> <a href="command-line-options.html#vignette">&#x2011;vignette</a> <span class='bull'></span> <a href="command-line-options.html#virtual-pixel">&#x2011;virtual&#x2011;pixel</a> <span class='bull'></span> <a href="command-line-options.html#visual">&#x2011;visual</a> <span class='bull'></span> <a href="command-line-options.html#watermark">&#x2011;watermark</a> <span class='bull'></span> <a href="command-line-options.html#wave">&#x2011;wave</a> <span class='bull'></span> <a href="command-line-options.html#weight">&#x2011;weight</a> <span class='bull'></span> <a href="command-line-options.html#white-point">&#x2011;white&#x2011;point</a> <span class='bull'></span> <a href="command-line-options.html#white-threshold">&#x2011;white&#x2011;threshold</a> <span class='bull'></span> <a href="command-line-options.html#window">&#x2011;window</a> <span class='bull'></span> <a href="command-line-options.html#window-group">&#x2011;window&#x2011;group</a> <span class='bull'></span> <a href="command-line-options.html#write">&#x2011;write</a> </p>
cristyad41c0c2012-10-31 00:49:28 +000063
cristyd2432012015-05-04 23:15:15 +000064<p class="lead magick-description">Below is list of command-line options recognized by the ImageMagick <a href="command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands: <a href="convert.html">convert</a> and <a href="mogrify.html">mogrify</a>.</p>
65
66<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +000067 <h3 class="magick-header"><a id="adaptive-blur"></a>-adaptive-blur <var>radius</var>[x<var>sigma</var>]</h3>
cristyad41c0c2012-10-31 00:49:28 +000068</div>
69
cristyd2432012015-05-04 23:15:15 +000070<p class="magick-description">Adaptively blur pixels, with decreasing effect near edges.</p>
cristy8ee7f242013-06-20 16:08:44 +000071
cristyd2432012015-05-04 23:15:15 +000072<p>A Gaussian operator of the given radius and standard deviation (<var>sigma</var>) is used. If <var>sigma</var> is not given it
73defaults to 1.</p>
74
75<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +000076 <h3 class="magick-header"><a id="adaptive-resize"></a>-adaptive-resize <var>geometry</var></h3>
cristy149d58c2013-08-07 19:44:54 +000077</div>
cristyd2432012015-05-04 23:15:15 +000078
79<p class="magick-description">Resize the image using data-dependent triangulation.</p>
80
81<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="command-line-options.html#adaptive-resize">-adaptive-resize</a>
cristy29dc8652015-05-12 16:26:21 +000082option defaults to data-dependent triangulation. Use the <a
83href="command-line-options.html#filter">-filter</a> to choose a different resampling algorithm.
84Offsets, if present in the geometry string, are ignored, and the <a
85href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
cristyd2432012015-05-04 23:15:15 +000086
87<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +000088 <h3 class="magick-header"><a id="adaptive-sharpen"></a>-adaptive-sharpen <var>radius</var>[x<var>sigma</var>]</h3>
cristy149d58c2013-08-07 19:44:54 +000089</div>
cristyd2432012015-05-04 23:15:15 +000090
91<p class="magick-description">Adaptively sharpen pixels, with increasing effect near edges.</p>
92
93<p>A Gaussian operator of the given radius and standard deviation
94(<var>sigma</var>) is used. If <var>sigma</var> is not given it
95defaults to 1.</p>
96
97<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +000098 <h3 class="magick-header"><a id="adjoin"></a>-adjoin</h3>
cristyd2432012015-05-04 23:15:15 +000099</div>
100
101<p class="magick-description">Join images into a single multi-image file.</p>
102
103<p>This option is enabled by default. An attempt is made to save all images of
104an image sequence into the given output file. However, some formats, such as
105JPEG and PNG, do not support more than one image per file, and in that case
106ImageMagick is forced to write each image as a separate file. As such, if
107more than one image needs to be written, the filename given is modified by
108adding a <a href="command-line-options.html#scene">-scene</a> number before the suffix, in order to
109make distinct names for each image. </p>
110
111<p>Use <a href="command-line-options.html#adjoin">+adjoin</a> to force each image to be written to
112separate files, whether or not the file format allows multiple images per file
113(for example, GIF, MIFF, and TIFF). </p>
114
115<p>Including a C-style integer format string in the output filename will
116automagically enable <a href="command-line-options.html#adjoin">+adjoin</a> and are used to specify
117where the <a href="command-line-options.html#scene">-scene</a> number is placed in the filenames. These
118strings, such as '<code>%d</code>' or '<code>%03d</code>', are familiar to those
119who have used the standard <code>printf()</code>' C-library function. As an
120example, the command</p>
121
122<pre>
123convert logo: rose: -morph 15 my%02dmorph.jpg
124</pre>
125
126<p>will create a sequence of 17 images (the two given plus 15 more created by
127<a href="command-line-options.html#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg,
128my02morph.jpg, ..., my16morph.jpg. </p>
129
130<p>In summary, ImageMagick tries to write all images to one file, but will
131save to multiple files, if any of the following conditions exist...</p>
132<ol>
133<li>the output image's file format does not allow multi-image files,</li>
134<li>the <a href="command-line-options.html#adjoin">+adjoin</a> option is given, or</li>
135<li>a printf() integer format string (eg: "%d") is present in the output
136 filename.</li>
137</ol>
138
139
140<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000141 <h3 class="magick-header"><a id="affine"></a>-affine
142 <var>s<sub>x</sub></var>,<var>r<sub>x</sub></var>,<var>r<sub>y</sub></var>,<var>s<sub>y</sub></var>[,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>]</h3>
cristyd2432012015-05-04 23:15:15 +0000143</div>
144
145<p class="magick-description">Set the drawing transformation matrix for combined rotating and scaling.</p>
146
cristy29dc8652015-05-12 16:26:21 +0000147<p>This option sets a transformation matrix, for use by subsequent <a
148href="command-line-options.html#draw">-draw</a> or <a href="command-line-options.html#transform">-transform</a> options. </p>
cristyd2432012015-05-04 23:15:15 +0000149
150<p>The matrix entries are entered as comma-separated numeric values either in
151quotes or without spaces. </p>
152
153<p>Internally, the transformation matrix has 3x3 elements, but three of them
154are omitted from the input because they are constant. The new (transformed)
155coordinates (<var>x'</var>, <var>y'</var>) of a pixel at
156position (<var>x</var>, <var>y</var>) in the original
157image are calculated using the following matrix equation.</p>
158
159<div class="eqn">
cristy29dc8652015-05-12 16:26:21 +0000160<img alt="affine transformation" src="../images/affine.png"/>
cristyd2432012015-05-04 23:15:15 +0000161</div>
162
163<p> The size of the resulting image is that of the smallest rectangle that
164contains the transformed source image. The parameters
165<var>t<sub>x</sub></var> and <var>t<sub>y</sub></var>
166subsequently shift the image pixels so that those that are moved out of the
167image area are cut off.</p>
168
169<p>The transformation matrix complies with the left-handed pixel coordinate
170system: positive <var>x</var> and <var>y</var> directions
171are rightward and downward, resp.; positive rotation is clockwise.</p>
172
173<p> If the translation coefficients <var>t<sub>x</sub></var> and
174<var>t<sub>y</sub></var> are omitted they default to 0,0. Therefore,
175four parameters suffice for rotation and scaling without translation.</p>
176
177<p>Scaling by the factors <var>s<sub>x</sub></var> and
178<var>s<sub>y</sub></var> in the <var>x</var> and <var>y</var> directions,
179respectively, is accomplished with the following.</p>
180
cristy29dc8652015-05-12 16:26:21 +0000181<p>See <a href="command-line-options.html#transform">-transform</a>, and the <a
182href="command-line-options.html#distort">-distort</a> method '<code>Affineprojection</code> for more
cristyd2432012015-05-04 23:15:15 +0000183information </p>
184
185
186<pre>
187-affine <var>s<sub>x</sub></var>,0,0,<var>s<sub>y</sub></var>
188</pre>
189
190<p>Translation by a displacement (<var>t<sub>x</sub></var>, <var>t<sub>y</sub></var>) is accomplished like so:</p>
191
192<pre>
193-affine 1,0,0,1,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>
194</pre>
195
196<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle
197<var>a</var> by letting <var>c</var> = cos(<var>a</var>), <var>s</var>
198= sin(<var>a</var>), and using the following.</p>
199
200<pre>
201-affine <var>c</var>,<var>s</var>,-<var>s</var>,<var>c</var>
202</pre>
203
cristy29dc8652015-05-12 16:26:21 +0000204<p>The cumulative effect of a sequence of <a href="command-line-options.html#affine" >-affine</a>
205transformations can be accomplished by instead by a single <a href="command-line-options.html#affine"
206>-affine</a> operation using the matrix equal to the product of the matrices
cristyd2432012015-05-04 23:15:15 +0000207of the individual transformations.</p>
208
209<p>An attempt is made to detect near-singular transformation matrices. If the
210matrix determinant has a sufficiently small absolute value it is rejected.</p>
211
212<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000213 <h3 class="magick-header"><a id="alpha"></a>-alpha <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +0000214</div>
215
216<p class="magick-description">Gives control of the alpha/matte channel of an image.</p>
217
218<p>Used to set a flag on an image indicating whether or not to use existing alpha
219channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <var>type</var> from the list below.</p>
220
221
222<div class="table-responsive">
223<table class="table table-condensed table-striped">
224 <tbody>
225 <tr>
226 <th>Type</th>
227 <th>Description</th>
228 </tr>
229
230 <tr>
231 <td><code>Activate</code> or <code>On</code></td>
232 <td>
233 Enable the image's transparency channel. Note normally <code>Set</code>
234 should be used instead of this, unless you specifically need to
235 preserve existing (but specifically turned <code>Off</code>) transparency
236 channel. </td></tr>
237
238 <tr>
239 <td><code>Associate</code></td>
240 <td>
241 associate the alpha channel with the image.</td></tr>
242
243 <tr>
244 <td><code>Deactivate</code> or <code>Off</code></td>
245 <td>
246 Disables the image's transparency channel. Does not delete or change the
247 existing data, just turns off the use of that data.</td></tr>
248
249 <tr>
250 <td><code>Disassociate</code></td>
251 <td>
252 disassociate the alpha channel from the image.</td></tr>
253
254 <tr>
255 <td><code>Set</code></td>
256 <td>
257 Activates the alpha/matte channel. If it was previously turned off
258 then it also resets the channel to opaque. If the image already had
259 the alpha channel turned on, it will have no effect.</td></tr>
260
261 <tr>
262 <td><code>Opaque</code></td>
263 <td>
264 Enables the alpha/matte channel and forces it to be fully opaque.
265 </td></tr>
266
267 <tr>
268 <td><code>Transparent</code></td>
269 <td>
270 Activates the alpha/matte channel and forces it to be fully
271 transparent. This effectively creates a fully transparent image the
272 same size as the original and with all its original RGB data still
273 intact, but fully transparent. </td></tr>
274
275 <tr>
276 <td><code>Extract</code></td>
277 <td>
278 Copies the alpha channel values into all the color channels and turns
279 '<code>Off</code>' the the image's transparency, so as to generate
280 a gray-scale mask of the image's shape. The alpha channel data is left
281 intact just deactivated. This is the inverse of '<code>Copy</code>'.
282 </td></tr>
283
284 <tr>
285 <td><code>Copy</code></td>
286 <td>
287 Turns '<code>On</code>' the alpha/matte channel, then copies the
288 gray-scale intensity of the image, into the alpha channel, converting
289 a gray-scale mask into a transparent shaped mask ready to be colored
290 appropriately. The color channels are not modified. </td></tr>
291
292 <tr>
293 <td><code>Shape</code></td>
294 <td>
295 As per '<code>Copy</code>' but also colors the resulting shape mask with
296 the current background color. That is the RGB color channels is
297 replaced, with appropriate alpha shape.
298 </td></tr>
299
300 <tr>
301 <td><code>Remove</code></td>
302 <td>
303 Composite the image over the background color.
304 </td></tr>
305
306 <tr>
307 <td><code>Background</code></td>
308 <td>
309 Set any fully-transparent pixel to the background color, while leaving
310 it fully-transparent. This can make some image file formats, such as
311 PNG, smaller as the RGB values of transparent pixels are more uniform,
312 and thus can compress better.
313 </td></tr>
314 </tbody>
315</table>
316</div>
317
318<p>Note that while the obsolete <code>+matte</code> operation was the
cristy29dc8652015-05-12 16:26:21 +0000319same as "<code><a href="command-line-options.html#alpha" >-alpha</a> Off</code>", the <code>
320>-matte</code> operation was the same as "<code><a href="command-line-options.html#alpha" >-alpha</a>
321Set</code>" and not "<code><a href="command-line-options.html#alpha" >-alpha</a> On</code>". </p>
cristyd2432012015-05-04 23:15:15 +0000322
323
324<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000325 <h3 class="magick-header"><a id="annotate"></a>
326 -annotate <var>degrees</var> <var>text</var><br />
327 -annotate <var>Xdegrees</var>x<var>Ydegrees</var> <var>text</var><br /> -annotate <var>Xdegrees</var>x<var>Ydegrees</var> {+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var><br /> -annotate {+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var></h3>
cristyd2432012015-05-04 23:15:15 +0000328</div>
329
330<p class="magick-description">Annotate an image with text</p>
331
332<p>This is a convenience for annotating an image with text. For more precise
333control over text annotations, use <a href="command-line-options.html#draw">-draw</a>.</p>
334
335
336<p>The values <var>Xdegrees</var> and <var>Ydegrees</var>
cristy29dc8652015-05-12 16:26:21 +0000337control the shears applied to the text, while <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are offsets that give the location of the text relative any <a href="command-line-options.html#gravity" >-gravity</a> setting and defaults to the upper left corner of the image.</p>
cristyd2432012015-05-04 23:15:15 +0000338
339<p>Using <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>
340or <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>x<var>degrees</var> produces an unsheared rotation of the text. The
341direction of the rotation is positive, which means a clockwise rotation if <var>degrees</var> is positive. (This conforms to the usual mathematical
342convention once it is realized that the positive <var>y</var>–direction is
343conventionally considered to be <var>downward</var> for images.)</p>
344
345<p>The new (transformed) coordinates (<var>x'</var>, <var>y'</var>) of a pixel at position (<var>x</var>, <var>y</var>) in the image are calculated using the following matrix
cristy29dc8652015-05-12 16:26:21 +0000346equation.</p> <div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"/></div>
cristyd2432012015-05-04 23:15:15 +0000347
348<p>If <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are omitted, they default to 0. This makes the
349bottom-left of the text becomes the upper-left corner of the image, which is
cristy29dc8652015-05-12 16:26:21 +0000350probably undesirable. Adding a <a href="command-line-options.html#gravity" >-gravity</a> option in this
cristyd2432012015-05-04 23:15:15 +0000351case leads to nice results.</p>
352
353<p>Text is any UTF-8 encoded character sequence. If <var>text</var>
354is of the form '@mytext.txt', the text is read from the file
355<code>mytext.txt</code>. Text in a file is taken literally; no embedded
356formatting characters are recognized.</p>
357
358<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000359 <h3 class="magick-header"><a id="antialias"></a>-antialias</h3>
cristyd2432012015-05-04 23:15:15 +0000360</div>
361
362<p class="magick-description">Enable/Disable of the rendering of anti-aliasing pixels when drawing fonts and lines.</p>
363
364<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
365drawn. Use <a href="command-line-options.html#antialias">+antialias</a> to disable the addition of
366antialiasing edge pixels. This will then reduce the number of colors added to
367an image to just the colors being directly drawn. That is, no mixed colors
368are added when drawing such objects. </p>
369
370<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000371 <h3 class="magick-header"><a id="append"></a>-append</h3>
cristyd2432012015-05-04 23:15:15 +0000372</div>
373
374<p class="magick-description">Join current images vertically or horizontally.</p>
375
376<p>This option creates a single longer image, by joining all the current
377images in sequence top-to-bottom. Use <a href="command-line-options.html#append">+append</a> to
378stack images left-to-right. </p>
379
380<p>If they are not of the same width, narrower images are padded with the
381current <a href="command-line-options.html#background">-background</a> color setting, and their
cristy29dc8652015-05-12 16:26:21 +0000382position relative to each other can be controlled by the current <a
383href="command-line-options.html#gravity">-gravity</a> setting. </p>
cristyd2432012015-05-04 23:15:15 +0000384
385
386<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000387 <h3 class="magick-header"><a id="attenuate"></a>-attenuate <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +0000388</div>
389
390<p class="magick-description">Lessen (or intensify) when adding noise to an image.</p>
391
392<p>If unset the value is equivalent to 1.0, or a maximum noise addition</p>
393
394<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000395 <h3 class="magick-header"><a id="authenticate"></a>-authenticate <var>password</var></h3>
cristyd2432012015-05-04 23:15:15 +0000396</div>
397
398<p class="magick-description">Decrypt a PDF with a password.</p>
399
400<p>Use this option to supply a <var>password</var> for decrypting
401a PDF that has been encrypted using Microsoft Crypto API (MSC API). The
402encrypting using the MSC API is not supported.</p>
403
404<p>For a different encryption method, see <a href="command-line-options.html#encipher">-encipher</a>
405and <a href="command-line-options.html#decipher">-decipher</a>. </p>
406
407
408<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000409 <h3 class="magick-header"><a id="auto-gamma"></a>-auto-gamma</h3>
cristyd2432012015-05-04 23:15:15 +0000410</div>
411
412<p class="magick-description">Automagically adjust gamma level of image.</p>
413
cristy29dc8652015-05-12 16:26:21 +0000414<p>This calculates the mean values of an image, then applies a calculated <a
415href="command-line-options.html#gamma" >-gamma</a> adjustment so that is the mean color exists in the
cristyd2432012015-05-04 23:15:15 +0000416image it will get a have a value of 50%. </p>
417
418<p>This means that any solid 'gray' image becomes 50% gray. </p>
419
420<p>This works well for real-life images with little or no extreme dark and
421light areas, but tend to fail for images with large amounts of bright sky or
422dark shadows. It also does not work well for diagrams or cartoon like images.
423</p>
424
cristy29dc8652015-05-12 16:26:21 +0000425<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the
cristyd2432012015-05-04 23:15:15 +0000426'<var>sync</var>' flag for channel synchronization), to determine which color
cristy29dc8652015-05-12 16:26:21 +0000427values is used and modified. As the default <a href="command-line-options.html#channel"
428>-channel</a> setting is '<var>RGB,sync</var>', channels are modified
cristyd2432012015-05-04 23:15:15 +0000429together by the same gamma value, preserving colors. </p>
430
431
432
433<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000434 <h3 class="magick-header"><a id="auto-level"></a>-auto-level</h3>
cristyd2432012015-05-04 23:15:15 +0000435</div>
436
437<p class="magick-description">Automagically adjust color levels of image.</p>
438
439<p>This is a 'perfect' image normalization operator. It finds the exact
cristy29dc8652015-05-12 16:26:21 +0000440minimum and maximum color values in the image and then applies a <a
441href="command-line-options.html#level" >-level</a> operator to stretch the values to the full range of
cristyd2432012015-05-04 23:15:15 +0000442values. </p>
443
444<p>The operator is not typically used for real-life images, image scans, or
445JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
cristy29dc8652015-05-12 16:26:21 +0000446for the <a href="command-line-options.html#level" >-level</a> operation. On the other hand it is the
cristyd2432012015-05-04 23:15:15 +0000447right operator to use for color stretching gradient images being used to
448generate Color lookup tables, distortion maps, or other 'mathematically'
449defined images. </p>
450
cristy29dc8652015-05-12 16:26:21 +0000451<p>The operator is very similar to the <a href="command-line-options.html#normalize">-normalize</a>, <a
452href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>, and <a href="command-line-options.html#linear-stretch"
453>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
454problems that these operators may have. That is <a href="command-line-options.html#auto-level"
455>-auto-level</a> is the perfect or ideal version these operators. </p>
cristyd2432012015-05-04 23:15:15 +0000456
cristy29dc8652015-05-12 16:26:21 +0000457<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the
cristyd2432012015-05-04 23:15:15 +0000458special '<var>sync</var>' flag for channel synchronization), to determine
cristy29dc8652015-05-12 16:26:21 +0000459which color values are used and modified. As the default <a
460href="command-line-options.html#channel" >+channel</a> setting is '<var>RGB,sync</var>', the
cristyd2432012015-05-04 23:15:15 +0000461'<var>sync</var>' ensures that the color channels will are modified
462together by the same gamma value, preserving colors, and ignoring
463transparency. </p>
464
465
466<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000467 <h3 class="magick-header"><a id="auto-orient"></a>-auto-orient</h3>
cristyd2432012015-05-04 23:15:15 +0000468</div>
469
470<p class="magick-description">adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).</p>
471
472<p>This operator reads and resets the EXIF image profile setting 'Orientation'
473and then performs the appropriate 90 degree rotation on the image to orient
474the image, for correct viewing. </p>
475
476<p>This EXIF profile setting is usually set using a gravity sensor in digital
477camera, however photos taken directly downward or upward may not have an
478appropriate value. Also images that have been orientation 'corrected' without
479reseting this setting, may be 'corrected' again resulting in a incorrect
cristy29dc8652015-05-12 16:26:21 +0000480result. If the EXIF profile was previously stripped, the <a
481href="command-line-options.html#auto-orient" >-auto-orient</a> operator will do nothing. </p>
cristyd2432012015-05-04 23:15:15 +0000482
483
484<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000485 <h3 class="magick-header"><a id="average"></a>-average</h3>
cristyd2432012015-05-04 23:15:15 +0000486</div>
487
488<p class="magick-description">Average a set of images.</p>
489
490<p>An error results if the images are not identically sized.</p>
491
492
493<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000494 <h3 class="magick-header"><a id="backdrop"></a>-backdrop</h3>
cristyd2432012015-05-04 23:15:15 +0000495</div>
496
497<p class="magick-description">Display the image centered on a backdrop.</p>
498
499<p>This backdrop covers the entire workstation screen and is useful for hiding
500other X window activity while viewing the image. The color of the backdrop is
501specified as the background color. The color is specified using the format
502described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
503
504<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000505 <h3 class="magick-header"><a id="background"></a>-background <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +0000506</div>
507
508<p class="magick-description">Set the background color.</p>
509
cristy29dc8652015-05-12 16:26:21 +0000510<p>The color is specified using the format described under the <a
511href="command-line-options.html#fill">-fill</a> option. The default background color (if none is
cristyd2432012015-05-04 23:15:15 +0000512specified or found in the image) is white.</p>
513
514<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000515 <h3 class="magick-header"><a id="bench"></a>-bench <var>iterations</var></h3>
cristyd2432012015-05-04 23:15:15 +0000516</div>
517
518<p class="magick-description">Measure performance.</p>
519
520<p>Repeat the entire command for the given number of <var>iterations</var> and report the user-time and elapsed time. For instance,
521consider the following command and its output. Modify the benchmark with the
522-duration to run the benchmark for a fixed number of seconds and -concurrent
523to run the benchmark in parallel (requires the OpenMP feature).</p>
524
525<pre>
526convert logo: -resize 1000% -bench 5 logo.png
527Performance[4]: 5i 0.875657ips 6.880u 0:05.710
528</pre>
529
530<p>In this example, 5 iterations were completed at 0.875657 iterations per
531second, using 4 threads and 6.88 seconds of the user's allotted time, for
532a total elapsed time of 5.71 seconds.</p>
533
534<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000535 <h3 class="magick-header"><a id="bias"></a>-bias <var>value</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +0000536</div>
537
538<p class="magick-description">Add bias when convolving an image.</p>
539
cristy29dc8652015-05-12 16:26:21 +0000540<p>This option shifts the output of <a href="command-line-options.html#convolve">&#x2011;convolve</a> so that
cristyd2432012015-05-04 23:15:15 +0000541positive and negative results are relative to the specified bias value. </p>
542
543<p>This is important for non-HDRI compilations of ImageMagick when dealing
544with convolutions that contain negative as well as positive values. This is
545especially the case with convolutions involving high pass filters or edge
546detection. Without an output bias, the negative values are clipped at
547zero.</p>
548
cristy29dc8652015-05-12 16:26:21 +0000549<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">&#x2011;bias</a> is not needed, as ImageMagick is able to store/handle any
cristyd2432012015-05-04 23:15:15 +0000550negative results without clipping to the color value range
551(0..QuantumRange).</p>
552
cristy29dc8652015-05-12 16:26:21 +0000553<p>See the discussion on HDRI implementations of ImageMagick on the page <a
554href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more
555about HDRI go the ImageMagick <a
556href="http://www.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages or this
557<a
558href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
cristyd2432012015-05-04 23:15:15 +0000559entry. </p>
560
561<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000562 <h3 class="magick-header"><a id="black-point-compensation"></a>-black-point-compensation</h3>
cristyd2432012015-05-04 23:15:15 +0000563</div>
564
565<p class="magick-description">Use black point compensation.</p>
566
567<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000568 <h3 class="magick-header"><a id="black-threshold"></a>-black-threshold <var>value</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +0000569</div>
570
571<p class="magick-description">Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</p>
572
573<p> The threshold value can be given as a percentage or as an absolute integer
574value within [0, <var>QuantumRange</var>] corresponding to the
cristy29dc8652015-05-12 16:26:21 +0000575desired <a href="command-line-options.html#channel">&#x2011;channel</a> value. See <a href="command-line-options.html#threshold">&#x2011;threshold</a>for more details on thresholds and resulting values. </p>
cristyd2432012015-05-04 23:15:15 +0000576
577
578<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000579 <h3 class="magick-header"><a id="blend"></a>-blend <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +0000580</div>
581
582<p class="magick-description">blend an image into another by the given absolute value or percent.</p>
583
584<p>Blend will average the images together ('plus') according to the
585percentages given and each pixels transparency. If only a single percentage
586value is given it sets the weight of the composite or 'source' image, while
587the background image is weighted by the exact opposite amount. That is a
588<code>-blend 30%</code> merges 30% of the 'source' image with 70% of the
589'destination' image. Thus it is equivalent to <code>-blend 30x70%</code>.</p>
590
591
592<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000593 <h3 class="magick-header"><a id="blue-primary"></a>-blue-primary <var>x</var>,<var>y</var></h3>
cristyd2432012015-05-04 23:15:15 +0000594</div>
595
596<p class="magick-description">Set the blue chromaticity primary point.</p>
597
598<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000599 <h3 class="magick-header"><a id="blue-shift"></a>-blue-shift <var>factor</var></h3>
cristyd2432012015-05-04 23:15:15 +0000600</div>
601
602<p class="magick-description">simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</p>
603
604<div style="margin: auto;">
605
606<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000607 <h3 class="magick-header"><a id="blur"></a>-blur <var>radius</var><br />-blur <var>radius</var>x<var>sigma</var></h3>
cristyd2432012015-05-04 23:15:15 +0000608</div>
609
610<p class="magick-description">Reduce image noise and reduce detail levels.</p>
611
612<p>Convolve the image with a Gaussian or normal distribution using the given
cristy29dc8652015-05-12 16:26:21 +0000613<var >Sigma</var> value. The formula is:</p>
cristyd2432012015-05-04 23:15:15 +0000614
cristy29dc8652015-05-12 16:26:21 +0000615<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
cristyd2432012015-05-04 23:15:15 +0000616</div>
617
cristy29dc8652015-05-12 16:26:21 +0000618<p>The <var >Sigma</var> value is the important argument, and
cristyd2432012015-05-04 23:15:15 +0000619determines the actual amount of blurring that will take place. </p>
620
cristy29dc8652015-05-12 16:26:21 +0000621<p>The <var >Radius</var> is only used to determine the size of the
cristyd2432012015-05-04 23:15:15 +0000622array which will hold the calculated Gaussian distribution. It should be an
623integer. If not given, or set to zero, IM will calculate the largest possible
624radius that will provide meaningful results for the Gaussian distribution.
625</p>
626
cristy29dc8652015-05-12 16:26:21 +0000627<p>The larger the <var >Radius</var> the slower the
628operation is. However too small a <var >Radius</var>, and sever
629aliasing effects may result. As a guideline, <var >Radius</var>
630should be at least twice the <var >Sigma</var> value, though three
cristyd2432012015-05-04 23:15:15 +0000631times will produce a more accurate result. </p>
632
633<p>This option differs from <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a> simply
634by taking advantage of the separability properties of the distribution. Here
635we apply a single-dimensional Gaussian matrix in the horizontal direction,
636then repeat the process in the vertical direction.</p>
637
638<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
639pixels which are outside the image proper are blurred into the final result.
640</p>
641
642
643<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000644 <h3 class="magick-header">-blur <var>Width</var>[x<var>Height</var>[+<var>Angle</var>]]</h3>
cristyd2432012015-05-04 23:15:15 +0000645</div>
646
647<p class="magick-description">Variably blur an image according to the overlay mapping.</p>
648
649<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
650Average (EWA) of the source image, scaled according to the grayscale
651mapping. </p>
652
cristy29dc8652015-05-12 16:26:21 +0000653<p>The ellipse is weighted with sigma set to the given <var>Width</var> and <var >Height</var>. The <var >Height</var>
654defaults to the <var >Width</var> for a normal circular Gaussian
655weighting. The <var >Angle</var> will rotate the ellipse from
cristyd2432012015-05-04 23:15:15 +0000656horizontal clock-wise. </p>
657
658<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
659pixels which are outside the image proper are blurred into the final result.
660</p>
661
662
663<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000664 <h3 class="magick-header"><a id="border"></a>-border <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +0000665</div>
666
667<p class="magick-description">Surround the image with a border of color. </p>
668
669<p>Set the width and height using the <var>size</var> portion of the
670<var>geometry</var> argument. See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are
671ignored. </p>
672
673<p>As of IM 6.7.8-8, the <var>geometry</var> arguments behave as follows:</p>
674
675<table id="borderTable">
cristy29dc8652015-05-12 16:26:21 +0000676 <col width="20%"/> <col width="80%"/>
cristyd2432012015-05-04 23:15:15 +0000677 <thead>
678 <tr>
679 <th style="text-align:center"><var>size</var></th>
680 <th>General description</th>
681 </tr>
682 </thead>
683 <tbody>
684 <tr>
685 <td><var>value</var></td>
686 <td>value is added to both left/right and top/bottom</td>
687 </tr>
688 <tr>
689 <td><var>value-x</var>x</td>
690 <td>value-x is added only to left/right and top/bottom are unchanged</td>
691 </tr>
692 <tr>
693 <td>x<var>value-y</var></td>
694 <td>value-y is added only to top/bottom and left/right are unchanged</td>
695 </tr>
696 <tr>
697 <td><var>value-x</var>x<var>value-y</var></td>
698 <td>value-x is added to left/right and value-y added to top/bottom</td>
699 </tr>
700 <tr>
701 <td><var>value-x</var>x<code>0</code></td>
702 <td>value-x is added only to left/right and top/bottom are unchanged</td>
703 </tr>
704 <tr>
705 <td><code>0</code>x<var>value-y</var></td>
706 <td>value-y is added only to top/bottom and left/right are unchanged</td>
707 </tr>
708 <tr>
709 <td> </td>
710 <td> </td>
711 </tr>
712 <tr>
713 <td><var>value</var>%</td>
714 <td>value % of width is added to left/right and value % of height is added to top/bottom</td>
715 </tr>
716 <tr>
717 <td><var>value-x</var>x%</td>
718 <td>value-x % of width is added to left/right and to top/bottom</td>
719 </tr>
720 <tr>
721 <td>x<var>value-y</var>%</td>
722 <td>value-y % of height is added to top/bottom and to left/right</td>
723 </tr>
724 <tr>
725 <td><var>value-x</var>%x<var>value-y</var>%</td>
726 <td>value-x % of width is added to left/right and value-y % of height is added to top/bottom</td>
727 </tr>
728 <tr>
729 <td><var>value-x</var>%x<code>0</code>%</td>
730 <td>value-x % of width is added to left/right and top/bottom are unchanged</td>
731 </tr>
732 <tr>
733 <td><code>0</code>%x<var>value-y</var>%</td>
734 <td>value-y % of height is added to top/bottom and left/right are unchanged</td>
735 </tr>
736 </tbody>
737 </table>
738
739
cristy29dc8652015-05-12 16:26:21 +0000740<p>Set the border color by preceding with the <a
741href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
cristyd2432012015-05-04 23:15:15 +0000742
cristy29dc8652015-05-12 16:26:21 +0000743<p>The <a href="command-line-options.html#border">-border</a> operation is affected by the current <a
744href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
cristyd2432012015-05-04 23:15:15 +0000745'<code>Over</code>' composition method. It generates an image of the appropriate
746size colors by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> before
747overlaying the original image in the center of this net image. This means that
748with the default compose method of '<code>Over</code>' any transparent parts may
749be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
750<p>See also the <a href="command-line-options.html#frame">-frame</a> option, which has more
751functionality.</p>
752
753<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000754 <h3 class="magick-header"><a id="bordercolor"></a>-bordercolor <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +0000755</div>
756
757<p class="magick-description">Set the border color.</p>
758
759<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
760
761<p>The default border color is <code>#DFDFDF</code>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
762
763<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000764 <h3 class="magick-header"><a id="borderwidth"></a>-borderwidth <var>geometry</var> </h3>
cristyd2432012015-05-04 23:15:15 +0000765</div>
766
767<p class="magick-description">Set the border width.</p>
768
769<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000770 <h3 class="magick-header"><a id="brightness-contrast"></a>-brightness-contrast <var>brightness</var><br />-brightness-contrast <var>brightness</var>{x<var>contrast</var>}{<var>%</var>}}</h3>
cristyd2432012015-05-04 23:15:15 +0000771</div>
772
773<p class="magick-description">Adjust the brightness and/or contrast of the image.</p>
774
775<p>Brightness and Contrast values apply changes to the input image. They are
776not absolute settings. A brightness or contrast value of zero means no change.
777The range of values is -100 to +100 on each. Positive values increase the
778brightness or contrast and negative values decrease the brightness or contrast.
779To control only contrast, set the brightness=0. To control only brightness,
780set contrast=0 or just leave it off.</p>
781
782<p>You may also use <a href="command-line-options.html#fill">-channel</a> to control which channels to
783apply the brightness and/or contrast change. The default is to apply the same
784transformation to all channels.</p>
785
786<p>Brightness and Contrast arguments are converted to offset and slope of a
787linear transform and applied
788using <a href="command-line-options.html#fill">-function polynomial "slope,offset"</a>.</p>
789
790<p>The slope varies from 0 at contrast=-100 to almost vertical at
791contrast=+100. For brightness=0 and contrast=-100, the result are totally
792midgray. For brightness=0 and contrast=+100, the result will approach but
793not quite reach a threshold at midgray; that is the linear transformation
794is a very steep vertical line at mid gray.</p>
795
796<p>Negative slopes, i.e. negating the image, are not possible with this
797function. All achievable slopes are zero or positive.</p>
798
799<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5
800at brightness=+100. Thus, when contrast=0 and brightness=100, the result is
801totally white. Similarly, when contrast=0 and brightness=-100, the result is
802totally black.</p>
803
804<p>As the range of values for the arguments are -100 to +100, adding the '%'
805symbol is no different than leaving it off.</p>
806
807<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000808 <h3 class="magick-header"><a id="cache"></a>-cache <var>threshold</var></h3>
cristyd2432012015-05-04 23:15:15 +0000809</div>
810
cristy29dc8652015-05-12 16:26:21 +0000811<p class="magick-description">(This option has been replaced by the <a href='command-line-options.html#limit'>-limit</a> option).</p>
cristyd2432012015-05-04 23:15:15 +0000812
813<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000814 <h3 class="magick-header"><a id="canny"></a>-canny <var>radius</var><br/>-canny <var>radius</var>x<var>sigma</var>{<var>+lower-percent</var>}{<var>+upper-percent</var>}</h3>
cristyd2432012015-05-04 23:15:15 +0000815</div>
816
817<p class="magick-description">Canny edge detector uses a multi-stage algorithm to detect a wide range of edges in the image.</p>
818
819<p>The thresholds range from 0 to 100% (e.g. -canny 0x1+10%+30%) with {<var>+lower-percent</var>} &lt; {<var>+upper-percent</var>}. If {<var>+upper-percent</var>} is increased but {<var>+lower-percent</var>} remains the same, lesser edge components will be detected, but their lengths will be the same. If {<var>+lower-percent</var>} is increased but {<var>+upper-percent</var>} is the same, the same number of edge components will be detected but their lengths will be shorter. The default thresholds are shown. The <var>radius</var>x<var>sigma</var> controls a gaussian blur applied to the input image to reduce noise and smooth the edges.</p>
820
821<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000822 <h3 class="magick-header"><a id="caption"></a>-caption <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +0000823</div>
824
825<p class="magick-description">Assign a caption to an image.</p>
826
827<p>This option sets the caption meta-data of an image read in after this
828option has been given. To modify a caption of images already in memory use
829"<code><a href="command-line-options.html#set">-set</a> caption</code>". </p>
830
cristy29dc8652015-05-12 16:26:21 +0000831<p>The caption can contain special format characters listed in the <a
832href="escape.html">Format and
cristyd2432012015-05-04 23:15:15 +0000833Print Image Properties</a>. These attributes are expanded when the caption
834is finally assigned to the individual images. </p>
835
836<p>If the first character of <var>string</var> is <var>@</var>, the image caption is read from a file titled by the
837remaining characters in the string. Comments read in from a file are literal;
838no embedded formatting characters are recognized.</p>
839
840<p>Caption meta-data is not visible on the image itself. To do that use the
841<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
842instead.</p>
843
844<p>For example,</p>
845
cristy29dc8652015-05-12 16:26:21 +0000846<pre>
847-caption "%m:%f %wx%h" bird.miff
848</pre>
cristyd2432012015-05-04 23:15:15 +0000849
850<p>produces an image caption of <code>MIFF:bird.miff 512x480</code> (assuming
851that the image <code>bird.miff</code> has a width of 512 and a height of
852480.</p>
853
854
855<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000856 <h3 class="magick-header"><a id="cdl"></a>-cdl <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +0000857</div>
858
859<p class="magick-description">color correct with a color decision list.</p>
860
861<p>Here is an example color correction collection:</p>
862
863<pre>
864&lt;?xml version="1.0" encoding="UTF-8"?&gt;
865&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"&gt;
866 &lt;ColorCorrection id="cc06668"&gt;
867 &lt;SOPNode&gt;
868 &lt;Slope&gt; 0.9 1.2 0.5 &lt;/Slope&gt;
869 &lt;Offset&gt; 0.4 -0.5 0.6 &lt;/Offset&gt;
870 &lt;Power&gt; 1.0 0.8 1.5 &lt;/Power&gt;
871 &lt;/SOPNode&gt;
872 &lt;SATNode&gt;
873 &lt;Saturation&gt; 0.85 &lt;/Saturation&gt;
874 &lt;/SATNode&gt;
875 &lt;/ColorCorrection&gt;
876&lt;/ColorCorrectionCollection&gt;
877</pre>
878
879<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +0000880 <h3 class="magick-header"><a id="channel"></a>-channel <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +0000881</div>
882
883<p class="magick-description">Specify those image color channels to which subsequent operators are limited.</p>
884
885<p>Choose from: <code>Red</code>, <code>Green</code>, <code>Blue</code>,
886<code>Alpha</code>, <code>Gray</code>, <code>Cyan</code>, <code>Magenta</code>,
887<code>Yellow</code>, <code>Black</code>, <code>Opacity</code>,
888<code>Index</code>, <code>RGB</code>, <code>RGBA</code>, <code>CMYK</code>, or
889<code>CMYKA</code>.</p>
890
891<p>The channels above can also be specified as a comma-separated list or can be
892abbreviated as a concatenation of the letters '<code>R</code>', '<code>G</code>',
893'<code>B</code>', '<code>A</code>', '<code>O</code>', '<code>C</code>',
894'<code>M</code>', '<code>Y</code>', '<code>K</code>'.
895
896For example, to only select the <code>Red</code> and <code>Blue</code> channels
897you can either use </p>
cristy29dc8652015-05-12 16:26:21 +0000898<pre>
899-channel Red,Blue
900</pre>
cristyd2432012015-05-04 23:15:15 +0000901<p>or you can use the short hand form</p>
cristy29dc8652015-05-12 16:26:21 +0000902<pre>
903-channel RB
904</pre>
cristyd2432012015-05-04 23:15:15 +0000905
906<p>All the channels that are present in an image can be specified using the
907special channel type <code>All</code>. Not all operators are 'channel capable',
908but generally any operators that are generally 'grey-scale' image operators,
909will understand this setting. See individual operator documentation. </p>
910
cristy29dc8652015-05-12 16:26:21 +0000911<br/>
cristyd2432012015-05-04 23:15:15 +0000912
913<p>On top of the normal channel selection an extra flag can be specified,
914'<code>Sync</code>'. This is turned on by default and if set means that
915operators that understand this flag should perform: cross-channel
916synchronization of the channels. If not specified, then most grey-scale
917operators will apply their image processing operations to each individual
918channel (as specified by the rest of the <a href="command-line-options.html#channel">-channel</a>
919setting) completely independently from each other. </p>
920
921<p>For example for operators such as <a href="command-line-options.html#auto-level">-auto-level</a> and
922<a href="command-line-options.html#auto-gamma">-auto-gamma</a> the color channels are modified
923together in exactly the same way so that colors will remain in-sync. Without
924it being set, then each channel is modified separately and
925independently, which may produce color distortion. </p>
926
927<p>The <a href="command-line-options.html#morphology">-morphology</a> '<code>Convolve</code>' method
928and the <a href="command-line-options.html#compose">-compose</a> mathematical methods, also understands
929the '<code>Sync</code>' flag to modify the behaviour of pixel colors according
930to the alpha channel (if present). That is to say it will modify the image
931processing with the understanding that fully-transparent colors should not
932contribute to the final result. </p>
933
934<p>Basically, by default, operators work with color channels in synchronous, and
935treats transparency as special, unless the <a href="command-line-options.html#channel">-channel</a>
936setting is modified so as to remove the effect of the '<code>Sync</code>' flag.
937How each operator does this depends on that operators current implementation.
938Not all operators understands this flag at this time, but that is changing.
939</p>
940
941<p>To print a complete list of channel types, use <a href="command-line-options.html#list">-list
942channel</a>.</p>
943
cristy29dc8652015-05-12 16:26:21 +0000944<br />
cristyd2432012015-05-04 23:15:15 +0000945
946<p>By default, ImageMagick sets <a href="command-line-options.html#channel">-channel</a> to the value
947'<code>RGBK,sync</code>', which specifies that operators act on all color
948channels except the transparency channel, and that all the color channels are
949to be modified in exactly the same way, with an understanding of transparency
cristy29dc8652015-05-12 16:26:21 +0000950(depending on the operation being applied). The 'plus' form <a
951href="command-line-options.html#channel" >+channel</a> will reset the value back to this default. </p>
cristyd2432012015-05-04 23:15:15 +0000952
cristy29dc8652015-05-12 16:26:21 +0000953<p>Options that are affected by the <a href="command-line-options.html#channel" >-channel</a> setting
cristyd2432012015-05-04 23:15:15 +0000954include the following.
955
956<a href="command-line-options.html#auto-gamma">-auto-gamma</a>,
957<a href="command-line-options.html#auto-level">-auto-level</a>,
958<a href="command-line-options.html#black-threshold">-black-threshold</a>,
959<a href="command-line-options.html#blur">-blur</a>,
960<a href="command-line-options.html#clamp">-clamp</a>,
961<a href="command-line-options.html#clut">-clut</a>,
962<a href="command-line-options.html#combine">-combine</a>,
963<a href="command-line-options.html#composite">-composite</a> (Mathematical compose methods only),
964<a href="command-line-options.html#convolve">-convolve</a>,
965<a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
966<a href="command-line-options.html#evaluate">-evaluate</a>,
967<a href="command-line-options.html#function">-function</a>,
968<a href="command-line-options.html#fx">-fx</a>,
969<a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>,
970<a href="command-line-options.html#hald-clut">-hald-clut</a>,
971<a href="command-line-options.html#motion-blur">-motion-blur</a>,
972<a href="command-line-options.html#morphology">-morphology</a>,
973<a href="command-line-options.html#negate">-negate</a>,
974<a href="command-line-options.html#normalize">-normalize</a>,
975<a href="command-line-options.html#ordered-dither">-ordered-dither</a>,
976<a href="command-line-options.html#radial-blur">-radial-blur</a>,
977<a href="command-line-options.html#random-threshold">-random-threshold</a>,
978<a href="command-line-options.html#separate">-separate</a>,
979<a href="command-line-options.html#threshold">-threshold</a>, and
980<a href="command-line-options.html#white-threshold">-white-threshold</a>.
981</p>
982
cristy29dc8652015-05-12 16:26:21 +0000983<p>Warning, some operators behave differently when the <a href="command-line-options.html#channel"
984>+channel</a> default setting is in effect, verses ANY user defined <a
985href="command-line-options.html#channel" >-channel</a> setting (including the equivalent of the
cristyd2432012015-05-04 23:15:15 +0000986default). These operators have yet to be made to understand the newer 'Sync'
987flag. </p>
988
989<p>For example <a href="command-line-options.html#threshold">-threshold</a> will by default gray-scale
cristy29dc8652015-05-12 16:26:21 +0000990the image before thresholding, if no <a href="command-line-options.html#channel" >-channel</a> setting
cristyd2432012015-05-04 23:15:15 +0000991has been defined. This is not 'Sync flag controlled, yet. </p>
992
cristy29dc8652015-05-12 16:26:21 +0000993<p>Also some operators such as <a href="command-line-options.html#blur">-blur</a>, <a
994href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
995color channels if the '<code>alpha</code>' channel is also enabled by <a
996href="command-line-options.html#channel" >-channel</a>. Generally this done to ensure that
cristyd2432012015-05-04 23:15:15 +0000997fully-transparent colors are treated as being fully-transparent, and thus any
998underlying 'hidden' color has no effect on the final results. Typically
999resulting in 'halo' effects. The newer <a href="command-line-options.html#morphology">-morphology</a>
1000convolution equivalents however does have a understanding of the 'Sync' flag
1001and will thus handle transparency correctly by default. </p>
1002
1003<p>As a alpha channel is optional within images, some operators will read the
1004color channels of an image as a greyscale alpha mask, when the image has no
cristy29dc8652015-05-12 16:26:21 +00001005alpha channel present, and the <a href="command-line-options.html#channel" >-channel</a> setting tells
1006the operator to apply the operation using alpha channels. The <a
1007href="command-line-options.html#clut">-clut</a> operator is a good example of this. </p>
cristyd2432012015-05-04 23:15:15 +00001008
1009
1010
1011<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001012 <h3 class="magick-header"><a id="charcoal"></a>-charcoal <var>factor</var></h3>
cristyd2432012015-05-04 23:15:15 +00001013</div>
1014
1015<p class="magick-description">Simulate a charcoal drawing.</p>
1016
1017<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001018 <h3 class="magick-header"><a id="chop"></a>-chop <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00001019</div>
1020
1021<p class="magick-description">Remove pixels from the interior of an image.</p>
1022
1023<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>width</var>
1024and <var>height</var> given in the of the <var>size</var>
1025portion of the <var>geometry</var> argument give the number of
1026columns and rows to remove. The <var>offset</var> portion of
1027the <var>geometry</var> argument is influenced by
1028a <a href="command-line-options.html#gravity">-gravity</a> setting, if present.</p>
1029
1030<p>The <a href="command-line-options.html#chop">-chop</a> option removes entire rows and columns,
1031and moves the remaining corner blocks leftward and upward to close the gaps.</p>
1032
1033<p>While it can remove internal rows and columns of pixels, it is more
1034typically used with as <a href="command-line-options.html#gravity">-gravity</a> setting and zero
cristy29dc8652015-05-12 16:26:21 +00001035offsets so as to remove a single edge from an image. Compare this to <a
1036href="command-line-options.html#shave" >-shave</a> which removes equal numbers of pixels from oppisite
cristyd2432012015-05-04 23:15:15 +00001037sides of the image. </p>
1038
cristy29dc8652015-05-12 16:26:21 +00001039<p>Using <a href="command-line-options.html#chop">-chop</a> effectively undoes the results of a <a
1040href="command-line-options.html#splice">-splice</a> that was given the same <var>geometry</var> and <a href="command-line-options.html#gravity">-gravity</a> settings. </p>
cristyd2432012015-05-04 23:15:15 +00001041
1042<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001043 <h3 class="magick-header"><a id="clamp"></a>-clamp</h3>
cristyd2432012015-05-04 23:15:15 +00001044</div>
1045
1046<p class="magick-description">set each pixel whose value is below zero to zero and any the pixel whose value is above the quantum range to the quantum range (e.g. 65535) otherwise the pixel value remains unchanged.</p>
1047
1048<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001049 <h3 class="magick-header"><a id="clip"></a>-clip</h3>
cristyd2432012015-05-04 23:15:15 +00001050</div>
1051
1052<p class="magick-description">Apply the clipping path if one is present.</p>
1053
1054<p>If a clipping path is present, it is applied to subsequent operations.</p>
1055
1056<p>For example, in the command</p>
1057
1058<pre>
1059convert cockatoo.tif -clip -negate negated.tif
1060</pre>
1061
1062<p>only the pixels within the clipping path are negated.</p>
1063
1064<p>The <a href="command-line-options.html#clip">-clip</a> feature requires SVG support. If the SVG
1065delegate library is not present, the option is ignored.</p>
1066
1067<p>Use <a href="command-line-options.html#clip">+clip</a> to disable clipping for subsequent operations.</p>
1068
1069<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001070 <h3 class="magick-header"><a id="clip-mask"></a>-clip-mask</h3>
cristyd2432012015-05-04 23:15:15 +00001071</div>
1072
1073<p class="magick-description">Clip the image as defined by this mask.</p>
1074
1075<p>Use the alpha channel of the current image as a mask. Any areas that is
1076white is not modified by any of the 'image processing operators' that follow,
1077until the mask is removed. Pixels in the black areas of the clip mask are
1078modified per the requirements of the operator. </p>
1079
1080<p>In some ways this is similar to (though not the same) as defining
cristy29dc8652015-05-12 16:26:21 +00001081a rectangular <a href="command-line-options.html#region" >-region</a>, or using the negative of the
1082mask (third) image in a three image <a href="command-line-options.html#composite" >-composite</a>,
cristyd2432012015-05-04 23:15:15 +00001083operation. </p>
1084
1085<p>Use <a href="command-line-options.html#clip-mask">+clip-mask</a> to disable clipping for subsequent operations.</p>
1086
1087<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001088 <h3 class="magick-header"><a id="clip-path"></a>-clip-path <var>id</var></h3>
cristyd2432012015-05-04 23:15:15 +00001089</div>
1090
1091<p class="magick-description">Clip along a named path from the 8BIM profile.</p>
1092
1093<p>This is identical to <a href="command-line-options.html#clip">-clip</a> except choose a specific clip path in the event the image has more than one path available. </p>
1094
1095<p>Use <a href="command-line-options.html#clip-path">+clip-path</a> to disable clipping for subsequent operations.</p>
1096
1097<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001098 <h3 class="magick-header"><a id="clone"></a>-clone <var>index(s)</var></h3>
cristyd2432012015-05-04 23:15:15 +00001099</div>
1100
1101<p class="magick-description">make a clone of an image (or images).</p>
1102
1103<p>Inside parenthesis (where the operator is normally used) it will make a
1104clone of the images from the last 'pushed' image sequence, and adds them to
1105the end of the current image sequence. Outside parenthesis
1106(not recommended) it clones the images from the current image sequence. </p>
1107
1108<p>Specify the image by its index in the sequence. The first image is index
11090. Negative indexes are relative to the end of the sequence; for
1110example, <code>−1</code>
1111represents the last image of the sequence. Specify a range of images with a
1112dash (e.g. <code>0−4</code>). Separate multiple indexes with commas but no
1113spaces (e.g. <code>0,2,5</code>). A value of '<code>0−−1</code> will
1114effectively clone all the images. </p>
1115
1116<p>The <a href="command-line-options.html#clone">+clone</a> will simply make a copy of the last image
1117in the image sequence, and is thus equivalent to using a argument of
1118'<code>−1</code>'. </p>
1119
1120<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001121 <h3 class="magick-header"><a id="clut"></a>-clut</h3>
cristyd2432012015-05-04 23:15:15 +00001122</div>
1123
1124<p class="magick-description">Replace the channel values in the first image using each corresponding channel in the second image as a <b>c</b>olor <b>l</b>ook<b>u</b>p <b>t</b>able.</p>
1125
1126<p>The second (LUT) image is ordinarily a gradient image containing the
1127histogram mapping of how each channel should be modified. Typically it is a
1128either a single row or column image of replacement color values. If larger
1129than a single row or column, values are taken from a diagonal line from
1130top-left to bottom-right corners.</p>
1131
cristy29dc8652015-05-12 16:26:21 +00001132<p>The lookup is further controlled by the <a
1133href="command-line-options.html#interpolate">-interpolate</a> setting, which is especially handy for an
cristyd2432012015-05-04 23:15:15 +00001134LUT which is not the full length needed by the ImageMagick installed Quality
1135(Q) level. Good settings for this are the '<code>bilinear</code>' and
1136'<code>bicubic</code>' interpolation settings, which give smooth color
1137gradients, and the '<code>integer</code>' setting for a direct, unsmoothed
1138lookup of color values. </p>
1139
1140<p>This operator is especially suited to replacing a grayscale image with a
1141specific color gradient from the CLUT image. </p>
1142
1143<p>Only the channel values defined by the <a href="command-line-options.html#channel">-channel</a>
cristy29dc8652015-05-12 16:26:21 +00001144setting will have their values replaced. In particular, since the default <a
1145href="command-line-options.html#channel">-channel</a> setting is <code>RGB</code>, this means that
1146transparency (alpha/matte channel) is not affected, unless the <a
1147href="command-line-options.html#channel">-channel</a> setting is modified. When the alpha channel is
1148set, it is treated by the <a href="command-line-options.html#clut" >-clut</a> operator in the same way
cristyd2432012015-05-04 23:15:15 +00001149as the other channels, implying that alpha/matte values are replaced using the
1150alpha/matte values of the original image. </p>
1151
1152<p>If either the image being modified, or the lookup image, contains no
cristy29dc8652015-05-12 16:26:21 +00001153transparency (i.e. <a href="command-line-options.html#alpha" >-alpha</a> is turned 'off') but the <a
1154href="command-line-options.html#channel">-channel</a> setting includes alpha replacement, then it is
cristyd2432012015-05-04 23:15:15 +00001155assumed that image represents a gray-scale gradient which is used for the
1156replacement alpha values. That is you can use a gray-scale CLUT image to
1157adjust a existing images alpha channel, or you can color a gray-scale image
1158using colors form CLUT containing the desired colors, including transparency.
1159</p>
1160
cristy29dc8652015-05-12 16:26:21 +00001161<p>See also <a href="command-line-options.html#hald-clut" >-hald-clut</a> which replaces colors
cristyd2432012015-05-04 23:15:15 +00001162according to the lookup of the full color RGB value from a 2D representation
1163of a 3D color cube. </p>
1164
1165
1166<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001167 <h3 class="magick-header"><a id="coalesce"></a>-coalesce</h3>
cristyd2432012015-05-04 23:15:15 +00001168</div>
1169
1170<p class="magick-description">Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</p>
1171
1172<p>Overlay each image in an image sequence according to
1173its <a href="command-line-options.html#dispose">-dispose</a> meta-data, to reproduce the look of
1174an animation at each point in the animation sequence. All images should be
1175the same size, and are assigned appropriate GIF disposal settings for the
1176animation to continue working as expected as a GIF animation. Such frames
1177are more easily viewed and processed than the highly optimized GIF overlay
1178images. </p>
1179
1180<p>The animation can be re-optimized after processing using
1181the <a href="command-line-options.html#layers">-layers</a> method '<code>optimize</code>', although
1182there is no guarantee that the restored GIF animation optimization is
1183better than the original. </p>
1184
1185
1186<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001187 <h3 class="magick-header"><a id="colorize"></a>-colorize <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00001188</div>
1189
cristy29dc8652015-05-12 16:26:21 +00001190<p class="magick-description">Colorize the image by an amount specified by <var>value</var> using the color specified by the most recent <a href="command-line-options.html#fill" >-fill</a> setting.</p>
cristyd2432012015-05-04 23:15:15 +00001191
1192<p>Specify the amount of colorization as a percentage. Separate colorization
1193values can be applied to the red, green, and blue channels of the image with
1194a comma-delimited list of colorization
1195values (e.g., <code>-colorize 0,0,50</code>).</p>
1196
1197<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001198 <h3 class="magick-header"><a id="colormap"></a>-colormap <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00001199</div>
1200
1201<p class="magick-description">Define the colormap type.</p>
1202
1203<p>The <var>type</var> can be <code>shared</code> or <code>private</code>.</p>
1204
1205<p>This option only applies when the default X server visual
1206is <code>PseudoColor</code> or <code>GrayScale</code>. Refer
1207to <a href="command-line-options.html#visual">-visual</a> for more details. By default,
1208a shared colormap is allocated. The image shares colors with
1209other X clients. Some image colors could be approximated,
1210therefore your image may look very different than intended.
1211If <code>private</code> is chosen, the image colors appear exactly
1212as they are defined. However, other clients may go <var>technicolor</var>
1213when the image colormap is installed.</p>
1214
1215<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001216 <h3 class="magick-header"><a id="colors"></a>-colors <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00001217</div>
1218
1219<p class="magick-description">Set the preferred number of colors in the image.</p>
1220
1221<p>The actual number of colors in the image may be less than your request,
1222but never more. Note that this a color reduction option. Images with fewer
1223unique colors than specified by <var>value</var> will have any
1224duplicate or unused colors removed. The ordering of an existing color
1225palette may be altered. When converting an image from color to grayscale,
1226it is more efficient to convert the image to the gray colorspace before
1227reducing the number of colors. Refer to
1228the <a href="quantize.html">
1229color reduction algorithm</a> for more details.</p>
1230
1231<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001232 <h3 class="magick-header"><a id="color-matrix"></a>-color-matrix <var>matrix</var></h3>
cristyd2432012015-05-04 23:15:15 +00001233</div>
1234
1235<p class="magick-description">apply color correction to the image.</p>
1236
1237<p>This option permits saturation changes, hue rotation, luminance to alpha,
1238and various other effects. Although variable-sized transformation matrices
1239can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6
1240for CMYKA (or RGBA with offsets). The matrix is similar to those used by
1241Adobe Flash except offsets are in column 6 rather than 5 (in support of
1242CMYKA images) and offsets are normalized (divide Flash offset by 255).</p>
1243
1244<p>As an example, to add contrast to an image with offsets, try this command:</p>
1245
1246<pre>
cristy29dc8652015-05-12 16:26:21 +00001247convert kittens.jpg -color-matrix \
1248 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \
1249 0.0 1.5 0.0 0.0, 0.0, -0.157 \
1250 0.0 0.0 1.5 0.0, 0.0, -0.157 \
1251 0.0 0.0 0.0 1.0, 0.0, 0.0 \
1252 0.0 0.0 0.0 0.0, 1.0, 0.0 \
1253 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png
cristyd2432012015-05-04 23:15:15 +00001254</pre>
1255<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001256 <h3 class="magick-header"><a id="colorspace"></a>-colorspace <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00001257</div>
1258
1259<p class="magick-description">Set the image colorspace.</p>
1260
1261<p>Choices are:</p>
1262
1263<pre>
cristy29dc8652015-05-12 16:26:21 +00001264CMY CMYK Gray HCL
1265HCLp HSB HSI HSL
1266HSV HWB Lab LCHab
1267LCHuv LMS Log Luv
1268OHTA Rec601YCbCr Rec709YCbCr RGB
1269scRGB sRGB Transparent xyY
1270XYZ YCbCr YCC YDbDr
1271YIQ YPbPr YUV
cristyd2432012015-05-04 23:15:15 +00001272</pre>
1273
1274<p>To print a complete list of colorspaces, use <a href="command-line-options.html#list">-list colorspace</a>.</p>
1275
1276<p>For a more accurate color conversion to or from the linear RGB, CMYK, or grayscale colorspaces, use the <a href="command-line-options.html#profile">-profile</a> option. Note, ImageMagick assumes the sRGB colorspace if the image format does not indicate otherwise. For colorspace conversion, the gamma function is first removed to produce linear RGB.</p>
1277
1278<table class="table table-condensed table-striped">
1279 <caption>Conversion of RGB to Other Color Spaces</caption>
1280 <tr><th valign="middle">CMY</th></tr>
1281 <tr><td valign="middle">C=<var>QuantumRange</var>−R</td></tr>
1282 <tr><td valign="middle">M=<var>QuantumRange</var>−G</td></tr>
1283 <tr><td valign="middle">Y=<var>QuantumRange</var>−B</td></tr>
1284 <tr><th valign="middle">CMYK — starts with CMY from above</th></tr>
1285 <tr><td valign="middle">K=min(C,Y,M)</td></tr>
1286 <tr><td valign="middle">C=<var>QuantumRange</var>*(C−K)/(<var>QuantumRange</var>−K)</td></tr>
1287 <tr><td valign="middle">M=<var>QuantumRange</var>*(M−K)/(<var>QuantumRange</var>−K)</td></tr>
1288 <tr><td valign="middle">Y=<var>QuantumRange</var>*(Y−K)/(<var>QuantumRange</var>−K)</td></tr>
1289
1290 <tr><th valign="middle">Gray</th></tr>
1291 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1292
1293 <tr><th valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr>
1294 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1295 <tr><td valign="middle">S=distance from axis outward</td></tr>
1296 <tr><td valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <var>intensity-like</var></td></tr>
1297
1298 <tr><th valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
1299 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1300 <tr><td valign="middle">S=distance from axis outward</td></tr>
1301 <tr><td valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <var>intensity-like</var></td></tr>
1302
1303 <tr><th valign="middle">HWB — Hue, Whiteness, Blackness</th></tr>
1304 <tr><td valign="middle">Hue (complicated equation)</td></tr>
1305 <tr><td valign="middle">Whiteness (complicated equation)</td></tr>
1306 <tr><td valign="middle">Blackness (complicated equation)</td></tr>
1307
1308 <tr><th valign="middle">LAB</th></tr>
1309 <tr><td valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1310 <tr><td valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1311 <tr><td valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1312
1313 <tr><th valign="middle">LOG</th></tr>
1314 <tr><td valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1315 <tr><td valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1316 <tr><td valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1317
1318 <tr><th valign="middle">OHTA — approximates principal components transformation</th></tr>
1319 <tr><td valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <var>intensity-like</var></td></tr>
1320 <tr><td valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1321 <tr><td valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1322
1323 <tr><th valign="middle">Rec601Luma</th></tr>
1324 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1325
1326 <tr><th valign="middle">Rec601YCbCr</th></tr>
1327 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1328 <tr><td valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1329 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1330
1331 <tr><th valign="middle">Rec709Luma</th></tr>
1332 <tr><td valign="middle">Gray=0.212656*R+0.715158*G+0.072186*B</td></tr>
1333
1334 <tr><th valign="middle">Rec709YCbCr</th></tr>
1335 <tr><td valign="middle">Y=0.212656*R+0.715158*G+0.072186*B; <var>intensity-like</var></td></tr>
1336 <tr><td valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1337 <tr><td valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1338
1339 <tr><th valign="middle">sRGB</th></tr>
1340 <tr><td valign="middle">if R ≤ .0.0031308 then Rs=R/12.92 else Rs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1341 <tr><td valign="middle">if G ≤ .0.0031308 then Gs=B/12.92 else Gs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1342 <tr><td valign="middle">if B ≤ .0.0031308 then Bs=B/12.92 else Bs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1343
1344 <tr><th valign="middle">XYZ</th></tr>
1345 <tr><td valign="middle">X=0.4124564*R+0.3575761*G+0.1804375*B</td></tr>
1346 <tr><td valign="middle">Y=0.2126729*R+0.7151522*G+0.0721750*B</td></tr>
1347 <tr><td valign="middle">Z=0.0193339*R+0.1191920*G+0.9503041*B</td></tr>
1348
1349 <tr><th valign="middle">YCC</th></tr>
1350 <tr><td valign="middle">Y=(0.298839*R+0.586811*G+0.114350*B) (with complicated scaling); <var>intensity-like</var></td></tr>
1351 <tr><td valign="middle">C1=(−0.298839*R−0.586811*G+0.88600*B) (with complicated scaling)</td></tr>
1352 <tr><td valign="middle">C2=(0.70100*R−0.586811*G−0.114350*B) (with complicated scaling)</td></tr>
1353
1354 <tr><th valign="middle">YCbCr</th></tr>
1355 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1356 <tr><td valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1357 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1358
1359 <tr><th valign="middle">YIQ</th></tr>
1360 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1361 <tr><td valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1362 <tr><td valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1363
1364 <tr><th valign="middle">YPbPr</th></tr>
1365 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1366 <tr><td valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1367 <tr><td valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1368
1369 <tr><th valign="middle">YUV</th></tr>
1370 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1371 <tr><td valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1372 <tr><td valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1373</table>
1374
1375<p>Note the scRGB colorspace requires HDRI support otherwise it behaves just like linear RGB.</p>
1376
1377<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001378 <h3 class="magick-header"><a id="combine"></a>-combine</h3>
cristyd2432012015-05-04 23:15:15 +00001379</div>
1380
1381<p class="magick-description">Combine one or more images into a single image.</p>
1382
1383<p>The channels (previously set by <a href="command-line-options.html#channel">-channel</a>) of the
1384combined image are taken from the grayscale values of each image in the
1385sequence, in order. For the default -channel setting of <code>RGB</code>, this
1386means the first image is assigned to the <code>Red</code> channel, the second
1387to the <code>Green</code> channel, the third to the <code>Blue</code>.</p>
1388
cristy29dc8652015-05-12 16:26:21 +00001389<p>This option can be thought of as the inverse to <a
1390href="command-line-options.html#separate">-separate</a>, so long as the channel settings are the same.
cristyd2432012015-05-04 23:15:15 +00001391Thus, in the following example, the final image should be a copy of the
1392original. </p>
1393
1394<pre>
1395convert original.png -channel RGB -separate sepimage.png
1396convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \
1397 -combine imagecopy.png
1398</pre>
1399
1400<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001401 <h3 class="magick-header"><a id="comment"></a>-comment <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00001402</div>
1403
1404<p class="magick-description">Embed a comment in an image.</p>
1405
1406<p>This option sets the comment meta-data of an image read in after this
1407option has been given. To modify a comment of images already in memory use
1408"<code><a href="command-line-options.html#set">-set</a> comment</code>". </p>
1409
cristy29dc8652015-05-12 16:26:21 +00001410<p>The comment can contain special format characters listed in the <a
1411href="escape.html">Format and
cristyd2432012015-05-04 23:15:15 +00001412Print Image Properties</a>. These attributes are expanded when the comment
1413is finally assigned to the individual images. </p>
1414
1415<p>If the first character of <var>string</var> is <var>@</var>, the image comment is read from a file titled by the
1416remaining characters in the string. Comments read in from a file are literal;
1417no embedded formatting characters are recognized.</p>
1418
1419<p>Comment meta-data are not visible on the image itself. To do that use the
1420<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
1421instead.</p>
1422
1423<p>For example,</p>
1424
cristy29dc8652015-05-12 16:26:21 +00001425<pre>
1426-comment "%m:%f %wx%h" bird.miff
1427</pre>
cristyd2432012015-05-04 23:15:15 +00001428
1429<p>produces an image comment of <code>MIFF:bird.miff 512x480</code> (assuming
1430that the image <code>bird.miff</code> has a width of 512 and a height of
1431480.</p>
1432
1433<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001434 <h3 class="magick-header"><a id="compare"></a>-compare</h3>
cristyd2432012015-05-04 23:15:15 +00001435</div>
1436
1437<p class="magick-description">mathematically and visually annotate the difference between an image and its reconstruction</p>
1438
1439<p>This is a convert version of "<code>compare</code>" for two same sized images. The syntax is as follows, but other metrics are allowed.</p>
1440
1441<pre>
cristy29dc8652015-05-12 16:26:21 +00001442convert image.png reference.png -metric RMSE -compare \ <br/> difference.png
cristyd2432012015-05-04 23:15:15 +00001443</pre>
1444
1445<p>To get the metric value use the string format "%[distortion]".</p>
1446
1447<pre>
1448convert image.png reference.png -metric RMSE -compare -format \
1449 "%[distortion]" info:
1450</pre>
1451
1452<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001453 <h3 class="magick-header"><a id="complex"></a>-complex <var>operator</var></h3>
cristyd2432012015-05-04 23:15:15 +00001454</div>
1455
1456<p class="magick-description">perform complex mathematics on an image sequence</p>
1457
1458Choose from these operators:
1459
1460<pre>
cristy29dc8652015-05-12 16:26:21 +00001461add
1462conjugate
1463divide
1464magnuitude-phase
1465multiply
1466real-imaginary
1467subtract
cristyd2432012015-05-04 23:15:15 +00001468</pre>
1469
1470<p>Optionally specify the <code>divide</code> operator SNR with <code><a href="command-line-options.html#define">-define</a> complex:snr=float</code>.</p>
1471
1472<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001473 <h3 class="magick-header"><a id="compose"></a>-compose <var>operator</var></h3>
cristyd2432012015-05-04 23:15:15 +00001474</div>
1475
1476<p class="magick-description">Set the type of image composition.</p>
1477
1478<p>See <a href="compose.html">Alpha Compositing</a> for
1479a detailed discussion of alpha compositing.</p>
1480
1481<p>This setting effects image processing operators that merge two (or more)
1482images together in some way. This includes the operators,
1483<a href="command-line-options.html#composite">-compare</a>,
1484<a href="command-line-options.html#composite">-composite</a>,
1485<a href="command-line-options.html#layers">-layers</a> composite,
1486<a href="command-line-options.html#flatten">-flatten</a>,
1487<a href="command-line-options.html#mosaic">-mosaic</a>,
1488<a href="command-line-options.html#layers">-layers</a> merge,
1489<a href="command-line-options.html#border">-border</a>,
1490<a href="command-line-options.html#frame">-frame</a>,
1491and <a href="command-line-options.html#extent">-extent</a>. </p>
1492
1493<p>It is also one of the primary options for the "<code>composite</code>"
1494command. </p>
1495
1496
1497<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001498 <h3 class="magick-header"><a id="composite"></a>-composite</h3>
cristyd2432012015-05-04 23:15:15 +00001499</div>
1500
1501<p class="magick-description">Perform alpha composition on two images and an optional mask</p>
1502
1503<p>Take the first image 'destination' and overlay the second 'source' image
1504according to the current <a href="command-line-options.html#compose">-compose</a> setting. The location
cristy29dc8652015-05-12 16:26:21 +00001505of the 'source' or 'overlay' image is controlled according to <a
1506href="command-line-options.html#geometry" >-geometry</a>, and <a href="command-line-options.html#geometry" >-geometry</a>
cristyd2432012015-05-04 23:15:15 +00001507settings. </p>
1508
1509<p>If a third image is given this is treated as a gray-scale blending 'mask' image
1510relative to the first 'destination' image. This mask is blended with the
1511source image. However for the '<code>displace</code>' compose method, the
1512mask is used to provide a separate Y-displacement image instead. </p>
1513
1514<p>If a <a href="command-line-options.html#compose">-compose</a> method requires extra numerical
cristy29dc8652015-05-12 16:26:21 +00001515arguments or flags these can be provided by setting the <a
1516href="command-line-options.html#set">-set</a> '<code>option:compose:args</code>'
cristyd2432012015-05-04 23:15:15 +00001517appropriately for the compose method. </p>
1518
1519<p>Some <a href="command-line-options.html#compose">-compose</a> methods can modify the 'destination'
cristy29dc8652015-05-12 16:26:21 +00001520image outside the overlay area. You can disable this by setting the special <a
1521href="command-line-options.html#set">-set</a> '<code>option:compose:outside-overlay</code>'
cristyd2432012015-05-04 23:15:15 +00001522to '<code>false</code>'. </p>
1523
1524<p>The SVG compositing specification requires that color and opacity values range between zero and QuantumRange inclusive. You can permit values outside this range with this option: <a href="command-line-options.html#set">-set</a> '<code>option:compose:clamp=false</code></p>
1525
1526
1527<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001528 <h3 class="magick-header"><a id="compress"></a>-compress <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00001529</div>
1530
1531<p class="magick-description">Use pixel compression specified by <var>type</var> when writing the image.</p>
1532
cristy29dc8652015-05-12 16:26:21 +00001533<p>Choices are: <code>None</code>, <code>BZip</code>, <code
1534>Fax</code>, <code>Group4</code>, <code
1535>JPEG</code>, <code>JPEG2000</code>, <code
1536>Lossless</code>, <code>LZW</code>, <code
1537>RLE</code> or <code>Zip</code>.</p>
cristyd2432012015-05-04 23:15:15 +00001538
1539<p>To print a complete list of compression types, use <a href="command-line-options.html#list">-list
1540compress</a>.</p>
1541
1542<p>Specify <a href="command-line-options.html#compress">+compress</a> to store the binary image in an
1543uncompressed format. The default is the compression type of the specified
1544image file.</p>
1545
1546<p>If <code>LZW</code> compression is specified but LZW compression has not been
1547enabled, the image data is written in an uncompressed LZW format that can be
1548read by LZW decoders. This may result in larger-than-expected GIF files.</p>
1549
1550<p><code>Lossless</code> refers to lossless JPEG, which is only available if the
1551JPEG library has been patched to support it. Use of lossless JPEG is generally
1552not recommended.</p>
1553
1554<p>
1555When writing an ICO file, you may request that the images be encoded in
1556PNG format, by specifying <code>Zip</code> compression.</p>
1557
1558<p>
1559When writing a JNG file, specify <code>Zip</code> compression to request that
1560the alpha channel be encoded in PNG "IDAT" format, or <code>JPEG</code>
1561to request that it be encoded in JPG "JDAA" format.</p>
1562
1563<p>Use the <a href="command-line-options.html#quality">-quality</a> option to set the compression level
1564to be used by JPEG, PNG, MIFF, and MPEG encoders.
1565Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to set the
1566sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling
1567the chroma channels.</p>
1568
1569<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001570 <h3 class="magick-header"><a id="connected-components"></a>-connected-components <var>connectivity</var></h3>
cristyd2432012015-05-04 23:15:15 +00001571</div>
1572
1573<p class="magick-description">connected-components uniquely labeled, choose from 4 or 8 way connectivity.</p>
1574
cristy29dc8652015-05-12 16:26:21 +00001575<p>Use <code><a href="command-line-options.html#define" >-define</a> connected-components:verbose=true</code> to output statistics associated with each unique label.</p>
cristyd2432012015-05-04 23:15:15 +00001576
1577<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001578 <h3 class="magick-header"><a id="contrast"></a>-contrast</h3>
cristyd2432012015-05-04 23:15:15 +00001579</div>
1580
1581<p class="magick-description">Enhance or reduce the image contrast.</p>
1582
1583<p>This option enhances the intensity differences between the lighter and
1584darker elements of the image. Use <a href="command-line-options.html#contrast">-contrast</a> to enhance
1585the image or <a href="command-line-options.html#contrast">+contrast</a> to reduce the image
1586contrast.</p>
1587
1588<p>For a more pronounced effect you can repeat the option:</p>
1589
1590<pre>
1591convert rose: -contrast -contrast rose_c2.png
1592</pre>
1593
1594<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001595 <h3 class="magick-header"><a id="contrast-stretch"></a>-contrast-stretch <var>black-point</var><br />-contrast-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}}</h3>
cristyd2432012015-05-04 23:15:15 +00001596</div>
1597
1598<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
1599
1600<p>While performing the stretch, black-out at most <var>black-point</var> pixels and white-out at most <var>white-point</var> pixels. Or, if percent is used, black-out at most
cristy29dc8652015-05-12 16:26:21 +00001601<var >black-point %</var> pixels and white-out at most <var>white-point %</var> pixels.</p>
cristyd2432012015-05-04 23:15:15 +00001602
cristy29dc8652015-05-12 16:26:21 +00001603<p>Prior to ImageMagick 6.4.7-0, <a href="command-line-options.html#contrast-stretch"
1604>-contrast-stretch</a> will black-out at most <var>black-point</var> pixels and white-out at most <var >total pixels
cristyd2432012015-05-04 23:15:15 +00001605minus white-point</var> pixels. Or, if percent is used, black-out at most <var>black-point %</var> pixels and white-out at most <var>100% minus white-point %</var> pixels.</p>
1606
1607<p>Note that <code>-contrast-stretch 0</code> will modify the image such that
1608the image's min and max values are stretched to 0 and <var>QuantumRange</var>, respectively, without any loss of data due to burn-out or
cristy29dc8652015-05-12 16:26:21 +00001609clipping at either end. This is not the same as <a href="command-line-options.html#normalize"
1610>-normalize</a>, which is equivalent to <code>-contrast-stretch 0.15x0.05%</code> (or
cristyd2432012015-05-04 23:15:15 +00001611prior to ImageMagick 6.4.7-0, <code>-contrast-stretch 2%x99%</code>).</p>
1612
1613<p>Internally operator works by creating a histogram bin, and then uses that
1614bin to modify the image. As such some colors may be merged together when they
1615originally fell into the same 'bin'. </p>
1616
1617<p>All the channels are normalized in concert by the came amount so as to
cristy29dc8652015-05-12 16:26:21 +00001618preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a>
1619setting is in use. Specifying any other <a href="command-line-options.html#channel" >-channel</a>
cristyd2432012015-05-04 23:15:15 +00001620setting will normalize the RGB channels independently.</p>
1621
cristy29dc8652015-05-12 16:26:21 +00001622<p>See also <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect'
cristyd2432012015-05-04 23:15:15 +00001623normalization of mathematical images. </p>
1624
1625<p>This operator is under review for re-development. </p>
1626
1627
1628<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001629 <h3 class="magick-header"><a id="convolve"></a>-convolve <var>kernel</var></h3>
cristyd2432012015-05-04 23:15:15 +00001630</div>
1631
1632<p class="magick-description">Convolve an image with a user-supplied convolution kernel.</p>
1633
1634<p>The <var>kernel</var> is a matrix specified as
1635a comma-separated list of integers (with no spaces), ordered left-to right,
1636starting with the top row. Presently, only odd-dimensioned kernels are
1637supported, and therefore the number of entries in the specified <var>kernel</var> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
16387<sup>2</sup>=49, etc. </p>
1639
cristy29dc8652015-05-12 16:26:21 +00001640<p>Note that the <a href="command-line-options.html#convolve">&#x2011;convolve</a> operator supports the <a href="command-line-options.html#bias">&#x2011;bias</a> setting. This option shifts the convolution so that
cristyd2432012015-05-04 23:15:15 +00001641positive and negative results are relative to a user-specified bias value.
1642This is important for non-HDRI compilations of ImageMagick when dealing with
1643convolutions that contain negative as well as positive values. This is
1644especially the case with convolutions involving high pass filters or edge
1645detection. Without an output bias, the negative values is clipped at zero.
1646</p>
1647
cristy29dc8652015-05-12 16:26:21 +00001648<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">&#x2011;bias</a> is not needed, as ImageMagick is able to store/handle any
cristyd2432012015-05-04 23:15:15 +00001649negative results without clipping to the color value range (0..QuantumRange).
cristy29dc8652015-05-12 16:26:21 +00001650See the discussion on HDRI implementations of ImageMagick on the page <a
1651href="high-dynamic-range.html">High
1652Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a
1653href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
cristyd2432012015-05-04 23:15:15 +00001654<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1655entry. </p>
1656
1657
1658<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001659 <h3 class="magick-header"><a id="crop"></a>-crop <var>geometry</var>{<var>@</var>}{<var>!</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00001660</div>
1661
1662<p class="magick-description">Cut out one or more rectangular regions of the image.</p>
1663
1664<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
1665
1666<p>The <var>width</var> and <var>height</var> of the <var>geometry</var> argument give the size of the image that remains
1667after cropping, and <var>x</var> and <var>y</var> in the
1668<var>offset</var> (if present) gives the location of the top left
1669corner of the cropped image with respect to the original image. To specify the
1670amount to be removed, use <a href="command-line-options.html#shave">-shave</a> instead.</p>
1671
1672<p>If the <var>x</var> and <var>y</var> offsets are
1673present, a single image is generated, consisting of the pixels from the
1674cropping region. The offsets specify the location of the upper left corner of
1675the cropping region measured downward and rightward with respect to the upper
1676left corner of the image. If the <a href="command-line-options.html#gravity">-gravity</a> option is
1677present with <code>NorthEast</code>, <code>East</code>, or <code>SouthEast</code>
1678gravity, it gives the distance leftward from the right edge of the image to
cristy29dc8652015-05-12 16:26:21 +00001679the right edge of the cropping region. Similarly, if the <a
1680href="command-line-options.html#gravity">-gravity</a> option is present with <code>SouthWest</code>,
cristyd2432012015-05-04 23:15:15 +00001681<code>South</code>, or <code>SouthEast</code> gravity, the distance is measured
1682upward between the bottom edges.</p>
1683
1684<p>If the <var>x</var> and <var>y</var> offsets are
1685omitted, a set of tiles of the specified geometry, covering the entire input
1686image, is generated. The rightmost tiles and the bottom tiles are smaller if
1687the specified geometry extends beyond the dimensions of the input image.</p>
1688
1689<p>You can add the <var>@</var> to the geometry argument to equally divide the image into the number of tiles generated.</p>
1690
1691<p>By adding a exclamation character flag to the geometry argument, the
1692cropped images virtual canvas page size and offset is set as if the
1693geometry argument was a viewport or window. This means the canvas page size
1694is set to exactly the same size you specified, the image offset set
1695relative top left corner of the region cropped. </p>
1696
1697<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1698special single pixel transparent 'missed' image is returned, and a 'crop
1699missed' warning given. </p>
1700
cristy29dc8652015-05-12 16:26:21 +00001701<p>It might be necessary to <a href="command-line-options.html#repage" >+repage</a> the image prior to
cristyd2432012015-05-04 23:15:15 +00001702cropping the image to ensure the crop coordinate frame is relocated to the
1703upper-left corner of the visible image.
1704
cristy29dc8652015-05-12 16:26:21 +00001705Similarly you may want to use <a href="command-line-options.html#repage" >+repage</a> after cropping to
cristyd2432012015-05-04 23:15:15 +00001706remove the page offset that will be left behind. This is especially true when
1707you are going to write to an image format such as PNG that supports an image
1708offset.</p>
1709
1710<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001711 <h3 class="magick-header"><a id="cycle"></a>-cycle <var>amount</var></h3>
cristyd2432012015-05-04 23:15:15 +00001712</div>
1713
1714<p class="magick-description">displace image colormap by amount.</p>
1715
1716<p><var>Amount</var> defines the number of positions each
1717colormap entry is shifted.</p>
1718
1719
1720<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001721 <h3 class="magick-header"><a id="debug"></a>-debug <var>events</var></h3>
cristyd2432012015-05-04 23:15:15 +00001722</div>
1723
1724<p class="magick-description">enable debug printout.</p>
1725
1726<p>The <code>events</code> parameter specifies which events are to be logged. It
1727can be either <code>None</code>, <code>All</code>, <code>Trace</code>, or
1728a comma-separated list consisting of one or more of the following domains:
1729<code>Accelerate</code>, <code>Annotate</code>, <code>Blob</code>, <code>Cache</code>,
1730<code>Coder</code>, <code>Configure</code>, <code>Deprecate</code>,
1731<code>Exception</code>, <code>Locale</code>, <code>Render</code>,
1732<code>Resource</code>, <code>Security</code>, <code>TemporaryFile</code>,
1733<code>Transform</code>, <code>X11</code>, or <code>User</code>. </p>
1734
1735
1736<p>For example, to log cache and blob events, use.</p>
1737
1738<pre>
1739convert -debug "Cache,Blob" rose: rose.png
1740</pre>
1741
1742<p>The <code>User</code> domain is normally empty, but developers can log user
1743events in their private copy of ImageMagick.</p>
1744
1745<p>To print the complete list of debug methods, use <a href="command-line-options.html#list">-list
1746debug</a>.</p>
1747
1748<p>Use the <a href="command-line-options.html#log">-log</a> option to specify the format for debugging
1749output.</p>
1750
1751<p>Use <a href="command-line-options.html#debug">+debug</a> to turn off all logging.</p>
1752
cristy29dc8652015-05-12 16:26:21 +00001753<p>Debugging may also be set using the <code>MAGICK_DEBUG</code> <a href="resources.html#environment"
1754>environment variable</a>. The allowed values for the <code>MAGICK_DEBUG</code>
cristyd2432012015-05-04 23:15:15 +00001755environment variable are the same as for the <a href="command-line-options.html#debug">-debug</a>
1756option.</p>
1757
1758
1759<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001760 <h3 class="magick-header"><a id="decipher"></a>-decipher <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00001761</div>
1762
1763<p class="magick-description">Decipher and restore pixels that were previously transformed by <a href="command-line-options.html#encipher">-encipher</a>.</p>
1764
1765<p>Get the passphrase from the file specified by <var>filename</var>.</p>
1766
cristy29dc8652015-05-12 16:26:21 +00001767<p>For more information, see the webpage, <a
1768href="../www/cipher.html">ImageMagick: Encipher or
cristyd2432012015-05-04 23:15:15 +00001769Decipher an Image</a>.</p>
1770
1771
1772<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001773 <h3 class="magick-header"><a id="deconstruct"></a>-deconstruct</h3>
cristyd2432012015-05-04 23:15:15 +00001774</div>
1775
1776<p class="magick-description">find areas that has changed between images </p>
1777
cristy29dc8652015-05-12 16:26:21 +00001778<p>Given a sequence of images all the same size, such as produced by <a
1779href="command-line-options.html#coalesce">-coalesce</a>, replace the second and later images, with
cristyd2432012015-05-04 23:15:15 +00001780a smaller image of just the area that changed relative to the previous image.
1781</p>
1782
1783<p>The resulting sequence of images can be used to optimize an animation
1784sequence, though will not work correctly for GIF animations when parts of the
1785animation can go from opaque to transparent. </p>
1786
1787<p>This option is actually equivalent to the <a href="command-line-options.html#layers">-layers</a>
1788method '<code>compare-any</code>'. </p>
1789
1790
1791<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00001792 <h3 class="magick-header"><a id="define"></a>-define <var>key</var>{<var>=value</var>}<var>...</var></h3>
cristyd2432012015-05-04 23:15:15 +00001793</div>
1794
1795<p class="magick-description">add specific global settings generally used to control coders and image processing operations.</p>
1796
1797<p>This option creates one or more definitions for coders and decoders to use
1798while reading and writing image data. Definitions are generally used to
1799control image file format coder modules, and image processing operations,
cristy29dc8652015-05-12 16:26:21 +00001800beyond what is provided by normal means. Defined settings are listed in <a
1801href="command-line-options.html#verbose" >-verbose</a> information ("<code>info:</code>" output format)
cristyd2432012015-05-04 23:15:15 +00001802as "Artifacts". </p>
1803
1804<p>If <var>value</var> is missing for a definition, an empty-valued
1805definition of a flag is created with that name. This used to control on/off
1806options. Use <a href="command-line-options.html#define">+define key</a> to remove definitions
1807previously created. Use <a href="command-line-options.html#define">+define "*"</a> to remove all
1808existing definitions.</p>
1809
cristy29dc8652015-05-12 16:26:21 +00001810<p>The same 'artifact' settings can also be defined using the <a
1811href="command-line-options.html#set" >-set "option:<var>key</var>" "<var>value</var>"</a> option, which also allows the use of <a href="escape.html" >Format and Print Image
cristyd2432012015-05-04 23:15:15 +00001812Properties</a> in the defined value. </p>
1813
1814<p>The <var>option</var> and <var>key</var> are case-independent (they are
1815converted to lowercase for use within the decoders) while the <var>value</var>
1816is case-dependent.</p>
1817
1818<p>Such settings are global in scope, and affect all images and operations. </p>
1819
1820<p>The following definitions are just some of the artifacts that are
1821available:</p>
1822
cristy29dc8652015-05-12 16:26:21 +00001823<table class="table table-condensed table-striped">
1824 <tr>
1825 <td>bmp:format=<var>value</var></td>
1826 <td> valid values are <var>bmp2</var>, <var>bmp3</var>,
cristyd2432012015-05-04 23:15:15 +00001827 and <var>bmp4</var>. This option can be useful when the
1828 method of prepending "BMP2:" to the output filename is inconvenient or
cristy29dc8652015-05-12 16:26:21 +00001829 is not available, such as when using the <a href="mogrify.html">mogrify</a> utility.</td>
1830 </tr>
cristyd2432012015-05-04 23:15:15 +00001831
cristy29dc8652015-05-12 16:26:21 +00001832 <tr>
1833 <td>complex:snr=<var>value</var></td>
1834 <td>Set the divide SNR constant<a href="command-line-options.html#complex"
1835 >-complex</a></td>
1836 </tr>
cristyd2432012015-05-04 23:15:15 +00001837
cristy29dc8652015-05-12 16:26:21 +00001838 <tr>
1839 <td>compose:args=<var>arguments</var></td>
1840 <td>Sets certain compose argument values when using convert ... -compose ...
1841 -composite. See <a href="compose.html"
1842 >Image Composition</a></td>
1843 </tr>
cristyd2432012015-05-04 23:15:15 +00001844
cristy29dc8652015-05-12 16:26:21 +00001845 <tr>
1846 <td>convolve:scale=<var>{kernel_scale}[!^] [,{origin_addition}] [%]</var></td>
1847 <td>Defines the kernel scaling. The special flag ! automatically scales to
cristyd2432012015-05-04 23:15:15 +00001848 full dynamic range. The ! flag can be used in combination with a factor or
1849 percent. The factor or percent is then applied after the automatic scaling.
1850 An example is 50%!. This produces a result 50% darker than full dynamic
1851 range scaling. The ^ flag assures the kernel is 'zero-summing', for
1852 example when some values are positive and some are negative as in edge
1853 detection kernels. The origin addition adds that value to the center
1854 pixel of the kernel. This produces and effect that is like adding the image
1855 that many times to the result of the filtered image. The typical value
1856 is 1 so that the original image is added to the result of the convolution.
cristy29dc8652015-05-12 16:26:21 +00001857 The default is 0.</td>
1858 </tr>
cristyd2432012015-05-04 23:15:15 +00001859
cristy29dc8652015-05-12 16:26:21 +00001860 <tr>
1861 <td>convolve:showkernel=<var>1</var></td>
1862 <td>Outputs (to 'standard error') all the information about a specified <a
1863 href="command-line-options.html#morphology" >-morphology convolve</a> kernel.</td>
1864 </tr>
cristyd2432012015-05-04 23:15:15 +00001865
cristy29dc8652015-05-12 16:26:21 +00001866 <tr>
1867 <td>dcm:display-range=<var>reset</var></td>
1868 <td>Sets the display range to the minimum and maximum pixel values for the
1869 DCM image format.</td>
1870 </tr>
cristyd2432012015-05-04 23:15:15 +00001871
cristy29dc8652015-05-12 16:26:21 +00001872 <tr>
1873 <td>dds:cluster-fit=<var>true|false</var></td>
1874 <td>Enables the dds cluster-fit.</td>
1875 </tr>
cristyd2432012015-05-04 23:15:15 +00001876
cristy29dc8652015-05-12 16:26:21 +00001877 <tr>
1878 <td>dds:compression=<var>dxt1|dxt5|none</var></td>
1879 <td>Sets the dds compression.</td>
1880 </tr>
cristyd2432012015-05-04 23:15:15 +00001881
cristy29dc8652015-05-12 16:26:21 +00001882 <tr>
1883 <td>dds:mipmaps=<var>value</var></td>
1884 <td>Sets the dds number of mipmaps.</td>
1885 </tr>
cristyd2432012015-05-04 23:15:15 +00001886
cristy29dc8652015-05-12 16:26:21 +00001887 <tr>
1888 <td>dds:weight-by-alpha=<var>true|false</var></td>
1889 <td>Enables the dds alpha weighting.</td>
1890 </tr>
cristyd2432012015-05-04 23:15:15 +00001891
cristy29dc8652015-05-12 16:26:21 +00001892 <tr>
1893 <td>delegate:bimodal=<var>true</var></td>
1894 <td>Specifies direct conversion from Postscript to PDF.</td>
1895 </tr>
cristyd2432012015-05-04 23:15:15 +00001896
cristy29dc8652015-05-12 16:26:21 +00001897 <tr>
1898 <td>distort:scale=<var>value</var></td>
1899 <td>Sets the output scaling factor for use with <a href="command-line-options.html#distort"
1900 >-distort</a></td>
1901 </tr>
cristyd2432012015-05-04 23:15:15 +00001902
cristy29dc8652015-05-12 16:26:21 +00001903 <tr>
1904 <td>distort:viewport=<var>WxH+X+Y</var></td>
1905 <td>Sets the viewport for use with <a href="command-line-options.html#distort">-distort</a></td>
1906 </tr>
cristyd2432012015-05-04 23:15:15 +00001907
cristy29dc8652015-05-12 16:26:21 +00001908 <tr>
1909 <td>dot:layout-engine=<var>value</var></td>
1910 <td>Specifies the layout engine for the DOT image format (e.g.
1911 <code>neato</code>).</td>
1912 </tr>
cristyd2432012015-05-04 23:15:15 +00001913
cristy29dc8652015-05-12 16:26:21 +00001914 <tr>
1915 <td>filter:option=<var>value</var></td>
1916 <td>Set a filter option for use with <a href="command-line-options.html#resize">-resize</a>.
1917 See <a href="command-line-options.html#filter">-filter</a> for details.</td>
1918 </tr>
cristyd2432012015-05-04 23:15:15 +00001919
cristy29dc8652015-05-12 16:26:21 +00001920 <tr>
1921 <td>fourier:normalize=<var>inverse</var></td>
1922 <td>Sets the location for the FFT/IFT normalization as use by
cristyd2432012015-05-04 23:15:15 +00001923 <a href="command-line-options.html#fft">+-fft</a> and <a href="command-line-options.html#ift">+-ift</a>. The default is
cristy29dc8652015-05-12 16:26:21 +00001924 forward.</td>
1925 </tr>
cristyd2432012015-05-04 23:15:15 +00001926
cristy29dc8652015-05-12 16:26:21 +00001927 <tr>
1928 <td>icon:auto-resize</td>
1929 <td>Automatically stores multiple sizes when writing an ico image
1930 (requires a 256x256 input image).</td>
1931 </tr>
cristyd2432012015-05-04 23:15:15 +00001932
cristy29dc8652015-05-12 16:26:21 +00001933 <tr>
1934 <td>jp2:layer-number=<var>value</var></td>
1935 <td>Sets the maximum number of quality layers to decode. Same for JPT, JC2,
1936 and J2K</td>
1937 </tr>
cristyd2432012015-05-04 23:15:15 +00001938
cristy29dc8652015-05-12 16:26:21 +00001939 <tr>
1940 <td>jp2:number-resolutions=<var>value</var></td>
1941 <td>Sets the number of resolutions to encode.Same for JPT, JC2, and J2K</td>
1942 </tr>
cristyd2432012015-05-04 23:15:15 +00001943
cristy29dc8652015-05-12 16:26:21 +00001944 <tr>
1945 <td>jp2:progression-order=<var>value</var></td>
1946 <td>choose from LRCP, RLCP, RPCL, PCRL or CPRL. Same for JPT, JC2, and
1947 J2K</td>
1948 </tr>
cristyd2432012015-05-04 23:15:15 +00001949
cristy29dc8652015-05-12 16:26:21 +00001950 <tr>
1951 <td>jp2:quality=<var>value,value...</var></td>
1952 <td>Sets the quality layer PSNR, given in dB. The order is from left to
cristyd2432012015-05-04 23:15:15 +00001953 right in ascending order. The default is a single lossless quality layer.
cristy29dc8652015-05-12 16:26:21 +00001954 Same for JPT, JC2, and J2K</td>
1955 </tr>
cristyd2432012015-05-04 23:15:15 +00001956
cristy29dc8652015-05-12 16:26:21 +00001957 <tr>
1958 <td>jp2:rate=<var>value</var></td>
1959 <td>Specify the compression factor to use while writing JPEG-2000 files. The
cristyd2432012015-05-04 23:15:15 +00001960 compression factor is the reciprocal of the compression ratio. The valid
1961 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined,
1962 this value overrides the -quality setting. A quality setting of 75
cristy29dc8652015-05-12 16:26:21 +00001963 results in a rate value of 0.06641. Same for JPT, JC2, and J2K</td>
1964 </tr>
cristyd2432012015-05-04 23:15:15 +00001965
cristy29dc8652015-05-12 16:26:21 +00001966 <tr>
1967 <td>jp2:reduce-factor=<var>value</var></td>
1968 <td>Sets the number of highest resolution levels to be discarded.Same for
1969 JPT, JC2, and J2K</td>
1970 </tr>
cristyd2432012015-05-04 23:15:15 +00001971
cristy29dc8652015-05-12 16:26:21 +00001972 <tr>
1973 <td>jpeg:block-smoothing=<var>on|off</var></td>
cristyd2432012015-05-04 23:15:15 +00001974
cristy29dc8652015-05-12 16:26:21 +00001975 <tr>
1976 <td>jpeg:colors=<var>value</var></td>
1977 <td>Set the desired number of colors and let the JPEG encoder do the
1978 quantizing.</td>
1979 </tr>
cristyd2432012015-05-04 23:15:15 +00001980
cristy29dc8652015-05-12 16:26:21 +00001981 <tr>
1982 <td>jpeg:dct-method=<var>value</var></td>
1983 <td>Choose from <code>default</code>, <code>fastest</code>,
1984 <code>float</code>, <code>ifast</code>, and <code>islow</code>.</td>
1985 </tr>
cristyd2432012015-05-04 23:15:15 +00001986
cristy29dc8652015-05-12 16:26:21 +00001987 <tr>
1988 <td>jpeg:extent=<var>value</var></td>
1989 <td>Restrict the maximum JPEG file size, for example <code>-define
cristyd2432012015-05-04 23:15:15 +00001990 jpeg:extent=400KB</code>. The JPEG encoder will search for the highest
1991 compression quality level that results in an output file that does not
1992 exceed the value. The <code>-quality</code> option is ignored if it
cristy29dc8652015-05-12 16:26:21 +00001993 is also present.</td>
1994 </tr>
cristyd2432012015-05-04 23:15:15 +00001995
cristy29dc8652015-05-12 16:26:21 +00001996 <tr>
1997 <td>jpeg:fancy-upsampling=<var>on|off</var></td>
cristyd2432012015-05-04 23:15:15 +00001998
cristy29dc8652015-05-12 16:26:21 +00001999 <tr>
2000 <td>jpeg:optimize-coding=<var>on|off</var></td>
cristyd2432012015-05-04 23:15:15 +00002001
cristy29dc8652015-05-12 16:26:21 +00002002 <tr>
2003 <td>jpeg:q-table=<var>table</var></td>
cristyd2432012015-05-04 23:15:15 +00002004
cristy29dc8652015-05-12 16:26:21 +00002005 <tr>
2006 <td>jpeg:sampling-factor=<var>sampling-factor-string</var></td>
cristyd2432012015-05-04 23:15:15 +00002007
cristy29dc8652015-05-12 16:26:21 +00002008 <tr>
2009 <td>jpeg:size=<var>geometry</var></td>
2010 <td>Set the size hint of a JPEG image, for
cristyd2432012015-05-04 23:15:15 +00002011 example, <code>-define jpeg:size=128x128</code>.
2012 It is most useful for increasing performance and reducing the memory
cristy29dc8652015-05-12 16:26:21 +00002013 requirements when reducing the size of a large JPEG image.</td>
2014 </tr>
cristyd2432012015-05-04 23:15:15 +00002015
cristy29dc8652015-05-12 16:26:21 +00002016 <tr>
2017 <td>json:features</td>
2018 <td>includes features in verbose information</td>
2019 </tr>
cristyd2432012015-05-04 23:15:15 +00002020
cristy29dc8652015-05-12 16:26:21 +00002021 <tr>
2022 <td>json:limit</td>
cristyd2432012015-05-04 23:15:15 +00002023
cristy29dc8652015-05-12 16:26:21 +00002024 <tr>
2025 <td>json:locate</td>
cristyd2432012015-05-04 23:15:15 +00002026
cristy29dc8652015-05-12 16:26:21 +00002027 <tr>
2028 <td>json:moments</td>
2029 <td>includes image moments in verbose information</td>
2030 </tr>
cristyd2432012015-05-04 23:15:15 +00002031
cristy29dc8652015-05-12 16:26:21 +00002032 <tr>
2033 <td>mng:need-cacheoff</td>
2034 <td>turn playback caching off for streaming MNG.</td>
2035 </tr>
cristyd2432012015-05-04 23:15:15 +00002036
cristy29dc8652015-05-12 16:26:21 +00002037 <tr>
2038 <td>morphology:compose=<var>compose-method</var></td>
2039 <td>Specifies how to merge results generated by multiple<a
2040 href="command-line-options.html#morphology" >-morphology</a> kernel. The default is none. One
cristyd2432012015-05-04 23:15:15 +00002041 typical value is 'lighten' as used, for example, with the sobel edge
cristy29dc8652015-05-12 16:26:21 +00002042 kernels. </td>
2043 </tr>
cristyd2432012015-05-04 23:15:15 +00002044
cristy29dc8652015-05-12 16:26:21 +00002045 <tr>
2046 <td>morphology:showkernel=<var>1</var></td>
2047 <td>Outputs (to 'standard error') all the information about a generated <a
2048 href="command-line-options.html#morphology" >-morphology</a> kernel.</td>
2049 </tr>
cristyd2432012015-05-04 23:15:15 +00002050
cristy29dc8652015-05-12 16:26:21 +00002051 <tr>
2052 <td>pcl:fit-to-page=<var>true</var></td>
cristyd2432012015-05-04 23:15:15 +00002053
cristy29dc8652015-05-12 16:26:21 +00002054 <tr>
2055 <td>pdf:fit-page=<var>geometry</var></td>
2056 <td> geometry specifies the scaling dimensions for resizing when the PDF is
cristyd2432012015-05-04 23:15:15 +00002057 being read. The geometry is either WxH{%} or page size. No offsets are
cristy29dc8652015-05-12 16:26:21 +00002058 allowed. (introduced in IM 6.8.8-8)</td>
2059 </tr>
cristyd2432012015-05-04 23:15:15 +00002060
cristy29dc8652015-05-12 16:26:21 +00002061 <tr>
2062 <td>pdf:fit-to-page=<var>true</var></td>
cristyd2432012015-05-04 23:15:15 +00002063
cristy29dc8652015-05-12 16:26:21 +00002064 <tr>
2065 <td>pdf:use-cropbox=<var>true</var></td>
cristyd2432012015-05-04 23:15:15 +00002066
cristy29dc8652015-05-12 16:26:21 +00002067 <tr>
2068 <td>pdf:use-trimbox=<var>true</var></td>
cristyd2432012015-05-04 23:15:15 +00002069
cristy29dc8652015-05-12 16:26:21 +00002070 <tr>
2071 <td>png:bit-depth=<var>value</var></td>
2072 <tr>
2073 <td>png:color-type=<var>value</var></td>
2074 <td>desired bit-depth and color-type for PNG output. You can force the PNG
cristyd2432012015-05-04 23:15:15 +00002075 encoder to use a different bit-depth and color-type than it would have
2076 normally selected, but only if this does not cause any loss of image
2077 quality. Any attempt to reduce image quality is treated as an error and no
2078 PNG file is written. E.g., if you have a 1-bit black-and-white image, you
2079 can use these "defines" to cause it to be written as an 8-bit grayscale,
2080 indexed, or even a 64-bit RGBA. But if you have a 16-million color image,
2081 you cannot force it to be written as a grayscale or indexed PNG. If you
2082 wish to do this, you must use the appropriate <a href="command-line-options.html#depth">-depth</a>,
2083 <a href="command-line-options.html#colors">-colors</a>, or <a href="command-line-options.html#type">-type</a> directives to
2084 reduce the image quality prior to using the PNG encoder. Note that in
2085 indexed PNG files, "bit-depth" refers to the number of bits per index,
2086 which can be 1, 2, 4, or 8. In such files, the color samples always have
cristy29dc8652015-05-12 16:26:21 +00002087 8-bit depth.</td>
2088 </tr>
cristyd2432012015-05-04 23:15:15 +00002089
cristy29dc8652015-05-12 16:26:21 +00002090 <tr>
2091 <td>png:compression-filter=<var>value</var></td>
2092 <td> valid values are 0 through 9. 0-4 are the corresponding PNG filters,
cristyd2432012015-05-04 23:15:15 +00002093 5 means adaptive filtering except for images with a colormap, 6 means
2094 adaptive filtering for all images, 7 means MNG "loco" compression, 8 means
2095 Z_RLE strategy with adaptive filtering, and 9 means Z_RLE strategy with no
cristy29dc8652015-05-12 16:26:21 +00002096 filtering.</td>
2097 </tr>
cristyd2432012015-05-04 23:15:15 +00002098
cristy29dc8652015-05-12 16:26:21 +00002099 <tr>
2100 <td>png:compression-level=<var>value</var></td>
2101 <td> valid values are 0 through 9, with 0 providing the least but fastest
2102 compression and 9 usually providing the best and always the slowest.</td>
2103 </tr>
cristyd2432012015-05-04 23:15:15 +00002104
cristy29dc8652015-05-12 16:26:21 +00002105 <tr>
2106 <td>png:compression-strategy=<var>value</var></td>
2107 <td> valid values are 0 through 4, meaning default, filtered, huffman_only,
cristyd2432012015-05-04 23:15:15 +00002108 rle, and fixed ZLIB compression strategy. If you are using an old zlib
2109 that does not support Z_RLE (before 1.2.0) or Z_FIXED (before 1.2.2.2),
2110 values 3 and 4, respectively, will use the zlib default strategy
cristy29dc8652015-05-12 16:26:21 +00002111 instead.</td>
2112 </tr>
cristyd2432012015-05-04 23:15:15 +00002113
cristy29dc8652015-05-12 16:26:21 +00002114 <tr>
2115 <td>png:format=<var>value</var></td>
2116 <td> valid values are <var>png8</var>, <var>png24</var>,
cristyd2432012015-05-04 23:15:15 +00002117 <var>png32</var>, <var>png48</var>,
2118 <var>png64</var>, and <var>png00</var>.
2119 This property can be useful for specifying
2120 the specific PNG format to be used, when the usual method of prepending the
2121 format name to the output filename is inconvenient, such as when writing
2122 a PNG-encoded ICO file or when using <a href="mogrify.html">mogrify</a>.
2123 Value = <var>png8</var> reduces the number of colors to 256,
2124 only one of which may be fully transparent, if necessary. The other
2125 values do not force any reduction of quality; it is an error to request
2126 a format that cannot represent the image data without loss (except that
2127 it is allowed to reduce the bit-depth from 16 to 8 for all formats).
2128 Value = <var>png24</var> and <var>png48</var>
2129 allow transparency, only if a single color is fully transparent and that
2130 color does not also appear in an opaque pixel; such transparency is
2131 written in a PNG <code>tRNS</code> chunk.
2132 Value = <var>png00</var> causes the image to inherit its
2133 color-type and bit-depth from the input image, if the input was also
cristy29dc8652015-05-12 16:26:21 +00002134 a PNG.</td>
2135 </tr>
cristyd2432012015-05-04 23:15:15 +00002136
cristy29dc8652015-05-12 16:26:21 +00002137 <tr>
2138 <td>png:exclude-chunk=<var>value</var></td>
cristyd2432012015-05-04 23:15:15 +00002139
cristy29dc8652015-05-12 16:26:21 +00002140 <tr>
2141 <td>png:include-chunk=<var>value</var></td>
2142 <td>ancillary chunks to be excluded from or included in PNG output.
cristyd2432012015-05-04 23:15:15 +00002143
2144 <p>The <var>value</var> can be the name of a PNG chunk-type such
2145 as <var>bKGD</var>, a comma-separated list of chunk-names
2146 (which can include the word <var>date</var>, the word
2147 <var>all</var>, or the word <var>none</var>).
2148 Although PNG chunk-names are case-dependent, you can use all lowercase
2149 names if you prefer.</p>
2150
2151 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior
2152 of the PNG encoder and have no effect on the PNG decoder.</p>
2153
2154 <p>As a special case, if the <code>sRGB</code> chunk is excluded and
2155 the <code>gAMA</code> chunk is included, the <code>gAMA</code> chunk will
2156 only be written if gamma is not 1/2.2, since most decoders assume
2157 sRGB and gamma=1/2.2 when no colorspace information is included in
2158 the PNG file. Because the list is processed from left to right, you
2159 can achieve this with a single define:</p>
2160
2161<pre>
cristy29dc8652015-05-12 16:26:21 +00002162-define png:include-chunk=none,gAMA
cristyd2432012015-05-04 23:15:15 +00002163</pre>
2164
2165 <p>As a special case, if the <code>sRGB</code> chunk is not excluded and
2166 the PNG encoder recognizes that the image contains the sRGB ICC profile,
2167 the PNG encoder will write the <code>sRGB</code> chunk instead of the
2168 entire ICC profile. To force the PNG encoder to write the sRGB
2169 profile as an <code>iCCP</code> chunk in the output PNG instead of the
2170 <code>sRGB</code> chunk, exclude the <code>sRGB</code> chunk.</p>
2171
2172 <p>The critical PNG chunks <code>IHDR</code>, <code>PLTE</code>,
2173 <code>IDAT</code>, and <code>IEND</code> cannot be excluded. Any such
2174 entries appearing in the list will be ignored.</p>
2175
2176 <p>If the ancillary PNG <code>tRNS</code> chunk is excluded and the
2177 image has transparency, the PNG colortype is forced to be 4 or 6
2178 (GRAY_ALPHA or RGBA). If the image is not transparent, then the
2179 <code>tRNS</code> chunk isn't written anyhow, and there is no effect
2180 on the PNG colortype of the output image.</p>
2181
2182 <p>The <a href="command-line-options.html#strip">-strip</a> option does the equivalent of the
2183 following for PNG output:</p>
2184
2185<pre>
cristy29dc8652015-05-12 16:26:21 +00002186-define png:exclude-chunk=EXIF,iCCP,iTXt,sRGB,tEXt,zCCP,zTXt,date
cristyd2432012015-05-04 23:15:15 +00002187</pre>
2188
2189 <p>The default behavior is to include all known PNG ancillary chunks
2190 plus ImageMagick's private <code>vpAg</code> ("virtual page") chunk,
2191 and to exclude all PNG chunks that are unknown to ImageMagick,
2192 regardless of their PNG "copy-safe" status as described in the
2193 PNG specification.</p>
2194
2195 <p>Any chunk names that are not known to ImageMagick are ignored
2196 if they appear in either the "include-chunk" or "exclude-chunk" list.
2197 The ancillary chunks currently known to ImageMagick are
2198 <code>bKGD</code>, <code>cHRM</code>, <code>gAMA</code>, <code>iCCP</code>,
2199 <code>oFFs</code>, <code>pHYs</code>, <code>sRGB</code>, <code>tEXt</code>,
2200 <code>tRNS</code>, <code>vpAg</code>, and <code>zTXt</code>.</p>
2201
2202 <p>You can also put <code>date</code> in the list to include or exclude
2203 the "Date:create" and "Date:modify" text chunks that ImageMagick normally
cristy29dc8652015-05-12 16:26:21 +00002204 inserts in the output PNG.</p></td>
2205 </tr>
cristyd2432012015-05-04 23:15:15 +00002206
cristy29dc8652015-05-12 16:26:21 +00002207 <tr>
2208 <td>png:preserve-colormap[=<var>true</var>]</td>
2209 <td>Use the existing image->colormap. Normally the PNG encoder will
cristyd2432012015-05-04 23:15:15 +00002210 try to optimize the palette, eliminating unused entries and putting
2211 the transparent colors first. If this flag is set, that behavior
cristy29dc8652015-05-12 16:26:21 +00002212 is suppressed.</td>
2213 </tr>
cristyd2432012015-05-04 23:15:15 +00002214
cristy29dc8652015-05-12 16:26:21 +00002215 <tr>
2216 <td>png:preserve-iCCP[=<var>true</var>]</td>
2217 <td>By default, the PNG decoder and encoder examine any ICC profile
cristyd2432012015-05-04 23:15:15 +00002218 that is present, either from an <code>iCCP</code> chunk in the PNG
2219 input or supplied via an option, and if the profile is recognized
2220 to be the sRGB profile, converts it to the <code>sRGB</code> chunk.
2221 You can use <code>-define png:preserve-iCCP</code> to prevent
2222 this from happening; in such cases the <code>iCCP</code> chunk
2223 will be read or written and no <code>sRGB</code> chunk will be
2224 written. There are some ICC profiles that claim to be sRGB but
2225 have various errors that cause them to be rejected by libpng16; such
2226 profiles are recognized anyhow and converted to the <code>sRGB</code>
2227 chunk, but are rejected if the <code>-define png:preserve-iCCP</code>
2228 is present. Note that not all "sRGB" ICC profiles are recognized
cristy29dc8652015-05-12 16:26:21 +00002229 yet; we will add them to the list as we encounter them.</td>
2230 </tr>
cristyd2432012015-05-04 23:15:15 +00002231
cristy29dc8652015-05-12 16:26:21 +00002232 <tr>
2233 <td>png:swap-bytes[=<var>true</var>]</td>
2234 <td>The PNG specification requires that any multi-byte integers be stored in
cristyd2432012015-05-04 23:15:15 +00002235 network byte order (MSB-LSB endian). This option allows you to
2236 fix any invalid PNG files that have 16-bit samples stored incorrectly
2237 in little-endian order (LSB-MSB). The "-define png:swap-bytes" option
2238 must appear before the input filename on the commandline. The swapping
cristy29dc8652015-05-12 16:26:21 +00002239 is done during the libpng decoding operation.</td>
2240 </tr>
cristyd2432012015-05-04 23:15:15 +00002241
cristy29dc8652015-05-12 16:26:21 +00002242 <tr>
2243 <td>profile:skip=<var>name1,name2,...</var></td>
2244 <td>Skip the named profile[s] when reading the image. Use skip="*" to
cristyd2432012015-05-04 23:15:15 +00002245 skip all named profiles in the image. Many named profiles exist,
cristy29dc8652015-05-12 16:26:21 +00002246 including ICC, EXIF, APP1, IPTC, XMP, and others.</td>
2247 </tr>
cristyd2432012015-05-04 23:15:15 +00002248
cristy29dc8652015-05-12 16:26:21 +00002249 <tr>
2250 <td>ps:imagemask</td>
2251 <td>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create
cristyd2432012015-05-04 23:15:15 +00002252 Postscript files that render bilevel images with the Postscript imagemask
cristy29dc8652015-05-12 16:26:21 +00002253 operator instead of the image operator.</td>
2254 </tr>
cristyd2432012015-05-04 23:15:15 +00002255
cristy29dc8652015-05-12 16:26:21 +00002256 <tr>
2257 <td>quantum:format=<var>type</var></td>
2258 <td>Set the type to <code>floating-point</code> to specify a floating-point
cristyd2432012015-05-04 23:15:15 +00002259 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode
2260 to preserve negative values. If <a href="command-line-options.html#depth">-depth</a> 16 is
2261 included, the result is a single precision floating point format.
2262 If <a href="command-line-options.html#depth">-depth</a> 32 is included, the result is
cristy29dc8652015-05-12 16:26:21 +00002263 double precision floating point format.</td>
2264 </tr>
cristyd2432012015-05-04 23:15:15 +00002265
cristy29dc8652015-05-12 16:26:21 +00002266 <tr>
2267 <td>quantum:polarity=<var>photometric-interpretation</var></td>
2268 <td>Set the photometric-interpretation of an image (typically for TIFF image
cristyd2432012015-05-04 23:15:15 +00002269 file format) to either <code>min-is-black</code> (default) or
cristy29dc8652015-05-12 16:26:21 +00002270 <code>min-is-white</code>.</td>
2271 </tr>
cristyd2432012015-05-04 23:15:15 +00002272
cristy29dc8652015-05-12 16:26:21 +00002273 <tr>
2274 <td>sample:offset=<var>geometry</var></td>
2275 <td>Location of the sampling point within the sub-region being sampled,
2276 expressed as percentages (see <a href="command-line-options.html#sample" >-sample</a>).</td>
2277 </tr>
cristyd2432012015-05-04 23:15:15 +00002278
cristy29dc8652015-05-12 16:26:21 +00002279 <tr>
2280 <td>showkernel=<var>1</var></td>
2281 <td>Outputs (to 'standard error') all the information about a generated <a
2282 href="command-line-options.html#morphology" >-morphology</a> kernel.</td>
2283 </tr>
cristyd2432012015-05-04 23:15:15 +00002284
cristy29dc8652015-05-12 16:26:21 +00002285 <tr>
2286 <td>stream:buffer-size=<var>value</var></td>
2287 <td>Set the stream buffer size. Select 0 for unbuffered I/O.</td>
2288 </tr>
cristyd2432012015-05-04 23:15:15 +00002289
cristy29dc8652015-05-12 16:26:21 +00002290 <tr>
2291 <td>tiff:alpha=<var>associated|unassociated|unspecified</var></td>
2292 <td>Specify the alpha extra samples as associated, unassociated or unspecified </td>
2293 </tr>
cristyd2432012015-05-04 23:15:15 +00002294
cristy29dc8652015-05-12 16:26:21 +00002295 <tr>
2296 <td>tiff:endian=<var>msb|lsb</var></td>
cristyd2432012015-05-04 23:15:15 +00002297
cristy29dc8652015-05-12 16:26:21 +00002298 <tr>
2299 <td>tiff:exif-properties=<var>false</var></td>
2300 <td>Skips reading the EXIF properties.</td>
2301 </tr>
cristyd2432012015-05-04 23:15:15 +00002302
cristy29dc8652015-05-12 16:26:21 +00002303 <tr>
2304 <td>tiff:fill-order=<var>msb|lsb</var></td>
cristyd2432012015-05-04 23:15:15 +00002305
cristy29dc8652015-05-12 16:26:21 +00002306 <tr>
2307 <td>tiff:ignore-tags=<var>comma-separate-list-of-tag-IDs</var></td>
2308 <td>Allows one or more tag ID values to be ignored.</td>
2309 </tr>
cristyd2432012015-05-04 23:15:15 +00002310
cristy29dc8652015-05-12 16:26:21 +00002311 <tr>
2312 <td>tiff:rows-per-strip=<var>value</var></td>
2313 <td>Sets the number of rows per strip</td>
2314 </tr>
cristyd2432012015-05-04 23:15:15 +00002315
cristy29dc8652015-05-12 16:26:21 +00002316 <tr>
2317 <td>tiff:tile-geometry=<var>WxH</var></td>
2318 <td>Sets the tile size for pyramid tiffs. Requires the suffix
2319 PTIF: before the outputname</td>
2320 </tr>
2321</table>
cristyd2432012015-05-04 23:15:15 +00002322
2323<p>For example, to create a postscript file that will render only the black
2324pixels of a bilevel image, use:</p>
2325
2326<pre>
2327convert bilevel.tif -define ps:imagemask eps3:stencil.ps
2328</pre>
2329
2330<p>Set attributes of the image registry by prefixing the value with
2331<code>registry:</code>. For example, to set a temporary path to put work files,
2332use:</p>
2333
cristy29dc8652015-05-12 16:26:21 +00002334<pre>
cristyd2432012015-05-04 23:15:15 +00002335-define registry:temporary-path=/data/tmp
cristy29dc8652015-05-12 16:26:21 +00002336</pre>
cristyd2432012015-05-04 23:15:15 +00002337
2338<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002339 <h3 class="magick-header"><a id="delay"></a>-delay <var>ticks</var> <br />-delay <var>ticks</var>x<var>ticks-per-second</var> {<var>&lt;</var>} {<var>&gt;</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00002340</div>
2341
2342<p class="magick-description">display the next image after pausing.</p>
2343
2344<p>This option is useful for regulating the animation of image sequences
2345<var>ticks/ticks-per-second</var> seconds must expire before the display of the
2346next image. The default is no delay between each showing of the image
2347sequence. The default ticks-per-second is 100.</p>
2348
2349<p>Use <code>&gt;</code> to change the image delay <var>only</var> if its current
2350value exceeds the given delay. <code>&lt;</code> changes the image delay
2351<var>only</var> if current value is less than the given delay. For example, if
2352you specify <code>30&gt;</code> and the image delay is 20, the image delay does
2353not change. However, if the image delay is 40 or 50, the delay it is changed
2354to 30. Enclose the given delay in quotation marks to prevent the
2355<code>&lt;</code> or <code>&gt;</code> from being interpreted by your shell as
2356a file redirection.</p>
2357
2358
2359<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002360 <h3 class="magick-header"><a id="delete"></a>-delete <var>indexes</var></h3>
cristyd2432012015-05-04 23:15:15 +00002361</div>
2362
2363<p class="magick-description">delete the images specified by index, from the image sequence.</p>
2364
2365<p>Specify the image by its index in the sequence. The first image is index
23660. Negative indexes are relative to the end of the sequence, for example, -1
2367represents the last image of the sequence. Specify a range of images with
2368a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use
2369<code>+delete</code> to delete the last image in the current image sequence.</p>
2370
2371
2372<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002373 <h3 class="magick-header"><a id="density"></a>-density <var>width</var><br />-density <var>width</var>x<var>height</var></h3>
cristyd2432012015-05-04 23:15:15 +00002374</div>
2375
2376<p class="magick-description">Set the horizontal and vertical resolution of an image for rendering to devices.</p>
2377
2378<p>This option specifies the image resolution to store while encoding a raster
2379image or the canvas resolution while rendering (reading) vector formats such
2380as Postscript, PDF, WMF, and SVG into a raster image. Image resolution
2381provides the unit of measure to apply when rendering to an output device or
cristy29dc8652015-05-12 16:26:21 +00002382raster image. The default unit of measure is in dots per inch (DPI). The <a
2383href="command-line-options.html#units">-units</a> option may be used to select dots per centimeter
cristyd2432012015-05-04 23:15:15 +00002384instead.</p>
2385
2386<p>The default resolution is 72 dots per inch, which is equivalent to one
2387point per pixel (Macintosh and Postscript standard). Computer screens are
2388normally 72 or 96 dots per inch, while printers typically support 150, 300,
2389600, or 1200 dots per inch. To determine the resolution of your display, use
2390a ruler to measure the width of your screen in inches, and divide by the
2391number of horizontal pixels (1024 on a 1024x768 display).</p>
2392
2393<p>If the file format supports it, this option may be used to update the
2394stored image resolution. Note that Photoshop stores and obtains image
2395resolution from a proprietary embedded profile. If this profile is not
2396stripped from the image, then Photoshop will continue to treat the image using
2397its former resolution, ignoring the image resolution specified in the standard
2398file header.</p>
2399
2400<p>The <a href="command-line-options.html#density">-density</a> option sets an <var>attribute</var> and
2401does not alter the underlying raster image. It may be used to adjust the
2402rendered size for desktop publishing purposes by adjusting the scale applied
2403to the pixels. To resize the image so that it is the same size at a different
2404resolution, use the <a href="command-line-options.html#resample">-resample</a> option.</p>
2405
2406<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002407 <h3 class="magick-header"><a id="depth"></a>-depth <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00002408</div>
2409
2410<p class="magick-description">depth of the image.</p>
2411
2412<p>This the number of bits in a color sample within a pixel. Use this option
2413to specify the depth of raw images whose depth is unknown such as GRAY, RGB,
2414or CMYK, or to change the depth of any image after it has been read.</p>
2415
2416<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002417 <h3 class="magick-header"><a id="descend"></a>-descend</h3>
cristyd2432012015-05-04 23:15:15 +00002418</div>
2419
2420<p class="magick-description">obtain image by descending window hierarchy.</p>
2421
2422<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002423 <h3 class="magick-header"><a id="deskew"></a>-deskew <var>threshold</var></h3>
cristyd2432012015-05-04 23:15:15 +00002424</div>
2425
2426<p class="magick-description">straighten an image. A threshold of 40% works for most images.</p>
2427
2428<p>Use <a href="command-line-options.html#set">-set</a> <code>option:deskew:auto-crop
2429<var>width</var></code> to auto crop the image. The set argument is the pixel
2430width of the image background (e.g 40).</p>
2431
2432<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002433 <h3 class="magick-header"><a id="despeckle"></a>-despeckle</h3>
cristyd2432012015-05-04 23:15:15 +00002434</div>
2435
2436<p class="magick-description">reduce the speckles within an image.</p>
2437
2438<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002439 <h3 class="magick-header"><a id="direction"></a>-direction <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00002440</div>
2441
2442<p class="magick-description">render text right-to-left or left-to-right.</p>
2443
2444<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002445 <h3 class="magick-header"><a id="displace"></a>-displace <var>horizontal-scale</var><br />-displace <var>horizontal-scale</var>x<var>vertical-scale</var></h3>
cristyd2432012015-05-04 23:15:15 +00002446</div>
2447
2448<p class="magick-description">shift image pixels as defined by a displacement map.</p>
2449
2450<p>With this option, the 'overlay' image, and optionally the 'mask' image,
2451is used as a displacement map, which is used to displace the lookup of
2452what part of the 'background' image is seen at each point of the overlaid
2453area. Much like the displacement map is a 'lens' that redirects light shining
2454through it so as to present a distorted view the original 'background' image
2455behind it. </p>
2456
2457<p>Any perfect grey areas of the displacement map produce a zero
2458displacement of the image. Black areas produce the given maximum negative
2459displacement of the lookup point, while white produce a maximum positive
2460displacement of the lookup. </p>
2461
2462<p>Note that it is the lookup of the 'background' that is displaced, not a
2463displacement of the image itself. As such an area of the displacement map
2464containing 'white' will have the lookup point 'shifted' by a positive amount,
2465and thus generating a copy of the destination image to the right/downward from
2466the correct position. That is the image will look like it may have been
2467'shifted' in a negative left/upward direction. Understanding this is a very
2468important in understanding how displacement maps work. </p>
2469
2470<p>The given arguments define the maximum amount of displacement in pixels
2471that a particular map can produce. If the displacement scale is large enough
2472it is also possible to lookup parts of the 'background' image that lie well
2473outside the bounds of the displacement map itself. That is you could very
2474easily copy a section of the original image from outside the overlay area
2475into the overlay area. </p>
2476
2477<p>The '%' flag makes the displacement scale relative to the size of the
2478overlay image (100% = half width/height of image). Using '!' switches
2479percentage arguments to refer to the destination image size instead.
2480these flags were added as of IM v6.5.3-5.</p>
2481
2482<p>Normally a single grayscale displacement map is provided, which with the
2483given scaling values will determine a single direction (vector) in which
2484displacements can occur (positively or negatively). However, if you also
2485specify a third image which is normally used as a <var>mask</var>,
2486the <var>composite image</var> is used for horizontal X
2487displacement, while the <var>mask image</var> is used for vertical Y
2488displacement. This allows you to define completely different displacement
2489values for the X and Y directions, and allowing you to lookup any point within
2490the <var>scale</var> bounds. In other words each pixel can lookup
2491any other nearby pixel, producing complex 2 dimensional displacements, rather
2492than a simple 1 dimensional vector displacements. </p>
2493
2494<p>Alternatively rather than supplying two separate images, as of IM v6.4.4-0,
2495you can use the 'red' channel of the overlay image to specify the horizontal
2496or X displacement, and the 'green' channel for the vertical or Y displacement.
2497</p>
2498
2499<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a
2500mask the transparency of the destination image. However areas outside the
2501overlaid areas will not be effected. </p>
2502
2503
2504<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002505 <h3 class="magick-header"><a id="display"></a>-display <var>host:display[.screen]</var></h3>
cristyd2432012015-05-04 23:15:15 +00002506</div>
2507
2508<p class="magick-description">Specifies the X server to contact.</p>
2509
2510<p>This option is used with convert for obtaining image or font from this
2511X server. See <var>X(1)</var>.</p>
2512
2513<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002514 <h3 class="magick-header"><a id="dispose"></a>-dispose <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00002515</div>
2516
2517<p class="magick-description">define the GIF disposal image setting for images that are being created or read in. </p>
2518
2519<p>The layer disposal method defines the way each the displayed image is to be
2520modified after the current 'frame' of an animation has finished being
2521displayed (after its 'delay' period), but before the next frame on an
2522animation is to be overlaid onto the display. </p>
2523
2524<p>Here are the valid methods:</p>
2525
cristy29dc8652015-05-12 16:26:21 +00002526<dl class="dl-horizontal">
2527<dt>Undefined</dt><dd>0: No disposal specified (equivalent to '<code>none</code>').</dd>
2528<dt>None</dt><dd>1: Do not dispose, just overlay next frame image.</dd>
2529<dt>Background</dt><dd>2: Clear the frame area with the background color.</dd>
2530<dt>Previous</dt><dd>3: Clear to the image prior to this frames overlay.</dd>
2531</dl>
cristyd2432012015-05-04 23:15:15 +00002532
2533<p>You can also use the numbers given above, which is what the GIF format
2534uses internally to represent the above settings. </p>
2535
2536<p>To print a complete list of dispose methods, use <a href="command-line-options.html#list">-list dispose</a>.</p>
2537
cristy29dc8652015-05-12 16:26:21 +00002538<p>Use <a href="command-line-options.html#dispose" >+dispose</a>, turn off the setting and prevent
cristyd2432012015-05-04 23:15:15 +00002539resetting the layer disposal methods of images being read in. </p>
2540
2541<p>Use <a href="command-line-options.html#set">-set</a> '<code>dispose</code>' method to set the image
2542disposal method for images already in memory.</p>
2543
2544<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002545 <h3 class="magick-header"><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00002546</div>
2547
2548<p class="magick-description">maximum RMSE for subimage match (default 0.2).</p>
2549
2550
2551<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002552 <h3 class="magick-header"><a id="dissolve"></a>-dissolve <var>src_percent</var>[x<var>dst_percent</var>]</h3>
cristyd2432012015-05-04 23:15:15 +00002553</div>
2554
2555<p class="magick-description">dissolve an image into another by the given percent.</p>
2556
2557<p>The opacity of the composite image is multiplied by the given percent, then
2558it is composited 'over' the main image. If <var>src_percent</var>
2559is greater than 100, start dissolving the main image so it becomes
2560transparent at a value of '<code>200</code>'. If both percentages
2561are given, each image are dissolved to the percentages given. </p>
2562
2563<p>Note that dissolve percentages do not add, two opaque images dissolved
2564'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2565images, you would need to use dissolve values of '50,100'. </p>
2566
2567<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002568 <h3 class="magick-header"><a id="distort"></a>-distort <var>method arguments</var></h3>
cristyd2432012015-05-04 23:15:15 +00002569</div>
2570
2571<p class="magick-description">distort an image, using the given <var>method</var> and its required <var>arguments</var>.</p>
2572
2573<p>The <var>arguments</var> is a single string containing a list
2574of floating point numbers separated by commas or spaces. The number of
2575and meaning of the floating point values depends on the distortion <var>method</var> being used. </p>
2576
2577<p>Choose from these distortion types:</p>
2578
2579<table class="table table-condensed table-striped">
2580 <tr>
2581 <th style="width: 8%">Method</th>
2582 <th>Description</th>
2583 </tr>
2584
2585 <tr>
2586 <td><code>ScaleRotateTranslate</code>
cristy29dc8652015-05-12 16:26:21 +00002587 <br/>or <code>SRT</code></td>
cristyd2432012015-05-04 23:15:15 +00002588 <td>
2589 Distort image by first scaling and rotating about a given 'center',
2590 before translating that 'center' to the new location, in that order. It
2591 is an alternative method of specifying a '<code>Affine</code>' type of
2592 distortion, but without shearing effects. It also provides a good way
2593 of rotating and displacing a smaller image for tiling onto a larger
cristy29dc8652015-05-12 16:26:21 +00002594 background (IE 2-dimensional animations). <br/>
cristyd2432012015-05-04 23:15:15 +00002595
2596 The number of arguments determine the specific meaning of each
cristy29dc8652015-05-12 16:26:21 +00002597 argument for the scales, rotation, and translation operations. <br/>
cristyd2432012015-05-04 23:15:15 +00002598
cristy29dc8652015-05-12 16:26:21 +00002599 <table class="table table-condensed table-striped">
cristyd2432012015-05-04 23:15:15 +00002600 <tr><td>2:</td><td><var>Scale Angle</var></td></tr>
2601 <tr><td>3:</td><td><var>X,Y Angle</var></td></tr>
2602 <tr><td>4:</td><td><var>X,Y Scale Angle</var></td></tr>
2603 <tr><td>5:</td>
2604 <td><var>X,Y ScaleX,ScaleY Angle</var></td></tr>
2605 <tr><td>6:</td>
2606 <td><var>X,Y Scale Angle NewX,NewY</var></td></tr>
2607 <tr><td>7:</td>
2608 <td><var>X,Y ScaleX,ScaleY Angle
2609 NewX,NewY</var></td></tr>
2610 </table>
2611
2612 This is actually an alternative way of specifying a 2 dimensional linear
2613 '<code>Affine</code>' or '<code>AffineProjection</code>' distortion. </td> </tr>
2614
2615 <tr>
2616 <td><code>Affine</code></td>
2617 <td>
2618 Distort the image linearly by moving a list of at least 3 or more sets
2619 of control points (as defined below). Ideally 3 sets or 12 floating
2620 point values are given allowing the image to be linearly scaled,
2621 rotated, sheared, and translated, according to those three points. See
2622 also the related '<code>AffineProjection</code>' and '<code>SRT</code>'
cristy29dc8652015-05-12 16:26:21 +00002623 distortions. <br/>
cristyd2432012015-05-04 23:15:15 +00002624
2625 More than 3 sets given control point pairs (12 numbers) is least
2626 squares fitted to best match a linear affine distortion. If only 2
2627 control point pairs (8 numbers) are given a two point image translation
2628 rotation and scaling is performed, without any possible shearing,
2629 flipping or changes in aspect ratio to the resulting image. If only one
2630 control point pair is provides the image is only translated, (which may
cristy29dc8652015-05-12 16:26:21 +00002631 be a floating point non-integer translation). <br/>
cristyd2432012015-05-04 23:15:15 +00002632
2633 This distortion does not include any form of perspective distortion.
2634 </td>
2635
2636 </tr>
2637
2638 <tr>
2639 <td><code>AffineProjection</code></td>
2640 <td>
2641 Linearly distort an image using the given Affine Matrix of 6
2642 pre-calculated coefficients forming a set of Affine Equations to map
2643 the source image to the destination image.
2644
2645 <div style="text-align: center"><var>
2646 s<sub>x</sub>, r<sub>x</sub>,
2647 r<sub>y</sub>, s<sub>y</sub>,
2648 t<sub>x</sub>, t<sub>y</sub>
2649 </var></div>
2650
cristy29dc8652015-05-12 16:26:21 +00002651 See <a href="command-line-options.html#affine" >-affine</a> setting for more detail, and
2652 meanings of these coefficients. <br/>
cristyd2432012015-05-04 23:15:15 +00002653
2654 The distortions '<code>Affine</code>' and '<code>SRT</code>' provide
2655 alternative methods of defining this distortion, with ImageMagick doing
2656 the calculations needed to generate the required coefficients. You can
cristy29dc8652015-05-12 16:26:21 +00002657 see the internally generated coefficients, by using a <a
2658 href="command-line-options.html#verbose" >-verbose</a> setting with those other variants. </td>
cristyd2432012015-05-04 23:15:15 +00002659
2660 </tr>
2661
2662 <tr>
cristy29dc8652015-05-12 16:26:21 +00002663 <td><code>BilinearForward</code><br/>
cristyd2432012015-05-04 23:15:15 +00002664 <code>BilinearReverse</code></td>
2665 <td>
2666 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
2667 16 values (see below). Not that lines may not appear straight after
2668 distortion, though the distance between coordinates will remain
cristy29dc8652015-05-12 16:26:21 +00002669 consistent. <br/>
cristyd2432012015-05-04 23:15:15 +00002670
2671 The '<code>BilinearForward</code>' is used to map rectangles to any
2672 quadrilateral, while the '<code>BilinearReverse</code>' form maps any
2673 quadrilateral to a rectangle, while preserving the straight line edges
cristy29dc8652015-05-12 16:26:21 +00002674 in each case. <br/>
cristyd2432012015-05-04 23:15:15 +00002675
2676 Note that '<code>BilinearForward</code>' can generate invalid pixels
cristy29dc8652015-05-12 16:26:21 +00002677 which will be colored using the <a href="command-line-options.html#mattecolor" >-mattecolor</a>
cristyd2432012015-05-04 23:15:15 +00002678 color setting. Also if the quadrilateral becomes 'flipped' the image
cristy29dc8652015-05-12 16:26:21 +00002679 may disappear. <br/>
cristyd2432012015-05-04 23:15:15 +00002680
2681 There are future plans to produce a true Bilinear distortion that will
2682 attempt to map any quadrilateral to any other quadrilateral, while
2683 preserving edges (and edge distance ratios).
2684
2685 </td>
2686 </tr>
2687
2688 <tr>
2689 <td><code>Perspective</code></td>
2690 <td>
2691 Perspective distort the images, using a list of 4 or more sets of
2692 control points (as defined below). More that 4 sets (16 numbers) of
2693 control points provide least squares fitting for more accurate
2694 distortions (for the purposes of image registration and panorama
2695 effects). Less than 4 sets will fall back to a '<code>Affine</code>'
cristy29dc8652015-05-12 16:26:21 +00002696 linear distortion. <br/>
cristyd2432012015-05-04 23:15:15 +00002697
2698 Perspective Distorted images ensures that straight lines remain
2699 straight, but the scale of the distorted image will vary. The horizon
2700 is anti-aliased, and the 'sky' color may be set using the
cristy29dc8652015-05-12 16:26:21 +00002701 <a href="command-line-options.html#mattecolor" >-mattecolor</a> setting. </td>
cristyd2432012015-05-04 23:15:15 +00002702 </tr>
2703
2704 <tr>
2705 <td><code>PerspectiveProjection</code> </td>
2706 <td>
2707 Do a '<code>Perspective</code>' distortion biased on a set of 8
2708 pre-calculated coefficients. You can get these coefficients by looking
cristy29dc8652015-05-12 16:26:21 +00002709 at the <a href="command-line-options.html#verbose" >-verbose</a> output of a
cristyd2432012015-05-04 23:15:15 +00002710 '<code>Perspective</code>' distortion, or by calculating them yourself.
2711 If the last two perspective scaling coefficients are zero, the
2712 remaining 6 represents a transposed 'Affine Matrix'. </td>
2713
2714 </tr>
2715
2716 <tr>
2717 <td><code>Arc</code></td>
2718 <td>
2719 Arc the image (variation of polar mapping) over the angle given around
cristy29dc8652015-05-12 16:26:21 +00002720 a circle. <br/>
2721 <table class="table table-condensed table-striped">
cristyd2432012015-05-04 23:15:15 +00002722 <tr><td>Argument</td>
2723 <td>Meaning</td></tr>
2724 <tr><td><var>arc_angle</var></td>
2725 <td>The angle over which to arc the image side-to-side</td></tr>
2726 <tr><td><var>rotate_angle</var></td>
2727 <td>Angle to rotate resulting image from vertical center</td></tr>
2728 <tr><td><var>top_radius</var></td>
2729 <td>Set top edge of source image at this radius</td></tr>
2730 <tr><td><var>bottom_radius</var> </td>
2731 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2732 </table>
2733
2734 The resulting image is always resized to best fit the resulting image,
cristy29dc8652015-05-12 16:26:21 +00002735 (as if using <a href="command-line-options.html#distort" >+distort</a>) while attempting to
cristyd2432012015-05-04 23:15:15 +00002736 preserve scale and aspect ratio of the original image as much as
2737 possible with the arguments given by the user. All four arguments will
cristy29dc8652015-05-12 16:26:21 +00002738 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
cristyd2432012015-05-04 23:15:15 +00002739
2740 This a variation of a polar distortion designed to try to preserve the
2741 aspect ratio of the image rather than direct Cartesian to Polar
2742 conversion. </td>
2743 </tr>
2744
2745 <tr>
2746 <td><code>Polar</code></td>
2747 <td>
2748 Like '<code>Arc</code>' but do a complete Cartesian to Polar mapping of
2749 the image. that is the height of the input image is mapped to the
2750 radius limits, while the width is wrapped around between the
cristy29dc8652015-05-12 16:26:21 +00002751 angle limits. <br/>
cristyd2432012015-05-04 23:15:15 +00002752
cristy29dc8652015-05-12 16:26:21 +00002753 Arguments: <var>Rmax,Rmin CenterX,CenterY, start,end_angle</var> <br/>
cristyd2432012015-05-04 23:15:15 +00002754
2755 All arguments are optional. With <var>Rmin</var> defaulting to zero, the
2756 center to the center of the image, and the angles going from -180 (top)
2757 to +180 (top). If <var>Rmax</var> is given the special value of
2758 '<code>0</code>', the the distance from the center to the nearest edge
2759 is used for the radius of the output image, which will ensure the whole
2760 image is visible (though scaled smaller). However a special value of
2761 '<code>-1</code>' will use the distance from the center to the furthest
2762 corner, This may 'clip' the corners from the input rectangular image,
2763 but will generate the exact reverse of a '<code>DePolar</code>' with
cristy29dc8652015-05-12 16:26:21 +00002764 the same arguments. <br/>
cristyd2432012015-05-04 23:15:15 +00002765
cristy29dc8652015-05-12 16:26:21 +00002766 If the plus form of distort (<a href="command-line-options.html#distort" >+distort</a>) is used
cristyd2432012015-05-04 23:15:15 +00002767 output image center will default to <code>0,0</code> of the virtual
2768 canvas, and the image size adjusted to ensure the whole input image is
2769 made visible in the output image on the virtual canvas. </td>
2770
2771 </tr>
2772
2773 <tr>
2774 <td><code>DePolar</code></td>
2775 <td>
2776 Uses the same arguments and meanings as a '<code>Polar</code>' distortion
cristy29dc8652015-05-12 16:26:21 +00002777 but generates the reverse Polar to Cartesian distortion. <br/>
cristyd2432012015-05-04 23:15:15 +00002778
2779 The special <var>Rmax</var> setting of '<code>0</code>' may however clip
2780 the corners of the input image. However using the special
2781 <var>Rmax</var> setting of '<code>-1</code>' (maximum center to corner
2782 distance) will ensure the whole distorted image is preserved in the
2783 generated result, so that the same argument to '<code>Polar</code>' will
2784 reverse the distortion re-producing the original.
2785
2786 Note that as this distortion requires the area resampling of a circular
2787 arc, which can not be handled by the builtin EWA resampling function.
2788 As such the normal EWA filters are turned off. It is recommended some
2789 form of 'super-sampling' image processing technique be used to produce
2790 a high quality result. </td>
2791
2792 </tr>
2793
2794 <tr>
2795 <td><code>Barrel</code></td>
2796 <td>
cristy29dc8652015-05-12 16:26:21 +00002797 Given the four coefficients (A,B,C,D) as defined by <a
2798 href="http://wiki.panotools.org/Lens_correction_model" >Helmut
cristyd2432012015-05-04 23:15:15 +00002799 Dersch</a>, perform a barrel or pin-cushion distortion appropriate to
2800 correct radial lens distortions. That is in photographs, make straight
cristy29dc8652015-05-12 16:26:21 +00002801 lines straight again. <br/>
cristyd2432012015-05-04 23:15:15 +00002802
2803 Arguments: <var>A B C</var> [ <var>D</var> [
cristy29dc8652015-05-12 16:26:21 +00002804 <var>X</var> , <var>Y</var> ] ] <br/>
cristyd2432012015-05-04 23:15:15 +00002805 or <var>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub>
2806 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></var>
cristy29dc8652015-05-12 16:26:21 +00002807 [ <var>X</var> , <var>Y</var> ] <br/>
2808 So that it forms the function <br/>
cristyd2432012015-05-04 23:15:15 +00002809 Rsrc = r * ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
cristy29dc8652015-05-12 16:26:21 +00002810 <var>C</var>*r + <var>D</var> )<br/>
cristyd2432012015-05-04 23:15:15 +00002811
2812 Where <var>X</var>,<var>Y</var> is the optional center of the distortion
cristy29dc8652015-05-12 16:26:21 +00002813 (defaulting to the center of the image). <br/>
cristyd2432012015-05-04 23:15:15 +00002814 The second form is typically used to distort images, rather than
cristy29dc8652015-05-12 16:26:21 +00002815 correct lens distortions. <br/>
cristyd2432012015-05-04 23:15:15 +00002816 </td>
2817
2818 </tr>
2819
2820 <tr>
2821 <td><code>BarrelInverse</code></td>
2822 <td>
2823 This is very similar to '<code>Barrel</code>' with the same set of
2824 arguments, and argument handling. However it uses the inverse
2825 of the radial polynomial,
cristy29dc8652015-05-12 16:26:21 +00002826 so that it forms the function <br/>
cristyd2432012015-05-04 23:15:15 +00002827 Rsrc = r / ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
cristy29dc8652015-05-12 16:26:21 +00002828 <var>C</var>*r + <var>D</var> )<br/>
cristyd2432012015-05-04 23:15:15 +00002829 Note that this is not the reverse of the '<code>Barrel</code>'
2830 distortion, just a different barrel-like radial distortion method.
2831
2832 </td>
2833 </tr>
2834
2835 <tr>
2836 <td><code>Shepards</code></td>
2837 <td>
2838 Distort the given list control points (any number) using an Inverse
cristy29dc8652015-05-12 16:26:21 +00002839 Squared Distance Interpolation Method (<a
2840 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards
cristyd2432012015-05-04 23:15:15 +00002841 Method</a>). The control points in effect do 'localized' displacement
2842 of the image around the given control point (preserving the look and
2843 the rotation of the area near the control points. For best results
2844 extra control points should be added to 'lock' the positions of the
2845 corners, edges and other unchanging parts of the image, to prevent
cristy29dc8652015-05-12 16:26:21 +00002846 their movement. <br/>
cristyd2432012015-05-04 23:15:15 +00002847
2848 The distortion has been likened to 'taffy pulling' using nails, or
2849 pins' stuck in a block of 'jelly' which is then moved to the new
cristy29dc8652015-05-12 16:26:21 +00002850 position, distorting the surface of the jelly. <br/>
cristyd2432012015-05-04 23:15:15 +00002851
cristy29dc8652015-05-12 16:26:21 +00002852 Internally it is equivalent to generating a displacement map (see <a
2853 href="command-line-options.html#displace" >-displace</a>) for source image color look-up using
2854 the <a href="command-line-options.html#sparse-color" >-sparse-color</a> method of the same name.
cristyd2432012015-05-04 23:15:15 +00002855
2856 </td>
2857 </tr>
2858
2859</table>
2860
2861<p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list
2862distort</a>.</p>
2863
2864<p>Many of the above distortion methods such as '<code>Affine</code>',
2865'<code>Perspective</code>', and '<code>Shepards</code>' use a list control points
2866defining how these points in the given image should be distorted in the
2867destination image. Each set of four floating point values represent a source
2868image coordinate, followed immediately by the destination image coordinate.
2869This produces a list of values such as...</p>
2870<div style="text-align: center"><var>
2871 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub>
2872 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub>
2873 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub>
2874 ...
2875 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub>
2876</var></div>
2877<p>where <var>U,V</var> on the source image is mapped to <var>X,Y</var> on the
2878destination image. </p>
2879
2880<p>For example, to warp an image using '<code>perspective</code>' distortion,
2881needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2882perspective distortion of the built-in "rose:" image. Note how spaces were
2883used to group the 4 sets of coordinate pairs, to make it easier to read and
2884understand.</p>
2885
2886<pre>
2887convert rose: -virtual-pixel black \
cristy29dc8652015-05-12 16:26:21 +00002888 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \
2889 rose_3d_rotated.gif"
cristyd2432012015-05-04 23:15:15 +00002890</pre>
2891
2892<p>If more that the required number of coordinate pairs are given for
2893a distortion, the distortion method is 'least squares' fitted to produce the
2894best result for all the coordinate pairs given. If less than the ideal number
2895of points are given, the distort will generally fall back to a simpler form of
2896distortion that can handles the smaller number of coordinates (usually a linear
2897'<code>Affine</code>' distortion). </p>
2898
2899<p>By using more coordinates you can make use of image registration tool to
2900find matching coordinate pairs in overlapping images, so as to improve the
2901'fit' of the distortion. Of course a bad coordinate pair can also make the
2902'fit' worse. Caution is always advised. </p>
2903
2904<p>Colors are acquired from the source image according to a cylindrical
cristy29dc8652015-05-12 16:26:21 +00002905resampling <a href="command-line-options.html#filter" >-filter</a>, using a special technique known as
cristyd2432012015-05-04 23:15:15 +00002906EWA resampling. This produces very high quality results, especially when
2907images become smaller (minified) in the output, which is very common when
2908using '<code>perspective</code>' distortion. For example here we view
2909a infinitely tiled 'plane' all the way to the horizon. </p>
2910
2911<pre>
2912convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \
cristy29dc8652015-05-12 16:26:21 +00002913 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \
2914 checks_tiled.jpg
cristyd2432012015-05-04 23:15:15 +00002915</pre>
2916
2917<p>Note that a infinitely tiled perspective images involving the horizon can
2918be very slow, because of the number of pixels that are compressed to generate
2919each individual pixel close to the 'horizon'. You can turn off EWA
cristy29dc8652015-05-12 16:26:21 +00002920resampling, by specifing the special <a href="command-line-options.html#filter" >-filter</a> setting of
cristyd2432012015-05-04 23:15:15 +00002921'<code>point</code>' (recommended if you plan to use super-sampling instead).
2922</p>
2923
2924<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
cristy29dc8652015-05-12 16:26:21 +00002925example, <a href="command-line-options.html#distort" >-distort</a> will use the current <a
2926href="command-line-options.html#mattecolor" >-mattecolor</a> setting for these pixels. If you do not
cristyd2432012015-05-04 23:15:15 +00002927what these pixels to be visible, set the color to match the rest of the
2928ground. </p>
2929
2930<p>The output image size will by default be the same as the input image. This
2931means that if the part of the distorted image falls outside the viewed area of
2932the 'distorted space', those parts is clipped and lost. However if you use
cristy29dc8652015-05-12 16:26:21 +00002933the plus form of the operator (<a href="command-line-options.html#distort" >+distort</a>) the operator
cristyd2432012015-05-04 23:15:15 +00002934will attempt (if possible) to show the whole of the distorted image, while
2935retaining a correct 'virtual canvas' offset, for image layering. This offset
cristy29dc8652015-05-12 16:26:21 +00002936may need to be removed using <a href="command-line-options.html#repage" >+repage</a>, to remove if it
cristyd2432012015-05-04 23:15:15 +00002937is unwanted. </p>
2938
cristy29dc8652015-05-12 16:26:21 +00002939<p>Setting <a href="command-line-options.html#verbose" >-verbose</a> setting, will cause <a
2940href="command-line-options.html#distort" >-distort</a> to attempt to output the internal coefficients,
2941and the <a href="command-line-options.html#fx" >-fx</a> equivalent to the distortion, for expert study,
cristyd2432012015-05-04 23:15:15 +00002942and debugging purposes. This many not be available for all distorts. </p>
2943
cristy29dc8652015-05-12 16:26:21 +00002944<p>You can alternatively specify a special "<code><a href="command-line-options.html#define"
2945>-define</a> distort:viewport={geometry_string}</code>" setting which will
cristyd2432012015-05-04 23:15:15 +00002946specify the size and the offset of the generated 'viewport' image of the
2947distorted image space.</p>
2948
cristy29dc8652015-05-12 16:26:21 +00002949<p>Setting a "<code><a href="command-line-options.html#define" >-define</a>
cristyd2432012015-05-04 23:15:15 +00002950distort:scale={scale_factor}</code>" will scale the output image (viewport or
2951otherwise) by that factor without changing the viewed contents of the
2952distorted image. This can be used either for 'super-sampling' the image for
2953a higher quality result, or for panning and zooming around the image (with
2954appropriate viewport changes, or post-distort cropping and resizing). </p>
2955
cristy29dc8652015-05-12 16:26:21 +00002956<p>Setting "<code><a href="command-line-options.html#define" >-define</a> resample:verbose=1</code>"
cristyd2432012015-05-04 23:15:15 +00002957will output the cylindrical filter lookup table created by the EWA (Elliptical
2958Weighted Average) resampling algorithm. Note this table uses a squared radius
2959lookup value. This is typically only used for debugging EWA resampling. </p>
2960
2961
2962<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002963 <h3 class="magick-header"><a id="distribute-cache"></a>-distribute-cache <var>port</var></h3>
cristyd2432012015-05-04 23:15:15 +00002964</div>
2965
2966<p class="magick-description">launch a distributed pixel cache server. </p>
2967
2968<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00002969 <h3 class="magick-header"><a id="dither"></a>-dither <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00002970</div>
2971
2972<p class="magick-description">Apply a Riemersma or Floyd-Steinberg error diffusion dither to
2973images when general color reduction is applied via an option, or automagically
2974when saving to specific formats. This enabled by default.</p>
2975
2976<p>Dithering places two or more colors in neighboring pixels so that to the
2977eye a closer approximation of the images original color is reproduced. This
2978reduces the number of colors needed to reproduce the image but at the cost of
2979a lower level pattern of colors. Error diffusion dithers can use any set of
2980colors (generated or user defined) to an image. </p>
2981
2982<p>Dithering is turned on by default, to turn it off use the plus form of the
2983setting, <a href="command-line-options.html#dither">+dither</a>. This will also also render PostScript
2984without text or graphic aliasing. Disabling dithering often (but not always)
2985leads to faster process, a smaller number of colors, but more cartoon like
2986image coloring. Generally resulting in 'color banding' effects in areas with
2987color gradients. </p>
2988
cristy29dc8652015-05-12 16:26:21 +00002989<p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a
2990href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap ">-remap</a>, and <a
2991href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced
cristyd2432012015-05-04 23:15:15 +00002992color set they created. These operators are also used as part of automatic
2993color reduction when saving images to formats with limited color support, such
2994as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used
2995in these cases. </p>
2996
2997<p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a>
cristy29dc8652015-05-12 16:26:21 +00002998to generate purely random dither. Or use <a
2999href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither
cristyd2432012015-05-04 23:15:15 +00003000patterns, using uniform color maps, rather than specific color maps. </p>
3001
3002
3003<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003004 <h3 class="magick-header"><a id="draw"></a>-draw <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00003005</div>
3006
3007<p class="magick-description">Annotate an image with one or more graphic primitives.</p>
3008
3009<p>Use this option to annotate or decorate an image with one or more graphic
3010primitives. The primitives include shapes, text, transformations, and pixel
3011operations.</p>
3012
3013<p>The shape primitives:</p>
3014
3015<pre>
cristy29dc8652015-05-12 16:26:21 +00003016point x,y
3017line x0,y0 x1,y1
3018rectangle x0,y0 x1,y1
3019roundRectangle x0,y0 x1,y1 wc,hc
3020arc x0,y0 x1,y1 a0,a1
3021ellipse x0,y0 rx,ry a0,a1
3022circle x0,y0 x1,y1
3023polyline x0,y0 ... xn,yn
3024polygon x0,y0 ... xn,yn
3025bezier x0,y0 ... xn,yn
3026path specification
3027image operator x0,y0 w,h filename
cristyd2432012015-05-04 23:15:15 +00003028</pre>
3029
3030<p>The text primitive:</p>
3031
3032<pre>
cristy29dc8652015-05-12 16:26:21 +00003033text x0,y0 string
cristyd2432012015-05-04 23:15:15 +00003034</pre>
3035<p>The text gravity primitive:</p>
3036
3037<pre>
cristy29dc8652015-05-12 16:26:21 +00003038gravity NorthWest, North, NorthEast, West, Center,
3039 East, SouthWest, South, or SouthEast
cristyd2432012015-05-04 23:15:15 +00003040</pre>
3041
3042<p>The text gravity primitive only affects the placement of text and does not
cristy29dc8652015-05-12 16:26:21 +00003043interact with the other primitives. It is equivalent to using the <a
3044href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in
cristyd2432012015-05-04 23:15:15 +00003045scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p>
3046
3047<p>The transformation primitives:</p>
3048
3049<pre>
cristy29dc8652015-05-12 16:26:21 +00003050rotate degrees
3051translate dx,dy
3052scale sx,sy
3053skewX degrees
3054skewY degrees
cristyd2432012015-05-04 23:15:15 +00003055</pre>
3056
3057<p>The pixel operation primitives:</p>
3058
3059<pre>
cristy29dc8652015-05-12 16:26:21 +00003060color x0,y0 method
3061matte x0,y0 method
cristyd2432012015-05-04 23:15:15 +00003062</pre>
3063
cristy29dc8652015-05-12 16:26:21 +00003064<p>The shape primitives are drawn in the color specified by the preceding <a
3065href="command-line-options.html#fill">-fill</a> setting. For unfilled shapes, use <a
3066href="command-line-options.html#fill">-fill none</a>. You can optionally control the stroke (the
3067"outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a
3068href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p>
cristyd2432012015-05-04 23:15:15 +00003069
3070<p>A <code>point</code> primitive is specified by a single <var>point</var> in the
3071pixel plane, that is, by an ordered pair of integer coordinates,
3072<var>x</var>,<var>y</var>. (As it involves only a single pixel, a <code>point</code>
cristy29dc8652015-05-12 16:26:21 +00003073primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a
3074href="command-line-options.html#strokewidth">-strokewidth</a>.)</p>
cristyd2432012015-05-04 23:15:15 +00003075
3076<p>A <code>line</code> primitive requires a start point and end point.</p>
3077
3078<p>A <code>rectangle</code> primitive is specified by the pair of points at the
3079upper left and lower right corners.</p>
3080
3081<p>A <code>roundRectangle</code> primitive takes the same corner points as
3082a <code>rectangle</code> followed by the width and height of the rounded corners
3083to be removed.</p>
3084
3085<p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled).
3086Give the center and any point on the perimeter (boundary).</p>
3087
3088<p>The <code>arc</code> primitive is used to inscribe an elliptical segment in
3089to a given rectangle. An <code>arc</code> requires the two corners used for
3090<code>rectangle</code> (see above) followed by the start and end angles of the
3091arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end
3092points produced are then joined with a line segment and the resulting segment
3093of an ellipse is filled.</p>
3094
3095<p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the
3096center point, the horizontal and vertical "radii" (the <var>semi-axes</var> of
3097the ellipse) and start and end angles in degrees (e.g. 100,100 100,150
30980,360).</p>
3099
3100<p>The <code>polyline</code> and <code>polygon</code> primitives require three or
3101more points to define their perimeters. A <code>polyline</code> is simply
3102a <code>polygon</code> in which the final point is not stroked to the start
cristy29dc8652015-05-12 16:26:21 +00003103point. When unfilled, this is a <var>polygonal line</var>. If the <a
3104href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then
cristyd2432012015-05-04 23:15:15 +00003105a <code>polyline</code> is identical to a <code>polygon</code>. </p>
3106
3107<p>A <var>coordinate</var> is a pair of integers separated by a space or
3108optional comma. </p>
3109
3110<p>As an example, to define a circle centered at 100,100 that extends to
3111150,150 use:</p>
3112
cristy29dc8652015-05-12 16:26:21 +00003113<pre>
3114-draw 'circle 100,100 150,150'
3115</pre>
cristyd2432012015-05-04 23:15:15 +00003116
3117<p>The <code>Bezier</code> primitive creates a spline curve and requires three
3118or points to define its shape. The first and last points are the
3119<var>knots</var> and these points are attained by the curve, while any
3120intermediate coordinates are <var>control points</var>. If two control points
3121are specified, the line between each end knot and its sequentially respective
3122control point determines the tangent direction of the curve at that end. If
3123one control point is specified, the lines from the end knots to the one
3124control point determines the tangent directions of the curve at each end. If
3125more than two control points are specified, then the additional control points
3126act in combination to determine the intermediate shape of the curve. In order
3127to draw complex curves, it is highly recommended either to use the
3128<code>path</code> primitive or to draw multiple four-point bezier segments with
3129the start and end knots of each successive segment repeated. For example:</p>
3130
cristy29dc8652015-05-12 16:26:21 +00003131<pre>
3132-draw 'bezier 20,50 45,100 45,0 70,50'
3133-draw 'bezier 70,50 95,100 95,0 120,50'
3134</pre>
cristyd2432012015-05-04 23:15:15 +00003135
3136<p>A <code>path</code> represents an outline of an object, defined in terms of
3137moveto (set a new current point), lineto (draw a straight line), curveto (draw
3138a Bezier curve), arc (elliptical or circular arc) and closepath (close the
3139current shape by drawing a line to the last moveto) elements. Compound paths
3140(i.e., a path with subpaths, each consisting of a single moveto followed by
3141one or more line or curve operations) are possible to allow effects such as
cristy29dc8652015-05-12 16:26:21 +00003142<var>donut holes</var> in objects. (See <a
3143href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
cristyd2432012015-05-04 23:15:15 +00003144
3145<p>Use <code>image</code> to composite an image with another image. Follow the
3146image keyword with the composite operator, image location, image size, and
3147filename:</p>
3148
cristy29dc8652015-05-12 16:26:21 +00003149<pre>
3150-draw 'image SrcOver 100,100 225,225 image.jpg'
3151</pre>
cristyd2432012015-05-04 23:15:15 +00003152
3153<p>You can use 0,0 for the image size, which means to use the actual
3154dimensions found in the image header. Otherwise, it is scaled to the given
3155dimensions. See <a href="compose.html">Alpha Compositing</a> for
3156a detailed discussion of alpha composition methods that are available. </p>
3157
3158<p>The "special augmented compose operators" such as "dissolve" that require
3159arguments cannot be used at present with the <code>-draw image</code> option.
3160 </p>
3161
3162<p>Use <code>text</code> to annotate an image with text. Follow the text
3163coordinates with a string. If the string has embedded spaces, enclose it in
3164single or double quotes.</p>
3165
3166<p>For example, the following annotates the image with <code>Works like
3167magick!</code> for an image titled <code>bird.miff</code>. </p>
3168
cristy29dc8652015-05-12 16:26:21 +00003169<pre>
3170-draw "text 100,100 'Works like magick!' "
3171</pre>
cristyd2432012015-05-04 23:15:15 +00003172
3173<p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way
3174to annotate an image with text.</p>
3175
3176<p>The <code>rotate</code> primitive rotates subsequent shape primitives and
cristy29dc8652015-05-12 16:26:21 +00003177text primitives about the origin of the main image. If the <a
3178href="command-line-options.html#region">-region</a> option precedes the <a href="command-line-options.html#draw">-draw</a>
cristyd2432012015-05-04 23:15:15 +00003179option, the origin for transformations is the upper left corner of the
3180region.</p>
3181
3182<p>The <code>translate</code> primitive translates subsequent shape and text
3183primitives.</p>
3184
3185<p>The <code>scale</code> primitive scales them.</p>
3186
3187<p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect
3188to the origin of the main image or the region.</p>
3189
3190<p>The transformations modify the current affine matrix, which is initialized
3191from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a>
3192option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a>
3193option. The initial affine matrix is not affected; that matrix is only changed
3194by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another
3195<a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is
3196reinitialized from the initial affine matrix.</p>
3197
3198<p>Use the <code>color</code> primitive to change the color of a pixel to the
3199fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with
3200a method:</p>
3201
3202<pre>
cristy29dc8652015-05-12 16:26:21 +00003203point
3204replace
3205floodfill
3206filltoborder
3207reset
cristyd2432012015-05-04 23:15:15 +00003208</pre>
3209
3210<p>Consider the target pixel as that specified by your coordinate. The
3211<code>point</code> method recolors the target pixel. The <code>replace</code>
3212method recolors any pixel that matches the color of the target pixel.
3213<code>Floodfill</code> recolors any pixel that matches the color of the target
3214pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor
3215pixel that is not the border color. Finally, <code>reset</code> recolors all
3216pixels.</p>
3217
3218<p>Use <code>matte</code> to the change the pixel matte value to transparent.
3219Follow the pixel coordinate with a method (see the <code>color</code> primitive
3220for a description of methods). The <code>point</code> method changes the matte
3221value of the target pixel. The <code>replace</code> method changes the matte
3222value of any pixel that matches the color of the target pixel.
3223<code>Floodfill</code> changes the matte value of any pixel that matches the
3224color of the target pixel and is a neighbor, whereas <code>filltoborder</code>
cristy29dc8652015-05-12 16:26:21 +00003225changes the matte value of any neighbor pixel that is not the border color (<a
3226href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the
cristyd2432012015-05-04 23:15:15 +00003227matte value of all pixels.</p>
3228
cristy29dc8652015-05-12 16:26:21 +00003229<p>You can set the primitive color, font, and font bounding box color with <a
3230href="command-line-options.html#fill">-fill</a>, <a href="command-line-options.html#font">-font</a>, and <a href="command-line-options.html#box">-box</a>
cristyd2432012015-05-04 23:15:15 +00003231respectively. Options are processed in command line order so be sure to use
3232these options <var>before</var> the <a href="command-line-options.html#draw">-draw</a> option.</p>
3233
3234<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather
3235than 1.png).</p>
3236
cristy29dc8652015-05-12 16:26:21 +00003237<p>Drawing primitives conform to the <a href="magick-vector-graphics.html" >Magick
cristyd2432012015-05-04 23:15:15 +00003238Vector Graphics</a> format.</p>
3239
3240
3241<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003242 <h3 class="magick-header"><a id="duplicate"></a>-duplicate <var>count,indexes</var></h3>
cristyd2432012015-05-04 23:15:15 +00003243</div>
3244
3245<p class="magick-description">duplicate an image one or more times.</p>
3246
3247<p>Specify the count and the image to duplicate by its index in the sequence.
3248The first image is index 0. Negative indexes are relative to the end of the
3249sequence, for example, -1 represents the last image of the sequence. Specify
3250a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g.
32510,2). Use <code>+duplicate</code> to duplicate the last image in the current
3252image sequence.</p>
3253
3254<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003255 <h3 class="magick-header"><a id="edge"></a>-edge <var>radius</var></h3>
cristyd2432012015-05-04 23:15:15 +00003256</div>
3257
3258<p class="magick-description">detect edges within an image.</p>
3259
3260<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003261 <h3 class="magick-header"><a id="emboss"></a>-emboss <var>radius</var></h3>
cristyd2432012015-05-04 23:15:15 +00003262</div>
3263
3264<p class="magick-description">emboss an image.</p>
3265
3266<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003267 <h3 class="magick-header"><a id="encipher"></a>-encipher <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00003268</div>
3269
3270<p class="magick-description">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</p>
3271
3272<p>Get the passphrase from the file specified by <var>filename</var>.</p>
3273
cristy29dc8652015-05-12 16:26:21 +00003274<p>For more information, see the webpage, <a
3275href="../www/cipher.html">ImageMagick: Encipher or
cristyd2432012015-05-04 23:15:15 +00003276Decipher an Image</a>.</p>
3277
3278
3279
3280<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003281 <h3 class="magick-header"><a id="encoding"></a>-encoding <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00003282</div>
3283
3284<p class="magick-description">specify the text encoding.</p>
3285
3286<p>Choose from <code>AdobeCustom</code>, <code>AdobeExpert</code>,
3287<code>AdobeStandard</code>, <code>AppleRoman</code>, <code>BIG5</code>,
3288<code>GB2312</code>, <code>Latin 2</code>, <code>None</code>, <code>SJIScode</code>,
3289<code>Symbol</code>, <code>Unicode</code>, <code>Wansung</code>.</p>
3290
3291<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003292 <h3 class="magick-header"><a id="endian"></a>-endian <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00003293</div>
3294
3295<p class="magick-description">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</p>
3296
3297<p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p>
3298
3299<p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p>
3300
3301
3302<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003303 <h3 class="magick-header"><a id="enhance"></a>-enhance</h3>
cristyd2432012015-05-04 23:15:15 +00003304</div>
3305
3306<p class="magick-description">Apply a digital filter to enhance a noisy image.</p>
3307
3308
3309<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003310 <h3 class="magick-header"><a id="equalize"></a>-equalize</h3>
cristyd2432012015-05-04 23:15:15 +00003311</div>
3312
3313<p class="magick-description">perform histogram equalization on the image channel-by-channel.</p>
3314
3315<p>To perform histogram equalization on all channels in concert, transform the
3316image into some other color space, such as HSL, OHTA, YIQ or YUV, then
3317equalize the appropriate intensity-like channel, then convert back to RGB.</p>
3318
3319<p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness
3320-equalize -colorspace RGB</code> ...</p>
3321
3322<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal
3323components transformation that puts most of the information in the first
3324channel. Here we have ... <code>-colorspace OHTA -channel red -equalize
3325-colorspace RGB</code> ...</p>
3326
3327<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00003328 <h3 class="magick-header"><a id="evaluate"></a>-evaluate <var>operator value</var></h3>
cristyd2432012015-05-04 23:15:15 +00003329</div>
3330
3331<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</p>
3332
cristy29dc8652015-05-12 16:26:21 +00003333<p>(See the <a href="command-line-options.html#function" >-function</a> operator for some
3334multi-parameter functions. See the <a href="command-line-options.html#fx" >-fx</a> operator if more
cristyd2432012015-05-04 23:15:15 +00003335elaborate calculations are needed.)</p>
3336
3337<p>The behaviors of each <var>operator</var> are summarized in the
3338following list. For brevity, the numerical value of a "pixel" referred to
3339below is the value of the corresponding channel of that pixel, while
3340a "normalized pixel" is that number divided by the maximum
3341(installation-dependent) value <var>QuantumRange</var>. (If
3342normalized pixels are used, they are restored, following the other
3343calculations, to the full range by multiplying by <var>QuantumRange</var>.)</p>
3344
3345<table class="table table-condensed table-striped">
cristy29dc8652015-05-12 16:26:21 +00003346 <tr><td># </td><td>arguments meaning</td></tr>
3347 <tr><td>1:</td><td><var>Angle_of_Rotation</var></td></tr>
3348 <tr><td>2:</td><td><var>Scale Angle</var></td></tr>
3349 <tr><td>3:</td><td><var>X,Y Angle</var></td></tr>
3350 <tr><td>4:</td><td><var>X,Y Scale Angle</var></td></tr>
3351 <tr><td>5:</td>
3352 <td><var>X,Y ScaleX,ScaleY Angle</var></td></tr>
3353 <tr><td>6:</td>
3354 <td><var>X,Y Scale Angle NewX,NewY</var></td></tr>
3355 <tr><td>7:</td>
3356 <td><var>X,Y ScaleX,ScaleY Angle
3357 NewX,NewY</var></td></tr>
3358 </table>
3359
3360 This is actually an alternative way of specifying a 2 dimensional linear
3361 '<code>Affine</code>' or '<code>AffineProjection</code>' distortion. </td> </tr>
3362
3363 <tr>
3364 <td><code>Affine</code></td>
3365 <td>
3366 Distort the image linearly by moving a list of at least 3 or more sets
3367 of control points (as defined below). Ideally 3 sets or 12 floating
3368 point values are given allowing the image to be linearly scaled,
3369 rotated, sheared, and translated, according to those three points. See
3370 also the related '<code>AffineProjection</code>' and '<code>SRT</code>'
3371 distortions. <br/>
3372
3373 More than 3 sets given control point pairs (12 numbers) is least
3374 squares fitted to best match a linear affine distortion. If only 2
3375 control point pairs (8 numbers) are given a two point image translation
3376 rotation and scaling is performed, without any possible shearing,
3377 flipping or changes in aspect ratio to the resulting image. If only one
3378 control point pair is provides the image is only translated, (which may
3379 be a floating point non-integer translation). <br/>
3380
3381 This distortion does not include any form of perspective distortion.
3382 </td>
3383
3384 </tr>
3385
3386 <tr>
3387 <td><code>AffineProjection</code></td>
3388 <td>
3389 Linearly distort an image using the given Affine Matrix of 6
3390 pre-calculated coefficients forming a set of Affine Equations to map
3391 the source image to the destination image.
3392
3393 <div style="text-align: center"><var>
3394 s<sub>x</sub>, r<sub>x</sub>,
3395 r<sub>y</sub>, s<sub>y</sub>,
3396 t<sub>x</sub>, t<sub>y</sub>
3397 </var></div>
3398
3399 See <a href="command-line-options.html#affine" >-affine</a> setting for more detail, and
3400 meanings of these coefficients. <br/>
3401
3402 The distortions '<code>Affine</code>' and '<code>SRT</code>' provide
3403 alternative methods of defining this distortion, with ImageMagick doing
3404 the calculations needed to generate the required coefficients. You can
3405 see the internally generated coefficients, by using a <a
3406 href="command-line-options.html#verbose" >-verbose</a> setting with those other variants. </td>
3407
3408 </tr>
3409
3410 <tr>
3411 <td><code>BilinearForward</code><br/>
3412 <code>BilinearReverse</code></td>
3413 <td>
3414 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
3415 16 values (see below). Not that lines may not appear straight after
3416 distortion, though the distance between coordinates will remain
3417 consistent. <br/>
3418
3419 The '<code>BilinearForward</code>' is used to map rectangles to any
3420 quadrilateral, while the '<code>BilinearReverse</code>' form maps any
3421 quadrilateral to a rectangle, while preserving the straight line edges
3422 in each case. <br/>
3423
3424 Note that '<code>BilinearForward</code>' can generate invalid pixels
3425 which will be colored using the <a href="command-line-options.html#mattecolor" >-mattecolor</a>
3426 color setting. Also if the quadrilateral becomes 'flipped' the image
3427 may disappear. <br/>
3428
3429 There are future plans to produce a true Bilinear distortion that will
3430 attempt to map any quadrilateral to any other quadrilateral, while
3431 preserving edges (and edge distance ratios).
3432
3433 </td>
3434 </tr>
3435
3436 <tr>
3437 <td><code>Perspective</code></td>
3438 <td>
3439 Perspective distort the images, using a list of 4 or more sets of
3440 control points (as defined below). More that 4 sets (16 numbers) of
3441 control points provide least squares fitting for more accurate
3442 distortions (for the purposes of image registration and panorama
3443 effects). Less than 4 sets will fall back to a '<code>Affine</code>'
3444 linear distortion. <br/>
3445
3446 Perspective Distorted images ensures that straight lines remain
3447 straight, but the scale of the distorted image will vary. The horizon
3448 is anti-aliased, and the 'sky' color may be set using the
3449 <a href="command-line-options.html#mattecolor" >-mattecolor</a> setting. </td>
3450 </tr>
3451
3452 <tr>
3453 <td><code>PerspectiveProjection</code> </td>
3454 <td>
3455 Do a '<code>Perspective</code>' distortion biased on a set of 8
3456 pre-calculated coefficients. You can get these coefficients by looking
3457 at the <a href="command-line-options.html#verbose" >-verbose</a> output of a
3458 '<code>Perspective</code>' distortion, or by calculating them yourself.
3459 If the last two perspective scaling coefficients are zero, the
3460 remaining 6 represents a transposed 'Affine Matrix'. </td>
3461
3462 </tr>
3463
3464 <tr>
3465 <td><code>Arc</code></td>
3466 <td>
3467 Arc the image (variation of polar mapping) over the angle given around
3468 a circle. <br/>
3469 <table class="table table-condensed table-striped">
3470 <tr><td>Argument</td>
3471 <td>Meaning</td></tr>
3472 <tr><td><var>arc_angle</var></td>
3473 <td>The angle over which to arc the image side-to-side</td></tr>
3474 <tr><td><var>rotate_angle</var></td>
3475 <td>Angle to rotate resulting image from vertical center</td></tr>
3476 <tr><td><var>top_radius</var></td>
3477 <td>Set top edge of source image at this radius</td></tr>
3478 <tr><td><var>bottom_radius</var> </td>
3479 <td>Set bottom edge to this radius (radial scaling)</td></tr>
3480 </table>
3481
3482 The resulting image is always resized to best fit the resulting image,
3483 (as if using <a href="command-line-options.html#distort" >+distort</a>) while attempting to
3484 preserve scale and aspect ratio of the original image as much as
3485 possible with the arguments given by the user. All four arguments will
3486 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
3487
3488 This a variation of a polar distortion designed to try to preserve the
3489 aspect ratio of the image rather than direct Cartesian to Polar
3490 conversion. </td>
3491 </tr>
3492
3493 <tr>
3494 <td><code>Polar</code></td>
3495 <td>
3496 Like '<code>Arc</code>' but do a complete Cartesian to Polar mapping of
3497 the image. that is the height of the input image is mapped to the
3498 radius limits, while the width is wrapped around between the
3499 angle limits. <br/>
3500
3501 Arguments: <var>Rmax,Rmin CenterX,CenterY, start,end_angle</var> <br/>
3502
3503 All arguments are optional. With <var>Rmin</var> defaulting to zero, the
3504 center to the center of the image, and the angles going from -180 (top)
3505 to +180 (top). If <var>Rmax</var> is given the special value of
3506 '<code>0</code>', the the distance from the center to the nearest edge
3507 is used for the radius of the output image, which will ensure the whole
3508 image is visible (though scaled smaller). However a special value of
3509 '<code>-1</code>' will use the distance from the center to the furthest
3510 corner, This may 'clip' the corners from the input rectangular image,
3511 but will generate the exact reverse of a '<code>DePolar</code>' with
3512 the same arguments. <br/>
3513
3514 If the plus form of distort (<a href="command-line-options.html#distort" >+distort</a>) is used
3515 output image center will default to <code>0,0</code> of the virtual
3516 canvas, and the image size adjusted to ensure the whole input image is
3517 made visible in the output image on the virtual canvas. </td>
3518
3519 </tr>
3520
3521 <tr>
3522 <td><code>DePolar</code></td>
3523 <td>
3524 Uses the same arguments and meanings as a '<code>Polar</code>' distortion
3525 but generates the reverse Polar to Cartesian distortion. <br/>
3526
3527 The special <var>Rmax</var> setting of '<code>0</code>' may however clip
3528 the corners of the input image. However using the special
3529 <var>Rmax</var> setting of '<code>-1</code>' (maximum center to corner
3530 distance) will ensure the whole distorted image is preserved in the
3531 generated result, so that the same argument to '<code>Polar</code>' will
3532 reverse the distortion re-producing the original.
3533
3534 Note that as this distortion requires the area resampling of a circular
3535 arc, which can not be handled by the builtin EWA resampling function.
3536 As such the normal EWA filters are turned off. It is recommended some
3537 form of 'super-sampling' image processing technique be used to produce
3538 a high quality result. </td>
3539
3540 </tr>
3541
3542 <tr>
3543 <td><code>Barrel</code></td>
3544 <td>
3545 Given the four coefficients (A,B,C,D) as defined by <a
3546 href="http://wiki.panotools.org/Lens_correction_model" >Helmut
3547 Dersch</a>, perform a barrel or pin-cushion distortion appropriate to
3548 correct radial lens distortions. That is in photographs, make straight
3549 lines straight again. <br/>
3550
3551 Arguments: <var>A B C</var> [ <var>D</var> [
3552 <var>X</var> , <var>Y</var> ] ] <br/>
3553 or <var>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub>
3554 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></var>
3555 [ <var>X</var> , <var>Y</var> ] <br/>
3556 So that it forms the function <br/>
3557 Rsrc = r * ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
3558 <var>C</var>*r + <var>D</var> )<br/>
3559
3560 Where <var>X</var>,<var>Y</var> is the optional center of the distortion
3561 (defaulting to the center of the image). <br/>
3562 The second form is typically used to distort images, rather than
3563 correct lens distortions. <br/>
3564 </td>
3565
3566 </tr>
3567
3568 <tr>
3569 <td><code>BarrelInverse</code></td>
3570 <td>
3571 This is very similar to '<code>Barrel</code>' with the same set of
3572 arguments, and argument handling. However it uses the inverse
3573 of the radial polynomial,
3574 so that it forms the function <br/>
3575 Rsrc = r / ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
3576 <var>C</var>*r + <var>D</var> )<br/>
3577 Note that this is not the reverse of the '<code>Barrel</code>'
3578 distortion, just a different barrel-like radial distortion method.
3579
3580 </td>
3581 </tr>
3582
3583 <tr>
3584 <td><code>Shepards</code></td>
3585 <td>
3586 Distort the given list control points (any number) using an Inverse
3587 Squared Distance Interpolation Method (<a
3588 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards
3589 Method</a>). The control points in effect do 'localized' displacement
3590 of the image around the given control point (preserving the look and
3591 the rotation of the area near the control points. For best results
3592 extra control points should be added to 'lock' the positions of the
3593 corners, edges and other unchanging parts of the image, to prevent
3594 their movement. <br/>
3595
3596 The distortion has been likened to 'taffy pulling' using nails, or
3597 pins' stuck in a block of 'jelly' which is then moved to the new
3598 position, distorting the surface of the jelly. <br/>
3599
3600 Internally it is equivalent to generating a displacement map (see <a
3601 href="command-line-options.html#displace" >-displace</a>) for source image color look-up using
3602 the <a href="command-line-options.html#sparse-color" >-sparse-color</a> method of the same name.
3603
3604 </td>
3605 </tr>
3606
3607</table>
3608
3609<p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list
3610distort</a>.</p>
3611
3612<p>Many of the above distortion methods such as '<code>Affine</code>',
3613'<code>Perspective</code>', and '<code>Shepards</code>' use a list control points
3614defining how these points in the given image should be distorted in the
3615destination image. Each set of four floating point values represent a source
3616image coordinate, followed immediately by the destination image coordinate.
3617This produces a list of values such as...</p>
3618<div style="text-align: center"><var>
3619 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub>
3620 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub>
3621 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub>
3622 ...
3623 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub>
3624</var></div>
3625<p>where <var>U,V</var> on the source image is mapped to <var>X,Y</var> on the
3626destination image. </p>
3627
3628<p>For example, to warp an image using '<code>perspective</code>' distortion,
3629needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
3630perspective distortion of the built-in "rose:" image. Note how spaces were
3631used to group the 4 sets of coordinate pairs, to make it easier to read and
3632understand.</p>
3633
3634<pre>
3635convert rose: -virtual-pixel black \
3636 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \
3637 rose_3d_rotated.gif"
3638</pre>
3639
3640<p>If more that the required number of coordinate pairs are given for
3641a distortion, the distortion method is 'least squares' fitted to produce the
3642best result for all the coordinate pairs given. If less than the ideal number
3643of points are given, the distort will generally fall back to a simpler form of
3644distortion that can handles the smaller number of coordinates (usually a linear
3645'<code>Affine</code>' distortion). </p>
3646
3647<p>By using more coordinates you can make use of image registration tool to
3648find matching coordinate pairs in overlapping images, so as to improve the
3649'fit' of the distortion. Of course a bad coordinate pair can also make the
3650'fit' worse. Caution is always advised. </p>
3651
3652<p>Colors are acquired from the source image according to a cylindrical
3653resampling <a href="command-line-options.html#filter" >-filter</a>, using a special technique known as
3654EWA resampling. This produces very high quality results, especially when
3655images become smaller (minified) in the output, which is very common when
3656using '<code>perspective</code>' distortion. For example here we view
3657a infinitely tiled 'plane' all the way to the horizon. </p>
3658
3659<pre>
3660convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \
3661 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \
3662 checks_tiled.jpg
3663</pre>
3664
3665<p>Note that a infinitely tiled perspective images involving the horizon can
3666be very slow, because of the number of pixels that are compressed to generate
3667each individual pixel close to the 'horizon'. You can turn off EWA
3668resampling, by specifing the special <a href="command-line-options.html#filter" >-filter</a> setting of
3669'<code>point</code>' (recommended if you plan to use super-sampling instead).
3670</p>
3671
3672<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
3673example, <a href="command-line-options.html#distort" >-distort</a> will use the current <a
3674href="command-line-options.html#mattecolor" >-mattecolor</a> setting for these pixels. If you do not
3675what these pixels to be visible, set the color to match the rest of the
3676ground. </p>
3677
3678<p>The output image size will by default be the same as the input image. This
3679means that if the part of the distorted image falls outside the viewed area of
3680the 'distorted space', those parts is clipped and lost. However if you use
3681the plus form of the operator (<a href="command-line-options.html#distort" >+distort</a>) the operator
3682will attempt (if possible) to show the whole of the distorted image, while
3683retaining a correct 'virtual canvas' offset, for image layering. This offset
3684may need to be removed using <a href="command-line-options.html#repage" >+repage</a>, to remove if it
3685is unwanted. </p>
3686
3687<p>Setting <a href="command-line-options.html#verbose" >-verbose</a> setting, will cause <a
3688href="command-line-options.html#distort" >-distort</a> to attempt to output the internal coefficients,
3689and the <a href="command-line-options.html#fx" >-fx</a> equivalent to the distortion, for expert study,
3690and debugging purposes. This many not be available for all distorts. </p>
3691
3692<p>You can alternatively specify a special "<code><a href="command-line-options.html#define"
3693>-define</a> distort:viewport={geometry_string}</code>" setting which will
3694specify the size and the offset of the generated 'viewport' image of the
3695distorted image space.</p>
3696
3697<p>Setting a "<code><a href="command-line-options.html#define" >-define</a>
3698distort:scale={scale_factor}</code>" will scale the output image (viewport or
3699otherwise) by that factor without changing the viewed contents of the
3700distorted image. This can be used either for 'super-sampling' the image for
3701a higher quality result, or for panning and zooming around the image (with
3702appropriate viewport changes, or post-distort cropping and resizing). </p>
3703
3704<p>Setting "<code><a href="command-line-options.html#define" >-define</a> resample:verbose=1</code>"
3705will output the cylindrical filter lookup table created by the EWA (Elliptical
3706Weighted Average) resampling algorithm. Note this table uses a squared radius
3707lookup value. This is typically only used for debugging EWA resampling. </p>
3708
3709
3710<div style="margin: auto;">
3711 <h3 class="magick-header"><a id="distribute-cache"></a>-distribute-cache <var>port</var></h3>
3712</div>
3713
3714<p class="magick-description">launch a distributed pixel cache server. </p>
3715
3716<div style="margin: auto;">
3717 <h3 class="magick-header"><a id="dither"></a>-dither <var>method</var></h3>
3718</div>
3719
3720<p class="magick-description">Apply a Riemersma or Floyd-Steinberg error diffusion dither to
3721images when general color reduction is applied via an option, or automagically
3722when saving to specific formats. This enabled by default.</p>
3723
3724<p>Dithering places two or more colors in neighboring pixels so that to the
3725eye a closer approximation of the images original color is reproduced. This
3726reduces the number of colors needed to reproduce the image but at the cost of
3727a lower level pattern of colors. Error diffusion dithers can use any set of
3728colors (generated or user defined) to an image. </p>
3729
3730<p>Dithering is turned on by default, to turn it off use the plus form of the
3731setting, <a href="command-line-options.html#dither">+dither</a>. This will also also render PostScript
3732without text or graphic aliasing. Disabling dithering often (but not always)
3733leads to faster process, a smaller number of colors, but more cartoon like
3734image coloring. Generally resulting in 'color banding' effects in areas with
3735color gradients. </p>
3736
3737<p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a
3738href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap ">-remap</a>, and <a
3739href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced
3740color set they created. These operators are also used as part of automatic
3741color reduction when saving images to formats with limited color support, such
3742as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used
3743in these cases. </p>
3744
3745<p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a>
3746to generate purely random dither. Or use <a
3747href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither
3748patterns, using uniform color maps, rather than specific color maps. </p>
3749
3750
3751<div style="margin: auto;">
3752 <h3 class="magick-header"><a id="draw"></a>-draw <var>string</var></h3>
3753</div>
3754
3755<p class="magick-description">Annotate an image with one or more graphic primitives.</p>
3756
3757<p>Use this option to annotate or decorate an image with one or more graphic
3758primitives. The primitives include shapes, text, transformations, and pixel
3759operations.</p>
3760
3761<p>The shape primitives:</p>
3762
3763<pre>
3764point x,y
3765line x0,y0 x1,y1
3766rectangle x0,y0 x1,y1
3767roundRectangle x0,y0 x1,y1 wc,hc
3768arc x0,y0 x1,y1 a0,a1
3769ellipse x0,y0 rx,ry a0,a1
3770circle x0,y0 x1,y1
3771polyline x0,y0 ... xn,yn
3772polygon x0,y0 ... xn,yn
3773bezier x0,y0 ... xn,yn
3774path specification
3775image operator x0,y0 w,h filename
3776</pre>
3777
3778<p>The text primitive:</p>
3779
3780<pre>
3781text x0,y0 string
3782</pre>
3783<p>The text gravity primitive:</p>
3784
3785<pre>
3786gravity NorthWest, North, NorthEast, West, Center,
3787 East, SouthWest, South, or SouthEast
3788</pre>
3789
3790<p>The text gravity primitive only affects the placement of text and does not
3791interact with the other primitives. It is equivalent to using the <a
3792href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in
3793scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p>
3794
3795<p>The transformation primitives:</p>
3796
3797<pre>
3798rotate degrees
3799translate dx,dy
3800scale sx,sy
3801skewX degrees
3802skewY degrees
3803</pre>
3804
3805<p>The pixel operation primitives:</p>
3806
3807<pre>
3808color x0,y0 method
3809matte x0,y0 method
3810</pre>
3811
3812<p>The shape primitives are drawn in the color specified by the preceding <a
3813href="command-line-options.html#fill">-fill</a> setting. For unfilled shapes, use <a
3814href="command-line-options.html#fill">-fill none</a>. You can optionally control the stroke (the
3815"outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a
3816href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p>
3817
3818<p>A <code>point</code> primitive is specified by a single <var>point</var> in the
3819pixel plane, that is, by an ordered pair of integer coordinates,
3820<var>x</var>,<var>y</var>. (As it involves only a single pixel, a <code>point</code>
3821primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a
3822href="command-line-options.html#strokewidth">-strokewidth</a>.)</p>
3823
3824<p>A <code>line</code> primitive requires a start point and end point.</p>
3825
3826<p>A <code>rectangle</code> primitive is specified by the pair of points at the
3827upper left and lower right corners.</p>
3828
3829<p>A <code>roundRectangle</code> primitive takes the same corner points as
3830a <code>rectangle</code> followed by the width and height of the rounded corners
3831to be removed.</p>
3832
3833<p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled).
3834Give the center and any point on the perimeter (boundary).</p>
3835
3836<p>The <code>arc</code> primitive is used to inscribe an elliptical segment in
3837to a given rectangle. An <code>arc</code> requires the two corners used for
3838<code>rectangle</code> (see above) followed by the start and end angles of the
3839arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end
3840points produced are then joined with a line segment and the resulting segment
3841of an ellipse is filled.</p>
3842
3843<p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the
3844center point, the horizontal and vertical "radii" (the <var>semi-axes</var> of
3845the ellipse) and start and end angles in degrees (e.g. 100,100 100,150
38460,360).</p>
3847
3848<p>The <code>polyline</code> and <code>polygon</code> primitives require three or
3849more points to define their perimeters. A <code>polyline</code> is simply
3850a <code>polygon</code> in which the final point is not stroked to the start
3851point. When unfilled, this is a <var>polygonal line</var>. If the <a
3852href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then
3853a <code>polyline</code> is identical to a <code>polygon</code>. </p>
3854
3855<p>A <var>coordinate</var> is a pair of integers separated by a space or
3856optional comma. </p>
3857
3858<p>As an example, to define a circle centered at 100,100 that extends to
3859150,150 use:</p>
3860
3861<pre>
3862-draw 'circle 100,100 150,150'
3863</pre>
3864
3865<p>The <code>Bezier</code> primitive creates a spline curve and requires three
3866or points to define its shape. The first and last points are the
3867<var>knots</var> and these points are attained by the curve, while any
3868intermediate coordinates are <var>control points</var>. If two control points
3869are specified, the line between each end knot and its sequentially respective
3870control point determines the tangent direction of the curve at that end. If
3871one control point is specified, the lines from the end knots to the one
3872control point determines the tangent directions of the curve at each end. If
3873more than two control points are specified, then the additional control points
3874act in combination to determine the intermediate shape of the curve. In order
3875to draw complex curves, it is highly recommended either to use the
3876<code>path</code> primitive or to draw multiple four-point bezier segments with
3877the start and end knots of each successive segment repeated. For example:</p>
3878
3879<pre>
3880-draw 'bezier 20,50 45,100 45,0 70,50'
3881-draw 'bezier 70,50 95,100 95,0 120,50'
3882</pre>
3883
3884
3885<p>A <code>path</code> represents an outline of an object, defined in terms of
3886moveto (set a new current point), lineto (draw a straight line), curveto (draw
3887a Bezier curve), arc (elliptical or circular arc) and closepath (close the
3888current shape by drawing a line to the last moveto) elements. Compound paths
3889(i.e., a path with subpaths, each consisting of a single moveto followed by
3890one or more line or curve operations) are possible to allow effects such as
3891<var>donut holes</var> in objects. (See <a
3892href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
3893
3894<p>Use <code>image</code> to composite an image with another image. Follow the
3895image keyword with the composite operator, image location, image size, and
3896filename:</p>
3897
3898<pre>
3899-draw 'image SrcOver 100,100 225,225 image.jpg'
3900</pre>
3901
3902<p>You can use 0,0 for the image size, which means to use the actual
3903dimensions found in the image header. Otherwise, it is scaled to the given
3904dimensions. See <a href="compose.html">Alpha Compositing</a> for
3905a detailed discussion of alpha composition methods that are available. </p>
3906
3907<p>The "special augmented compose operators" such as "dissolve" that require
3908arguments cannot be used at present with the <code>-draw image</code> option.
3909 </p>
3910
3911<p>Use <code>text</code> to annotate an image with text. Follow the text
3912coordinates with a string. If the string has embedded spaces, enclose it in
3913single or double quotes.</p>
3914
3915<p>For example, the following annotates the image with <code>Works like
3916magick!</code> for an image titled <code>bird.miff</code>. </p>
3917
3918<pre>
3919-draw "text 100,100 'Works like magick!' "
3920</pre>
3921
3922<p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way
3923to annotate an image with text.</p>
3924
3925<p>The <code>rotate</code> primitive rotates subsequent shape primitives and
3926text primitives about the origin of the main image. If the <a
3927href="command-line-options.html#region">-region</a> option precedes the <a href="command-line-options.html#draw">-draw</a>
3928option, the origin for transformations is the upper left corner of the
3929region.</p>
3930
3931<p>The <code>translate</code> primitive translates subsequent shape and text
3932primitives.</p>
3933
3934<p>The <code>scale</code> primitive scales them.</p>
3935
3936<p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect
3937to the origin of the main image or the region.</p>
3938
3939<p>The transformations modify the current affine matrix, which is initialized
3940from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a>
3941option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a>
3942option. The initial affine matrix is not affected; that matrix is only changed
3943by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another
3944<a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is
3945reinitialized from the initial affine matrix.</p>
3946
3947<p>Use the <code>color</code> primitive to change the color of a pixel to the
3948fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with
3949a method:</p>
3950
3951<pre>
3952point
3953replace
3954floodfill
3955filltoborder
3956reset
3957</pre>
3958
3959<p>Consider the target pixel as that specified by your coordinate. The
3960<code>point</code> method recolors the target pixel. The <code>replace</code>
3961method recolors any pixel that matches the color of the target pixel.
3962<code>Floodfill</code> recolors any pixel that matches the color of the target
3963pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor
3964pixel that is not the border color. Finally, <code>reset</code> recolors all
3965pixels.</p>
3966
3967<p>Use <code>matte</code> to the change the pixel matte value to transparent.
3968Follow the pixel coordinate with a method (see the <code>color</code> primitive
3969for a description of methods). The <code>point</code> method changes the matte
3970value of the target pixel. The <code>replace</code> method changes the matte
3971value of any pixel that matches the color of the target pixel.
3972<code>Floodfill</code> changes the matte value of any pixel that matches the
3973color of the target pixel and is a neighbor, whereas <code>filltoborder</code>
3974changes the matte value of any neighbor pixel that is not the border color (<a
3975href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the
3976matte value of all pixels.</p>
3977
3978<p>You can set the primitive color, font, and font bounding box color with <a
3979href="command-line-options.html#fill">-fill</a>, <a href="command-line-options.html#font">-font</a>, and <a href="command-line-options.html#box">-box</a>
3980respectively. Options are processed in command line order so be sure to use
3981these options <var>before</var> the <a href="command-line-options.html#draw">-draw</a> option.</p>
3982
3983<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather
3984than 1.png).</p>
3985
3986<p>Drawing primitives conform to the <a href="magick-vector-graphics.html" >Magick
3987Vector Graphics</a> format.</p>
3988
3989
3990<div style="margin: auto;">
3991 <h3 class="magick-header"><a id="duplicate"></a>-duplicate <var>count,indexes</var></h3>
3992</div>
3993
3994<p class="magick-description">duplicate an image one or more times.</p>
3995
3996<p>Specify the count and the image to duplicate by its index in the sequence.
3997The first image is index 0. Negative indexes are relative to the end of the
3998sequence, for example, -1 represents the last image of the sequence. Specify
3999a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g.
40000,2). Use <code>+duplicate</code> to duplicate the last image in the current
4001image sequence.</p>
4002
4003<div style="margin: auto;">
4004 <h3 class="magick-header"><a id="edge"></a>-edge <var>radius</var></h3>
4005</div>
4006
4007<p class="magick-description">detect edges within an image.</p>
4008
4009<div style="margin: auto;">
4010 <h3 class="magick-header"><a id="emboss"></a>-emboss <var>radius</var></h3>
4011</div>
4012
4013<p class="magick-description">emboss an image.</p>
4014
4015<div style="margin: auto;">
4016 <h3 class="magick-header"><a id="encipher"></a>-encipher <var>filename</var></h3>
4017</div>
4018
4019<p class="magick-description">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</p>
4020
4021<p>Get the passphrase from the file specified by <var>filename</var>.</p>
4022
4023<p>For more information, see the webpage, <a
4024href="../www/cipher.html">ImageMagick: Encipher or
4025Decipher an Image</a>.</p>
4026
4027
4028
4029<div style="margin: auto;">
4030 <h3 class="magick-header"><a id="encoding"></a>-encoding <var>type</var></h3>
4031</div>
4032
4033<p class="magick-description">specify the text encoding.</p>
4034
4035<p>Choose from <code>AdobeCustom</code>, <code>AdobeExpert</code>,
4036<code>AdobeStandard</code>, <code>AppleRoman</code>, <code>BIG5</code>,
4037<code>GB2312</code>, <code>Latin 2</code>, <code>None</code>, <code>SJIScode</code>,
4038<code>Symbol</code>, <code>Unicode</code>, <code>Wansung</code>.</p>
4039
4040<div style="margin: auto;">
4041 <h3 class="magick-header"><a id="endian"></a>-endian <var>type</var></h3>
4042</div>
4043
4044<p class="magick-description">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</p>
4045
4046<p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p>
4047
4048<p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p>
4049
4050
4051<div style="margin: auto;">
4052 <h3 class="magick-header"><a id="enhance"></a>-enhance</h3>
4053</div>
4054
4055<p class="magick-description">Apply a digital filter to enhance a noisy image.</p>
4056
4057
4058<div style="margin: auto;">
4059 <h3 class="magick-header"><a id="equalize"></a>-equalize</h3>
4060</div>
4061
4062<p class="magick-description">perform histogram equalization on the image channel-by-channel.</p>
4063
4064<p>To perform histogram equalization on all channels in concert, transform the
4065image into some other color space, such as HSL, OHTA, YIQ or YUV, then
4066equalize the appropriate intensity-like channel, then convert back to RGB.</p>
4067
4068<p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness
4069-equalize -colorspace RGB</code> ...</p>
4070
4071<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal
4072components transformation that puts most of the information in the first
4073channel. Here we have ... <code>-colorspace OHTA -channel red -equalize
4074-colorspace RGB</code> ...</p>
4075
4076<div style="margin: auto;">
4077 <h3 class="magick-header"><a id="evaluate"></a>-evaluate <var>operator value</var></h3>
4078</div>
4079
4080<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</p>
4081
4082<p>(See the <a href="command-line-options.html#function" >-function</a> operator for some
4083multi-parameter functions. See the <a href="command-line-options.html#fx" >-fx</a> operator if more
4084elaborate calculations are needed.)</p>
4085
4086<p>The behaviors of each <var>operator</var> are summarized in the
4087following list. For brevity, the numerical value of a "pixel" referred to
4088below is the value of the corresponding channel of that pixel, while
4089a "normalized pixel" is that number divided by the maximum
4090(installation-dependent) value <var>QuantumRange</var>. (If
4091normalized pixels are used, they are restored, following the other
4092calculations, to the full range by multiplying by <var>QuantumRange</var>.)</p>
4093
4094<table class="table table-condensed table-striped">
4095 <col width="25%" />
4096 <col width="75%" />
cristyd2432012015-05-04 23:15:15 +00004097 <thead>
4098 <tr>
4099 <th><var>operator</var></th>
4100 <th>Summary (see further below for details)</th>
4101 </tr>
4102 </thead>
4103 <tbody>
4104
4105 <tr><td>Abs </td> <td>Add <var>value</var> to pixels and return absolute value. </td></tr>
4106 <tr><td>Add </td> <td>Add <var>value</var> to pixels. </td></tr>
4107 <tr><td>AddModulus </td> <td>Add <var>value</var> to pixels modulo <var>QuantumRange</var>.</td></tr>
4108 <tr><td>And </td> <td>Binary AND of pixels with <var>value</var>.</td></tr>
4109 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
4110 <tr><td>Divide </td> <td>Divide pixels by <var>value</var>.</td></tr>
4111 <tr><td>Exp </td> <td>base-e exponential function</td></tr>
4112 <tr><td>Exponential </td> <td>base-e exponential function</td></tr>
4113 <tr><td>LeftShift </td> <td>Shift the pixel values left by <var>value</var> bits (i.e., multiply pixels by 2<sup><var>value</var></sup>).</td></tr>
4114 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
4115 <tr><td>Max </td> <td>Clip pixels at lower bound <var>value</var>.</td></tr>
4116 <tr><td>Mean </td> <td>Add the <var>value</var> and divide by 2.</td></tr>
4117 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr>
4118 <tr><td>Min </td> <td>Clip pixels at upper bound <var>value</var>.</td></tr>
4119 <tr><td>Multiply </td> <td>Multiply pixels by <var>value</var>.</td></tr>
4120 <tr><td>Or </td> <td>Binary OR of pixels with <var>value</var>.</td></tr>
4121 <tr><td>Pow </td> <td>Raise normalized pixels to the power <var>value</var>.</td></tr>
4122 <tr><td>RightShift </td> <td>Shift the pixel values right by <var>value</var> bits (i.e., divide pixels by 2<sup><var>value</var></sup>).</td></tr>
4123 <tr><td>RMS</td> <td>Square the pixel and add the <var>value</var>.</td></tr>
4124 <tr><td>RootMeanSquare</td> <td>Square the pixel and add the <var>value</var>.</td></tr>
4125 <tr><td>Set </td> <td>Set pixel equal to <var>value</var>.</td></tr>
4126 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
4127 <tr><td>Subtract </td> <td>Subtract <var>value</var> from pixels.</td></tr>
4128 <tr><td>Xor </td> <td>Binary XOR of pixels with <var>value.</var></td></tr>
4129
4130 <tr><td> </td></tr>
4131
cristy29dc8652015-05-12 16:26:21 +00004132 <tr><td>Gaussian-noise</td><td> </td></tr>
4133 <tr><td>Impulse-noise</td><td> </td></tr>
4134 <tr><td>Laplacian-noise</td><td> </td></tr>
4135 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="command-line-options.html#noise" >-noise</a> operators.)</td></tr>
4136 <tr><td>PoissonNoise</td><td> </td></tr>
4137 <tr><td>Uniform-noise</td><td> </td></tr>
cristyd2432012015-05-04 23:15:15 +00004138
4139 <tr><td> </td></tr>
4140
4141 <tr><td>Threshold </td> <td>Threshold pixels larger than <var>value</var>.</td></tr>
4142 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <var>value</var>.</td></tr>
4143 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <var>value</var>. </td></tr>
4144 </tbody>
4145 </table>
4146
cristy29dc8652015-05-12 16:26:21 +00004147<p>The specified functions are applied only to each previously set <a
4148href="command-line-options.html#channel" >-channel</a> in the image. If necessary, the results of the
cristyd2432012015-05-04 23:15:15 +00004149calculations are truncated (clipped) to fit in the interval [0, <var>QuantumRange</var>]. The transparency channel of the image is
4150represented as a 'alpha' values (0 = fully transparent), so, for example, a
4151<code>Divide</code> by 2 of the alpha channel will make the image
4152semi-transparent. Append the percent symbol '<code>%</code>' to specify a value
4153as a percentage of the <var>QuantumRange</var>.</p>
4154
4155<p>To print a complete list of <a href="command-line-options.html#evaluate">-evaluate</a> operators, use
4156<a href="command-line-options.html#list">-list evaluate</a>.</p>
4157
4158<p>The results of the <code>Add</code>, <code>Subtract</code> and
cristy29dc8652015-05-12 16:26:21 +00004159<code>Multiply</code> methods can also be achieved using either the <a
4160href="command-line-options.html#level" >-level</a> or the <a href="command-line-options.html#level" >+level</a> operator, with
cristyd2432012015-05-04 23:15:15 +00004161appropriate argument, to linearly modify the overall range of color values.
cristy29dc8652015-05-12 16:26:21 +00004162Please note, however, that <a href="command-line-options.html#level" >-level</a> treats transparency as
4163'matte' values (0 = opaque), while <a href="command-line-options.html#level" >-evaluate</a> works with
cristyd2432012015-05-04 23:15:15 +00004164'alpha' values.</p>
4165
4166<p><code>AddModulus</code> has been added as of ImageMagick 6.4.8-4 and provides
4167addition modulo the <var>QuantumRange</var>. It is therefore
4168equivalent to <code>Add</code> unless the resulting pixel value is outside the
4169interval [0, <var>QuantumRange</var>]. </p>
4170
4171<p><code>Exp or Exponential</code> has been added as of ImageMagick 6.6.5-1 and
4172works on normalized pixel values. The <var>value</var> used with
4173<code>Exp</code> should be negative so as to produce a decaying exponential
4174function. Non-negative values will always produce results larger unity and
4175thus outside the interval [0, <var>QuantumRange</var>]. The
4176formula is expressed below. </p>
4177
4178 <div style="text-align:center;">
4179 exp(<var>value</var> × <b><var>u</var></b>)
4180 </div>
4181
cristy29dc8652015-05-12 16:26:21 +00004182<p> If the input image is squared, for example, using <a href="command-line-options.html#-function"
4183>-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be
cristyd2432012015-05-04 23:15:15 +00004184the result.</p>
4185
4186<p><code>Log</code> has been added as of ImageMagick 6.4.2-1 and works on
4187normalized pixel values. This a <var>scaled</var> log function. The <var>value</var> used with <code>Log</code> provides a <var>scaling
4188factor</var> that adjusts the curvature in the graph of the log function. The
4189formula applied to a normalized value <b><var>u</var></b> is below. </p>
4190
4191 <div style="text-align:center;">
4192 log(<var>value</var> × <b><var>u</var></b> + 1) / log(<var>value</var> + 1)
4193 </div>
4194
4195<p><code>Pow</code> has been added as of ImageMagick 6.4.1-9, and works on
cristy29dc8652015-05-12 16:26:21 +00004196normalized pixel values. Note that <code>Pow</code> is related to the <a
4197href="command-line-options.html#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
cristyd2432012015-05-04 23:15:15 +00004198to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
cristy29dc8652015-05-12 16:26:21 +00004199with <a href="command-line-options.html#gamma" >-gamma</a> is simply the reciprocal of the value used
cristyd2432012015-05-04 23:15:15 +00004200with <code>Pow</code>.</p>
4201
4202<p><code>Cosine</code> and <code>Sine</code> was added as of IM v6.4.8-8 and
4203converts the image values into a value according to a (co)sine wave function.
4204The synonyms <code>Cos</code> and <code>Sin</code> may also be used. The output
4205is biased 50% and normalized by 50% so as to fit in the respective color value
4206range. The <var>value</var> scaling of the <var>period</var> of the
4207function (its frequency), and thus determines the number of 'waves' that will
4208be generated over the input color range. For example, if the <var>value</var> is 1, the effective period is simply the <var>QuantumRange</var>; but if the <var>value</var> is 2,
4209then the effective period is the <var>half</var> the <var>QuantumRange</var>.</p>
4210
4211 <div style="text-align:center;">
4212 0.5 + 0.5 × cos(2 π <b><var>u</var></b> × <var>value</var>).
4213 </div>
4214
cristy29dc8652015-05-12 16:26:21 +00004215<p>See also the <a href="command-line-options.html#function" >-function</a> operator, which is a
cristyd2432012015-05-04 23:15:15 +00004216multi-value version of evaluate. </p>
4217
4218<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004219 <h3 class="magick-header"><a id="evaluate-sequence"></a>-evaluate-sequence <var>operator</var></h3>
cristyd2432012015-05-04 23:15:15 +00004220</div>
4221
4222<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or
4223logical expression over a sequence of images.</p>
4224
cristy29dc8652015-05-12 16:26:21 +00004225<p>To print a complete list of <a
4226href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> operators, use <a
4227href="command-line-options.html#list">-list evaluate</a>.</p>
cristyd2432012015-05-04 23:15:15 +00004228
4229<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004230 <h3 class="magick-header"><a id="extent"></a>-extent <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00004231</div>
4232
4233<p class="magick-description">Set the image size and offset.</p>
4234
4235<p>If the image is enlarged, unfilled areas are set to the background color.
4236To position the image, use offsets in the <var>geometry</var>
4237specification or precede with a <a href="command-line-options.html#gravity">-gravity</a> setting. To
cristy29dc8652015-05-12 16:26:21 +00004238specify how to compose the image with the background, use <a href="command-line-options.html#compose"
4239>-compose</a>.</p>
cristyd2432012015-05-04 23:15:15 +00004240
4241<p>This command reduces or expands a JPEG image to fit on an 800x600
4242display. If the aspect ratio of the input image isn't exactly 4:3, then the
4243image is centered on an 800x600 black canvas: </p>
4244
4245<pre>
4246convert input.jpg -resize 800x600 -background black -compose Copy \
4247 -gravity center -extent 800x600 -quality 92 output.jpg
4248</pre>
4249
4250<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4251
4252<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004253 <h3 class="magick-header"><a id="extract"></a>-extract <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00004254</div>
4255
4256<p class="magick-description">Extract the specified area from image.</p>
4257
4258<p>This option is most useful for extracting a subregion of a very large raw
4259image. Note that these two commands are equivalent:</p>
4260
4261<pre>
4262convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \
4263 image.rgb image.png",
4264convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \
4265 image.rgb image.png"
4266</pre>
4267
4268<p>If you omit the offsets, as in</p>
4269
4270<pre>
4271convert -size 16000x16000 -depth 8 -extract 640x480 \
4272 image.rgb image.png
4273</pre>
4274
4275<p>the image is <var>resized</var> to the specified dimensions instead,
4276equivalent to:</p>
4277
4278<pre>
4279convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png
4280</pre>
4281
4282<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4283
4284<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004285 <h3 class="magick-header"><a id="family"></a>-family <var>fontFamily</var></h3>
cristyd2432012015-05-04 23:15:15 +00004286</div>
4287
4288<p class="magick-description">Set a font family for text.</p>
4289
4290<p>This setting suggests a font family that ImageMagick should try to use for
4291rendering text. If the family can be found it is used; if not, a default font
4292(e.g., "Arial") or a family known to be similar is substituted (e.g.,
4293"Courier" might be used if "System" is requested but not found). </p>
4294
cristy29dc8652015-05-12 16:26:21 +00004295<p>For other settings that affect fonts, see the options <a
4296href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a
4297href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
cristyd2432012015-05-04 23:15:15 +00004298
4299<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004300 <h3 class="magick-header"><a id="features"></a>-features <var>distance</var></h3>
cristyd2432012015-05-04 23:15:15 +00004301</div>
4302
4303<p class="magick-description">display (cooccurrence matrix) texture measure features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</p>
4304
4305<pre>
cristy29dc8652015-05-12 16:26:21 +00004306Angular Second Moment
4307Contrast
4308Correlation
4309Sum of Squares Variance
4310Inverse Difference Moment
4311Sum Average
4312Sum Variance
4313Sum Entropy
4314Entropy
4315Difference Variance
4316Difference Entropy
4317Information Measure of Correlation 1
4318Information Measure of Correlation 2
4319Maximum Correlation Coefficient
cristyd2432012015-05-04 23:15:15 +00004320</pre>
4321
4322
4323<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004324 <h3 class="magick-header"><a id="fft"></a>-fft</h3>
cristyd2432012015-05-04 23:15:15 +00004325</div>
4326
4327<p class="magick-description">implements the forward discrete Fourier transform (DFT).</p>
4328
4329<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
4330users in ImageMagick 6.6.0-9). It transforms an image from the normal
4331(spatial) domain to the frequency domain. In the frequency domain, an image is
4332represented as a superposition of complex sinusoidal waves of varying
4333amplitudes. The image x and y coordinates are the possible frequencies along
4334the x and y directions, respectively, and the pixel intensity values are
4335complex numbers that correspond to the sinusoidal wave amplitudes. See for
4336example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier
4337Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier
4338Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier
4339Transform</a>.</p>
4340
4341<p>A single image name is provided as output for this option. However, the
4342output result will have two components. It is either a two-frame image or two
4343separate images, depending upon whether the image format specified supports
4344multi-frame images. The reason that we get a dual output result is because the
4345frequency domain represents an image using complex numbers, which cannot be
4346visualized directly. Therefore, the complex values are automagically separated
4347into a two-component image representation. The first component is the
4348magnitude of the complex number and the second is the phase of the complex
cristy29dc8652015-05-12 16:26:21 +00004349number. See for example, <a
4350href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p>
cristyd2432012015-05-04 23:15:15 +00004351
4352<p>The magnitude and phase component images must be specified using image
4353formats that do not limit the color or compress the image. Thus, MIFF, TIF,
4354PFM, EXR and PNG are the recommended image formats to use. All of these
4355formats, except PNG support multi-frame images. So for example,</p>
4356
4357<pre>
4358convert image.png -fft fft_image.miff
4359</pre>
4360
4361<p>generates a magnitude image as <code>fft_image.miff[0]</code> and a phase
4362image as <code>fft_image.miff[1]</code>. Similarly,</p>
4363
4364<pre>
4365convert image.png -fft fft_image.png
4366</pre>
4367
4368<p>generates a magnitude image as <code>fft_image-0.png</code> and a phase image
4369as <code>fft_image-1.png</code>. If you prefer this representation, then you can
cristy29dc8652015-05-12 16:26:21 +00004370force any of the other formats to produce two output images by including <a
4371href="command-line-options.html#adjoin">+adjoin</a> following -fft in the command line.</p>
cristyd2432012015-05-04 23:15:15 +00004372
4373<p>The input image can be any size, but if not square and even-dimensioned, it
4374is padded automagically to the larger of the width or height of the input
4375image and to an even number of pixels. The padding will occur at the bottom
4376and/or right sides of the input image. The resulting output magnitude and
cristy29dc8652015-05-12 16:26:21 +00004377phase images is square at this size. The kind of padding relies on the <a
4378href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting.</p>
cristyd2432012015-05-04 23:15:15 +00004379
4380<p>Both output components will have dynamic ranges that fit within
4381[0, <var>QuantumRange</var>], so that HDRI need not be enabled.
4382Phase values nominally range from 0 to 2*π, but is scaled to span the full
4383dynamic range. (The first few releases had non-HDRI scaled but HDRI not
4384scaled). The magnitude image is not scaled and thus generally will contain
4385very small values. As such, the image normally will appear totally black. In
4386order to view any detail, the magnitude image typically is enhanced with a log
4387function into what is usually called the spectrum. A log function is used to
4388enhance the darker values more in comparison to the lighter values. This can
4389be done, for example, as follows:</p>
4390
4391<pre>
4392convert fft_image.miff[0] -contrast-stretch 0 \
4393 -evaluate log 1000 fft_image_spectrum.png"
4394</pre>
4395
cristy29dc8652015-05-12 16:26:21 +00004396<p>where either <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> 0 or <a
4397href="command-line-options.html#auto-level">-auto-level</a> is used to scale the image to full dynamic
cristyd2432012015-05-04 23:15:15 +00004398range, first. The argument to the <a href="command-line-options.html#evaluate">-evaluate</a> log
4399typically is specified between 100 and 10,000, depending upon the amount of
4400detail that one wants to bring out in the spectrum. Larger values produce more
4401visible detail. Too much detail, however, may hide the important features.</p>
4402
4403<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
4404use <a href="command-line-options.html#fft">-fft</a>.</p>
4405
4406<p>Use <a href="command-line-options.html#fft">+fft</a> to produce two output images that are the real
4407and imaginary components of the complex valued Fourier transform.</p>
4408
4409<p>However, as the real and imaginary components can contain negative values,
4410this requires that IM be configured with HDRI enabled. In this case, you must
4411use either MIFF, TIF, PFM or MPC formats for the real and imaginary component
4412results, since they are formats that preserve both negative and fractional
4413values without clipping them or truncating the fractional part. With either
4414MIFF or TIF, one should add -define quantum:format=32, to allow those image
4415types to work properly in HDRI mode without clipping.</p>
4416
cristy29dc8652015-05-12 16:26:21 +00004417<p>The real and imaginary component images resulting from <a
4418href="command-line-options.html#fft">+fft</a> are also square, even dimensioned images due to the same
cristyd2432012015-05-04 23:15:15 +00004419padding that was discussed above for the magnitude and phase component
4420images.</p>
4421
cristy29dc8652015-05-12 16:26:21 +00004422<p>See the discussion on HDRI implementations of ImageMagick on the page <a
4423href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more
4424about HDRI go the ImageMagick <a
4425href="http://www.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages, <a
4426href="http://www.fmwconcepts.com/imagemagick/fourier_transforms/fourier.html"
4427>Fred's Fourier Processing With ImageMagick page</a> or this <a
4428 href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging" >Wikipedia</a>
cristyd2432012015-05-04 23:15:15 +00004429 entry. </p>
4430
cristy29dc8652015-05-12 16:26:21 +00004431<p>By default the FFT is normalized (and the IFT is not). Use "<code><a href="command-line-options.html#define" >-define</a> fourier:normalize=forward</code> to explicityly normalize the FFT and unnormalize the IFT.</p>
cristyd2432012015-05-04 23:15:15 +00004432
4433
4434<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004435 <h3 class="magick-header"><a id="fill"></a>-fill <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00004436</div>
4437
4438<p class="magick-description">color to use when filling a graphic primitive.</p>
4439
4440<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA,
cristy29dc8652015-05-12 16:26:21 +00004441HSL, HSLA, CMYK, or CMYKA specification. See <a href="color.html" >Color Names</a> for
cristyd2432012015-05-04 23:15:15 +00004442a description of how to properly specify the color argument.</p>
4443
4444<p>Enclose the color specification in quotation marks to prevent the "#" or
4445the parentheses from being interpreted by your shell.</p>
4446
4447<p>For example,</p>
4448
cristy29dc8652015-05-12 16:26:21 +00004449<pre>
4450-fill blue
4451-fill "#ddddff"
4452-fill "rgb(255,255,255)"
4453</pre>
cristyd2432012015-05-04 23:15:15 +00004454
4455<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
4456
4457<p>To print a complete list of color names, use the <a href="command-line-options.html#list">-list color</a> option.</p>
4458
4459<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004460 <h3 class="magick-header"><a id="filter"></a>-filter <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00004461</div>
4462
4463<p class="magick-description">Use this <var>type</var> of filter when resizing or distorting an image.</p>
4464
4465<p>Use this option to affect the resizing operation of an image during
cristy29dc8652015-05-12 16:26:21 +00004466operations such as <a href="command-line-options.html#resize">-resize</a> and <a href="command-line-options.html#distort"
4467>-distort</a>. For example you can use a simple resize filter such as:</p>
cristyd2432012015-05-04 23:15:15 +00004468
4469<pre>
cristy29dc8652015-05-12 16:26:21 +00004470Point Hermite Cubic
4471Box Gaussian Catrom
4472Triangle Quadratic Mitchell
cristyd2432012015-05-04 23:15:15 +00004473</pre>
4474
4475<p>The <code>Bessel</code> and <code>Sinc</code> filter is also provided (as well
4476as a faster <code>SincFast</code> equivalent form). However these filters are
4477generally useless on their own as they are infinite filters that are being
4478clipped to the filters support size. Their direct use is not recommended
4479except via expert settings (see below). </p>
4480
4481<p>Instead these special filter functions are typically windowed by a windowing
cristy29dc8652015-05-12 16:26:21 +00004482function that the <a href="command-line-options.html#filter" >-filter</a> setting defines. That is
cristyd2432012015-05-04 23:15:15 +00004483using these functions will define a 'Windowed' filter, appropriate to the
4484operator involved. Windowed filters include: </p>
4485
4486<pre>
cristy29dc8652015-05-12 16:26:21 +00004487Lanczos Hamming Parzen
4488Blackman Kaiser Welsh
4489Hanning Bartlett Bohman
cristyd2432012015-05-04 23:15:15 +00004490</pre>
4491
4492<p>Also one special self-windowing filter is also provided
4493<code>Lagrange</code>, which will automagically re-adjust its function depending
4494on the current 'support' or 'lobes' expert settings (see below).</p>
4495
4496<p>If you do not select a filter with this option, the filter defaults to
4497<code>Mitchell</code> for a colormapped image, an image with a matte channel, or
4498if the image is enlarged. Otherwise the filter default to
4499<code>Lanczos</code>.</p>
4500
4501<p>To print a complete list of resize filters, use the <a href="command-line-options.html#list">-list
4502filter</a> option.</p>
4503
4504<p>You can modify how the filter behaves as it scales your image through the
cristy29dc8652015-05-12 16:26:21 +00004505use of these expert settings (see also <a href="command-line-options.html#define" >-define</a> and <a
4506href="command-line-options.html#set" >-set</a>):-</p>
cristyd2432012015-05-04 23:15:15 +00004507
cristy29dc8652015-05-12 16:26:21 +00004508<table class="table table-condensed table-striped">
4509 <tr>
4510 <td>-define filter:blur=<var>factor</var></td>
4511 <td>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
cristyd2432012015-05-04 23:15:15 +00004512 blurry or &lt; 1.0 for sharp. This should only be used with Gaussian and
4513 Gaussian-like filters simple filters, or you may not get the expected
cristy29dc8652015-05-12 16:26:21 +00004514 results. </td>
4515 </tr>
cristyd2432012015-05-04 23:15:15 +00004516
cristy29dc8652015-05-12 16:26:21 +00004517 <tr>
4518 <td>-define filter:support=<var>radius</var></td>
4519 <td>Set the filter support radius. Defines how large the filter should be and
cristyd2432012015-05-04 23:15:15 +00004520 thus directly defines how slow the filtered resampling process is. All
4521 filters have a default 'prefered' support size. Some filters like
4522 <code>Lagrange</code> and windowed filters adjust themselves depending on
4523 this value. With simple filters this value either does nothing (but slow
4524 the resampling), or will clip the filter function in a detrimental way.
cristy29dc8652015-05-12 16:26:21 +00004525 </td>
4526 </tr>
cristyd2432012015-05-04 23:15:15 +00004527
cristy29dc8652015-05-12 16:26:21 +00004528 <tr>
4529 <td>-define filter:lobes=<var>count</var></td>
4530 <td>Set the number of lobes to use for the Sinc/Bessel filter. This an
cristyd2432012015-05-04 23:15:15 +00004531 alternative way of specifying the 'support' range of the filter, that is
4532 designed to be more suited to windowed filters, especially when used for
cristy29dc8652015-05-12 16:26:21 +00004533 image distorts.</td>
4534 </tr>
cristyd2432012015-05-04 23:15:15 +00004535
cristy29dc8652015-05-12 16:26:21 +00004536 <tr>
4537 <td>-define filter:sigma=<var>value</var></td>
4538 <td>The 'sigma' value used to define the <code>Gaussian</code> filter. Default
cristyd2432012015-05-04 23:15:15 +00004539 sigma value is '<code>0.5</code>'. It only effects <code>Gaussian</code> but
4540 does not shrink (but may enlarge) the filter's 'support'. It can be used
4541 to generate very small blurs but without the filter 'missing' pixels due
4542 to using a small support setting. A larger value of '<code>0.707</code>'
cristy29dc8652015-05-12 16:26:21 +00004543 (a value of '1/sqrt(2)') is another common setting. </td>
4544 </tr>
cristyd2432012015-05-04 23:15:15 +00004545
cristy29dc8652015-05-12 16:26:21 +00004546 <tr>
4547 <td>-define filter:b=<var>b-spline_factor</var></td>
4548 <tr>
4549 <td>-define filter:c=<var>keys_alpha_factor</var></td>
4550 <td>Redefine the values used for cubic filters such as <code>Cubic</code>,
cristyd2432012015-05-04 23:15:15 +00004551 <code>Catrom</code>, <code>Mitchel</code>, and <code>Hermite</code>, as well as
4552 the <code>Parzen</code> cubic windowing function. If only one of the values
4553 are defined, the other is set so as to generate a 'Cubic-Keys' filter.
4554 The values meaning was defined by a research paper by
cristy29dc8652015-05-12 16:26:21 +00004555 Mitchell-Netravali.</td>
4556 </tr>
cristyd2432012015-05-04 23:15:15 +00004557
cristy29dc8652015-05-12 16:26:21 +00004558 <tr>
4559 <td>-define filter:kaiser-beta=<var>value</var></td>
4560 <td>The 'alpha' value used to as part of the Kaiser Windowing function.
cristyd2432012015-05-04 23:15:15 +00004561 Default value is '6.5'. It only effects Kaiser windowing function, and
cristy29dc8652015-05-12 16:26:21 +00004562 does not effect any other attributes.
4563 Before ImageMagick v6.7.6-10, this option was known as "filter:alpha", (an
cristyd2432012015-05-04 23:15:15 +00004564 inheritance from the very old "zoom" program). It was changed to bring the
4565 function in line with more modern academic research usage, and better
cristy29dc8652015-05-12 16:26:21 +00004566 assign it be more definitive. </td>
4567 </tr>
cristyd2432012015-05-04 23:15:15 +00004568
cristy29dc8652015-05-12 16:26:21 +00004569 <tr>
4570 <td>-define filter:kaiser-alpha=<var>value</var></td>
4571 <td>This value when multiplied by 'PI' is equivalent to "kaiser-beta", and
cristyd2432012015-05-04 23:15:15 +00004572 will override that setting. It only effects Kaiser windowing function,
cristy29dc8652015-05-12 16:26:21 +00004573 and does not effect any other attributes. </td>
4574 </tr>
cristyd2432012015-05-04 23:15:15 +00004575
cristy29dc8652015-05-12 16:26:21 +00004576 <tr>
4577 <td>-define filter:filter=<var>filter_function</var></td>
4578 <td>Use this function directly as the weighting filter. This will allow
cristyd2432012015-05-04 23:15:15 +00004579 you to directly use a windowing function such as <code>Blackman</code>,
4580 as a resampling filter, rather than as its normal usage as a windowing
cristy29dc8652015-05-12 16:26:21 +00004581 function. If defined, no windowing function also defined, the window function is set
cristyd2432012015-05-04 23:15:15 +00004582 to <code>Box</code>). Directly specifying <code>Sinc</code> or <code>Jinc</code>
cristy29dc8652015-05-12 16:26:21 +00004583 as a filter will also do this. </td>
4584 </tr>
cristyd2432012015-05-04 23:15:15 +00004585
cristy29dc8652015-05-12 16:26:21 +00004586 <tr>
4587 <td>-define filter:window=<var>filter_function</var></td>
4588 <td>The IIR (infinite impulse response) filters <code>Sinc</code> and
cristyd2432012015-05-04 23:15:15 +00004589 <code>Jinc</code> are windowed (brought down to zero over the defined
4590 support range) with the given filter. This allows you to specify a filter
cristy29dc8652015-05-12 16:26:21 +00004591 function to be used as a windowing function for these IIR filters.
4592 Many of the defined filters are actually windowing functions for these IIR
cristyd2432012015-05-04 23:15:15 +00004593 filters. A typical choices is <code>Box</code>, (which effectively turns
cristy29dc8652015-05-12 16:26:21 +00004594 off the windowing function). </td>
4595 </tr>
cristyd2432012015-05-04 23:15:15 +00004596
cristy29dc8652015-05-12 16:26:21 +00004597 <tr>
4598 <td>-define filter:win-support=<var>radius</var></td>
4599 <td>Scale windowing function to this size instead. This causes the windowing
cristyd2432012015-05-04 23:15:15 +00004600 (or self-windowing Lagrange filter) to act is if the support window is
4601 larger than what is actually supplied to the calling operator. The filter
4602 however is still clipped to the real support size given. If unset this
cristy29dc8652015-05-12 16:26:21 +00004603 will equal the normal filter support size. </td>
4604 </tr>
cristyd2432012015-05-04 23:15:15 +00004605
cristy29dc8652015-05-12 16:26:21 +00004606 <tr>
4607 <td>-define filter:verbose=<var>1</var></td>
4608 <td>This causes IM to print information on the final internal filter
cristyd2432012015-05-04 23:15:15 +00004609 selection to standard output. This includes a commented header on the
4610 filter settings being used, and data allowing the filter weights to be
cristy29dc8652015-05-12 16:26:21 +00004611 easily graphed. Note however that some filters are internally defined in terms of other filters. The <code>Lanczos</code> filter for example is defined in terms of
cristyd2432012015-05-04 23:15:15 +00004612 a <code>SincFast</code> windowed <code>SincFast</code> filter, while
4613 <code>Mitchell</code> is defined as a general <code>Cubic</code> family filter
cristy29dc8652015-05-12 16:26:21 +00004614 with specific 'B' and 'C' settings. </td>
4615 </tr>
cristyd2432012015-05-04 23:15:15 +00004616
cristy29dc8652015-05-12 16:26:21 +00004617</table>
cristyd2432012015-05-04 23:15:15 +00004618
4619<p>For example, to get a 8 lobe jinc windowed sinc filter (Genseng filter?):</p>
4620
4621<pre>
4622convert image.png \
4623 -filter sinc \
4624 -set filter:window=jinc \
4625 -set filter:lobes=8 \
4626 -resize 150% image.jpg"
4627</pre>
4628
4629<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
4630
4631<pre>
4632convert image.png \
4633 -set filter:filter=sinc \
4634 -set filter:lobes=4 \
4635 -resize 150% image.jpg"
4636</pre>
4637
4638<p>To extract the data for a raw windowing function, combine it with
4639a '<code>Box</code>' filter. For example the '<code>Welch</code> parabolic
4640windowing function. </p>
4641
4642<pre>
4643convert null: -define filter:filter=Box \
4644 -define filter:window=Welch \
4645 -define filter:support=1.0 \
4646 -define filter:verbose=1 \
cristy29dc8652015-05-12 16:26:21 +00004647 -resize 2 null: > window_welch.dat
cristyd2432012015-05-04 23:15:15 +00004648gnuplot
4649 set grid
4650 plot \"window_welch.dat\" with lines
4651</pre>
4652
4653<p>Note that the use of expert options is provided for image processing experts
4654who have studied and understand how resize filters work. Without this
4655knowledge, and an understanding of the definition of the actual filters
4656involved, using expert settings are more likely to be detrimental to your image
4657resizing.</p>
4658
4659
4660<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004661 <h3 class="magick-header"><a id="flatten"></a>-flatten</h3>
cristyd2432012015-05-04 23:15:15 +00004662</div>
4663
cristy29dc8652015-05-12 16:26:21 +00004664<p class="magick-description">This is a simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "flatten".</p>
cristyd2432012015-05-04 23:15:15 +00004665
4666
4667<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004668 <h3 class="magick-header"><a id="flip"></a>-flip</h3>
cristyd2432012015-05-04 23:15:15 +00004669</div>
4670
4671<p class="magick-description">create a <var>mirror image</var></p>
4672
4673<p>reflect the scanlines in the vertical direction. The image will be mirrored
4674upside-down. </p>
4675
4676
4677<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004678 <h3 class="magick-header"><a id="floodfill"></a>-floodfill {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var> <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00004679</div>
4680
4681<p class="magick-description">floodfill the image with color at the specified offset.</p>
4682
4683<p>Flood fill starts from the given 'seed point' which is not gravity effected.
cristy29dc8652015-05-12 16:26:21 +00004684Any color that matches within <a href="command-line-options.html#fuzz" >-fuzz</a> color distance of the
cristyd2432012015-05-04 23:15:15 +00004685given <var>color</var> argument, connected to that 'seed point'
cristy29dc8652015-05-12 16:26:21 +00004686will be replaced with the current <a href="command-line-options.html#fill" >-fill</a> color. </p>
cristyd2432012015-05-04 23:15:15 +00004687
4688<p>Note that if the pixel at the 'seed point' does not itself match the given
cristy29dc8652015-05-12 16:26:21 +00004689<var>color</var> (according to <a href="command-line-options.html#fuzz" >-fuzz</a>), then no
cristyd2432012015-05-04 23:15:15 +00004690action will be taken. </p>
4691
cristy29dc8652015-05-12 16:26:21 +00004692<p>This operator works more like the <a href="command-line-options.html#opaque" >-opaque</a> option, than
cristyd2432012015-05-04 23:15:15 +00004693a more general flood fill that reads the matching color directly at the 'seed
cristy29dc8652015-05-12 16:26:21 +00004694point'. For this form of flood fill, look at <a href="command-line-options.html#draw" >-draw</a> and
cristyd2432012015-05-04 23:15:15 +00004695its 'color floodfill' drawing method. </p>
4696
4697
4698<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004699 <h3 class="magick-header"><a id="flop"></a>-flop</h3>
cristyd2432012015-05-04 23:15:15 +00004700</div>
4701
4702<p class="magick-description">create a <var>mirror image</var>.</p>
4703
4704<p>Reflect the scanlines in the horizontal direction, just like the image in
4705a vertical mirror. </p>
4706
4707
4708<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004709 <h3 class="magick-header"><a id="font"></a>-font <var>name</var></h3>
cristyd2432012015-05-04 23:15:15 +00004710</div>
4711
4712<p class="magick-description">set the font to use when annotating images with text, or creating labels.</p>
4713
4714<p>To print a complete list of fonts, use the <a href="command-line-options.html#list">-list font</a>
4715option (for versions prior to 6.3.6, use 'type' instead of 'font').</p>
4716
4717<p>In addition to the fonts specified by the above pre-defined list, you can
4718also specify a font from a specific source. For example <code>Arial.ttf</code>
4719is a TrueType font file, <code>ps:helvetica</code> is PostScript font, and
4720<code>x:fixed</code> is X11 font.</p>
4721
cristy29dc8652015-05-12 16:26:21 +00004722<p>For other settings that affect fonts, see the options <a
4723href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a
4724href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
cristyd2432012015-05-04 23:15:15 +00004725
4726
4727<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004728 <h3 class="magick-header"><a id="foreground"></a>-foreground <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00004729</div>
4730
4731<p class="magick-description">Define the foreground color for menus.", "display</p>
4732
cristy29dc8652015-05-12 16:26:21 +00004733<p>The color is specified using the format described under the <a
4734href="command-line-options.html#fill">-fill</a> option.</p>
cristyd2432012015-05-04 23:15:15 +00004735
4736<p>The default foreground color is black.</p>
4737
4738<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004739 <h3 class="magick-header"><a id="format"></a>-format <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00004740</div>
4741
4742<p class="magick-description">the image format type.</p>
4743
4744<p>When used with the <code>mogrify</code> utility, this option converts any
4745image to the image <a href="formats.html">format</a> you specify.
cristy29dc8652015-05-12 16:26:21 +00004746For a list of image format types supported by ImageMagick, use <a
4747href="command-line-options.html#list">-list format</a>.</p>
cristyd2432012015-05-04 23:15:15 +00004748
4749<p>By default the file is written to its original name. However, if the
4750filename extension matches a supported format, the extension is replaced with
4751the image format type specified with <a href="command-line-options.html#format">-format</a>. For
4752example, if you specify <var>tiff</var> as the format type and the
4753input image filename is <var>image.gif</var>, the output image
4754filename becomes <var>image.tiff</var>.</p>
4755
4756<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004757 <h3 class="magick-header"><a id="format_identify_"></a>-format <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00004758</div>
4759
4760<p class="magick-description">output formatted image characteristics.</p>
4761
4762<p>See <a href="escape.html">Format and Print Image
4763Properties</a> for an explanation on how to specify the argument to this
4764option.</p>
4765
4766<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004767 <h3 class="magick-header"><a id="frame"></a>-frame <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00004768</div>
4769
4770<p class="magick-description">Surround the image with a border or beveled frame.</p>
4771
cristy29dc8652015-05-12 16:26:21 +00004772<p>The color of the border is specified with the <a href="command-line-options.html#mattecolor"
4773>-mattecolor</a> command line option. </p>
cristyd2432012015-05-04 23:15:15 +00004774
4775<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>size</var> portion of the <var>geometry</var> argument indicates the amount of extra width and
4776height that is added to the dimensions of the image. If no offsets are given
4777in the <var>geometry</var> argument, then the border added is
4778a solid color. Offsets <var>x</var> and <var>y</var>, if present, specify that
4779the width and height of the border is partitioned to form an outer bevel of
4780thickness <var>x</var> pixels and an inner bevel of thickness
4781<var>y</var> pixels. Negative offsets make no sense as frame arguments.
4782</p>
4783
cristy29dc8652015-05-12 16:26:21 +00004784<p>The <a href="command-line-options.html#frame">-frame</a> option is affected by the current <a
4785href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
cristyd2432012015-05-04 23:15:15 +00004786'<code>Over</code>' composition method. It generates an image of the appropriate
4787size with the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting, and then
cristy29dc8652015-05-12 16:26:21 +00004788draws the frame of four distinct colors close to the current <a
4789href="command-line-options.html#mattecolor">-mattecolor</a>. The original image is then overlaid onto
cristyd2432012015-05-04 23:15:15 +00004790center of this image. This means that with the default compose method of
cristy29dc8652015-05-12 16:26:21 +00004791'<code>Over</code>' any transparent parts may be replaced by the current <a
4792href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
cristyd2432012015-05-04 23:15:15 +00004793
4794<p>The image composition is not
4795affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
4796
4797
4798<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004799 <h3 class="magick-header"><a id="frame_import_"></a>-frame</h3>
cristyd2432012015-05-04 23:15:15 +00004800</div>
4801
4802<p class="magick-description">include the X window frame in the imported image. </p>
4803<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004804 <h3 class="magick-header"><a id="function"></a>-function <var>function</var> <var>parameters</var></h3>
cristyd2432012015-05-04 23:15:15 +00004805</div>
4806
4807<p class="magick-description">Apply a function to channel values.</p>
4808
4809<p>This operator performs calculations based on the given arguments to modify
cristy29dc8652015-05-12 16:26:21 +00004810each of the color values for each previously set <a
4811href="command-line-options.html#channel">-channel</a> in the image. See <a
4812href="command-line-options.html#evaluate">-evaluate</a> for details concerning how the results of the
cristyd2432012015-05-04 23:15:15 +00004813calculations are handled.</p>
4814
cristy29dc8652015-05-12 16:26:21 +00004815<p>This is can be considered a multi-argument version of the <a
4816href="command-line-options.html#evaluate">-evaluate</a> operator. (Added in
cristyd2432012015-05-04 23:15:15 +00004817ImageMagick 6.4.8−8.)</p>
4818
4819<p>Here, <var>parameters</var> is a comma-separated list of
4820numerical values. The number of values varies depending on which <var>function</var> is selected. Choose the <var>function</var> from:</p>
4821
4822<pre>
cristy29dc8652015-05-12 16:26:21 +00004823Polynomial
4824Sinusoid
4825Arcsin
4826Arctan
cristyd2432012015-05-04 23:15:15 +00004827</pre>
4828
4829<p>To print a complete list of <a href="command-line-options.html#function">-function</a> operators,
4830use <a href="command-line-options.html#list">-list function</a>. Descriptions follow.</p>
4831
cristy29dc8652015-05-12 16:26:21 +00004832<dl class="dl-horizontal">
4833 <dt>Polynomial</dt>
4834 <dd><p>The <code>Polynomial</code> function takes an arbitrary number of parameters,
cristyd2432012015-05-04 23:15:15 +00004835these being the coefficients of a polynomial, in decreasing order of degree.
4836That is, entering</p>
4837
cristy29dc8652015-05-12 16:26:21 +00004838<pre>
4839-function Polynomial <var>a</var><sub><var>n</var></sub>,<var>a</var><sub><var>n</var>-1</sub>,...<var>a</var><sub>1</sub>,<var>a</var><sub>0</sub>
4840</pre>
cristyd2432012015-05-04 23:15:15 +00004841
4842<p>will invoke a polynomial function given by</p>
4843
cristy29dc8652015-05-12 16:26:21 +00004844<pre>
4845<var>a</var><sub><var>n</var></sub> <b><var>u</var></b><sup><var>n</var></sup> + <var>a</var><sub><var>n</var>-1</sub> <b><var>u</var></b><sup><var>n</var>-1</sup> + ··· <var>a</var><sub>1</sub> <b><var>u</var></b> + <var>a</var><sub>0</sub>,
4846</pre>
cristyd2432012015-05-04 23:15:15 +00004847
4848<p>where <b><var>u</var></b> is pixel's original normalized channel value.</p>
4849
4850<p>The <code>Polynomial</code> function can be used in place of <code>Set</code>
4851(the <var>constant</var> polynomial) and <code>Add</code>, <code>Divide</code>,
4852<code>Multiply</code>, and <code>Subtract</code> (some <var>linear</var>
cristy29dc8652015-05-12 16:26:21 +00004853polynomials) of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. The <a
4854href="command-line-options.html#level">-level</a> operator also affects channels linearly. Some
cristyd2432012015-05-04 23:15:15 +00004855correspondences follow.</p>
4856
4857<table class="table table-condensed table-striped">
cristyd2432012015-05-04 23:15:15 +00004858 <tr>
4859 <td>-evaluate Set <var>value</var> </td>
4860 <td>-function Polynomial <var>value</var></td>
4861 <td>(Constant functions; set <var>value</var>×100% gray when channels are RGB.)</td>
4862 </tr>
4863 <tr>
4864 <td>-evaluate Add <var>value</var> </td>
4865 <td>-function Polynomial 1,<var>value</var></td>
4866 </tr>
4867 <tr>
4868 <td>-evaluate Subtract <var>value</var> </td>
4869 <td>-function Polynomial 1,−<var>value</var></td>
4870 </tr>
4871 <tr>
4872 <td>-evaluate Multiply <var>value</var> </td>
4873 <td>-function Polynomial <var>value</var>,0</td>
4874 </tr>
4875 <tr>
4876 <td>+level black% x white%</td>
4877 <td>-function Polynomial A,B</td>
4878 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
4879 </tr>
4880</table>
4881
4882<p>The <code>Polynomial</code> function gives great versatility, since
4883polynomials can be used to fit any continuous curve to any degree of accuracy
4884desired.</p>
4885
4886</dd>
cristy29dc8652015-05-12 16:26:21 +00004887<dt>Sinusoid</dt>
cristyd2432012015-05-04 23:15:15 +00004888<dd>
4889<p>The <code>Sinusoid</code> function can be used to vary the channel values
4890sinusoidally by setting frequency, phase shift, amplitude, and a bias. These
4891values are given as one to four parameters, as follows,</p>
4892
cristy29dc8652015-05-12 16:26:21 +00004893<pre>
4894-function <code>Sinusoid</code> <var>freq</var>,[<var>phase</var>,[<var>amp</var>,[<var>bias</var>]]]
4895</pre>
cristyd2432012015-05-04 23:15:15 +00004896
4897<p>where <var>phase</var> is in degrees. (The domain [0,1] of the function
4898corresponds to 0 through <var>freq</var>×360 degrees.)
4899The result is that if a pixel's normalized channel value is originally
4900<b><var>u</var></b>, its resulting normalized value is given by </p>
4901
cristy29dc8652015-05-12 16:26:21 +00004902<pre>
cristyd2432012015-05-04 23:15:15 +00004903<var>amp</var> * sin(2*π* (<var>freq</var> * <b><var>u</var></b> + <var>phase</var> / 360)) + <var>bias</var>
cristy29dc8652015-05-12 16:26:21 +00004904</pre>
cristyd2432012015-05-04 23:15:15 +00004905
4906<p> For example, the following generates a curve that starts and ends at 0.9
4907(when <b><var>u</var></b>=0 and 1, resp.), oscillating three times between
4908.7−.2=.5 and .7+.2=.9. </p>
4909
cristy29dc8652015-05-12 16:26:21 +00004910<pre>
4911-function Sinusoid 3,-90,.2,.7
4912</pre>
cristyd2432012015-05-04 23:15:15 +00004913
4914<p>The default values of <var>amp</var> and <var>bias</var> are both .5. The default for <var>phase</var>
4915is 0.</p>
4916
4917<p>The <code>Sinusoid</code> function generalizes <code>Sin</code> and
4918<code>Cos</code> of the <a href="command-line-options.html#evaluate">-evaluate</a> operator by allowing
4919varying amplitude, phase and bias. The correspondence is as follows.</p>
4920
4921<table class="table table-condensed table-striped">
4922 <tr>
4923 <td>-evaluate Sin <var>freq</var> </td>
4924 <td>-function Sinusoid <var>freq</var>,0 </td>
4925 </tr>
4926 <tr>
4927 <td>-evaluate Cos <var>freq</var> </td>
4928 <td>-function Sinusoid <var>freq</var>,90 </td>
4929 </tr>
4930</table>
cristy29dc8652015-05-12 16:26:21 +00004931 </dd>
4932<dt>ArcSin</dt>
cristyd2432012015-05-04 23:15:15 +00004933<dd>
4934<p>The <code>ArcSin</code> function generates the inverse curve of a Sinusoid,
4935and can be used to generate cylindrical distortion and displacement maps.
4936The curve can be adjusted relative to both the input values and output range
4937of values.</p>
4938
cristy29dc8652015-05-12 16:26:21 +00004939<pre>
4940-function <code>ArcSin</code> <var>width</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
4941</pre>
cristyd2432012015-05-04 23:15:15 +00004942
4943<p>with all values given in terms of normalized color values (0.0 for black,
49441.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
4945for bout input (<var>width</var>), and output (<var>width</var>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
4946
cristy29dc8652015-05-12 16:26:21 +00004947<pre>
cristyd2432012015-05-04 23:15:15 +00004948<var>range</var>/π * asin( 2/<var>width</var> * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
cristy29dc8652015-05-12 16:26:21 +00004949</pre>
cristyd2432012015-05-04 23:15:15 +00004950
4951</dd>
cristy29dc8652015-05-12 16:26:21 +00004952<dt>ArcTan</dt>
cristyd2432012015-05-04 23:15:15 +00004953<dd>
4954<p>The <code>ArcTan</code> function generates a curve that smooth crosses from
4955limit values at infinities, though a center using the given slope value.
4956All these values can be adjusted via the arguments.</p>
4957
cristy29dc8652015-05-12 16:26:21 +00004958<pre>
4959-function <code>ArcTan</code> <var>slope</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
4960</pre>
cristyd2432012015-05-04 23:15:15 +00004961
4962<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
4963</p>
4964
cristy29dc8652015-05-12 16:26:21 +00004965<pre>
cristyd2432012015-05-04 23:15:15 +00004966<var>range</var>/π * atan( <var>slope</var>*π * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
cristy29dc8652015-05-12 16:26:21 +00004967</pre>
4968 </dd>
4969 </tr>
cristyd2432012015-05-04 23:15:15 +00004970</dl>
4971
4972
cristy29dc8652015-05-12 16:26:21 +00004973
cristyd2432012015-05-04 23:15:15 +00004974<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004975 <h3 class="magick-header"><a id="fuzz"></a>-fuzz <var>distance</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00004976</div>
4977
4978<p class="magick-description">Colors within this <var>distance</var> are considered equal.</p>
4979
4980<p>A number of algorithms search for a target color. By default the color must
4981be exact. Use this option to match colors that are close to the target color
4982in RGB space. For example, if you want to automagically trim the edges of an
4983image with <a href="command-line-options.html#trim">-trim</a> but the image was scanned and the target
4984background color may differ by a small amount. This option can account for
4985these differences.</p>
4986
4987<p>The <var>distance</var> can be in absolute intensity units or, by
4988appending <code>%</code> as a percentage of the maximum possible intensity (255,
498965535, or 4294967295).</p>
4990
cristy29dc8652015-05-12 16:26:21 +00004991<p>Use <a href="command-line-options.html#fuzz" >+fuzz</a> to reset the fuzz value to 0.</p>
cristyd2432012015-05-04 23:15:15 +00004992
4993
4994<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00004995 <h3 class="magick-header"><a id="fx"></a>-fx <var>expression</var></h3>
cristyd2432012015-05-04 23:15:15 +00004996</div>
4997
4998<p class="magick-description">apply a mathematical expression to an image or image channels.</p>
4999
5000<p>If the first character of <var>expression</var> is <code>@</code>,
5001the expression is read from a file titled by the remaining characters in the
5002string.</p>
5003
5004<p>See <a href="fx.html">FX,
5005The Special Effects Image Operator</a> for a detailed discussion of this
5006option.</p>
5007
5008
5009<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005010 <h3 class="magick-header"><a id="gamma"></a>-gamma <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00005011</div>
5012
5013<p class="magick-description">level of gamma correction.</p>
5014
5015<p>The same color image displayed on two different workstations may look
5016different due to differences in the display monitor. Use gamma correction to
5017adjust for this color difference. Reasonable values extend from
5018<code>0.8</code> to <code>2.3</code>. Gamma less than 1.0 darkens the image and
5019gamma greater than 1.0 lightens it. Large adjustments to image gamma may
5020result in the loss of some image information if the pixel quantum size is only
5021eight bits (quantum range 0 to 255).</p>
5022
5023<p>Gamma adjusts the image's channel values pixel-by-pixel according to
5024a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the
5025normalized or 0 to 1 color value. For example, using a value of gamma=2 is the
5026same as taking the square root of the image.</p>
5027
5028<p>You can apply separate gamma values to the red, green, and blue channels of
5029the image with a gamma value list delimited with commas (e.g.,
5030<code>1.7,2.3,1.2</code>).</p>
5031
5032<p>Use <a href="command-line-options.html#gamma">+gamma <var>value</var></a> to set the
5033image gamma level without actually adjusting the image pixels. This option
5034is useful if the image is of a known gamma but not set as an image attribute
5035(e.g. PNG images). Write the "file gamma" which is the reciprocal of the
5036display gamma; e.g., if your image is sRGB and you want to write a PNG gAMA
5037chunk, use</p>
5038
5039<pre>
5040convert input.png +gamma .45455 output.png
5041</pre>
5042
5043<p>(0.45455 is 1/2.2)</p>
5044
5045<p>Note that gamma adjustments are also available via the <a href="command-line-options.html#level">-level</a> operator.</p>
5046
5047<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005048 <h3 class="magick-header"><a id="gaussian-blur"></a>-gaussian-blur <var>radius</var><br />-gaussian-blur <var>radius</var>x<var>sigma</var></h3>
cristyd2432012015-05-04 23:15:15 +00005049</div>
5050
5051<p class="magick-description">Blur the image with a Gaussian operator.</p>
5052
5053<p>Convolve the image with a Gaussian or normal distribution using the given
cristy29dc8652015-05-12 16:26:21 +00005054<var >Sigma</var> value. The formula is:</p>
cristyd2432012015-05-04 23:15:15 +00005055
cristy29dc8652015-05-12 16:26:21 +00005056<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
cristyd2432012015-05-04 23:15:15 +00005057</div>
5058
cristy29dc8652015-05-12 16:26:21 +00005059<p>The <var >Sigma</var> value is the important argument, and
cristyd2432012015-05-04 23:15:15 +00005060determines the actual amount of blurring that will take place. </p>
5061
cristy29dc8652015-05-12 16:26:21 +00005062<p>The <var >Radius</var> is only used to determine the size of the
cristyd2432012015-05-04 23:15:15 +00005063array which will hold the calculated Gaussian distribution. It should be an
5064integer. If not given, or set to zero, IM will calculate the largest possible
5065radius that will provide meaningful results for the Gaussian distribution.
5066</p>
5067
cristy29dc8652015-05-12 16:26:21 +00005068<p>The larger the <var >Radius</var> the radius the slower the
5069operation is. However too small a <var >Radius</var>, and sever
5070aliasing effects may result. As a guideline, <var >Radius</var>
5071should be at least twice the <var >Sigma</var> value, though three
cristyd2432012015-05-04 23:15:15 +00005072times will produce a more accurate result. </p>
5073
5074<p>This differs from the faster <a href="command-line-options.html#blur">-blur</a> operator in that a
5075full 2-dimensional convolution is used to generate the weighted average of the
5076neighboring pixels. </p>
5077
5078<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5079pixels which are outside the image proper are blurred into the final result.
5080</p>
5081
5082
5083<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005084 <h3 class="magick-header"><a id="geometry"></a>-geometry <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00005085</div>
5086
5087<p class="magick-description">Set the preferred size and location of the image.</p>
5088
5089<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5090
5091<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005092 <h3 class="magick-header"><a id="gravity"></a>-gravity <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00005093</div>
5094
5095<p class="magick-description">Sets the current gravity suggestion for various other settings and options.</p>
5096
5097<p>Choices include: <code>NorthWest</code>, <code>North</code>,
5098<code>NorthEast</code>, <code>West</code>, <code>Center</code>, <code>East</code>,
cristy29dc8652015-05-12 16:26:21 +00005099<code>SouthWest</code>, <code>South</code>, <code>SouthEast</code>. Use <a
5100href="command-line-options.html#list">-list gravity</a> to get a complete list of <a
5101href="command-line-options.html#gravity">-gravity</a> settings available in your ImageMagick
cristyd2432012015-05-04 23:15:15 +00005102installation.</p>
5103
5104<p>The direction you choose specifies where to position text or subimages. For
5105example, a gravity of <code>Center</code> forces the text to be centered within
cristy29dc8652015-05-12 16:26:21 +00005106the image. By default, the image gravity is <code>NorthWest</code>. See <a
5107href="command-line-options.html#draw">-draw</a> for more details about graphic primitives. Only the
5108text primitive of <a href="command-line-options.html#draw">-draw</a> is affected by the <a
5109href="command-line-options.html#gravity">-gravity</a> option.</p>
cristyd2432012015-05-04 23:15:15 +00005110
5111<p>The <a href="command-line-options.html#gravity">-gravity</a> option is also used in concert with the
5112<a href="command-line-options.html#geometry">-geometry</a> setting and other settings or options that
cristy29dc8652015-05-12 16:26:21 +00005113take <var>geometry</var> as an argument, such as the <a
5114href="command-line-options.html#crop">-crop</a> option. </p>
cristyd2432012015-05-04 23:15:15 +00005115
5116<p>If a <a href="command-line-options.html#gravity">-gravity</a> setting occurs before another option
5117or setting having a <var>geometry</var> argument that specifies an
5118offset, the offset is usually applied to the point within the image suggested
5119by the <a href="command-line-options.html#gravity">-gravity</a> argument. Thus, in the following
5120command, for example, suppose the file <code>image.png</code> has dimensions
5121200x100. The offset specified by the argument to <a href="command-line-options.html#region">-region</a>
5122is (−40,+20). The argument to <a href="command-line-options.html#gravity">-gravity</a> is
5123<code>Center</code>, which suggests the midpoint of the image, at the point
5124(100,50). The offset (−40,20) is applied to that point, giving
5125(100−40,50+20)=(60,70), so the specified 10x10 region is located at
5126that point. (In addition, the <a href="command-line-options.html#gravity">-gravity</a> affects the
5127region itself, which is <var>centered</var> at the pixel
5128coordinate (60,70). (See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p>
5129
5130<pre>
5131convert image.png -gravity Center -region 10x10-40+20 \
5132 -negate output.png
5133</pre>
5134
cristy29dc8652015-05-12 16:26:21 +00005135<p>When used as an option to <a href="composite.html">composite</a>, <a
5136href="command-line-options.html#gravity">-gravity</a> gives the direction that the image gravitates
cristyd2432012015-05-04 23:15:15 +00005137within the composite.</p>
5138
cristy29dc8652015-05-12 16:26:21 +00005139<p>When used as an option to <a href="montage.html">montage</a>, <a
5140href="command-line-options.html#gravity">-gravity</a> gives the direction that an image gravitates
cristyd2432012015-05-04 23:15:15 +00005141within a tile. The default gravity is <code>Center</code> for this purpose.</p>
5142
5143
5144<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005145 <h3 class="magick-header"><a id="grayscale"></a>-grayscale <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00005146</div>
5147
5148<p class="magick-description">convert image to grayscale.</p>
5149
cristy29dc8652015-05-12 16:26:21 +00005150<p>This will use one of the <a href="command-line-options.html#intensity" >-intensity</a> methods to
cristyd2432012015-05-04 23:15:15 +00005151convert the given image into a linear-grayscale image. </p>
5152
5153<p>For example, to convert an image to (linear) Rec709Luminance grayscale, type:</p>
5154
5155<pre>
5156convert in.png -grayscale Rec709Luminance out.png
5157</pre>
5158
5159<p>which is equivalent to:</p>
5160
5161<pre>
5162convert in.png -colorspace gray out.png
5163</pre>
5164
5165<p>Similarly, to convert an image to (non-linear) Rec709Luma grayscale, type:</p>
5166
5167<pre>
5168convert in.png -grayscale Rec709Luma out.png
5169</pre>
5170
5171<p>which is equivalent to:</p>
5172
5173<pre>
5174convert in.png -set colorspace RGB -colorspace gray out.png
5175</pre>
5176
5177<p>Note that a 'colorspace' intensity method will produce the same result
5178regardless of the current colorpsace of the image. But a 'mathematical'
5179intensity method will depend on the current colorspace the image is currently
5180using. </p>
5181
cristy29dc8652015-05-12 16:26:21 +00005182<p>While this operation uses an <a href="command-line-options.html#intensity" >-intensity</a> method,
5183it does not use or set the <a href="command-line-options.html#intensity" >-intensity</a> setting, so
cristyd2432012015-05-04 23:15:15 +00005184will not effect other operations that may use that setting.</p>
5185
5186
5187<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005188 <h3 class="magick-header"><a id="green-primary"></a>-green-primary <var>x,y</var></h3>
cristyd2432012015-05-04 23:15:15 +00005189</div>
5190
5191<p class="magick-description">green chromaticity primary point.</p>
5192
5193
5194<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005195 <h3 class="magick-header"><a id="hald-clut"></a>-hald-clut</h3>
cristyd2432012015-05-04 23:15:15 +00005196</div>
5197
5198<p class="magick-description">apply a Hald color lookup table to the image.</p>
5199
5200<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
5201dimensions. Create it with the <code>HALD:</code> prefix (e.g. HALD:8). You
5202can apply any color transformation to the Hald image and then use this option
5203to apply the transform to the image. </p>
5204
5205<pre>
5206convert image.png hald.png -hald-clut transform.png
5207</pre>
5208
5209<p>This option provides a convenient method for you to use Gimp or Photoshop
5210to make color corrections to the Hald CLUT image and subsequently apply them
5211to multiple images using an ImageMagick script. </p>
5212
5213<p>Note that the representation is only of the normal RGB color space and that
5214the whole color value triplet is used for the interpolated lookup of the
cristy29dc8652015-05-12 16:26:21 +00005215represented Hald color cube image. Because of this the operation is not <a
5216href="command-line-options.html#channel" >-channel</a> setting effected, nor can it adjust or modify an
cristyd2432012015-05-04 23:15:15 +00005217images transparency or alpha/matte channel.</p>
5218
cristy29dc8652015-05-12 16:26:21 +00005219<p>See also <a href="command-line-options.html#clut" >-clut</a> which provides color value replacement
cristyd2432012015-05-04 23:15:15 +00005220of the individual color channels, usually involving a simpler gray-scale
5221image. E.g: gray-scale to color replacement, or modification by a histogram
5222mapping. </p>
5223
5224
5225<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005226 <h3 class="magick-header"><a id="help"></a>-help</h3>
cristyd2432012015-05-04 23:15:15 +00005227</div>
5228
5229<p class="magick-description">print usage instructions.</p>
5230
5231<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005232 <h3 class="magick-header"><a id="highlight-color"></a>-highlight-color <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00005233</div>
5234
5235<p class="magick-description">when comparing images, emphasize pixel differences with this color.</p>
5236
5237<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005238 <h3 class="magick-header"><a id="hough-lines"></a>-hough-lines <var>width</var>x<var>height</var>{<var>+threshold</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00005239</div>
5240
5241<p class="magick-description">identify straight lines in the image (e.g. -hough-lines 9x9+195).</p>
5242
5243<p>Use the Hough line detector with any binary edge extracted image to locate and draw any straight lines that it finds.</p>
5244
5245<p>The process accumulates counts for every white pixel in the binary edge image for every possible orientation (for angles from 0 to 179 in 1 deg increments) and distance from the center of the image to the corners (in 1 px increments). It stores the counts in an accumulator matrix of angle vs distance. The size of the accumulator will be 180x(diagonal/2). Next it searches the accumulator for peaks in counts and converts the locations of the peaks to slope and intercept in the normal x,y input image space. The algorithm uses slope/intercepts to find the endpoints clipped to the bounds of the image. The lines are drawn from the given endpoints. The counts are a measure of the length of the lines.</p>.
5246
5247<p>The WxH arguments specify the filter size for locating the peaks in the Hough accumulator. The threshold excludes lines whose counts are less than the threshold value.</p>
5248
cristy29dc8652015-05-12 16:26:21 +00005249<p>Use <code><a href="command-line-options.html#background" >-background</a></code> to specify the color of the background onto which the lines will be drawn. The default is black.</p>
cristyd2432012015-05-04 23:15:15 +00005250
cristy29dc8652015-05-12 16:26:21 +00005251<p>Use <code><a href="command-line-options.html#fill" >-fill</a></code> to specify the color of the lines. The default is black.</p>
cristyd2432012015-05-04 23:15:15 +00005252
cristy29dc8652015-05-12 16:26:21 +00005253<p>Use <code><a href="command-line-options.html#stroke" >-stroke</a></code> and <code><a href="command-line-options.html#strokewidth" >-strokewidth</a></code> to specify the thickness of the lines. The default is black and no strokewidth.</p>
cristyd2432012015-05-04 23:15:15 +00005254
5255<p>A text file listing the endpoints and counts may be created by using the suffix, .mvg, for the output image.</p>
5256
cristy29dc8652015-05-12 16:26:21 +00005257<p>Use <code><a href="command-line-options.html#define" >-define</a> hough-lines:accumulator=true</code> to return the accumulator image in addition to the lines image.</p>
cristyd2432012015-05-04 23:15:15 +00005258
5259<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005260 <h3 class="magick-header"><a id="iconGeometry"></a>-iconGeometry <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00005261</div>
5262
5263<p class="magick-description">specify the icon geometry.</p>
5264
5265<p>Offsets, if present in the geometry specification, are handled in the same
5266manner as the <a href="command-line-options.html#geometry">-geometry</a> option, using X11 style to
5267handle negative offsets.</p>
5268
5269<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5270
5271<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005272 <h3 class="magick-header"><a id="iconic"></a>-iconic</h3>
cristyd2432012015-05-04 23:15:15 +00005273</div>
5274
5275<p class="magick-description">start in icon mode in X Windows", 'animate', 'display</p>
5276
5277<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005278 <h3 class="magick-header"><a id="identify"></a>-identify</h3>
cristyd2432012015-05-04 23:15:15 +00005279</div>
5280
5281<p class="magick-description">identify the format and characteristics of the image.</p>
5282
5283<p>This information is printed: image scene number; image name; image size;
5284the image class (<var>DirectClass</var> or <var>PseudoClass</var>); the total number of unique colors; and the
5285number of seconds to read and transform the image. Refer to <a href="miff.html">MIFF</a> for
5286a description of the image class.</p>
5287
5288<p>If <a href="command-line-options.html#colors">-colors</a> is also specified, the total unique colors
cristy29dc8652015-05-12 16:26:21 +00005289in the image and color reduction error values are printed. Refer to <a
5290href="quantize.html">color
cristyd2432012015-05-04 23:15:15 +00005291reduction algorithm</a> for a description of these values.</p>
5292
5293<p>If <a href="command-line-options.html#verbose">-verbose</a> precedes this option, copious
5294amounts of image properties are displayed including image statistics, profiles,
5295image histogram, and others.</p>
5296
5297<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005298 <h3 class="magick-header"><a id="ift"></a>-ift</h3>
cristyd2432012015-05-04 23:15:15 +00005299</div>
5300
5301<p class="magick-description">implements the inverse discrete Fourier transform (DFT).</p>
5302
5303<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
5304users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase
5305images from the frequency domain to a single image in the normal or spatial
cristy29dc8652015-05-12 16:26:21 +00005306domain. See for example, <a
5307href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>,
cristyd2432012015-05-04 23:15:15 +00005308<a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and
5309<a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p>
5310
5311<p>For example, depending upon the image format used to store the result of
5312the <a href="command-line-options.html#fft">-fft</a>, one would use either</p>
5313
5314<pre>
5315convert fft_image.miff -ift fft_image_ift.png
5316</pre>
5317
5318<p>or</p>
5319
5320<pre>
5321convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png
5322</pre>
5323
5324<p>The resulting image may need to be cropped due to padding introduced when
cristy29dc8652015-05-12 16:26:21 +00005325the original image, prior to the <a href="command-line-options.html#fft">-fft</a> or <a
5326href="command-line-options.html#fft">+fft</a>, was not square or even dimensioned. Any padding is at
cristyd2432012015-05-04 23:15:15 +00005327the right and/or bottom sides of the image.</p>
5328
5329<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
5330use <a href="command-line-options.html#ift">-ift</a>.</p>
5331
5332<p>Use <a href="command-line-options.html#ift">+ift</a> (with HDRI enabled) to transform a pair of real
5333and imaginary images from the frequency domain to a single image in the normal
5334(spatial) domain.</p>
5335
cristy29dc8652015-05-12 16:26:21 +00005336<p>By default the IFT is not normalized (and the FFT is). Use "<code><a href="command-line-options.html#define" >-define</a> fourier:normalize=inverse</code> to explictly normalize the IFT and unnormalize the FFT.</p>
cristyd2432012015-05-04 23:15:15 +00005337
5338<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005339 <h3 class="magick-header"><a id="immutable"></a>-immutable</h3>
cristyd2432012015-05-04 23:15:15 +00005340</div>
5341
5342<p class="magick-description">make image immutable.</p>
5343
5344<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005345 <h3 class="magick-header"><a id="implode"></a>-implode <var>factor</var></h3>
cristyd2432012015-05-04 23:15:15 +00005346</div>
5347
5348<p class="magick-description">implode image pixels about the center.</p>
5349
5350<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005351 <h3 class="magick-header"><a id="insert"></a>-insert <var>index</var></h3>
cristyd2432012015-05-04 23:15:15 +00005352</div>
5353
5354<p class="magick-description">insert the last image into the image sequence.</p>
5355
5356<p>This option takes last image in the current image sequence and inserts it
5357at the given index. If a negative index is used, the insert position is
5358calculated before the last image is removed from the sequence. As such
5359<code>-insert -1</code> will result in no change to the image sequence.</p>
5360
5361<p>The <code>+insert</code> option is equivalent to <code>-insert -1</code>. In
5362other words, insert the last image, at the end of the current image sequence.
5363Consequently this has no effect on the image sequence order.</p>
5364
5365<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005366 <h3 class="magick-header"><a id="intensity"></a>-intensity <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00005367</div>
5368
5369<p class="magick-description">method to generate intensity value from pixel.</p>
5370
5371<p>ImageMagick provides a number of methods used in situations where an
5372operatory needs to determine a single grayscale value for some purpose, from
5373an image with red, green, and blue pixel components. Typically the linear
5374<code>Rec709Luminance</code> formula is used, which is the same formula used when
5375converting images to <code>-colorspace gray</code>. </p>
5376
5377<p>The following formulas are currently provided, and will first convert
5378the pixel values to linear-RGB or non-linear sRGB colorspace before
5379being applied to calulate the final greyscale value. </p>
5380
5381<pre>
5382 Rec601Luma 0.298839R' + 0.586811G'+ 0.114350B'
5383 Rec601Luminance 0.298839R + 0.586811G + 0.114350B
5384 Rec709Luma 0.212656R' + 0.715158G' + 0.072186B'
5385 Rec709Luminance 0.212656R + 0.715158G + 0.072186B
5386 Brightness max(R', G', B')
5387 Lightness (min(R', G', B') + max(R', G', B')) / 2.0
5388</pre>
5389<p>Note that the above R,G,B values is the image's linear-RGB values, while
5390R',G',B' are sRGB non-linear values. </p>
5391
5392<p>These intensity methods are mathematical in nature and will use the
5393current value in the images respective R,G,B channel regardless of
5394what that is, or what colorspace the image is currently using.</p>
5395
5396<pre>
5397 Average (R + G + B) / 3.0
5398 MS (R^2 + G^2 + B^2) / 3.0
5399 RMS sqrt( (R^2 + G^2 + B^2) / 3.0 )
5400</pre>
5401
5402<p>These methods are often used for other purposes, such as generating a
cristy29dc8652015-05-12 16:26:21 +00005403grayscale difference image between two color images (using <a href="command-line-options.html#compose"
5404>-compose</a> '<code>Difference</code>' composition. </p>
cristyd2432012015-05-04 23:15:15 +00005405
5406<p> For example The 'MS' (Mean Squared) setting is good for minimizing color
5407error comparisions. While... The method 'RMS' (Root Mean Squared) for
5408example is appropriate for calculating color vector distance, from a color
cristy29dc8652015-05-12 16:26:21 +00005409difference image. This is equivalent to the color only component of the <a
5410href="command-line-options.html#fuzz" >-fuzz</a> factor color compare setting. </p>
cristyd2432012015-05-04 23:15:15 +00005411
cristy29dc8652015-05-12 16:26:21 +00005412<p>See also <a href="command-line-options.html#grayscale" >-grayscale</a> which applies one of the above
5413grayscaling formula directly to an image without setting the <a
5414href="command-line-options.html#intensity" >-intensity</a> setting.</p>
cristyd2432012015-05-04 23:15:15 +00005415
cristy29dc8652015-05-12 16:26:21 +00005416<p>The <a href="command-line-options.html#colorspace" >-colorspace gray</a> image conversion also uses
cristyd2432012015-05-04 23:15:15 +00005417the current intensity setting, but will always convert the image to the
5418appropriate sRGB or linear-RGB colorspace before appling the above
5419function.</p>
5420
5421<p>To print a complete list of posible pixel intensity setting methods, use <a href="command-line-options.html#list">-list intensity</a>.</p>
5422
cristy29dc8652015-05-12 16:26:21 +00005423<p>Operators affected by the <a href="command-line-options.html#intensity" >-intensity</a> setting include:</p>
cristyd2432012015-05-04 23:15:15 +00005424
5425<pre>
5426-adaptive-blur
5427-adaptive-sharpen
5428-black-threshold
5429-clut (when mapping greyscale CLUT image to alpha channel if set by -channels)
5430-colors for gray colorspace
5431-compose {LightenIntensity, DarkenIntensity, CopyOpacity, CopyBlack}
5432-contrast-stretch
5433-distort {ErodeIntensity, DilateIntensity}
5434-normalize
5435-random-threshold
5436-selective-blur
5437-shade
5438-threshold
5439-tint
5440-white-threshold
5441</pre>
5442
5443<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005444 <h3 class="magick-header"><a id="intent"></a>-intent <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00005445</div>
5446
5447<p class="magick-description">use this type of rendering intent when managing the image color.</p>
5448
5449<p>Use this option to affect the color management operation of an image (see
5450<a href="command-line-options.html#profile">-profile</a>). Choose from these intents: <code>Absolute,
5451Perceptual, Relative, Saturation</code>.</p>
5452
5453<p>The default intent is Perceptual for the sRGB colorspace and undefined for the RGB and gray colorspaces.</p>
5454
5455<p>To print a complete list of rendering intents, use <a href="command-line-options.html#list">-list intent</a>.</p>
5456
5457<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005458 <h3 class="magick-header"><a id="interlace"></a>-interlace <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00005459</div>
5460
5461<p class="magick-description">the type of interlacing scheme.</p>
5462
5463<p>Choose from:</p>
5464
5465<pre>
5466 none
5467 line
5468 plane
5469 partition
5470 JPEG
5471 GIF
5472 PNG
5473</pre>
5474
5475<p>This option is used to specify the type of interlacing scheme for raw image
5476formats such as <code>RGB</code> or <code>YUV</code>.</p>
5477
5478<p><code>None</code> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
5479
5480<p><code>Line</code> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
5481
5482<p><code>Plane</code> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
5483
5484<p><code>Partition</code> is like plane except the different planes are saved to
5485individual files (e.g. image.R, image.G, and image.B).</p>
5486
5487<p>Use <code>Line</code> or <code>Plane</code> to create an <code>interlaced
5488PNG</code> or <code>GIF</code> or <code>progressive JPEG</code> image.</p>
5489
5490<p>To print a complete list of interlacing schemes, use <a href="command-line-options.html#list">-list
5491interlace</a>.</p>
5492
5493<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005494 <h3 class="magick-header"><a id="interpolate"></a>-interpolate <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00005495</div>
5496
5497<p class="magick-description">Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</p>
5498
5499<p>When looking up the color of a pixel using a non-integer floating point
5500value, you typically fall in between the pixel colors defined by the source
5501image. This setting determines how the color is determined from the colors of
5502the pixels surrounding that point. That is how to determine the color of a
5503point that falls between two, or even four different colored pixels. </p>
5504
cristy29dc8652015-05-12 16:26:21 +00005505<dl class="dl-horizontal">
5506 <dt>integer</dt>
5507 <dd>The color of the top-left pixel (floor function)</dd>
5508 <dt>nearest-neighbor</dt>
5509 <dd>The nearest pixel to the lookup point (rounded function)</dd>
5510 <dt>average</dt>
5511 <dd>The average color of the surrounding four pixels</dd>
5512 <dt>bilinear</dt>
5513 <dd>A double linear interpolation of pixels (the default)</dd>
5514 <dt>mesh</dt>
5515 <dd>Divide area into two flat triangular interpolations</dd>
5516 <dt>bicubic</dt>
5517 <dd>Fitted bicubic-spines of surrounding 16 pixels</dd>
5518 <dt>spline</dt>
5519 <dd>Direct spline curves (colors are blurred)</dd>
5520 <dt>filter</dt>
5521 <dd>Use resize <a href="command-line-options.html#filter">-filter</a> settings</dd>
5522</dl>
cristyd2432012015-05-04 23:15:15 +00005523
cristy29dc8652015-05-12 16:26:21 +00005524<p>This most important for distortion operators such as <a href="command-line-options.html#distort"
5525>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, <a href="command-line-options.html#transform"
5526>-transform</a> and <a href="command-line-options.html#fx" >-fx</a>. </p>
cristyd2432012015-05-04 23:15:15 +00005527
5528<p>To print a complete list of interpolation methods, use <a href="command-line-options.html#list">-list interpolate</a>.</p>
5529
cristy29dc8652015-05-12 16:26:21 +00005530<p>See also <a href="command-line-options.html#virtual-pixel" >-virtual-pixel</a>, for control of the
cristyd2432012015-05-04 23:15:15 +00005531lookup for positions outside the boundaries of the image. </p>
5532
5533
5534<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005535 <h3 class="magick-header"><a id="interline-spacing"></a>-interline-spacing <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00005536</div>
5537
5538<p class="magick-description">the space between two text lines.</p>
5539
5540<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005541 <h3 class="magick-header"><a id="interword-spacing"></a>-interword-spacing <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00005542</div>
5543
5544<p class="magick-description">the space between two words.</p>
5545
5546<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005547 <h3 class="magick-header"><a id="kerning"></a>-kerning <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00005548</div>
5549
5550<p class="magick-description">the space between two letters.</p>
5551
5552<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005553 <h3 class="magick-header"><a id="kuwahara"></a>-kuwahara <var>radius</var><br />-kuwahara <var>radius</var>x<var>sigma</var></h3>
cristyd2432012015-05-04 23:15:15 +00005554</div>
5555
5556<p class="magick-description">edge preserving noise reduction filter.</p>
5557
cristy29dc8652015-05-12 16:26:21 +00005558<p>The <var >radius</var> is more important than the <var >sigma</var>. If <var >sigma</var> is left off, it will be computed automatically from the <var >radius</var> as <var >sigma</var>=<var >radius</var>-0.5. The <var >sigma</var> provides a bit of additional smoothing control.</p>
cristyd2432012015-05-04 23:15:15 +00005559
5560
5561<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005562 <h3 class="magick-header"><a id="label"></a>-label <var>name</var></h3>
cristyd2432012015-05-04 23:15:15 +00005563</div>
5564
5565<p class="magick-description">assign a label to an image.</p>
5566
5567<p>Use this option to assign a specific label to the image, as it is read in
cristy29dc8652015-05-12 16:26:21 +00005568or created. You can use the <a href="command-line-options.html#set" >-set</a> operation to re-assign
cristyd2432012015-05-04 23:15:15 +00005569a the labels of images already read in. Image formats such as TIFF, PNG,
5570MIFF, supports saving the label information with the image.</p>
5571
5572<p>When saving an image to a <var>PostScript</var> file, any label
5573assigned to an image is used as a header string to print above the postscript
5574image. </p>
5575
5576<p>You can include the image filename, type, width, height, or other image
5577attribute by embedding special format character. See <a href="escape.html">Format and Print Image
5578Properties</a> for details of the percent escape codes.</p>
5579
5580<p>For example,</p>
5581
cristy29dc8652015-05-12 16:26:21 +00005582<pre>
5583-label "%m:%f %wx%h" bird.miff
5584</pre>
cristyd2432012015-05-04 23:15:15 +00005585
5586<p>assigns an image label of <code>MIFF:bird.miff 512x480</code> to the
5587"<code>bird.miff</code>" image and whose width is 512 and height is 480, as it
5588is read in. If a <a href="command-line-options.html#label">+label</a> option was used instead, any
5589existing label present in the image would be used. You can remove all labels
5590from an image by assigning the empty string. </p>
5591
5592<p>A label is not drawn on the image, but is embedded in the image datastream
5593via <var>Label</var> tag or similar mechanism. If you want the label to be
5594visible on the image itself, use the <a href="command-line-options.html#draw">-draw</a> option, or
5595during the final processing in the creation of an image montage.</p>
5596
5597<p>If the first character of <var>string</var> is <var>@</var>, the image label is read from a file titled by the
5598remaining characters in the string. Labels in a file are literal, no embedded
5599formatting characters are recognized.</p>
5600
5601
5602<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005603 <h3 class="magick-header"><a id="lat"></a>-lat <var>width</var><br />-lat <var>width</var>x<var>height</var>{<var>+-</var>}<var>offset</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00005604</div>
5605
5606<p class="magick-description">perform local adaptive threshold.</p>
5607
5608<p>Adaptively threshold each pixel based on the value of pixels in a
5609surrounding window. If the current pixel is lighter than this average plus
5610the optional <code>offset</code>, then it is made white, otherwise it is made
5611black. Small variations in pixel values such as found in scanned documents
5612can be ignored if offset is positive. A negative offset will make it more
5613sensitive to those small variations. </p>
5614
5615<p>This is commonly used to threshold images with an uneven background. It is
5616based on the assumption that average color of the small window is the
5617the local background color, from which to separate the foreground color. </p>
5618
5619
5620<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005621 <h3 class="magick-header"><a id="layers"></a>-layers <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00005622</div>
5623
5624<p class="magick-description">handle multiple images forming a set of image layers or animation frames.</p>
5625
5626<p>Perform various image operation methods to a ordered sequence of images
5627which may represent either a set of overlaid 'image layers', a GIF disposal
5628animation, or a fully-'coalesced' animation sequence. </p>
5629
5630<table class="table table-condensed table-striped">
5631 <tbody>
5632 <tr>
5633 <th style="width: 8%">Method</th>
5634 <th>Description</th>
5635 </tr>
5636
5637 <tr>
5638 <td>compare-any</td>
5639 <td>Crop the second and later frames to the smallest rectangle
cristy29dc8652015-05-12 16:26:21 +00005640 that contains all the differences between the two images. No GIF <a
5641 href="command-line-options.html#dispose" >-dispose</a> methods are taken into account. </td>
cristyd2432012015-05-04 23:15:15 +00005642 </tr>
5643
cristy29dc8652015-05-12 16:26:21 +00005644 <tr><td></td><td>This exactly the same as the <a href="command-line-options.html#deconstruct"
5645 >-deconstruct</a> operator, and does not preserve animations normal
cristyd2432012015-05-04 23:15:15 +00005646 working, especially when animation used layer disposal methods such as
5647 '<code>Previous</code>' or '<code>Background</code>'. </td>
5648 </tr>
5649
5650 <tr>
5651 <td>compare-clear</td>
5652 <td>As '<code>compare-any</code>' but crop to the bounds of any
5653 opaque pixels which become transparent in the second frame. That is the
5654 smallest image needed to mask or erase pixels for the next frame. </td>
5655 </tr>
5656
5657 <tr>
5658 <td>compare-overlay</td>
5659 <td>As '<code>compare-any</code>' but crop to pixels that add
5660 extra color to the next image, as a result of overlaying color pixels.
5661 That is the smallest single overlaid image to add or change colors. </td>
5662 </tr>
5663
cristy29dc8652015-05-12 16:26:21 +00005664 <tr><td></td><td>This can be used with the <a href="command-line-options.html#compose" >-compose</a> alpha
cristyd2432012015-05-04 23:15:15 +00005665 composition method '<code>change-mask</code>', to reduce the image to
5666 just the pixels that need to be overlaid. </td>
5667 </tr>
5668
5669 <tr>
5670 <td>coalesce</td>
cristy29dc8652015-05-12 16:26:21 +00005671 <td>Equivalent to a call to the <a href="command-line-options.html#coalesce"
5672 >-coalesce</a> operator. Apply the layer disposal methods set in the
cristyd2432012015-05-04 23:15:15 +00005673 current image sequence to form a fully defined animation sequence, as
5674 it should be displayed. Effectively converting a GIF animation into a
5675 'film strip'-like animation. </td>
5676 </tr>
5677
5678 <tr>
5679 <td>composite</td>
5680 <td>Alpha Composition of two image lists, separated by a
5681 "<code>null:</code>" image, with the destination image list first, and
5682 the source images last. An image from each list are composited
5683 together until one list is finished. The separator image and source
5684 image lists are removed. </td>
5685 </tr>
5686
5687
5688 <tr><td></td>
cristy29dc8652015-05-12 16:26:21 +00005689 <td>The <a href="command-line-options.html#geometry" >-geometry</a> offset is adjusted according
5690 to <a href="command-line-options.html#gravity" >-gravity</a> in accordance of the virtual
5691 canvas size of the first image in each list. Unlike a normal <a
5692 href="command-line-options.html#composite" >-composite</a> operation, the canvas offset is also
cristyd2432012015-05-04 23:15:15 +00005693 added to the final composite positioning of each image. </td> </tr>
5694
5695 <tr><td></td>
5696 <td>If one of the image lists only contains one image, that image is
5697 applied to all the images in the other image list, regardless of which
5698 list it is. In this case it is the image meta-data of the list which
5699 preserved. </td>
5700 </tr>
5701
5702
5703 <tr>
5704 <td>dispose</td>
5705 <td>This like '<code>coalesce</code>' but shows the look of
5706 the animation after the layer disposal method has been applied, before
5707 the next sub-frame image is overlaid. That is the 'dispose' image that
cristy29dc8652015-05-12 16:26:21 +00005708 results from the application of the GIF <a href="command-line-options.html#dispose"
5709 >-dispose</a> method. This allows you to check what
cristyd2432012015-05-04 23:15:15 +00005710 is going wrong with a particular animation you may be developing.
5711 </td>
5712 </tr>
5713
5714 <tr>
5715 <td>flatten</td>
5716 <td>Create a canvas the size of the first images virtual
cristy29dc8652015-05-12 16:26:21 +00005717 canvas using the current <a href="command-line-options.html#background" >-background</a> color,
5718 and <a href="command-line-options.html#compose" >-compose</a> each image in turn onto that
cristyd2432012015-05-04 23:15:15 +00005719 canvas. Images falling outside that canvas is clipped. Final
5720 image will have a zero virtual canvas offset. </td>
5721 </tr>
5722
5723 <tr><td></td>
5724 <td>This usually used as one of the final 'image layering' operations
5725 overlaying all the prepared image layers into a final image. </td>
5726 </tr>
5727
5728 <tr><td></td>
5729 <td>For a single image this method can also be used to fillout a virtual
5730 canvas with real pixels, or to underlay an opaque color to remove
5731 transparency from an image.</td>
5732 </tr>
5733
5734
5735 <tr>
5736 <td>merge</td>
5737 <td>As 'flatten' method but merging all the given image
5738 layers to create a new layer image just large enough to hold all the
5739 image without clipping or extra space. The new images virtual offset
5740 will preserve the position of the new layer, even if this offset is
5741 negative. The virtual canvas size of the first image is preserved.
5742 </td>
5743 </tr>
5744
5745 <tr><td></td><td>Caution is advised when handling image layers with
5746 negative offsets as few image file formats handle them correctly.
cristy29dc8652015-05-12 16:26:21 +00005747 Following this operation method with <a href="command-line-options.html#repage" >+repage</a>
cristyd2432012015-05-04 23:15:15 +00005748 will remove the layer offset, and create an image in which all the
5749 overlaid image positions relative to each other is preserved, though
5750 not necessarily exactly where you specified them.
5751 </td>
5752 </tr>
5753
5754 <tr><td></td><td>See also 'trim-bounds' below which is closely related but
5755 without doing the'flatten' to merge the images together. </td>
5756 </tr>
5757
5758 <tr>
5759 <td>mosaic</td>
5760 <td>As 'flatten' method but expanding the initial canvas size
5761 of the first image in a positive direction only so as to hold all the
5762 image layers. However as a virtual canvas is 'locked' to the origin,
5763 by its own definition, image layers with a negative offsets will still
5764 become clipped by the top and left edges. See 'merge' or 'trim-bounds'
5765 if this could be a problem. </td>
5766
5767 </tr>
5768
5769 <tr><td></td><td>This method is commonly used to layout individual image
5770 using various offset but without knowing the final canvas size. The
5771 resulting image will, like 'flatten' not have any virtual offset, so
5772 can be saved to any image file format. </td>
5773 </tr>
5774
5775
5776 <tr>
5777 <td>optimize</td>
5778 <td>Optimize a coalesced animation, into GIF animation using
5779 a number of general techniques. This currently a short cut to
5780 apply both the '<code>optimize-frame</code>', and
5781 '<code>optimize-transparency</code>' methods but may be expanded to
5782 include other optimization methods as they are developed. </td>
5783 </tr>
5784
5785 <tr>
5786 <td>optimize-frame</td>
5787 <td>Optimize a coalesced animation, into GIF animation by
5788 reducing the number of pixels per frame as much as possible by
5789 attempting to pick the best layer disposal method to use, while ensuring
5790 the result will continue to animate properly. </td>
5791 </tr>
5792
5793 <tr><td></td><td> There is no guarantee that the best optimization is found.
5794 But then no reasonably fast GIF optimization algorithm can do this.
5795 However this does seem to do better than most other GIF frame
5796 optimizers seen. </td>
5797 </tr>
5798
5799 <tr>
5800 <td>optimize-plus</td>
5801 <td>As '<code>optimize-frame</code>' but attempt to improve the
5802 overall optimization by adding extra frames to the animation, without
5803 changing the final look or timing of the animation. The frames are
5804 added to attempt to separate the clearing of pixels from the
5805 overlaying of new additional pixels from one animation frame to the
5806 next. If this does not improve the optimization (for the next frame
5807 only), it will fall back to the results of the previous normal
5808 '<code>optimize-frame</code>' technique. </td>
5809 </tr>
5810
5811 <tr><td></td><td>There is the possibility that the change in the disposal
5812 style will result in a worsening in the optimization of later frames,
5813 though this is unlikely. In other words there no guarantee that it is
5814 better than the normal '<code>optimize-frame</code>' technique. For some
5815 animations however you can get a vast improvement in the final
5816 animation size. </td>
5817 </tr>
5818
5819 <tr>
5820 <td>optimize-transparency</td>
5821 <td>Given a GIF animation, replace any pixel in the sub-frame
5822 overlay images with transparency, if it does not change the resulting
cristy29dc8652015-05-12 16:26:21 +00005823 animation by more than the current <a href="command-line-options.html#fuzz" >-fuzz</a> factor.
cristyd2432012015-05-04 23:15:15 +00005824 </td>
5825 </tr>
5826
5827 <tr><td></td><td>This should allow a existing frame optimized GIF animation
5828 to compress into a smaller file size due to larger areas of one
5829 (transparent) color rather than a pattern of multiple colors repeating
5830 the current disposed image of the last frame. </td>
5831 </tr>
5832
5833 <tr>
5834 <td>remove-dups</td>
5835 <td>Remove (and merge time delays) of duplicate consecutive
5836 images, so as to simplify layer overlays of coalesced animations.
5837 </td>
5838 </tr>
5839
5840 <tr><td></td><td>Usually this a result of using a constant time delay
5841 across the whole animation, or after a larger animation was split into
5842 smaller sub-animations. The duplicate frames could also have been
5843 used as part of some frame optimization methods. </td>
5844 </tr>
5845
5846 <tr>
5847 <td>remove-zero</td>
5848 <td>Remove any image with a zero time delay, unless ALL the
5849 images have a zero time delay (and is not a proper timed animation, a
5850 warning is then issued). </td>
5851 </tr>
5852
5853 <tr><td></td><td>In a GIF animation, such images are usually frames which
5854 provide partial intermediary updates between the frames that are
5855 actually displayed to users. These frames are usually added for
5856 improved frame optimization in GIF animations. </td>
5857 </tr>
5858
5859 <tr>
5860 <td>trim-bounds</td>
5861 <td>Find the bounds of all the images in the current
5862 image sequence, then adjust the offsets so all images are contained on
5863 a minimal positive canvas. None of the image data is modified or
5864 merged, only the individual image virtual canvas size and offset.
5865 All the images is given the same canvas size, and and will have
5866 a positive offset, but will remain in the same position relative to
5867 each other. As a result of the minimal canvas size at least one image
5868 will touch every edge of that canvas. The image data touching those
5869 edges however may be transparent. </td>
5870 </tr>
5871
5872 <tr><td></td><td>The result is much like if you used 'merge' followed by a
cristy29dc8652015-05-12 16:26:21 +00005873 <a href="command-line-options.html#repage" >+repage</a> option, except that all the images
cristyd2432012015-05-04 23:15:15 +00005874 have been kept separate. If 'flatten' is used after using
5875 'trim-bounds' you will get the same result. </td>
5876 </tr>
5877
5878 </tbody>
5879</table>
5880
5881<p>To print a complete list of layer types, use <a href="command-line-options.html#list">-list layers</a>.</p>
5882
cristy29dc8652015-05-12 16:26:21 +00005883<p>The operators <a href="command-line-options.html#coalesce" >-coalesce</a>, <a href="command-line-options.html#deconstruct"
5884>-deconstruct</a>, <a href="command-line-options.html#flatten" >-flatten</a>, and <a href="command-line-options.html#mosaic"
5885>-mosaic</a> are only aliases for the above methods and may be depreciated in
5886the future. Also see <a href="command-line-options.html#page" >-page</a>, <a href="command-line-options.html#repage"
5887>-repage</a> operators, the <a href="command-line-options.html#compose" >-compose</a> setting, and the
5888GIF <a href="command-line-options.html#dispose" >-dispose</a> and <a href="command-line-options.html#delay" >-delay</a>
cristyd2432012015-05-04 23:15:15 +00005889settings. </p>
5890
5891
5892<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005893 <h3 class="magick-header"><a id="level"></a>-level <var>black_point</var>{,<var>white_point</var>}{<var>%</var>}{,<var>gamma</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00005894</div>
5895
5896<p class="magick-description">adjust the level of image channels.</p>
5897
5898<p>Given one, two or three values delimited with commas: black-point,
5899white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
5900white points range from 0 to <var>QuantumRange</var>, or from 0 to
5901100%; if the white point is omitted it is set to (<var>QuantumRange</var> - black_point), so as to center contrast changes.
5902If a <code>%</code> sign is present anywhere in the string, both black and white
cristy29dc8652015-05-12 16:26:21 +00005903points are percentages of the full color range. Gamma will do a <a
5904href="command-line-options.html#gamma">-gamma</a> adjustment of the values. If it is omitted, the
cristyd2432012015-05-04 23:15:15 +00005905default of 1.0 (no gamma correction) is assumed.</p>
5906
5907<p>In normal usage (<code>-level</code>) the image values are stretched so that
5908the given '<code>black_point</code>' value in the original image is set to zero
5909(or black), while the given '<code>white_point</code>' value is set to <var>QuantumRange</var> (or white). This provides you with direct
5910contrast adjustments to the image. The '<code>gamma</code>' of the resulting
5911image will then be adjusted. </p>
5912
5913<p>From ImageMagick v6.4.1-9 using the plus form of the operator
5914(<code>+level</code>) or adding the special '!' flag anywhere in the argument
5915list, will cause the operator to do the reverse of the level adjustment. That
5916is a zero, or <var>QuantumRange</var> value (black, and white, resp.)
5917in the original image, is adjusted to the given level values, allowing you to
5918de-contrast, or compress the channel values within the image. The
5919'<code>gamma</code>' is adjusted before the level adjustment to de-contrast the
5920image is made. </p>
5921
5922<p>Only the channels defined by the current <a href="command-line-options.html#channel">-channel</a>
5923setting are adjusted (defaults to RGB color channels only), allowing you to
5924limit the effect of this operator. </p>
5925
5926<p>Please note that the transparency channel is treated as 'matte'
5927values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5928
5929
5930<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005931 <h3 class="magick-header"><a id="level-colors"></a>-level-colors {<var>black_color</var>}{,}{<var>white_color</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00005932</div>
5933
5934<p class="magick-description">adjust the level of an image using the provided dash separated colors.</p>
5935
5936<p>This function is exactly like <a href="command-line-options.html#level">-level</a>, except that the
5937value value for each color channel is determined by the
5938'<code>black_color</code>' and '<code>white_color</code>' colors given (as
5939described under the <a href="command-line-options.html#fill">-fill</a> option). </p>
5940
5941<p>This effectually means the colors provided to <code>-level-colors</code>
5942is mapped to become 'black' and 'white' respectively, with all the other
5943colors linearly adjusted (or clipped) to match that change. Each channel is
5944adjusted separately using the channel values of the colors specified. </p>
5945
5946<p>On the other hand the plus form of the operator (<code>+level-colors</code>)
5947will map the image color 'black' and 'white' to the given colors
5948respectively, resulting in a gradient (de-contrasting) tint of the image to
5949those colors. This can also be used to convert a plain gray-scale image into a
5950one using the gradient of colors specified. </p>
5951
5952<p>By supplying a single color with a comma separator either before or after
5953that color, will just replace the respective 'black' or 'white' point
5954respectively. But if no comma separator is provided, the given color is
5955used for both the black and white color points, making the operator either
5956threshold the images around that color (- form) or set all colors to that
5957color (+ form). </p>
5958
5959
5960<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00005961 <h3 class="magick-header"><a id="limit"></a>-limit <var>type value</var></h3>
cristyd2432012015-05-04 23:15:15 +00005962</div>
5963
5964<p class="magick-description">Set the pixel cache resource limit.</p>
5965
5966<p>Choose from: <code>area</code>, <code>disk</code>, <code>file</code>,
5967<code>map</code>, <code>memory</code>, <code>thread</code>, or <code>time</code>.</p>
5968
5969<p>The value for <code>file</code> is in number of files. The other limits are
5970in bytes. Define arguments for the memory, map, area, and disk resource limits
5971with SI prefixes (.e.g 100MB).</p>
5972
5973<p>By default the limits are 768 files, 3GB of image area, 1.5GiB memory, 3GiB
5974memory map, and 18.45EB of disk. These limits are adjusted relative to the
5975available resources on your computer if this information is available. When
5976any limit is reached, ImageMagick fails in some fashion but attempts to take
5977compensating actions, if possible. For example, the following limits
5978memory:</p>
5979
cristy29dc8652015-05-12 16:26:21 +00005980<pre>
5981-limit memory 32MiB -limit map 64MiB
5982</pre>
cristyd2432012015-05-04 23:15:15 +00005983
5984<p>Use <a href="command-line-options.html#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
5985
5986<pre>
cristy29dc8652015-05-12 16:26:21 +00005987-> identify -list resource
cristyd2432012015-05-04 23:15:15 +00005988Resource limits:
5989 Width: 100MP
5990 Height: 100MP
5991 Area: 25.181GB
5992 Memory: 11.726GiB
5993 Map: 23.452GiB
5994 Disk: unlimited
5995 File: 768
5996 Thread: 12
5997 Throttle: 0
5998 Time: unlimited
5999</pre>
6000
6001<p>Requests for pixel storage to keep intermediate images are satisfied by one
6002of three resource categories: in-memory pool, memory-mapped files pool, and
cristy29dc8652015-05-12 16:26:21 +00006003disk pool (in that order) depending on the <a href="command-line-options.html#limit">&#x2011;limit</a> settings
cristyd2432012015-05-04 23:15:15 +00006004and whether the system honors a resource request. If the total size of
6005allocated pixel storage in the given pool reaches the corresponding limit, the
6006request is passed to the next pool. Additionally, requests that exceed the
6007<code>area</code> limit automagically are allocated on disk.</p>
6008
6009<p>To illustrate how ImageMagick utilizes resource limits, consider a typical
6010image resource request. First, ImageMagick tries to allocate the pixels in
6011memory. The request might be denied if the resource request exceeds the
6012<code>memory</code> limit or if the system does not honor the request. If
6013a memory request is not honored, the pixels are allocated to disk and the file
6014is memory-mapped. However, if the allocation request exceeds the
6015<code>map</code> limit, the resource allocation goes to disk. In all cases, if
6016the resource request exceeds the <code>area</code> limit, the pixels are
6017automagically cached to disk. If the disk has a hard limit, the program
6018fails.</p>
6019
6020<p>In most cases you simply do not need to concern yourself with resource
6021limits. ImageMagick chooses reasonable defaults and most images do not tax
6022your computer resources. Where limits do come in handy is when you process
6023images that are large or on shared systems where ImageMagick can consume all
6024or most of the available memory. In this case, the ImageMagick workflow slows
6025other processes or, in extreme cases, brings the system to a halt. Under
6026these circumstances, setting limits give some assurances that the ImageMagick
6027workflow will not interfere with other concurrent uses of the computer. For
6028example, assume you have a web interface that processes images uploaded from
6029the Internet. To assure ImageMagick does not exceed 10MiB of memory you can
6030simply set the area limit to 10MiB:</p>
6031
cristy29dc8652015-05-12 16:26:21 +00006032<pre>
cristyd2432012015-05-04 23:15:15 +00006033-limit area 10MB
cristy29dc8652015-05-12 16:26:21 +00006034</pre>
cristyd2432012015-05-04 23:15:15 +00006035
6036<p>Now whenever a large image is processed, the pixels are automagically
6037cached to disk instead of memory. This of course implies that large images
6038typically process very slowly, simply because pixel processing in memory can
6039be an order of magnitude faster than on disk. Because your web site users
6040might inadvertently upload a huge image to process, you should set a disk
6041limit as well:</p>
6042
cristy29dc8652015-05-12 16:26:21 +00006043<pre>
cristyd2432012015-05-04 23:15:15 +00006044-limit area 10MB -limit disk 500MB
cristy29dc8652015-05-12 16:26:21 +00006045</pre>
cristyd2432012015-05-04 23:15:15 +00006046
6047<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
6048
6049<p>In addition to command-line resource limit option, resources can be set
cristy29dc8652015-05-12 16:26:21 +00006050with <a href="resources.html#environment" >environment variables</a>. Set the
cristyd2432012015-05-04 23:15:15 +00006051environment variables <code>MAGICK_AREA_LIMIT</code>,
6052<code>MAGICK_DISK_LIMIT</code>, <code>MAGICK_FILE_LIMIT</code>,
6053<code>MAGICK_MEMORY_LIMIT</code>, <code>MAGICK_MAP_LIMIT</code>,
6054<code>MAGICK_THREAD_LIMIT</code>, <code>MAGICK_TIME_LIMIT</code> for limits of
6055image area, disk space, open files, heap memory, memory map, number of threads
6056of execution, and maximum elapsed time in seconds respectively.</p>
6057
6058<p> Inquisitive users can try adding <a href="command-line-options.html#debug">-debug cache</a> to
6059their commands and then scouring the generated output for references to the
6060pixel cache, in order to determine how the pixel cache was allocated and how
6061resources were consumed. Advanced Unix/Linux users can pipe that output
6062through <code>grep memory|open|destroy|disk</code> for more readable sifting.
6063</p>
6064
6065<p>For more about ImageMagick's use of resources, see the section <b>Cache
cristy29dc8652015-05-12 16:26:21 +00006066Storage and Resource Requirements</b> on the <a href="architecture.html#cache
6067">Architecture</a> page. </p>
cristyd2432012015-05-04 23:15:15 +00006068
6069<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006070 <h3 class="magick-header"><a id="linear-stretch"></a>-linear-stretch <var>black-point</var><br />-linear-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}}</h3>
cristyd2432012015-05-04 23:15:15 +00006071</div>
6072
6073<p class="magick-description">Linear with saturation stretch.</p>
6074
cristy29dc8652015-05-12 16:26:21 +00006075<p>This is very similar to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>,
cristyd2432012015-05-04 23:15:15 +00006076and uses a 'histogram bin' to determine the range of color values that needs to
cristy29dc8652015-05-12 16:26:21 +00006077be stretched. However it then stretches those colors using the <a
6078href="command-line-options.html#level" >-level</a> operator.</p>
cristyd2432012015-05-04 23:15:15 +00006079
6080<p>As such while the initial determination may have 'binning' round off
6081effects, the image colors are stretched mathematically, rather than using the
6082histogram bins. This makes the operator more accurate. </p>
6083
cristy29dc8652015-05-12 16:26:21 +00006084<p>note however that a <a href="command-line-options.html#linear-stretch" >-linear-stretch</a> of
cristyd2432012015-05-04 23:15:15 +00006085'<code>0</code>' does nothing, while a value of '<code>1</code>' does a near
6086perfect stretch of the color range. </p>
6087
cristy29dc8652015-05-12 16:26:21 +00006088<p>See also <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect'
cristyd2432012015-05-04 23:15:15 +00006089normalization of mathematical images. </p>
6090
6091<p>This operator is under review for re-development. </p>
6092
6093
6094<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006095 <h3 class="magick-header"><a id="linewidth"></a>-linewidth</h3>
cristyd2432012015-05-04 23:15:15 +00006096</div>
6097
6098<p class="magick-description">the line width for subsequent draw operations.</p>
6099
6100<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006101 <h3 class="magick-header"><a id="liquid-rescale"></a>-liquid-rescale <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00006102</div>
6103
6104<p class="magick-description">rescale image with seam-carving.</p>
6105
6106<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6107
6108<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006109 <h3 class="magick-header"><a id="list"></a>-list <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00006110</div>
6111
6112<p class="magick-description">Print a list of supported arguments for various options or settings. Choose from these list types:</p>
6113
6114<pre>
6115 Align Alpha Boolean Channel
6116 Class ClipPath Coder Color
6117 Colorspace Command Compose Compress
6118 Configure DataType Debug Decoration
6119 Delegate Direction Dispose Distort
6120 Dither Endian Evaluate FillRule
6121 Filter Font Format Function
6122 Gravity ImageList Intent Interlace
6123 Interpolate Kernel Layers LineCap
6124 LineJoin List Locale LogEvent
6125 Log Magic Method Metric
6126 Mime Mode Morphology Module
6127 Noise Orientation Policy PolicyDomain
6128 PolicyRights Preview Primitive QuantumFormat
6129 Resource SparseColor Storage Stretch
6130 Style Threshold Type Units
6131 Validate VirtualPixel
6132</pre>
6133
6134<p>These lists vary depending on your version of ImageMagick. Use "<code>-list
6135list</code>" to get a complete listing of all the "<code>-list</code>" arguments
6136available:</p>
6137
6138<pre>
6139identify -list list
6140</pre>
6141
6142<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006143 <h3 class="magick-header"><a id="log"></a>-log <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00006144</div>
6145
6146<p class="magick-description">Specify format for debug log.</p>
6147
cristy29dc8652015-05-12 16:26:21 +00006148<p>This option specifies the format for the log printed when the <a
6149href="command-line-options.html#debug">-debug</a> option is active.</p>
cristyd2432012015-05-04 23:15:15 +00006150
6151<p>You can display the following components by embedding special format
6152characters:</p>
6153
6154<pre>
cristy29dc8652015-05-12 16:26:21 +00006155%d domain
6156%e event
6157%f function
6158%l line
6159%m module
6160%p process ID
6161%r real CPU time
6162%t wall clock time
6163%u user CPU time
6164%% percent sign
6165\n newline
6166\r carriage return
cristyd2432012015-05-04 23:15:15 +00006167</pre>
6168
6169<p>For example:</p>
6170
6171<pre>
6172convert -debug coders -log "%u %m:%l %e" in.gif out.png
6173</pre>
6174
6175<p>The default behavior is to print all of the components.</p>
6176
6177<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006178 <h3 class="magick-header"><a id="loop"></a>-loop <var>iterations</var></h3>
cristyd2432012015-05-04 23:15:15 +00006179</div>
6180
6181<p class="magick-description">add Netscape loop extension to your GIF animation.</p>
6182
6183<p>Set iterations to zero to repeat the animation an infinite number of times,
6184otherwise the animation repeats itself up to <var>iterations</var>
6185times.</p>
6186
6187<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006188 <h3 class="magick-header"><a id="lowlight-color"></a>-lowlight-color <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00006189</div>
6190
6191<p class="magick-description">when comparing images, de-emphasize pixel differences with this color.</p>
6192
6193<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006194 <h3 class="magick-header"><a id="magnify"></a>-magnify</h3>
cristyd2432012015-05-04 23:15:15 +00006195</div>
6196
6197<p class="magick-description">double the size of the image with pixel art scaling.</p>
6198
6199
6200<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006201 <h3 class="magick-header"><a id="map"></a>-map <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00006202</div>
6203
6204<p class="magick-description">Display image using this <var>type</var>.</p>
6205
6206<p>Choose from these <var>Standard Colormap</var> types:</p>
6207
6208<pre>
cristy29dc8652015-05-12 16:26:21 +00006209best
6210default
6211gray
6212red
6213green
6214blue
cristyd2432012015-05-04 23:15:15 +00006215</pre>
6216
6217<p>The <var>X server</var> must support the <var>Standard
6218Colormap</var> you choose, otherwise an error occurs. Use <code>list</code> as
6219the type and <code>display</code> searches the list of colormap types in
6220<code>top-to-bottom</code> order until one is located. See <var>xstdcmap(1)</var> for one way of creating Standard Colormaps.</p>
6221
6222
6223<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006224 <h3 class="magick-header"><a id="map_stream_"></a>-map <var>components</var></h3>
cristyd2432012015-05-04 23:15:15 +00006225</div>
6226
6227<p class="magick-description">pixel map.</p>
6228
6229<p>Here are the valid components of a map:</p>
6230
6231<pre>
cristy29dc8652015-05-12 16:26:21 +00006232r red pixel component
6233g green pixel component
6234b blue pixel component
6235a alpha pixel component (0 is transparent)
6236o opacity pixel component (0 is opaque)
6237i grayscale intensity pixel component
6238c cyan pixel component
6239m magenta pixel component
6240y yellow pixel component
6241k black pixel component
6242p pad component (always 0)
cristyd2432012015-05-04 23:15:15 +00006243</pre>
6244
6245<p>You can specify as many of these components as needed in any order (e.g.
6246bgr). The components can repeat as well (e.g. rgbr).</p>
6247
6248
6249<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006250 <h3 class="magick-header"><a id="mask"></a>-mask
6251<var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00006252</div>
6253
6254<p class="magick-description">Prevent updates to image pixels specified by the mask.</p>
6255
6256<p>This the same as using a mask used for composite masking operations, with
6257grayscale values causing blended updates of the image the mask is attached to.
6258</p>
6259
6260<p>Use <a href="command-line-options.html#mask">+mask</a> to remove the mask from images.</p>
6261
6262<p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way,
6263but with strict boolean masking. </p>
6264
6265<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006266 <h3 class="magick-header"><a id="mattecolor"></a>-mattecolor <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00006267</div>
6268
6269<p class="magick-description">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</p>
6270
6271<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6272
cristy29dc8652015-05-12 16:26:21 +00006273<p>The default matte color is <code>#BDBDBD</code>, <span
6274style="background-color: #bdbdbd;">this shade of gray</span>.</p>
cristyd2432012015-05-04 23:15:15 +00006275
6276<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006277 <h3 class="magick-header"><a id="maximum"></a>-maximum</h3>
cristyd2432012015-05-04 23:15:15 +00006278</div>
6279
6280<p class="magick-description">return the maximum intensity of an image sequence.</p>
6281
6282<p>Select the 'maximum' value from all the surrounding pixels. </p>
6283
cristy29dc8652015-05-12 16:26:21 +00006284<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
cristyd2432012015-05-04 23:15:15 +00006285name. </p>
6286
6287<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006288 <h3 class="magick-header"><a id="median"></a>-median <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00006289</div>
6290
6291<p class="magick-description">apply a median filter to the image.</p>
6292
6293<p>Select the 'middle' value from all the surrounding pixels. </p>
6294
cristy29dc8652015-05-12 16:26:21 +00006295<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
cristyd2432012015-05-04 23:15:15 +00006296name. </p>
6297
6298<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006299 <h3 class="magick-header"><a id="mean-shift"></a>-mean-shift <var>width</var>x<var>height</var>{<var>+distance</var>{%}}</h3>
cristyd2432012015-05-04 23:15:15 +00006300</div>
6301
6302<p class="magick-description">image noise removal and color reduction/segmentation (e.g. -mean-shift 7x7+10%).</p>
6303
6304<p><var>width</var>x<var>height</var> is the window size and <var>distance</var> is the color distance measured in the range 0 to 1 or 0 to 100%</p>
6305
6306<p>The mean shift algorithm is iterative and thus slower the larger the window size. For each pixel, it gets all the pixels in the window centered at the pixel and excludes those that are outside the radius=sqrt((width-1)(height-1)/4) surrounding the pixel. From those pixels, it finds which of them are within the specified squared color distance from the current mean. It then computes a new x,y centroid from those coordinates and a new mean. This new x,y centroid is used as the center for a new window. This process is iterated until it converges and the final mean is then used to replace the original pixel value. It repeats this process for the next pixel, etc, until it processes all pixels in the image. Results are better when using other colorspaces rather than RGB. Recommend YIQ, YUV or YCbCr, which seem to give equivalent results.</p>
6307
6308<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006309 <h3 class="magick-header"><a id="metric"></a>-metric <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00006310</div>
6311
6312<p class="magick-description">Output to STDERR a measure of the differences between images according to the <var>type</var> given metric.</p>
6313
6314<p>Choose from:</p>
6315
cristy29dc8652015-05-12 16:26:21 +00006316<dl class="dl-horizontal">
6317<dt>AE</dt><dd> absolute error count, number of different pixels (-fuzz effected)</dd>
6318<dt>FUZZ</dt><dd> mean color distance</dd>
6319<dt>MAE</dt><dd> mean absolute error (normalized), average channel error distance</dd>
6320<dt>MEPP</dt><dd> mean error per pixel (normalized mean error, normalized peak error)</dd>
6321<dt>MSE</dt><dd> mean error squared, average of the channel error squared</dd>
6322<dt>NCC</dt><dd> normalized cross correlation</dd>
6323<dt>PAE</dt><dd> peak absolute (normalized peak absolute)</dd>
6324<dt>PHASH</dt><dd> perceptual hash</dd>
6325<dt>PSNR</dt><dd> peak signal to noise ratio</dd>
6326<dt>RMSE</dt><dd> root mean squared (normalized root mean squared)</dd>
6327</dl>
cristyd2432012015-05-04 23:15:15 +00006328
6329<p>Control the '<code>AE</code>', or absolute count of pixels that are different,
cristy29dc8652015-05-12 16:26:21 +00006330with the <a href="command-line-options.html#fuzz" >-fuzz</a> factor (ignore pixels which
cristyd2432012015-05-04 23:15:15 +00006331only changed by a small amount). Use '<code>PAE</code>' to find the
cristy29dc8652015-05-12 16:26:21 +00006332size of the <a href="command-line-options.html#fuzz" >-fuzz</a> factor needed to make all pixels
cristyd2432012015-05-04 23:15:15 +00006333'similar', while '<code>MAE</code>' determines the factor needed
6334for about half the pixels to be similar. </p>
6335
6336<p>The '<code>MEPP</code>' metric returns three different metrics
6337('<code>MAE</code>', '<code>MAE</code>' normalized, and '<code>PAE</code>'
6338normalized) from a single comparison run. </p>
6339
6340<p>To print a complete list of metrics, use the <a href="command-line-options.html#list">-list
6341metric</a> option.</p>
6342
6343
6344<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006345 <h3 class="magick-header"><a id="minimum"></a>-minimum</h3>
cristyd2432012015-05-04 23:15:15 +00006346</div>
6347
6348<p class="magick-description">return the minimum intensity of an image sequence.</p>
6349
6350<p>Select the 'minimal' value from all the surrounding pixels. </p>
6351
cristy29dc8652015-05-12 16:26:21 +00006352<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
cristyd2432012015-05-04 23:15:15 +00006353name. </p>
6354
6355
6356
6357<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006358 <h3 class="magick-header"><a id="mode"></a>-mode <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00006359</div>
6360
6361<p class="magick-description">make each pixel the \'predominant color\' of the neighborhood.'</p>
6362
6363<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006364 <h3 class="magick-header">-mode <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00006365</div>
6366
6367<p class="magick-description">Mode of operation.</p>
6368
6369<p>Choose the <var>value</var> from these styles: <code>Frame,
6370Unframe, or Concatenate</code></p>
6371
cristy29dc8652015-05-12 16:26:21 +00006372<p>Use the <a href="command-line-options.html#list" >-list</a> option with a '<code>Mode</code>' argument
6373for a list of <a href="command-line-options.html#mode" >-mode</a> arguments available in your
cristyd2432012015-05-04 23:15:15 +00006374ImageMagick installation.</p>
6375
6376
6377<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006378 <h3 class="magick-header"><a id="modulate"></a>-modulate <var>brightness</var>[,<var>saturation</var>,<var>hue</var>]</h3>
cristyd2432012015-05-04 23:15:15 +00006379</div>
6380
6381<p class="magick-description">Vary the <var>brightness</var>, <var>saturation</var>, and <var>hue</var> of an image.</p>
6382
6383<p>The arguments are given as a percentages of variation. A value of 100 means
6384no change, and any missing values are taken to mean 100.</p>
6385
6386<p>The <var>brightness</var> is a multiplier of the overall
6387brightness of the image, so 0 means pure black, 50 is half as bright, 200 is
6388twice as bright. To invert its meaning <a href="command-line-options.html#negate">-negate</a> the image
6389before and after. </p>
6390
6391<p>The <var>saturation</var> controls the amount of color in an
6392image. For example, 0 produce a grayscale image, while a large value such as
6393200 produce a very colorful, 'cartoonish' color.</p>
6394
6395<p>The <var>hue</var> argument causes a "rotation" of the colors
6396within the image by the amount specified. For example, 50 results in
6397a counter-clockwise rotation of 90, mapping red shades to purple, and so on.
6398A value of either 0 or 200 results in a complete 180 degree rotation of the
6399image. Using a value of 300 is a 360 degree rotation resulting in no change to
6400the original image. </p>
6401
6402<p>For example, to increase the color brightness by 20% and decrease the color
cristy29dc8652015-05-12 16:26:21 +00006403saturation by 10% and leave the hue unchanged, use <a
6404href="command-line-options.html#modulate">-modulate 120,90</a>.</p>
cristyd2432012015-05-04 23:15:15 +00006405
cristy29dc8652015-05-12 16:26:21 +00006406<p>Use <a href="command-line-options.html#set">-set</a> attribute of '<code
6407>option:modulate:colorspace</code>' to specify which colorspace to
cristyd2432012015-05-04 23:15:15 +00006408modulate. Choose from <code>HCL</code>, <code>HCLp</code>, <code>HSB</code>, <code>HSI</code>, <code>HSL</code> (the default), <code>HSV</code>, <code>HWB</code>, or <code>LCH</code> (LCHuv). For example,</p>
6409
6410<pre>
6411convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png
6412</pre>
6413
6414<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006415 <h3 class="magick-header"><a id="moments"></a>-moments</h3>
cristyd2432012015-05-04 23:15:15 +00006416</div>
6417
6418<p class="magick-description">report image moments and perceptual hash.</p>
6419
6420
6421<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006422 <h3 class="magick-header"><a id="monitor"></a>-monitor</h3>
cristyd2432012015-05-04 23:15:15 +00006423</div>
6424
6425<p class="magick-description">monitor progress.</p>
6426
6427
6428<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006429 <h3 class="magick-header"><a id="monochrome"></a>-monochrome</h3>
cristyd2432012015-05-04 23:15:15 +00006430</div>
6431
6432<p class="magick-description">transform the image to black and white.</p>
6433
6434<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006435 <h3 class="magick-header"><a id="morph"></a>-morph <var>frames</var></h3>
cristyd2432012015-05-04 23:15:15 +00006436</div>
6437
6438<p class="magick-description">morphs an image sequence.</p>
6439
6440<p>Both the image pixels and size are linearly interpolated to give the
6441appearance of a metamorphosis from one image to the next, over all the images
cristy29dc8652015-05-12 16:26:21 +00006442in the current image list. The added images are the equivalent of a <a
6443href="command-line-options.html#blend">-blend</a> composition. The <var>frames</var>
cristyd2432012015-05-04 23:15:15 +00006444argument determine how many images to interpolate between each image. </p>
6445
6446
6447<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006448 <h3 class="magick-header"><a id="morphology"></a>-morphology</h3>
6449 <h3 class="magick-header">-morphology <var>method</var> <var>kernel</var></h3>
cristyd2432012015-05-04 23:15:15 +00006450</div>
6451
6452<p class="magick-description">apply a morphology method to the image.</p>
6453
cristy29dc8652015-05-12 16:26:21 +00006454<p>Until I get around to writing an option summary for this, see <a
6455href="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples,
cristyd2432012015-05-04 23:15:15 +00006456Morphology</a>. </p>
6457
6458
6459<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006460 <h3 class="magick-header"><a id="mosaic"></a>-mosaic</h3>
cristyd2432012015-05-04 23:15:15 +00006461</div>
6462
cristy29dc8652015-05-12 16:26:21 +00006463<p class="magick-description">an simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "mosaic"</p>
cristyd2432012015-05-04 23:15:15 +00006464
6465
6466<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006467 <h3 class="magick-header"><a id="motion-blur"></a>-motion-blur <var>radius</var><br />-motion-blur <var>radius</var>x<var>sigma</var>+<var>angle</var></h3>
cristyd2432012015-05-04 23:15:15 +00006468</div>
6469
6470<p class="magick-description">simulate motion blur.</p>
6471
6472<p>Blur with the given radius, standard deviation (sigma), and angle. The
6473angle given is the angle toward which the image is blurred. That is the
6474direction people would consider the object is coming from. </p>
6475
6476<p>Note that the blur is not uniform distribution, giving the motion a
6477definite sense of direction of movement. </p>
6478
6479<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
6480pixels which are outside the image proper are blurred into the final result.
6481</p>
6482
6483<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006484 <h3 class="magick-header"><a id="name"></a>-name</h3>
cristyd2432012015-05-04 23:15:15 +00006485</div>
6486
6487<p class="magick-description">name an image.</p>
6488<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006489 <h3 class="magick-header"><a id="negate"></a>-negate</h3>
cristyd2432012015-05-04 23:15:15 +00006490</div>
6491
6492<p class="magick-description">replace each pixel with its complementary color.</p>
6493
6494<p>The red, green, and blue intensities of an image are negated. White becomes
6495black, yellow becomes blue, etc. Use <a href="command-line-options.html#negate">+negate</a> to only
6496negate the grayscale pixels of the image.</p>
6497
6498<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006499 <h3 class="magick-header"><a id="noise"></a>-noise <var>geometry</var><br/>
6500 +noise <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00006501</div>
6502
6503<p class="magick-description">Add or reduce noise in an image.</p>
6504
6505<p>The principal function of noise peak elimination filter is to smooth the
6506objects within an image without losing edge information and without creating
6507undesired structures. The central idea of the algorithm is to replace a pixel
6508with its next neighbor in value within a pixel window, if this pixel has been
6509found to be noise. A pixel is defined as noise if and only if this pixel is
6510a maximum or minimum within the pixel window.</p>
6511
6512<p>Use <code><a href="command-line-options.html#noise">-noise</a> <var>radius</var></code> to
6513specify the width of the neighborhood when reducing noise. This is equivalent
cristy29dc8652015-05-12 16:26:21 +00006514to using a <code><a href="command-line-options.html#statistic" >-statistic</a> NonPeak</code> operation,
cristyd2432012015-05-04 23:15:15 +00006515which should be used in preference.</p>
6516
6517<p>Use <a href="command-line-options.html#noise">+noise</a> followed by a noise <var>type</var> to add noise to an image. Choose from these noise
6518types:</p>
6519
6520<pre>
cristy29dc8652015-05-12 16:26:21 +00006521Gaussian
6522Impulse
6523Laplacian
6524Multiplicative
6525Poisson
6526Random
6527Uniform
cristyd2432012015-05-04 23:15:15 +00006528</pre>
6529
cristy29dc8652015-05-12 16:26:21 +00006530<p>The amount of noise added can be controled by the <code><a
6531href="command-line-options.html#attunuuate" >-attenuate</a></code> setting. If unset the value is
cristyd2432012015-05-04 23:15:15 +00006532equivalent to 1.0, or a maximum noise addition.</p>
6533
6534<p>Note that Random will replace the image with noise rather than add noise to the image. Use Uniform, if you wish to add random noise to the image.</p>
6535
6536<p>To print a complete list of noises, use the <a href="command-line-options.html#list">-list noise</a> option.</p>
6537
6538<p>Also see the <a href="command-line-options.html#evaluate">-evaluate</a> noise functions that allows
6539the use of a controlling value to specify the amount of noise that should be
6540added to an image. </p>
6541
6542
6543<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006544 <h3 class="magick-header"><a id="normalize"></a>-normalize</h3>
cristyd2432012015-05-04 23:15:15 +00006545</div>
6546
6547<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
6548
6549<p>The intensity values are stretched to cover the entire range of possible
6550values. While doing so, black-out at most <var>2%</var> of the pixels and
6551white-out at most <var>1%</var> of the pixels.</p>
6552
cristy29dc8652015-05-12 16:26:21 +00006553<p>Note that as of ImageMagick 6.4.7-0, <a href="command-line-options.html#normalize" >-normalize</a>
6554is equivalent to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch 2%x1%</a>.
6555(Before this version, it was equivalent to <a href="command-line-options.html#contrast-stretch"
6556>-contrast-stretch 2%x99%</a>).</p>
cristyd2432012015-05-04 23:15:15 +00006557
6558<p>All the channels are normalized in concert by the came amount so as to
cristy29dc8652015-05-12 16:26:21 +00006559preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a>
6560setting is in use. Specifying any other <a href="command-line-options.html#channel" >-channel</a>
cristyd2432012015-05-04 23:15:15 +00006561setting will normalize the RGB channels independently.</p>
6562
cristy29dc8652015-05-12 16:26:21 +00006563<p>See <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a> for more details.
6564Also see <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect' normalization
cristyd2432012015-05-04 23:15:15 +00006565that is better suited to mathematically generated images. </p>
6566
6567<p>This operator is under review for re-development. </p>
6568
6569
6570<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006571 <h3 class="magick-header"><a id="opaque"></a>-opaque <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00006572</div>
6573
6574<p class="magick-description">change this color to the fill color within the image.</p>
6575
6576<p>The <var>color</var> argument is defined using the format
cristy29dc8652015-05-12 16:26:21 +00006577described under the <a href="command-line-options.html#fill" >-fill</a> option. The <a href="command-line-options.html#fuzz"
6578>-fuzz</a> setting can be used to match and replace colors similar to the one
cristyd2432012015-05-04 23:15:15 +00006579given.</p>
6580
6581<p>Use <a href="command-line-options.html#opaque">+opaque</a> to paint any pixel that does not match
6582the target color. </p>
6583
6584<p>The <a href="command-line-options.html#transparent">-transparent</a> operator is exactly the same
cristy29dc8652015-05-12 16:26:21 +00006585as <a href="command-line-options.html#opaque" >-opaque</a> but replaces the matching color with
cristyd2432012015-05-04 23:15:15 +00006586transparency rather than the current <a href="command-line-options.html#fill">-fill</a> color setting.
6587To ensure that it can do this it also ensures that the image has an alpha
cristy29dc8652015-05-12 16:26:21 +00006588channel enabled, as per "<code><a href="command-line-options.html#alpha" >-alpha</a> set</code>", for
6589the new transparent colors, and does not require you to modify the <a
6590href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
cristyd2432012015-05-04 23:15:15 +00006591
6592
6593<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006594 <h3 class="magick-header"><a id="ordered-dither"></a>-ordered-dither <var>threshold_map</var>{,<var>level</var>...}</h3>
cristyd2432012015-05-04 23:15:15 +00006595</div>
6596
6597<p class="magick-description">dither the image using a pre-defined ordered dither <var>threshold map</var> specified, and a uniform color map with the
6598given number of <var>levels</var> per color channel.</p>
6599
6600<p>You can choose from these standard threshold maps:</p>
6601
6602<pre>
cristy29dc8652015-05-12 16:26:21 +00006603threshold 1x1 Threshold 1x1 (non-dither)
6604checks 2x1 Checkerboard 2x1 (dither)
6605o2x2 2x2 Ordered 2x2 (dispersed)
6606o3x3 3x3 Ordered 3x3 (dispersed)
6607o4x4 4x4 Ordered 4x4 (dispersed)
6608o8x8 8x8 Ordered 8x8 (dispersed)
6609h3x4a 4x1 Halftone 4x4 (angled)
6610h6x6a 6x1 Halftone 6x6 (angled)
6611h8x8a 8x1 Halftone 8x8 (angled)
6612h3x4o Halftone 4x4 (orthogonal)
6613h6x6o Halftone 6x6 (orthogonal)
6614h8x8o Halftone 8x8 (orthogonal)
6615h36x16o Halftone 16x16 (orthogonal)
6616c5x5b c5x5 Circles 5x5 (black)
6617c5x5w Circles 5x5 (white)
6618c6x6b c6x6 Circles 6x6 (black)
6619c6x6w Circles 6x6 (white)
6620c7x7b c7x7 Circles 7x7 (black)
6621c7x7w Circles 7x7 (white)
cristyd2432012015-05-04 23:15:15 +00006622</pre>
6623
6624<p> The <code>threshold</code> generated a simple 50% threshold of the image.
cristy29dc8652015-05-12 16:26:21 +00006625This could be used with <var >level</var> to do the equivalent of <a
6626href="command-line-options.html#posterize" >-posterize</a> to reduce an image to basic primary colors.
cristyd2432012015-05-04 23:15:15 +00006627</p>
6628
6629<p>The <code>checks</code> pattern produces a 3 level checkerboard dither
6630pattern. That is a grayscale will become a pattern of solid black, solid
6631white, and mid-tone colors into a checkerboard pattern of black and white.
6632</p>
6633
cristy29dc8652015-05-12 16:26:21 +00006634<p>You can define your own <var >threshold map</var> for ordered
cristyd2432012015-05-04 23:15:15 +00006635dithering and halftoning your images, in either personal or system
cristy29dc8652015-05-12 16:26:21 +00006636<code>thresholds.xml</code> XML file. See <a href="resources.html" >Resources</a>
cristyd2432012015-05-04 23:15:15 +00006637for more details of configuration files. </p>
6638
6639<p>To print a complete list of the thresholds that have been defined, use the
cristy29dc8652015-05-12 16:26:21 +00006640<a href="command-line-options.html#list" >-list threshold</a> option.</p>
cristyd2432012015-05-04 23:15:15 +00006641
6642<p>Note that at this time the same threshold dithering map is used for all
6643color channels, no attempt is made to offset or rotate the map for different
6644channels is made, to create an offset printing effect. Also as the maps are
6645simple threshold levels, the halftone and circle maps will create incomplete
6646circles along the edges of a colored area. Also all the effects are purely
6647on/off boolean effects, without anti-aliasing to make the circles smooth
6648looking. Large dots can be made to look better with a small amount of blurring
6649after being created. </p>
6650
6651
6652<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006653 <h3 class="magick-header"><a id="orient"></a>-orient <var>image orientation</var></h3>
cristyd2432012015-05-04 23:15:15 +00006654</div>
6655
6656<p class="magick-description">specify orientation of a digital camera image.</p>
6657
6658<p>Choose from these orientations:</p>
6659
6660<pre>
cristy29dc8652015-05-12 16:26:21 +00006661bottom-left
6662bottom-right
6663left-bottom
6664left-top
6665right-bottom
6666right-top
6667top-left
6668top-right
6669undefined
cristyd2432012015-05-04 23:15:15 +00006670</pre>
6671
cristy29dc8652015-05-12 16:26:21 +00006672<p>To print a complete list of orientations, use the <a href="command-line-options.html#list" >-list
cristyd2432012015-05-04 23:15:15 +00006673orientation</a> option.</p>
6674
6675
6676<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006677 <h3 class="magick-header"><a id="page"></a>-page <var>geometry</var><br/>
6678 -page <var>media</var>[<var>offset</var>][{<var>^!&lt;&gt;</var>}]<br/>
cristyd2432012015-05-04 23:15:15 +00006679 +page
cristy29dc8652015-05-12 16:26:21 +00006680 </h3>
cristyd2432012015-05-04 23:15:15 +00006681</div>
6682
6683<p class="magick-description">Set the size and location of an image on the larger virtual canvas.</p>
6684
6685<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6686
6687<p>For convenience you can specify the page size using <var>media</var> (see below). Offsets can then be added as with other
cristy29dc8652015-05-12 16:26:21 +00006688<var>geometry</var> arguments (e.g. <a
6689href="command-line-options.html#page">-page</a> <code>Letter+43+43</code>).</p>
cristyd2432012015-05-04 23:15:15 +00006690
6691<p>Use <var>media</var> as shorthand to specify the dimensions (<var>width</var>x<var>height</var>) of the <var>PostScript</var> page in dots per inch or a TEXT page in pixels.
6692The choices for a PostScript page are:</p>
6693
6694<div class="table-responsive">
6695<table class="table table-condensed table-striped">
6696 <tr>
cristy29dc8652015-05-12 16:26:21 +00006697 <td><var>Media</var></td>
6698 <td align="right"><var>Width</var></td>
6699 <td align="right"><var>Height</var></td>
cristyd2432012015-05-04 23:15:15 +00006700 </tr>
6701<tr><td> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
6702<tr><td> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
6703<tr><td> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
6704<tr><td> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
6705<tr><td> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
6706<tr><td> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
6707<tr><td> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
6708<tr><td> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
6709<tr><td> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
6710<tr><td> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
6711<tr><td> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
6712<tr><td> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
6713<tr><td> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
6714<tr><td> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
6715<tr><td> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
6716<tr><td> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
6717<tr><td> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
6718<tr><td> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
6719<tr><td> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
6720<tr><td> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
6721<tr><td> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
6722<tr><td> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
6723<tr><td> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
6724<tr><td> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
6725<tr><td> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
6726<tr><td> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
6727<tr><td> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
6728<tr><td> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
6729<tr><td> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
6730<tr><td> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
6731<tr><td> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
6732<tr><td> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
6733<tr><td> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
6734<tr><td> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
6735<tr><td> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
6736<tr><td> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
6737<tr><td> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
6738<tr><td> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
6739</table></div>
6740
6741<p>This option is also used to place subimages when writing to a multi-image
6742format that supports offsets, such as GIF89 and MNG. When used for this
6743purpose the offsets are always measured from the top left corner of the canvas
6744and are not affected by the <a href="command-line-options.html#gravity">-gravity</a> option. To
6745position a GIF or MNG image, use <a href="command-line-options.html#page">-page</a><var>{+-}x{+-}y</var> (e.g. -page +100+200). When writing to a MNG
6746file, a <a href="command-line-options.html#page">-page</a> option appearing ahead of the first image in
6747the sequence with nonzero width and height defines the width and height values
6748that are written in the <code>MHDR</code> chunk. Otherwise, the MNG width and
6749height are computed from the bounding box that contains all images in the
6750sequence. When writing a GIF89 file, only the bounding box method is used to
6751determine its dimensions.</p>
6752
cristy29dc8652015-05-12 16:26:21 +00006753<p>For a PostScript page, the image is sized as in <a
6754href="command-line-options.html#geometry">-geometry</a> but positioned relative to the <var>lower
6755left-hand corner</var> of the page by {+-}<code>x</code><var>offset</var>{+-}<code>y</code> <var>offset</var>. Use <a
6756href="command-line-options.html#page">-page 612x792</a>, for example, to center the image within the
cristyd2432012015-05-04 23:15:15 +00006757page. If the image size exceeds the PostScript page, it is reduced to fit the
6758page. The default gravity for the <a href="command-line-options.html#page">-page</a> option is <var>NorthWest</var>, i.e., positive <code>x</code> and <code>y</code> <var>offset</var> are measured rightward and downward from the top left
6759corner of the page, unless the <a href="command-line-options.html#gravity">-gravity</a> option is
6760present with a value other than <var>NorthWest</var>.</p>
6761
6762<p>The default page dimensions for a TEXT image is 612x792.</p>
6763
6764<p>This option is used in concert with <a href="command-line-options.html#density">-density</a>.</p>
6765
6766<p>Use <a href="command-line-options.html#page">+page</a> to remove the page settings for an image.</p>
6767
6768<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006769 <h3 class="magick-header"><a id="paint"></a>-paint <var>radius</var></h3>
cristyd2432012015-05-04 23:15:15 +00006770</div>
6771
6772<p class="magick-description">simulate an oil painting.</p>
6773
6774<p>Each pixel is replaced by the most frequent color in a circular
6775neighborhood whose width is specified with <var>radius</var>.</p>
6776
6777<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006778 <h3 class="magick-header"><a id="path"></a>-path <var>path</var></h3></div>
cristyd2432012015-05-04 23:15:15 +00006779
6780<p class="magick-description">write images to this path on disk.</p>
6781
6782<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006783 <h3 class="magick-header"><a id="pause_animate_"></a>-pause <var>seconds</var></h3>
cristyd2432012015-05-04 23:15:15 +00006784</div>
6785
6786<p class="magick-description">Pause between animation loops</p>
6787
6788<p>Pause for the specified number of seconds before repeating the animation.</p>
6789
6790<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006791 <h3 class="magick-header"><a id="pause_import_"></a>-pause <var>seconds</var></h3>
cristyd2432012015-05-04 23:15:15 +00006792</div>
6793
6794<p class="magick-description">Pause between snapshots.</p>
6795
6796<p>Pause for the specified number of seconds before taking the next snapshot.</p>
6797
6798<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006799 <h3 class="magick-header"><a id="perceptible"></a>-perceptible <var>epsilon</var></h3>
cristyd2432012015-05-04 23:15:15 +00006800</div>
6801
6802<p class="magick-description">set each pixel whose value is less than |<var>epsilon</var>| to <var>-epsilon</var> or <var>epsilon</var> (whichever is closer) otherwise the pixel value remains unchanged.</p>
6803
6804<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006805 <h3 class="magick-header"><a id="ping"></a>-ping</h3>
cristyd2432012015-05-04 23:15:15 +00006806</div>
6807
6808<p class="magick-description">efficiently determine image characteristics.</p>
6809
6810<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006811 <h3 class="magick-header"><a id="pointsize"></a>-pointsize <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00006812</div>
6813
6814<p class="magick-description">pointsize of the PostScript, OPTION1, or TrueType font.</p>
6815
6816<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006817 <h3 class="magick-header"><a id="polaroid"></a>-polaroid <var>angle</var></h3>
cristyd2432012015-05-04 23:15:15 +00006818</div>
6819
6820<p class="magick-description">simulate a Polaroid picture.</p>
6821
6822<p>Use <code>+polaroid</code> to rotate the image at a random angle between -15 and +15 degrees.</p>
6823
6824<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006825 <h3 class="magick-header"><a id="poly"></a>-poly <var>"wt,exp ..."</var></h3>
cristyd2432012015-05-04 23:15:15 +00006826</div>
6827
6828<p class="magick-description">combines multiple images according to a weighted sum of polynomials; one floating point weight (coefficient) and one floating point polynomial exponent (power) for each image expressed as comma separated pairs.</p>
6829
6830<p> The weights should typically be fractions between -1 and 1. But the sum of weights should be 1 or at least between 0 and 1 to avoid clamping in non-hdri mode at black and white.</p>
6831
6832<p>The exponents may be positive, negative or zero. A negative exponent is equivalent to 1 divided by the image raised to the corresponding positive exponent. A zero exponent always produces 1 scaled by quantumrange to white, i.e. wt*white, no matter what the image.</p>
6833
6834<p>The format is: output = wt1*image1^exp1 + wt2*image2^exp2 ...</p>
6835
6836<p>Some simple uses are:</p>
6837<ul>
6838<li>A weighted sum of each image provided all weights add to unity and all exponents=1. If the the weights are all equal to 1/(number of images), then this is equivalent to <a href="command-line-options.html#profile">-evaluate-sequence</a> <var>mean</var>.</li>
6839<li>The sum of squares of two or more images, provided the weights are equal (and sum to 1 to avoid clamping) and the exponents equal 2.</li>
6840</ul>
6841
6842<p>Note that one may add a constant color to the expression simply by using xc:somecolor for one of the images and specifying the desired weight and exponent equal to 0.</p>
6843
6844<p>Similarly one may add white to the expression by simply using null: (or xc:white) for one of the images with the appropriate weight and exponent equal to 0.</p>
6845
6846
6847<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006848 <h3 class="magick-header"><a id="posterize"></a>-posterize <var>levels</var></h3>
cristyd2432012015-05-04 23:15:15 +00006849</div>
6850
6851<p class="magick-description">reduce the image to a limited number of color levels per channel.</p>
6852
6853<p>Very low values of <var>levels</var>, e.g., 2, 3, 4, have the most
6854visible effect.</p>
6855
6856<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006857 <h3 class="magick-header"><a id="precision"></a>-precision <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00006858</div>
6859
6860<p class="magick-description">set the maximum number of significant digits to be printed.</p>
6861
6862<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006863 <h3 class="magick-header"><a id="preview"></a>-preview <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00006864</div>
6865
6866<p class="magick-description">image preview type.</p>
6867
6868<p>Use this option to affect the preview operation of an image (e.g.
6869<code>convert file.png -preview Gamma Preview:gamma.png</code>). Choose from
6870these previews:</p>
6871
6872<pre>
cristy29dc8652015-05-12 16:26:21 +00006873Rotate Shear Roll Hue
6874Saturation Brightness Gamma Spiff
6875Dull Grayscale Quantize Despeckle
6876ReduceNoise Add Noise Sharpen Blur
6877Threshold EdgeDetect Spread Shade
6878Raise Segment Solarize Swirl
6879Implode Wave OilPaint CharcoalDrawing
6880JPEG
cristyd2432012015-05-04 23:15:15 +00006881</pre>
6882
6883<p>To print a complete list of previews, use the <a href="command-line-options.html#list">-list preview</a> option.</p>
6884
6885<p>The default preview is <code>JPEG</code>.</p>
6886
6887<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006888 <h3 class="magick-header"><a id="print"></a>-print <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00006889</div>
6890
6891<p class="magick-description">interpret string and print to console.</p>
6892
6893<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006894 <h3 class="magick-header"><a id="process"></a>-process <var>command</var></h3>
cristyd2432012015-05-04 23:15:15 +00006895</div>
6896
6897<p class="magick-description">process the image with a custom image filter.</p>
6898
6899<p>The command arguments has the form <code>"module arg1 arg2 arg3 ...
6900argN"</code> where <code>module</code> is the name of the module to invoke (e.g.
6901"Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to
6902pass to the process module.</p>
6903
6904<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006905 <h3 class="magick-header"><a id="profile"></a>-profile <var>filename</var><br/>
6906 +profile <var>profile_name</var></h3>
cristyd2432012015-05-04 23:15:15 +00006907</div>
6908
6909<p class="magick-description">Manage ICM, IPTC, or generic profiles in an image.</p>
6910
6911<p>Using <a href="command-line-options.html#profile">-profile</a> <var>filename</var> adds an
6912ICM (ICC color management), IPTC (newswire information), or a generic profile
6913to the image.</p>
6914
6915<p>Use <a href="command-line-options.html#profile">+profile <var>profile_name</var></a> to
6916remove the indicated profile. ImageMagick uses standard filename globbing, so
6917wildcard expressions may be used to remove more than one profile. Here we
6918remove all profiles from the image except for the XMP profile: <code>+profile
6919"!xmp,*"</code>. </p>
6920
6921<p>Use <code>identify -verbose</code> to find out which profiles are in the
6922image file. Use <a href="command-line-options.html#strip">-strip</a> to remove all profiles (and
6923comments).</p>
6924
6925<p>To extract a profile, the <a href="command-line-options.html#profile">-profile</a> option is not
6926used. Instead, simply write the file to an image format such as <var>APP1, 8BIM, ICM,</var> or <var>IPTC</var>.</p>
6927
6928<p>For example, to extract the Exif data (which is stored in JPEG files in the
6929<var>APP1</var> profile), use.</p>
6930
6931<pre>
6932convert cockatoo.jpg profile.exif
6933</pre>
6934
6935<p>It is important to note that results may depend on whether or not the
cristy29dc8652015-05-12 16:26:21 +00006936original image already has an included profile. Also, keep in mind that <a
6937href="command-line-options.html#profile">-profile</a> is an "operator" (as opposed to a "setting") and
cristyd2432012015-05-04 23:15:15 +00006938therefore a conversion is made each time it is encountered, in order, in the
6939command-line. For instance, in the following example, if the original image is
6940CMYK with profile, a CMYK-CMYK-RGB conversion results.</p>
6941
6942<pre>
6943convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff
6944</pre>
6945
6946<p>Furthermore, since ICC profiles are not necessarily symmetric, extra
6947conversion steps can yield unwanted results. CMYK profiles are often very
6948asymmetric since they involve 3−&gt;4 and 4−&gt;3 channel mapping.
6949</p>
6950
6951<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00006952 <h3 class="magick-header"><a id="quality"></a>-quality <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00006953</div>
6954
6955<p class="magick-description">JPEG/MIFF/PNG compression level.</p>
6956
6957<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and
6958highest compression) to 100 (best quality but least effective compression).
6959The default is to use the estimated quality of your input image if it can
6960be determined, otherwise 92. When the quality is greater than 90, then the
6961chroma channels are not downsampled.
6962Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to specify the
6963factors for chroma downsampling.</p>
6964
6965<p>For the MIFF image format, quality/10 is the zlib compression level, which
6966is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect
6967on the image appearance, since the compression is always lossless.</p>
6968
6969<p>For the JPEG-2000 image format, quality is mapped using a non-linear
6970equation to the compression ratio required by the Jasper library. This
6971non-linear equation is intended to loosely approximate the quality provided by
6972the JPEG v1 format. The default quality value 100, a request for non-lossy
6973compression. A quality of 75 results in a request for 16:1 compression.</p>
6974
6975<p>For the MNG and PNG image formats, the quality value sets the zlib
6976compression level (quality / 10) and filter-type (quality % 10). The default
6977PNG "quality" is 75, which means compression level 7 with adaptive PNG
6978filtering, unless the image has a color map, in which case it means
6979compression level 7 with no PNG filtering.</p>
6980
6981<p>For compression level 0 (quality value less than 10), the Huffman-only
6982strategy is used, which is fastest but not necessarily the worst
6983compression.</p>
6984
6985<p>If filter-type is 4 or less, the specified PNG filter-type is used for
6986all scanlines:</p>
6987
6988<pre>
cristy29dc8652015-05-12 16:26:21 +000069890: none
69901: sub
69912: up
69923: average
69934: Paeth
cristyd2432012015-05-04 23:15:15 +00006994</pre>
6995
6996<p>If filter-type is 5, adaptive filtering is used when quality is greater
6997than 50 and the image does not have a color map, otherwise no filtering is
6998used.</p>
6999
7000<p>If filter-type is 6, adaptive filtering
7001with <var>minimum-sum-of-absolute-values</var> is used.</p>
7002
7003<p>Only if the output is MNG, if filter-type is 7, the LOCO color
7004transformation (intrapixel differencing) and adaptive filtering
7005with <var>minimum-sum-of-absolute-values</var> are used.</p>
7006
7007<p>If the filter-type is 8 the zlib Z_RLE compression strategy (or the
7008Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
7009adaptive PNG filtering.</p>
7010
7011<p>If the filter-type is 9 the zlib Z_RLE compression strategy (or the
7012Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
7013no PNG filtering.</p>
7014
7015<p>The quality setting has no effect on the appearance or signature of PNG
7016and MNG images, since the compression is always lossless.</p>
7017
7018<p>Not all combinations of compression level, strategy, and PNG filter type
7019can be obtained using the -quality option. For more precise control,
7020you can use the PNG:compression-level=N, PNG:compression-strategy=N, and
7021PNG:compression-filter=N defines, respectively, instead.
7022See <a href="command-line-options.html#define">-define</a>. Values from the defines take precedence
7023over values from the -quality option.</p>
7024
7025<p>For further information, see
7026the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
7027
7028<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007029 <h3 class="magick-header"><a id="quantize"></a>-quantize <var>colorspace</var></h3>
cristyd2432012015-05-04 23:15:15 +00007030</div>
7031
7032<p class="magick-description">reduce colors using this colorspace.</p>
7033
7034<p>This setting defines the colorspace used to sort out and reduce the number
cristy29dc8652015-05-12 16:26:21 +00007035of colors needed by an image (for later dithering) by operators such as <a
7036href="command-line-options.html#colors" >-colors</a>, Note that color reduction also happens
cristyd2432012015-05-04 23:15:15 +00007037automatically when saving images to color-limited image file formats, such as
7038GIF, and PNG8.</p>
7039
7040
7041<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007042 <h3 class="magick-header"><a id="quiet"></a>-quiet</h3>
cristyd2432012015-05-04 23:15:15 +00007043</div>
7044
7045<p class="magick-description">suppress all warning messages. Error messages are still reported.</p>
7046
7047<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007048 <h3 class="magick-header"><a id="radial-blur"></a>-radial-blur <var>angle</var></h3>
cristyd2432012015-05-04 23:15:15 +00007049</div>
7050
7051<p class="magick-description">Blur around the center of the image.</p>
7052
7053<p>Note that this is actually a rotational blur rather than a radial and as
7054such actually mis-named. </p>
7055
7056<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
7057pixels which are outside the image proper are blurred into the final result.
7058</p>
7059
7060
7061<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007062 <h3 class="magick-header"><a id="raise"></a>-raise <var>thickness</var></h3>
cristyd2432012015-05-04 23:15:15 +00007063</div>
7064
7065<p class="magick-description">Lighten or darken image edges.</p>
7066
7067<p>This will create a 3-D effect. Use <a href="command-line-options.html#raise">-raise</a> to create
7068a raised effect, otherwise use <a href="command-line-options.html#raise">+raise</a>. </p>
7069
cristy29dc8652015-05-12 16:26:21 +00007070<p>Unlike the similar <a href="command-line-options.html#frame">-frame</a> option, <a
7071href="command-line-options.html#raise">-raise</a> does not alter the dimensions of the image.</p>
cristyd2432012015-05-04 23:15:15 +00007072
7073<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007074 <h3 class="magick-header"><a id="random-threshold"></a>-random-threshold <var>low</var>x<var>high</var></h3>
cristyd2432012015-05-04 23:15:15 +00007075</div>
7076
7077<p class="magick-description">Apply a random threshold to the image.</p>
7078
7079<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007080 <h3 class="magick-header"><a id="red-primary"></a>-red-primary <var>x,y</var></h3>
cristyd2432012015-05-04 23:15:15 +00007081</div>
7082
7083<p class="magick-description">Set the red chromaticity primary point.</p>
7084
7085<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007086 <h3 class="magick-header"><a id="regard-warnings"></a>-regard-warnings</h3>
cristyd2432012015-05-04 23:15:15 +00007087</div>
7088
7089<p class="magick-description">Pay attention to warning messages.</p>
7090
7091<p>This option causes some warnings in some image formats to be treated
7092as errors. </p>
7093
7094<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007095 <h3 class="magick-header"><a id="remap"></a>-remap <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00007096</div>
7097
7098<p class="magick-description">Reduce the number of colors in an image to the colors used by this image.</p>
7099
7100<p>If the <a href="command-line-options.html#dither">-dither</a> setting is enabled (the default) then
7101the given colors are dithered over the image as necessary, otherwise the closest
7102color (in RGB colorspace) is selected to replace that pixel in the image. </p>
7103
7104<p>As a side effect of applying a <a href="command-line-options.html#remap">-remap</a> of colors across all
7105images in the current image sequence, all the images will have the same color
7106table. That means that when saved to a file format such as GIF, it will use
7107that color table as a single common or global color table, for all the images,
7108without requiring extra local color tables. </p>
7109
7110<p>Use <a href="command-line-options.html#remap">+remap</a> to reduce all images in the current image
7111sequence to use a common color map over all the images. This equivalent to
7112appending all the images together (without extra background colors) and color
7113reducing those images using <a href="command-line-options.html#colors">-colors</a> with a 256 color
7114limit, then <a href="command-line-options.html#remap">-remap</a> those colors over the original list of
7115images. This ensures all the images follow a single color map. </p>
7116
cristy29dc8652015-05-12 16:26:21 +00007117<p>If the number of colors over all the images is less than 256, then <a
7118href="command-line-options.html#remap">+remap</a> should not perform any color reduction or dithering, as
cristyd2432012015-05-04 23:15:15 +00007119no color changes are needed. In that case, its only effect is to force the use
cristy29dc8652015-05-12 16:26:21 +00007120of a global color table. This recommended after using either <a
7121href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to
cristyd2432012015-05-04 23:15:15 +00007122reduce the number of colors in an animated image sequence. </p>
7123
7124<p>Note, the remap image colormap has at most 8-bits of precision. Deeper color maps are automagically coalesced with other colors to meet this requirement.</p>
7125
7126<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007127 <h3 class="magick-header"><a id="region"></a>-region <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007128</div>
7129
7130<p class="magick-description">Set a region in which subsequent operations apply.</p>
7131
7132<p>The <var>x</var> and <var>y</var> offsets are treated
7133in the same manner as in <a href="command-line-options.html#crop">-crop</a>.</p>
7134
7135<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
7136
7137<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007138 <h3 class="magick-header"><a id="remote"></a>-remote</h3>
cristyd2432012015-05-04 23:15:15 +00007139</div>
7140
7141<p class="magick-description">perform a remote operation.</p>
7142
7143<p>The only command recognized is the name of an image file to load.</p>
7144
7145<p>If you have more than one <a href="display.html">display</a> application
7146running simultaneously, use the <a href="command-line-options.html#window"> window</a> option to
7147specify which application to control.</p>
7148
7149<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007150 <h3 class="magick-header"><a id="render"></a>-render</h3>
cristyd2432012015-05-04 23:15:15 +00007151</div>
7152
7153<p class="magick-description">render vector operations.</p>
7154
7155<p>Use <a href="command-line-options.html#render">+render</a> to turn off rendering vector operations.
7156This useful when saving the result to vector formats such as MVG or SVG.</p>
7157
7158<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007159<h3 class="magick-header"><a id="repage"></a>-repage <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007160</div>
7161
7162<p class="magick-description">Adjust the canvas and offset information of the image.</p>
7163
7164<p>This option is like <a href="command-line-options.html#page">-page</a> but acts as an image operator
7165rather than a setting. You can separately set the canvas size or the offset
7166of the image on that canvas by only providing those components. </p>
7167
7168<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
7169
7170<p>If a <code>!</code> flag is given the offset given is added to the existing
7171offset to move the image relative to its previous position. This useful for
7172animation sequences. </p>
7173
7174<p>A given a canvas size of zero such as '<code>0x0</code>' forces it to
7175recalculate the canvas size so the image (at its current offset) will appear
7176completely on that canvas (unless it has a negative offset).</p>
7177
7178<p>Use <a href="command-line-options.html#repage">+repage</a> to completely remove/reset the virtual
7179canvas meta-data from the images. </p>
7180
7181<p>The <a href="command-line-options.html#set">-set</a> '<code>page</code>' option can be used to
7182directly assign virtual canvas meta-data. </p>
7183
7184
7185<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007186 <h3 class="magick-header"><a id="resample"></a>-resample <var>horizontal</var>x<var>vertical</var></h3>
cristyd2432012015-05-04 23:15:15 +00007187</div>
7188
7189<p class="magick-description">Resample image to specified horizontal and vertical resolution.</p>
7190
7191<p>Resize the image so that its rendered size remains the same as the original
7192at the specified target resolution. For example, if a 300 DPI image renders at
71933 inches by 2 inches on a 300 DPI device, when the image has been resampled to
719472 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that
7195only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of
7196storing the image resolution. For formats which do not support an image
cristy29dc8652015-05-12 16:26:21 +00007197resolution, the original resolution of the image must be specified via <a
7198href="command-line-options.html#density">-density</a> on the command line prior to specifying the
cristyd2432012015-05-04 23:15:15 +00007199resample resolution.</p>
7200
7201<p>Note that Photoshop stores and obtains image resolution from a proprietary
7202embedded profile. If this profile exists in the image, then Photoshop will
7203continue to treat the image using its former resolution, ignoring the image
7204resolution specified in the standard file header.</p>
7205
7206<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007207 <h3 class="magick-header"><a id="resize"></a>-resize <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007208</div>
7209
7210<p class="magick-description">Resize an image.</p>
7211
7212<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
7213ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
7214
7215<p>If the <a href="command-line-options.html#filter">-filter</a> option
cristy29dc8652015-05-12 16:26:21 +00007216or <code>-define filter:option=value</code> precedes the <a
7217href="command-line-options.html#resize">-resize</a> option, the image is resized with the specified
cristyd2432012015-05-04 23:15:15 +00007218filter.</p>
7219
7220<p>Many image processing algorithms assume your image is in a linear-light
7221coding. If your image is gamma-corrected, you can remove the nonlinear gamma
7222correction, apply the transform, then restore it like this:</p>
7223
7224<pre>
cristy29dc8652015-05-12 16:26:21 +00007225convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \
7226 -quality 92 passport.jpg
cristyd2432012015-05-04 23:15:15 +00007227</pre>
7228
7229<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007230 <h3 class="magick-header"><a id="respect-parentheses"></a>-respect-parentheses</h3>
cristyd2432012015-05-04 23:15:15 +00007231</div>
7232
7233<p class="magick-description">settings remain in effect until parenthesis boundary.</p>
7234
7235<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007236 <h3 class="magick-header"><a id="reverse"></a>-reverse</h3>
cristyd2432012015-05-04 23:15:15 +00007237</div>
7238
7239<p class="magick-description">Reverse the order of images in the current image list.</p>
7240
7241
7242<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007243 <h3 class="magick-header"><a id="roll"></a>-roll {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3>
cristyd2432012015-05-04 23:15:15 +00007244</div>
7245
7246<p class="magick-description">roll an image vertically or horizontally by the amount given.</p>
7247
7248<p>A negative <var>x</var> offset rolls the image right-to-left.
7249A negative <var>y</var> offset rolls the image bottom-to-top.</p>
7250
7251
7252<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007253 <h3 class="magick-header"><a id="rotate"></a>-rotate <var>degrees</var>{<var>&lt;</var>}{<var>&gt;</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00007254</div>
7255
7256<p class="magick-description">Apply Paeth image rotation (using shear operations) to the image.</p>
7257
7258<p>Use <code>&gt;</code> to rotate the image only if its width exceeds the
7259height. <code>&lt;</code> rotates the image <var>only</var> if its width is less
7260than the height. For example, if you specify <code>-rotate "-90&gt;"</code> and
7261the image size is 480x640, the image is not rotated. However, if the image is
7262640x480, it is rotated by -90 degrees. If you use <code>&gt;</code> or
7263<code>&lt;</code>, enclose it in quotation marks to prevent it from being
7264misinterpreted as a file redirection.</p>
7265
7266<p>Empty triangles in the corners, left over from rotating the image, are
7267filled with the <code>background</code> color. </p>
7268
7269<p>See also the <a href="command-line-options.html#distort">-distort</a> operator and specifically the
7270'<code>ScaleRotateTranslate</code>' distort method. </p>
7271
7272
7273<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007274 <h3 class="magick-header"><a id="sample"></a>-sample <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007275</div>
7276
7277<p class="magick-description">minify / magnify the image with pixel subsampling and pixel replication, respectively.</p>
7278
7279<p>Change the image size simply by directly sampling the pixels original
7280from the image. When magnifying, pixels are replicated in blocks. When
7281minifying, pixels are sub-sampled (i.e., some rows and columns are skipped
7282over). </p>
7283
7284<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
7285a <a href="command-line-options.html#filter">-filter</a> setting of <code>point</code> (nearest
7286neighbour), though <a href="command-line-options.html#sample">-sample</a> is a lot faster, as it
7287avoids all the filter processing of the image. As such it completely ignores
7288the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
7289
7290<p>The key feature of the <a href="command-line-options.html#sample">-sample</a> is that no new colors
7291will be added to the resulting image, though some colors may disappear. </p>
7292
7293<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
7294ignored, unlike <a href="command-line-options.html#resize">-resize</a>. </p>
7295
7296
7297<p>The actual sampling point is the middle of the sub-region being sampled.
7298As such a single pixel sampling of an image will take the middle pixel, (or
cristy29dc8652015-05-12 16:26:21 +00007299top-left-middle if image has even dimensions). However the <a
7300href="command-line-options.html#define">-define</a> '<code>sample:offset</code>' can be set to modify
cristyd2432012015-05-04 23:15:15 +00007301this position some other location within each sub-region being sampled, as
7302a percentage offset.</p>
7303
7304<p>By default this value is '<code>50</code>' for the midpoint, but could be set
7305to '<code>0</code>' for top-left, '<code>100</code>' for bottom-right, or with
7306separate X and Y offsets such as '<code>0x50</code>' for left-middle edge of
7307sampling sub-region.</p>
7308
7309
7310<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007311 <h3 class="magick-header"><a id="sampling-factor"></a>-sampling-factor <var>horizontal-factor</var>x<var>vertical-factor</var></h3>
cristyd2432012015-05-04 23:15:15 +00007312</div>
7313
7314<p class="magick-description">sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</p>
7315
7316<p>This option specifies the sampling factors to be used by the JPEG encoder
7317for chroma downsampling. If this option is omitted, the JPEG library will use
7318its own default values. When reading or writing the YUV format and when
cristy29dc8652015-05-12 16:26:21 +00007319writing the M2V (MPEG-2) format, use <a
7320href="command-line-options.html#sampling-factor">-sampling-factor 2x1</a> or <a
7321href="command-line-options.html#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2
cristyd2432012015-05-04 23:15:15 +00007322downsampling method.</p>
7323
7324<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007325 <h3 class="magick-header"><a id="scale"></a>-scale <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007326</div>
7327
7328<p class="magick-description">minify / magnify the image with pixel block averaging and pixel replication, respectively.</p>
7329
7330<p>Change the image size simply by replacing pixels by averaging pixels
7331together when minifying, or replacing pixels when magnifying. </p>
7332
7333<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
7334a <a href="command-line-options.html#filter">-filter</a> setting of <code>box</code>. Though it is a lot
7335faster, as it avoids all the filter processing of the image. As such it
7336completely ignores the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
7337
7338<p>If when shrinking (minifying) images the original image is some integer
7339multiple of the new image size, the number of pixels averaged together to
7340produce the new pixel color is the same across the whole image. This is
7341a special case known as 'binning' and is often used as a method of reducing
7342noise in image such as those generated by digital cameras, especially in low
7343light conditions. </p>
7344
7345
7346<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007347 <h3 class="magick-header"><a id="scene"></a>-scene <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00007348</div>
7349
7350<p class="magick-description">set scene number.</p>
7351
7352<p>This option sets the scene number of an image or the first image in an image sequence.</p>
7353
7354<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007355 <h3 class="magick-header"><a id="screen"></a>-screen</h3>
cristyd2432012015-05-04 23:15:15 +00007356</div>
7357
7358<p class="magick-description">specify the screen to capture.</p>
7359
7360<p>This option indicates that the GetImage request used to obtain the image
7361should be done on the root window, rather than directly on the specified
7362window. In this way, you can obtain pieces of other windows that overlap the
7363specified window, and more importantly, you can capture menus or other popups
7364that are independent windows but appear over the specified window.</p>
7365
7366<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007367 <h3 class="magick-header"><a id="seed"></a>-seed</h3>
cristyd2432012015-05-04 23:15:15 +00007368</div>
7369
7370<p class="magick-description">seed a new sequence of pseudo-random numbers</p>
7371
7372<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007373 <h3 class="magick-header"><a id="segment"></a>-segment <var>cluster-threshold</var>x<var>smoothing-threshold</var></h3>
cristyd2432012015-05-04 23:15:15 +00007374</div>
7375
7376<p class="magick-description">segment the colors of an image.</p>
7377
7378<p>Segment an image by analyzing the histograms of the color components and
7379identifying units that are homogeneous with the fuzzy c-means technique. This
7380is part of the ImageMagick color quantization routines. </p>
7381
7382<p>Specify <var>cluster threshold</var> as the number of pixels in
7383each cluster that must exceed the cluster threshold to be considered valid.
7384<var>Smoothing threshold</var> eliminates noise in the second
7385derivative of the histogram. As the value is increased, you can expect
7386a smoother second derivative. The default is 1.5.</p>
7387
7388<p>If the <a href="command-line-options.html#verbose">-verbose</a> setting is defined, a detailed report
7389of the color clusters is returned.</p>
7390
7391
7392<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007393 <h3 class="magick-header"><a id="selective-blur"></a>-selective-blur <var>radius</var><br />-selective-blur <var>radius</var>x<var>sigma</var>{<var>+threshold</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00007394</div>
7395
7396<p class="magick-description">Selectively blur pixels within a contrast threshold.</p>
7397
7398<p>Blurs those pixels that are less than or equal to the threshold in
7399contrast. The threshold may be expressed as a fraction of <var>QuantumRange</var> or as a percentage.</p>
7400
7401<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007402 <h3 class="magick-header"><a id="separate"></a>-separate</h3>
cristyd2432012015-05-04 23:15:15 +00007403</div>
7404
7405<p class="magick-description">separate an image channel into a grayscale image. Specify the channel with <a href="command-line-options.html#channel">-channel</a>.</p>
7406
7407<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007408 <h3 class="magick-header"><a id="sepia-tone"></a>-sepia-tone <var>threshold</var></h3>
cristyd2432012015-05-04 23:15:15 +00007409</div>
7410
7411<p class="magick-description">simulate a sepia-toned photo.</p>
7412
7413<p>Specify <var>threshold</var> as the percent threshold of the intensity (0 - 99.9%).</p>
7414
7415<p>This option applies a special effect to the image, similar to the effect
7416achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <var>QuantumRange</var> and is a measure of the extent of the sepia
7417toning. A threshold of 80% is a good starting point for a reasonable
7418tone.</p>
7419
7420
7421
7422<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007423 <h3 class="magick-header"><a id="set"></a>-set <var>key value</var></h3>
7424 <h3 class="magick-header">+set <var>key</var></h3>
cristyd2432012015-05-04 23:15:15 +00007425</div>
7426
7427<p class="magick-description">sets image attributes and properties for images in the current image sequence.</p>
7428
7429<p>This will assign (or modify) specific settings attached to all the images
7430in the current image sequence. Using the <a href="command-line-options.html#set">+set</a> form of the
7431option will either remove, or reset that setting to a default state, as
7432appropriate. </p>
7433
7434<p>For example, it will modify specific well known image meta-data
cristy29dc8652015-05-12 16:26:21 +00007435'attributes' such as those normally overridden by: the options <a
7436href="command-line-options.html#delay" >-delay</a>, <a href="command-line-options.html#dispose" >-dispose</a>, and <a
7437href="command-line-options.html#page" >-page</a>, <a href="command-line-options.html#colorspace" >-colorspace</a>; generally
cristyd2432012015-05-04 23:15:15 +00007438assigned before the image is read in, by using a <var>key</var> of
7439the same name. </p>
7440
7441<p>If the given <var>key</var> does not match a specific known
7442'attribute ', such as shown above, the setting is stored as a a free form
cristy29dc8652015-05-12 16:26:21 +00007443'property' string. Such settings are listed in <a href="command-line-options.html#verbose"
7444>-verbose</a> information ("<code>info:</code>" output format) as "Properties".
cristyd2432012015-05-04 23:15:15 +00007445</p>
7446
7447<p>This includes string 'properties' that are set by and assigned to images
cristy29dc8652015-05-12 16:26:21 +00007448using the options <a href="command-line-options.html#comment" >-comment</a>, <a href="command-line-options.html#label"
7449>-label</a>, <a href="command-line-options.html#caption" >-caption</a>. These options actually assign
7450a global 'artifact' which are automatically assigned (and any <a href="escape.html" >Format Percent
cristyd2432012015-05-04 23:15:15 +00007451Escapes</a> expanded) to images as they are read in. For example:</p>
7452
7453<pre>
7454convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png
7455identify -format %c rose.png
7456Rose is a rose is a rose is a rose
7457</pre>
7458
cristy29dc8652015-05-12 16:26:21 +00007459<p>The set value can also make use of <a href="escape.html" >Format and Print Image
cristyd2432012015-05-04 23:15:15 +00007460Properties</a> in the defined value. For example:</p>
7461
7462<pre>
7463convert rose: -set origsize '%wx%h' -resize 50% \
7464 -format 'Old size = %[origsize] New size = %wx%h' info:
7465Old size = 70x46 New size = 35x23
7466</pre>
7467
7468<p>Other well known 'properties' that are availible include:
7469'<code>date:create</code>' and '<code>date:modify</code>' and
7470'<code>signature</code>'. </p>
7471
7472<p>The <a href="command-line-options.html#repage">-repage</a> operator will also allow you to modify
7473the '<code>page</code>' attribute of an image for images already in memory (also
7474see <a href="command-line-options.html#repage">-page</a>). However it is designed to provide a finer
7475control of the sub-parts of this 'attribute'. The <a href="command-line-options.html#set">-set page</a>
7476option will only provide a direct, unmodified assignment of '<code>page</code>'
7477attribute. </p>
7478
7479<p>This option can also associate a colorspace or profile with your image.
7480For example,</p>
7481
7482<pre>
7483convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd
7484</pre>
7485
7486<p>Some 'properties' must be defined in a specific way to be used. For
7487example only 'properties' prefixed with "<code>filename:</code>" can be used to
7488modify the output filename of an image. For example</p>
7489
7490<pre>
7491convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'
7492</pre>
7493
7494<p>If the setting value is prefixed with "<code>option:</code>" the setting will
cristy29dc8652015-05-12 16:26:21 +00007495be saved as a global "Artifact" exactly as if it was set using the <a
7496href="command-line-options.html#define" >-define</a> option. As such settings are global in scope, they
cristyd2432012015-05-04 23:15:15 +00007497can be used to pass 'attributes' and 'properties' of one specific image,
7498in a way that allows you to use them in a completely different image, even if
7499the original image has long since been modified or destroyed. For example: </p>
7500
7501<pre>
7502convert rose: -set option:rosesize '%wx%h' -delete 0 \
7503 label:'%[rosesize]' label_size_of_rose.gif"
7504</pre>
7505
cristy29dc8652015-05-12 16:26:21 +00007506<p>Note that <a href="escape.html" >Format Percent Escapes</a> will only match
cristyd2432012015-05-04 23:15:15 +00007507a 'artifact' if the given <var>key</var> does not match an existing
7508'attribute' or 'property'. </p>
7509
7510<p>You can set the attributes of the image registry by prefixing the value
7511with <code>registry:</code>.</p>
7512
7513<p>The <a href="command-line-options.html#set">-set profile</a> option can also be used to inject
7514previously-formatted ancillary chunks into the output PNG file, using
7515the commandline option as shown below or by setting the profile via a
7516programming interface:</p>
7517
7518<pre>
7519convert in.png -set profile PNG-chunk-x:&lt;filename&gt; out.png
7520</pre>
7521
7522<p>where <var>x</var> is a location flag and
7523<var>filename</var> is a file containing the chunk
7524name in the first 4 bytes, then a colon (":"), followed by the chunk data.
7525This encoder will compute the chunk length and CRC, so those must not
7526be included in the file.</p>
7527
7528<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT),
7529or "e" (end, i.e., after IDAT). If you want to write multiple chunks
7530of the same type, then add a short unique string after the "x" to prevent
7531subsequent profiles from overwriting the preceding ones, e.g.,</p>
7532
7533
7534<pre>
7535convert in.png -set profile PNG-chunk-b01:file01 \
7536 -profile PNG-chunk-b02:file02 out.png
7537</pre>
7538
7539<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007540 <h3 class="magick-header"><a id="shade"></a>-shade <var>azimuth</var>x<var>elevation</var></h3>
cristyd2432012015-05-04 23:15:15 +00007541</div>
7542
7543<p class="magick-description">shade the image using a distant light source.</p>
7544
7545<p>Specify <var>azimuth</var> and <var>elevation</var> as
7546the position of the light source. Use <a href="command-line-options.html#shade">+shade</a> to return
7547the shading results as a grayscale image.</p>
7548
7549<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007550 <h3 class="magick-header"><a id="shadow"></a>-shadow <var>percent-opacity</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00007551</div>
7552
7553<p class="magick-description">simulate an image shadow.</p>
7554
7555<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007556 <h3 class="magick-header"><a
7557id="shared-memory"></a>-shared-memory</h3>
cristyd2432012015-05-04 23:15:15 +00007558</div>
7559
7560<p class="magick-description">use shared memory.</p>
7561
7562<p>This option specifies whether the utility should attempt to use shared
7563memory for pixmaps. ImageMagick must be compiled with shared memory support,
7564and the display must support the <var>MIT-SHM</var> extension.
7565Otherwise, this option is ignored. The default is <code>True</code>.</p>
7566
7567<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007568 <h3 class="magick-header"><a id="sharpen"></a>-sharpen <var>radius</var><br />-sharpen <var>radius</var>x<var>sigma</var></h3>
cristyd2432012015-05-04 23:15:15 +00007569</div>
7570
7571<p class="magick-description">sharpen the image.</p>
7572
7573<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
7574
7575<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007576 <h3 class="magick-header"><a id="shave"></a>-shave <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007577</div>
7578
7579<p class="magick-description">Shave pixels from the image edges.</p>
7580
7581<p>The <var>size</var> portion of the <var>geometry</var>
7582argument specifies the width of the region to be removed from both sides of
7583the image and the height of the regions to be removed from top and bottom.
7584Offsets are ignored.</p>
7585
7586<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
7587
7588<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007589 <h3 class="magick-header"><a id="shear"></a>-shear <var>Xdegrees</var>[x<var>Ydegrees</var>]</h3>
cristyd2432012015-05-04 23:15:15 +00007590</div>
7591
7592<p class="magick-description">Shear the image along the x-axis and/or y-axis.</p>
7593
7594<p>The shear angles may be positive, negative, or zero. When <var>Ydegrees</var> is omitted it defaults to 0. When both angles are
7595given, the horizontal component of the shear is performed before the vertical
7596component.</p>
7597
7598<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e.,
7599horizontally or vertically, respectively),creating a parallelogram. The amount
7600of each is controlled by the respective shear angle. For horizontal shears,
7601<var>Xdegrees</var> is measured clockwise relative to "up" (the
7602negative y-axis), sliding the top edge to the right when 0°&lt;<var>Xdegrees</var>&lt;90° and to the left when 90°&lt;<var>Xdegrees</var>&lt;180°. For vertical shears <var>Ydegrees</var> is measured clockwise relative to "right" (the
7603positive x-axis), sliding the right edge down when 0°&lt;<var>Ydegrees</var>&lt;90° and up when 90°&lt;<var>Ydegrees</var>&lt;180°.</p>
7604
7605<p>Empty triangles left over from shearing the image are filled with the color
7606defined by the <a href="command-line-options.html#fill">-background</a> option. The color is specified
7607using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
7608
7609<p>The horizontal shear is performed before the vertical part. This is
7610important to note, since horizontal and vertical shears do not
7611<var>commute</var>, i.e., the order matters in a sequence of shears. For
7612example, the following two commands are not equivalent.</p>
7613
7614<pre>
7615convert logo: -shear 20x0 -shear 0x60 logo-sheared.png
7616convert logo: -shear 0x60 -shear 20x0 logo-sheared.png
7617</pre>
7618
7619<p>The first of the two commands above is equivalent to the following, except
7620for the amount of empty space created; the command that follows generates
7621a smaller image, and so is a better choice in terms of time and space.</p>
7622
7623<pre>
7624convert logo: -shear 20x60 logo-sheared.png
7625</pre>
7626
7627<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007628 <h3 class="magick-header"><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <var>contrast</var>x<var>mid-point</var></h3>
cristyd2432012015-05-04 23:15:15 +00007629</div>
7630
7631<p class="magick-description">increase the contrast without saturating highlights or shadows.</p>
7632
7633<p>Increase the contrast of the image using a sigmoidal transfer function
7634without saturating highlights or shadows. <var>Contrast</var>
7635indicates how much to increase the contrast. For example, 0 is none, 3 is
7636typical and 20 is a lot.
7637</p>
7638
7639<p>The <var>mid-point</var> indicates where the maximum change
7640'slope' in contrast should fall in the resultant image (0 is white; 50% is
7641middle-gray; 100% is black). </p>
7642
7643<p>By default the image contrast is increased, use <var>+sigmoidal-contrast</var> to decrease the contrast.</p>
7644
7645<p>To achieve the equivalent of a sigmoidal brightness change (similar to
7646a gamma adjustment), you would use <var>-sigmoidal-contrast
7647{brightness}x0%</var> to increase brightness and <var>+sigmoidal-contrast {brightness}x0%</var> to decrease brightness.
7648Note the use of '0' fo rthe mid-point of the sigmoidal curve. </p>
7649
7650<p>Using a very high <var>contrast</var> will produce a sort of
7651'smoothed thresholding' of the image. Not as sharp (with high aliasing
7652effects) of a true threshold, but with tapered gray-levels around the threshold
7653<var>mid-point</var>. </p>
7654
7655<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007656 <h3 class="magick-header"><a id="silent"></a>-silent</h3>
cristyd2432012015-05-04 23:15:15 +00007657</div>
7658
7659<p class="magick-description">operate silently.</p>
7660
7661<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007662 <h3 class="magick-header"><a id="similarity-threshold"></a>-similarity-threshold <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00007663</div>
7664
7665<p class="magick-description">minimum RMSE for subimage match.</p>
7666
7667<p>If this setting is used, then the search will stop as soon as it finds a match whose metric is less than or equal to the value. A partially filled second output image will result. Using a value of zero, will cause the search to stop at the first perfect match it finds. If this setting is left off, then the search will proceed to completion or as limited by <var>-dissimilarity-threshold</var>.</p>
7668
7669<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007670 <h3 class="magick-header"><a id="size"></a>-size <var>width</var>[x<var>height</var>][<var>+offset</var>]</h3>
cristyd2432012015-05-04 23:15:15 +00007671</div>
7672
7673<p class="magick-description">set the width and height of the image.</p>
7674
7675<p>Use this option to specify the width and height of raw images whose
7676dimensions are unknown such as <code>GRAY</code>, <code>RGB</code>, or
cristy29dc8652015-05-12 16:26:21 +00007677<code>CMYK</code>. In addition to width and height, use <a
7678href="command-line-options.html#size">-size</a> with an offset to skip any header information in the
cristyd2432012015-05-04 23:15:15 +00007679image or tell the number of colors in a <code>MAP</code> image file, (e.g. -size
7680640x512+256).</p>
7681
7682<p>For Photo CD images, choose from these sizes:</p>
7683
7684<pre>
cristy29dc8652015-05-12 16:26:21 +00007685192x128
7686384x256
7687768x512
76881536x1024
76893072x2048
cristyd2432012015-05-04 23:15:15 +00007690</pre>
7691
7692<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007693 <h3 class="magick-header"><a id="sketch"></a>-sketch <var>radius</var><br />-sketch <var>radius</var>x<var>sigma</var>+<var>angle</var></h3>
cristyd2432012015-05-04 23:15:15 +00007694</div>
7695
7696<p class="magick-description">simulate a pencil sketch.</p>
7697
7698<p>Sketch with the given radius, standard deviation (sigma), and angle. The
7699angle given is the angle toward which the image is sketched. That is the
7700direction people would consider the object is coming from. </p>
7701
7702<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007703 <h3 class="magick-header"><a id="smush"></a>-smush <var>offset</var></h3>
cristyd2432012015-05-04 23:15:15 +00007704</div>
7705
7706<p class="magick-description">smush an image sequence together.</p>
7707
7708<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007709 <h3 class="magick-header"><a id="snaps"></a>-snaps <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00007710</div>
7711
7712<p class="magick-description">Set the number of screen snapshots.</p>
7713
7714<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
7715
7716<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007717 <h3 class="magick-header"><a id="solarize"></a>-solarize <var>threshold</var></h3>
cristyd2432012015-05-04 23:15:15 +00007718</div>
7719
7720<p class="magick-description">negate all pixels above the threshold level.</p>
7721
7722<p>Specify <var>factor</var> as the percent threshold of the intensity (0 - 99.9%).</p>
7723
7724<p>This option produces a <var>solarization</var> effect seen when
7725exposing a photographic film to light during the development process.</p>
7726
7727<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007728 <h3 class="magick-header"><a id="sparse-color"></a>-sparse-color <var>method</var> '<var>x</var>,<var>y</var> <var>color</var> ...'</h3>
cristyd2432012015-05-04 23:15:15 +00007729</div>
7730
7731<p class="magick-description"> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </p>
7732
7733
7734<table class="table table-condensed table-striped">
7735 <tbody>
7736 <tr>
7737 <th style="width: 8%">Method</th>
7738 <th>Description</th>
7739 </tr>
7740
7741 <tr>
7742 <td>barycentric</td>
7743 <td>three point triangle of color given 3 points.
7744 Giving only 2 points will form a linear gradient between those points.
7745 The gradient generated extends beyond the triangle created by those
7746 3 points. </td>
7747 </tr>
7748
7749 <tr>
7750 <td>bilinear</td>
7751 <td>Like barycentric but for 4 points. Less than 4 points
7752 fall back to barycentric. </td>
7753 </tr>
7754 <tr>
7755 <td>voronoi</td>
7756 <td>Simply map each pixel to the to nearest color point
7757 given. The result are polygonal 'cells' of solid color. </td>
7758 </tr>
7759
7760 <tr>
7761 <td>shepards</td>
7762 <td>Colors points biased on the ratio of inverse distance
7763 squared. Generating spots of color in a sea of the average of
7764 colors. </td>
7765 </tr>
7766
7767 <tr>
7768 <td>inverse</td>
7769 <td>Colors points biased on the ratio of inverse distance.
7770 This generates sharper points of color rather than rounded spots of
7771 '<code>shepards</code>' Generating spots of color in a sea of the
7772 average of colors. </td>
7773 </tr>
7774
7775 </tbody>
7776</table>
7777
7778<p>The points are placed according to the images location on the virtual
cristy29dc8652015-05-12 16:26:21 +00007779canvas (<a href="command-line-options.html#page" >-page</a> or <a href="command-line-options.html#repage" >-repage</a>
cristyd2432012015-05-04 23:15:15 +00007780offset), and do not actually have to exist on the given image, but may be
7781some point beyond the edge of the image. All points are floating point values.
7782</p>
7783
cristy29dc8652015-05-12 16:26:21 +00007784<p>Only the color channels defined by the <a href="command-line-options.html#channel" >-channel</a> are
cristyd2432012015-05-04 23:15:15 +00007785modified, which means that by default matte/alpha transparency channel is not
7786effected. Typically transparency channel is turned off either before or after
7787the operation. </p>
7788
7789<p>Of course if some color points are transparent to generate a transparent
7790gradient, then the image also requires transparency enabled to store the
7791values. </p>
7792
7793<p>All the above methods when given a single point of color will replace all
7794the colors in the image with the color given, regardless of the point. This is
7795logical, and provides an alternative technique to recolor an image to some
7796default value. </p>
7797
7798
7799<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007800 <h3 class="magick-header"><a id="splice"></a>-splice <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007801</div>
7802
7803<p class="magick-description">Splice the current background color into the image.</p>
7804
cristy29dc8652015-05-12 16:26:21 +00007805<p>This will add rows and columns of the current <a
7806href="command-line-options.html#background">-background</a> color into the given image according to the
cristyd2432012015-05-04 23:15:15 +00007807given <a href="command-line-options.html#gravity">-gravity</a> geometry setting. See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Essentially <a href="command-line-options.html#splice">-splice</a> will divide the
7808image into four quadrants, separating them by the inserted rows and columns.
7809</p>
7810
7811<p>If a dimension of geometry is zero no rows or columns will be added for that
cristy29dc8652015-05-12 16:26:21 +00007812dimension. Similarly using a zero offset with the appropriate <a
7813href="command-line-options.html#gravity">-gravity</a> setting will add rows and columns to the edges of
7814the image, padding the image only along that one edge. Edge padding is what <a
7815href="command-line-options.html#splice">-splice</a> is most commonly used for. </p>
cristyd2432012015-05-04 23:15:15 +00007816
cristy29dc8652015-05-12 16:26:21 +00007817<p>If the exact same <var>geometry</var> and <a
7818href="command-line-options.html#gravity">-gravity</a> is later used with <a href="command-line-options.html#chop">-chop</a> the
cristyd2432012015-05-04 23:15:15 +00007819added added all splices removed. </p>
7820
7821<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007822 <h3 class="magick-header"><a id="spread"></a>-spread <var>amount</var></h3>
cristyd2432012015-05-04 23:15:15 +00007823</div>
7824
7825<p class="magick-description">displace image pixels by a random amount.</p>
7826
7827<p>The argument <var>amount</var> defines the size of the
7828neighborhood around each pixel from which to choose a candidate pixel to
7829swap.</p>
7830
7831<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007832 <h3 class="magick-header"><a id="statistic"></a>-statistic <var>type</var> <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00007833</div>
7834
7835<p class="magick-description">replace each pixel with corresponding statistic from the neighborhood.</p>
7836
7837<p>Choose from these statistic types:</p>
cristy29dc8652015-05-12 16:26:21 +00007838<dl class="dl-horizontal">
7839<dt>Gradient</dt><dd>maximum difference (max - min) value in neighborhood</dd>
7840<dt>Maximum</dt><dd>maximum value per channel in neighborhood</dd>
7841<dt>Minimum</dt><dd>minimum value per channel in neighborhood</dd>
7842<dt>Mean</dt><dd>average value per channel in neighborhood</dd>
7843<dt>Median</dt><dd>median value per channel in neighborhood</dd>
7844<dt>Mode</dt><dd>mode (most frequent) value per channel in neighborhood</dd>
7845<dt>Nonpeak</dt><dd>value just before or after the median value per channel in neighborhood</dd>
7846<dt>RMS</dt><dd>root mean square value per channel in neighborhood</dd>
7847<dt>StandardDeviation</dt><dd> standard deviation value per channel in neighborhood</dd>
7848</dl>
cristyd2432012015-05-04 23:15:15 +00007849
7850<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007851 <h3 class="magick-header"><a id="stegano"></a>-stegano <var>offset</var></h3>
cristyd2432012015-05-04 23:15:15 +00007852</div>
7853
7854<p class="magick-description">hide watermark within an image.</p>
7855
7856<p>Use an offset to start the image hiding some number of pixels from the
7857beginning of the image. Note this offset and the image size. You will need
7858this information to recover the steganographic image (e.g. display -size
7859320x256+35 stegano:image.png).</p>
7860
7861<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007862 <h3 class="magick-header"><a id="stereo"></a>-stereo <var>+x</var>{<var>+y</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00007863</div>
7864
7865<p class="magick-description">composite two images to create a red / cyan stereo anaglyph.</p>
7866
7867<p>The left side of the stereo pair (second image) is saved as the red channel of the output image. The right side (first image) is saved as the green and blue channels. Red-green stereo glasses are required to properly view the stereo image.</p>
7868
7869<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007870 <h3 class="magick-header"><a id="storage-type"></a>-storage-type <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00007871</div>
7872
7873<p class="magick-description">pixel storage type. Here are the valid types:</p>
7874
7875<pre>
cristy29dc8652015-05-12 16:26:21 +00007876char unsigned characters
7877double doubles
7878float floats
7879integer integers
7880long longs
7881quantum pixels in the native depth of your ImageMagick distribution
7882short unsigned shorts
cristyd2432012015-05-04 23:15:15 +00007883</pre>
7884
7885<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
7886values range from 0 to the maximum value the storage type can support.</p>
7887
7888<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007889 <h3 class="magick-header"><a id="stretch"></a>-stretch <var>fontStretch</var></h3>
cristyd2432012015-05-04 23:15:15 +00007890</div>
7891
7892<p class="magick-description">Set a type of stretch style for fonts.</p>
7893
7894<p>This setting suggests a type of stretch that ImageMagick should try to
7895apply to the currently selected font family. Select <var>fontStretch</var> from the following.</p>
7896
7897<pre>
cristy29dc8652015-05-12 16:26:21 +00007898Any
7899Condensed
7900Expanded
7901ExtraCondensed
7902ExtraExpanded
7903Normal
7904SemiCondensed
7905SemiExpanded
7906UltraCondensed
7907UltraExpanded
cristyd2432012015-05-04 23:15:15 +00007908</pre>
7909
7910<p>To print a complete list of stretch types, use <a href="command-line-options.html#list">-list
7911stretch</a>.</p>
7912
cristy29dc8652015-05-12 16:26:21 +00007913<p>For other settings that affect fonts, see the options <a
7914href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
7915href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
cristyd2432012015-05-04 23:15:15 +00007916
7917<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007918 <h3 class="magick-header"><a id="strip"></a>-strip</h3>
cristyd2432012015-05-04 23:15:15 +00007919</div>
7920
7921<p class="magick-description">strip the image of any profiles or comments.</p>
7922
7923<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007924 <h3 class="magick-header"><a id="stroke"></a>-stroke <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00007925</div>
7926
7927<p class="magick-description">color to use when stroking a graphic primitive.</p>
7928
7929<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
7930
7931<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
7932
7933<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007934 <h3 class="magick-header"><a id="strokewidth"></a>-strokewidth <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00007935</div>
7936
7937<p class="magick-description">set the stroke width.</p>
7938
7939<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
7940
7941<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007942 <h3 class="magick-header"><a id="style"></a>-style <var>fontStyle</var></h3>
cristyd2432012015-05-04 23:15:15 +00007943</div>
7944
7945<p class="magick-description">Set a font style for text.</p>
7946
7947<p>This setting suggests a font style that ImageMagick should try to apply to
7948the currently selected font family. Select <var>fontStyle</var> from
7949the following.</p>
7950
7951<pre>
cristy29dc8652015-05-12 16:26:21 +00007952Any
7953Italic
7954Normal
7955Oblique
cristyd2432012015-05-04 23:15:15 +00007956</pre>
7957
cristy29dc8652015-05-12 16:26:21 +00007958<p>For other settings that affect fonts, see the options <a
7959href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
7960href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
cristyd2432012015-05-04 23:15:15 +00007961
7962<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007963 <h3 class="magick-header"><a id="subimage-search"></a>-subimage-search</h3>
cristyd2432012015-05-04 23:15:15 +00007964</div>
7965
7966<p class="magick-description">search for subimage.</p>
7967
7968<p>This option is required to have compare search for the best match location
7969of a small image within a larger image. This search will produce two images
7970(or two frames). The first is the "difference" image and the second will
7971be the "match score" image.</p>
7972
7973<p>The "match-score" image is smaller containing a pixel for ever possible
7974position of the top-left corner of the given sub-image. that is its size will
7975be the size of the larger_image - sub_image + 1. The brightest location in
7976this image is the location s the locate on the best match that is also
7977reported. Note that this may or may not be a perfect match, and the actual
7978brightness will reflect this. Other bright 'peaks' can be used to locate other
7979possible matching locations. </p>
7980
7981<p>Note that the search will try to compare the sub-image at every possible
7982location in the larger image, as such it can be very slow. The smaller the
7983sub-image the faster this search is. </p>
7984
7985
7986<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007987 <h3 class="magick-header"><a id="swap"></a>-swap <var>index,index</var></h3>
cristyd2432012015-05-04 23:15:15 +00007988</div>
7989
7990<p class="magick-description">Swap the positions of two images in the image sequence.</p>
7991
7992<p>For example, <a href="command-line-options.html#swap">-swap 0,2</a> swaps the first and the third
7993images in the current image sequence. Use <a href="command-line-options.html#swap">+swap</a> to switch
7994the last two images in the sequence.</p>
7995
7996<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00007997 <h3 class="magick-header"><a id="swirl"></a>-swirl <var>degrees</var></h3>
cristyd2432012015-05-04 23:15:15 +00007998</div>
7999
8000<p class="magick-description">swirl image pixels about the center.</p>
8001
8002<p><var>Degrees</var> defines the tightness of the swirl.</p>
8003
8004<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008005 <h3 class="magick-header"><a id="synchronize"></a>-synchronize</h3>
cristyd2432012015-05-04 23:15:15 +00008006</div>
8007
8008<p class="magick-description">synchronize image to storage device.</p>
8009
8010<p>Set to "true" to ensure all image data is fully flushed and synchronized
8011to disk. There is a performance penalty, but the benefits include ensuring a
8012valid image file in the event of a system crash and early reporting if there
8013is not enough disk space for the image pixel cache.</p>
8014
8015<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008016 <h3 class="magick-header"><a id="taint"></a>-taint</h3>
cristyd2432012015-05-04 23:15:15 +00008017</div>
8018
8019<p class="magick-description">Mark the image as modified.</p>
8020
8021<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008022 <h3 class="magick-header"><a id="text-font"></a>-text-font <var>name</var></h3>
cristyd2432012015-05-04 23:15:15 +00008023</div>
8024
8025<p class="magick-description">font for writing fixed-width text.</p>
8026
8027<p>Specifies the name of the preferred font to use in fixed (typewriter style)
8028formatted text. The default is 14 point <var>Courier</var>.</p>
8029
8030<p>You can tag a font to specify whether it is a PostScript, TrueType, or
8031OPTION1 font. For example, <code>Courier.ttf</code> is a TrueType font and
8032<code>x:fixed</code> is OPTION1.</p>
8033
8034<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008035 <h3 class="magick-header"><a id="texture"></a>-texture <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00008036</div>
8037
8038<p class="magick-description">name of texture to tile onto the image background.</p>
8039
8040<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008041 <h3 class="magick-header"><a id="threshold"></a>-threshold <var>value</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00008042</div>
8043
8044<!-- {<var>green,blue,opacity</var>}
8045<p>If the green or blue value is omitted, these channels use the same value as
8046the first one provided. If all three color values are the same, the result is
8047a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used
8048and any partially transparent pixel becomes fully transparent.</p>
8049-->
8050
8051<p class="magick-description">Apply simultaneous black/white threshold to the image.</p>
8052
cristy29dc8652015-05-12 16:26:21 +00008053<p>Any pixel values (more specifically, those channels set using <a href="command-line-options.html#channel">&#x2011;channel</a>) that exceed the specified threshold are reassigned the
cristyd2432012015-05-04 23:15:15 +00008054maximum channel value, while all other values are assigned the minimum.</p>
8055
8056<p> The threshold value can be given as a percentage or as an absolute integer
8057value corresponding to the desired channel value. When given as an integer,
8058the minimum attainable value is 0 (corresponding to black when all channels
8059are affected), but the maximum value (corresponding to white) is that of the
8060<code>quantum depth</code> of the particular build of ImageMagick, and is
8061therefore dependent on the installation. For that reason, a reasonable
8062recommendation for most applications is to specify the threshold values as
8063a percentage. </p>
8064
8065<p> The following would force pixels with red values above 50% to have 100%
8066red values, while those at or below 50% red would be set to 0 in the red
8067channel. The green, blue, and alpha channels (if present) would be unchanged.
8068</p>
8069
8070<pre>
8071convert in.png -channel red -threshold 50% out.png
8072</pre>
8073
8074<p>As (possibly) impractical but instructive examples, the following would
8075generate an all-black and an all-white image with the same dimensions as the
8076input image.</p>
8077
8078
8079<pre>
8080convert in.png -threshold 100% black.png
8081convert in.png -threshold -1 white.png
8082</pre>
8083
8084<p>Note that the values of the transparency channel is treated as 'matte'
8085values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
8086
cristy29dc8652015-05-12 16:26:21 +00008087<p> See also <a href="command-line-options.html#black-threshold">&#x2011;black&#x2011;threshold</a> and <a href="command-line-options.html#white-threshold">&#x2011;white&#x2011;threshold</a>.
cristyd2432012015-05-04 23:15:15 +00008088</p>
8089
8090<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008091 <h3 class="magick-header"><a id="thumbnail"></a>-thumbnail <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00008092</div>
8093
8094<p class="magick-description">Create a thumbnail of the image.</p>
8095
8096<p>This is similar to <a href="command-line-options.html#resize">-resize</a>, except it is optimized
8097for speed and any image profile, other than a color profile, is removed to
cristy29dc8652015-05-12 16:26:21 +00008098reduce the thumbnail size. To strip the color profiles as well, add <a
8099href="command-line-options.html#strip">-strip</a> just before of after this option.</p>
cristyd2432012015-05-04 23:15:15 +00008100
8101<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
8102
8103<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008104 <h3 class="magick-header"><a id="tile"></a>-tile <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00008105</div>
8106
8107<p class="magick-description">Set the tile image used for filling a subsequent graphic primitive.</p>
8108
8109<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008110 <h3 class="magick-header">-tile <var>geometry</var></h3>
cristyd2432012015-05-04 23:15:15 +00008111</div>
8112
8113<p class="magick-description">Specify the layout of images.</p>
8114
8115<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
8116
8117<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008118 <h3 class="magick-header">-tile</h3>
cristyd2432012015-05-04 23:15:15 +00008119</div>
8120
8121<p class="magick-description">Specifies that a subsequent composite operation is repeated across and down image.</p>
8122
8123<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008124 <h3 class="magick-header"><a id="tile-offset"></a>-tile-offset {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3>
cristyd2432012015-05-04 23:15:15 +00008125</div>
8126
8127<p class="magick-description">Specify the offset for tile images, relative to the background image it is tiled on.</p>
8128
cristy29dc8652015-05-12 16:26:21 +00008129<p>This should be set before the tiling image is set by <a href="command-line-options.html#tile"
8130>-tile</a> or <a href="command-line-options.html#texture" >-texture</a>, or directly applied for
cristyd2432012015-05-04 23:15:15 +00008131creating a tiled canvas using <code>TILE:</code> or <code>PATTERN:</code> input
8132formats. </p>
8133
cristy29dc8652015-05-12 16:26:21 +00008134<p>Internally ImageMagick does a <a href="command-line-options.html#roll" >-roll</a> of the tile image
cristyd2432012015-05-04 23:15:15 +00008135by the arguments given when the tile image is set. </p>
8136
8137<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008138 <h3 class="magick-header"><a id="tint"></a>-tint <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00008139</div>
8140
8141<p class="magick-description">Tint the image with the fill color.</p>
8142
8143<p>Tint the image with the fill color.</p>
8144
8145<p>Specify the amount of tinting as a percentage. Pure colors like black,
8146white red, yellow, will not be affected by -tint. Only mid-range colors such
8147as the various shades of grey.</p>
8148
8149<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008150 <h3 class="magick-header"><a id="title"></a>-title <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00008151</div>
8152
8153<p class="magick-description">Assign a title to displayed image.", "animate", "display", "montage</p>
8154
8155<p>Use this option to assign a specific title to the image. This assigned to
8156the image window and is typically displayed in the window title bar.
8157Optionally you can include the image filename, type, width, height, Exif data,
8158or other image attribute by embedding special format characters described
8159under the <a href="command-line-options.html#format">-format</a> option.</p>
8160
8161<p>For example,</p>
8162
cristy29dc8652015-05-12 16:26:21 +00008163<pre>
8164-title "%m:%f %wx%h"
8165</pre>
cristyd2432012015-05-04 23:15:15 +00008166
8167<p>produces an image title of <code>MIFF:bird.miff 512x480</code> for an image
8168titled <code>bird.miff</code> and whose width is 512 and height is 480.</p>
8169
8170
8171<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008172 <h3 class="magick-header"><a id="transform"></a>-transform</h3>
cristyd2432012015-05-04 23:15:15 +00008173</div>
8174
8175<p class="magick-description">transform the image.</p>
8176
8177<p>This option applies the transformation matrix from a previous <a href="command-line-options.html#affine">-affine</a> option.</p>
8178
8179<pre>
8180convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg
8181</pre>
8182
8183
cristy29dc8652015-05-12 16:26:21 +00008184<p>This operator has been now been superseded by the <a
8185href="command-line-options.html#distort">-distort</a> '<code>AffineProjection</code>' method. </p>
cristyd2432012015-05-04 23:15:15 +00008186
8187
8188<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008189 <h3 class="magick-header"><a id="transparent"></a>-transparent <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00008190</div>
8191
8192<p class="magick-description">Make this color transparent within the image.</p>
8193
8194<p>The <var>color</var> argument is defined using the format
cristy29dc8652015-05-12 16:26:21 +00008195described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz"
8196>-fuzz</a> setting can be used to match and replace colors similar to the one
cristyd2432012015-05-04 23:15:15 +00008197given. </p>
8198
cristy29dc8652015-05-12 16:26:21 +00008199<p>Use <a href="command-line-options.html#transparent" >+transparent</a> to invert the pixels matched.
cristyd2432012015-05-04 23:15:15 +00008200that is make all non-matching colors transparent. </p>
8201
cristy29dc8652015-05-12 16:26:21 +00008202<p>The <a href="command-line-options.html#opaque">-opaque</a> operator is exactly the same as <a
8203href="command-line-options.html#transparent" >-transparent</a> but replaces the matching color with the
cristyd2432012015-05-04 23:15:15 +00008204current <a href="command-line-options.html#fill">-fill</a> color setting, rather than transparent.
cristy29dc8652015-05-12 16:26:21 +00008205However the <a href="command-line-options.html#transparent" >-transparent</a> operator also ensures
8206that the image has an alpha channel enabled, as per "<code><a href="command-line-options.html#alpha"
8207>-alpha</a> set</code>", and does not require you to modify the <a
8208href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
cristyd2432012015-05-04 23:15:15 +00008209
8210<p>Note that this does not define the color as being the 'transparency color'
cristy29dc8652015-05-12 16:26:21 +00008211used for color-mapped image formats, such as GIF. For that use <a
8212href="command-line-options.html#transparent-color" >-transparent-color</a> </p>
cristyd2432012015-05-04 23:15:15 +00008213
8214
8215<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008216 <h3 class="magick-header"><a id="transparent-color"></a>-transparent-color <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00008217</div>
8218
8219<p class="magick-description">Set the transparent color.</p>
8220
8221<p>Sometimes this is used for saving to image formats such as
8222GIF and PNG8 which uses this color to represent boolean transparency. This
8223does not make a color transparent, it only defines what color the transparent
cristy29dc8652015-05-12 16:26:21 +00008224color is in the color palette of the saved image. Use <a
8225href="command-line-options.html#transparent">-transparent</a> to make an opaque color transparent.</p>
cristyd2432012015-05-04 23:15:15 +00008226
8227<p>This option allows you to have both an opaque visible color, as well as a
8228transparent color of the same color value without conflict. That is, you can
8229use the same color for both the transparent and opaque color areas within an
8230image. This, in turn, frees to you to select a transparent color that is
8231appropriate when an image is displayed by an application that does not handle a
8232transparent color index, while allowing ImageMagick to correctly handle images of this
8233type. </p>
8234
8235<p>The default transparent color is <code>#00000000</code>, which is fully transparent black.</p>
8236
8237<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008238 <h3 class="magick-header"><a id="transpose"></a>-transpose</h3>
cristyd2432012015-05-04 23:15:15 +00008239</div>
8240
8241<p class="magick-description">Mirror the image along the top-left to bottom-right diagonal.</p>
8242
8243<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <code>-flip -rotate 90</code>.
8244</p>
8245
8246<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008247 <h3 class="magick-header"><a id="transverse"></a>-transverse</h3>
cristyd2432012015-05-04 23:15:15 +00008248</div>
8249
8250<p class="magick-description">Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <code>-flop -rotate 90</code>.</p>
8251
8252
8253<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008254 <h3 class="magick-header"><a id="treedepth"></a>-treedepth <var>value</var></h3>
cristyd2432012015-05-04 23:15:15 +00008255</div>
8256
8257<p class="magick-description">tree depth for the color reduction algorithm.</p>
8258
8259<p>Normally, this integer value is zero or one. A value of zero or one causes
8260the use of an optimal tree depth for the color reduction algorithm.</p>
8261
8262<p>An optimal depth generally allows the best representation of the source
8263image with the fastest computational speed and the least amount of memory.
8264However, the default depth is inappropriate for some images. To assure the
8265best representation, try values between 2 and 8 for this parameter. Refer to
cristy29dc8652015-05-12 16:26:21 +00008266the <a href="quantize.html"
8267>color reduction algorithm</a> for more details.</p>
cristyd2432012015-05-04 23:15:15 +00008268
8269<p>The <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#monochrome">-monochrome</a>
8270option, or writing to an image format which requires color reduction, is
8271required for this option to take effect.</p>
8272
8273<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008274 <h3 class="magick-header"><a id="trim"></a>-trim</h3>
cristyd2432012015-05-04 23:15:15 +00008275</div>
8276
8277<p class="magick-description">trim an image.</p>
8278
8279<p>This option removes any edges that are exactly the same color as the corner
8280pixels. Use <a href="command-line-options.html#fuzz">-fuzz</a> to make <a href="command-line-options.html#trim">-trim</a> remove
8281edges that are nearly the same color as the corner pixels.</p>
8282
8283<p>The page or virtual canvas information of the image is preserved allowing
8284you to extract the result of the <a href="command-line-options.html#trim">-trim</a> operation from the
8285image. Use a <a href="command-line-options.html#repage">+repage</a> to remove the virtual canvas page
8286information if it is unwanted.</p>
8287
8288<p>If the trimmed image 'disappears' an warning is produced, and a special
8289single pixel transparent 'missed' image is returned, in the same way as when a
8290<a href="command-line-options.html#crop">-crop</a> operation 'misses' the image proper. </p>
8291
8292
8293<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008294 <h3 class="magick-header"><a id="type"></a>-type <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00008295</div>
8296
8297<p class="magick-description">the image type.</p> <p>Choose from: <code>Bilevel</code>,
8298<code>Grayscale</code>, <code>GrayscaleMatte</code>, <code>Palette</code>,
8299<code>PaletteMatte</code>, <code>TrueColor</code>, <code>TrueColorMatte</code>,
8300<code>ColorSeparation</code>, or <code>ColorSeparationMatte</code>.</p>
8301
8302<p>Normally, when a format supports different subformats such as grayscale and
cristy29dc8652015-05-12 16:26:21 +00008303truecolor, the encoder will try to choose an efficient subformat. The <a
8304href="command-line-options.html#type">-type</a> option can be used to override this behavior. For
cristyd2432012015-05-04 23:15:15 +00008305example, to prevent a JPEG from being written in grayscale format even though
8306only gray pixels are present, use.</p>
8307
8308<pre>
8309convert bird.png -type TrueColor bird.jpg
8310</pre>
8311
8312<p>Similarly, use <a href="command-line-options.html#type">-type TrueColorMatte</a> to force the
8313encoder to write an alpha channel even though the image is opaque, if the
8314output format supports transparency.</p>
8315
8316<p>Use <a href="command-line-options.html#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
8317
8318<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008319 <h3 class="magick-header"><a id="undercolor"></a>-undercolor <var>color</var></h3>
cristyd2432012015-05-04 23:15:15 +00008320</div>
8321
8322<p class="magick-description">set the color of the annotation bounding box.</p>
8323
8324<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
8325
8326<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
8327
8328
8329<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008330 <h3 class="magick-header"><a id="update"></a>-update <var>seconds</var></h3>
cristyd2432012015-05-04 23:15:15 +00008331</div>
8332
8333<p class="magick-description">detect when image file is modified and redisplay.</p>
8334
8335<p>Suppose that while you are displaying an image the file that is currently
8336displayed is over-written. <code>display</code> will automagically detect that
8337the input file has been changed and update the displayed image
8338accordingly.</p>
8339
8340
8341<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008342 <h3 class="magick-header"><a id="unique-colors"></a>-unique-colors</h3>
cristyd2432012015-05-04 23:15:15 +00008343</div>
8344
8345<p class="magick-description">discard all but one of any pixel color.</p>
8346
8347
8348<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008349 <h3 class="magick-header"><a id="units"></a>-units <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00008350</div>
8351
8352<p class="magick-description">the units of image resolution.</p>
8353
8354<p>Choose from: <code>Undefined</code>, <code>PixelsPerInch</code>, or
8355<code>PixelsPerCentimeter</code>. This option is normally used in conjunction
8356with the <a href="command-line-options.html#density">-density</a> option.</p>
8357
8358
8359<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008360 <h3 class="magick-header"><a id="unsharp"></a>-unsharp <var>radius</var><br />-unsharp <var>radius</var>x<var>sigma</var>{<var>+gain</var>}{<var>+threshold</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00008361</div>
8362
8363<p class="magick-description">sharpen the image with an unsharp mask operator.</p>
8364
8365<p>The <a href="command-line-options.html#unsharp">-unsharp</a> option sharpens an image. The image is
8366convolved with a Gaussian operator of the given radius and standard deviation
8367(sigma). For reasonable results, radius should be larger than sigma. Use
8368a radius of 0 to have the method select a suitable radius.</p>
8369
8370<p>The parameters are:</p>
8371
8372<pre>
8373 radius The radius of the Gaussian, in pixels, not counting the center
8374 pixel (default 0).
8375 sigma The standard deviation of the Gaussian, in pixels (default 1.0).
8376 gain The fraction of the difference between the original and the blur
8377 image that is added back into the original (default 1.0).
8378 threshold The threshold, as a fraction of <var>QuantumRange</var>, needed to apply the
8379 difference amount (default 0.05).
8380</pre>
8381
8382
8383<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008384 <h3 class="magick-header"><a id="verbose"></a>-verbose</h3>
cristyd2432012015-05-04 23:15:15 +00008385</div>
8386
8387<p class="magick-description">print detailed information about the image when this option precedes the <a href="command-line-options.html#identify">-identify</a> option or <code>info:</code>.</p>
8388
8389
8390<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008391 <h3 class="magick-header"><a id="version"></a>-version</h3>
cristyd2432012015-05-04 23:15:15 +00008392</div>
8393
8394<p class="magick-description">print ImageMagick version string and exit.</p>
8395
8396
8397<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008398 <h3 class="magick-header"><a id="view"></a>-view <var>string</var></h3>
cristyd2432012015-05-04 23:15:15 +00008399</div>
8400
8401<p class="magick-description">FlashPix viewing parameters.</p>
8402
8403
8404<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008405 <h3 class="magick-header"><a id="vignette"></a>-vignette <var>radius</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00008406</div>
8407
8408<p class="magick-description">soften the edges of the image in vignette style.</p>
8409
8410<p>The vignette effect rolloff is controlled by radiusxsigma. For nominal rolloff, this would be set to 0xsigma. A value of 0x0 will produce a circle/ellipse with no rolloff. The arguments x and y control the size of the circle. Larger values decrease the radii and smaller values increase the radii. Values of +0+0 will generate a circle/ellipse the same size as the image. The default values for x and y are 10% of the corresponding image dimension. Thus, the radii will be decreased by 10%, i.e., the diameters of the circle/ellipse will be 80% of the corresponding image dimension.</p>
8411
8412<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008413 <h3 class="magick-header"><a id="virtual-pixel"></a>-virtual-pixel <var>method</var></h3>
cristyd2432012015-05-04 23:15:15 +00008414</div>
8415
8416<p class="magick-description">Specify contents of <var>virtual pixels</var>.</p>
8417
8418<p>This option defines what color source should be used if and when a color
8419lookup completely 'misses' the source image. The color(s) that appear to
8420surround the source image. Generally this color is derived from the source
8421image, but could also be set to a specify background color. </p>
8422
8423<p>Choose from these methods:</p>
8424
cristy29dc8652015-05-12 16:26:21 +00008425<dl class="dl-horizontal">
8426<dt>background</dt><dd>the area surrounding the image is the background color</dd>
8427<dt>black</dt><dd>the area surrounding the image is black</dd>
8428<dt>checker-tile</dt><dd>alternate squares with image and background color</dd>
8429<dt>dither</dt><dd>non-random 32x32 dithered pattern</dd>
8430<dt>edge</dt><dd>extend the edge pixel toward infinity</dd>
8431<dt>gray</dt><dd>the area surrounding the image is gray</dd>
8432<dt>horizontal-tile</dt><dd>horizontally tile the image, background color above/below</dd>
8433<dt>horizontal-tile-edge</dt><dd>horizontally tile the image and replicate the side edge pixels</dd>
8434<dt>mirror</dt><dd>mirror tile the image</dd>
8435<dt>random</dt><dd>choose a random pixel from the image</dd>
8436<dt>tile</dt><dd>tile the image (default)</dd>
8437<dt>transparent</dt><dd>the area surrounding the image is transparent blackness</dd>
8438<dt>vertical-tile</dt><dd>vertically tile the image, sides are background color</dd>
8439<dt>vertical-tile-edge</dt><dd>vertically tile the image and replicate the side edge pixels</dd>
8440<dt>white</dt><dd>the area surrounding the image is white</dd>
8441</dl>
cristyd2432012015-05-04 23:15:15 +00008442
8443<p>The default value is "edge".</p>
8444
cristy29dc8652015-05-12 16:26:21 +00008445<p>This most important for distortion operators such as <a href="command-line-options.html#distort"
8446>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, and <a href="command-line-options.html#fx" >-fx</a>.
cristyd2432012015-05-04 23:15:15 +00008447However it also effects operations that may access pixels just outside the
cristy29dc8652015-05-12 16:26:21 +00008448image proper, such as <a href="command-line-options.html#convolve">-convolve</a>, <a
8449href="command-line-options.html#blur">-blur</a>, and <a href="command-line-options.html#sharpen">-sharpen</a>. </p>
cristyd2432012015-05-04 23:15:15 +00008450
cristy29dc8652015-05-12 16:26:21 +00008451<p>To print a complete list of virtual pixel types, use the <a
8452href="command-line-options.html#list">-list virtual-pixel</a> option.</p>
cristyd2432012015-05-04 23:15:15 +00008453
8454
8455<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008456 <h3 class="magick-header"><a id="visual"></a>-visual <var>type</var></h3>
cristyd2432012015-05-04 23:15:15 +00008457</div>
8458
8459<p class="magick-description">Animate images using this X visual type.", 'animate', 'display'</p>
8460
8461<p>Choose from these visual classes:</p>
8462
8463<pre>
cristy29dc8652015-05-12 16:26:21 +00008464StaticGray
8465GrayScale
8466StaticColor
8467PseudoColor
8468TrueColor
8469DirectColor
8470default
8471visual id
cristyd2432012015-05-04 23:15:15 +00008472</pre>
8473
8474<p>The X server must support the visual you choose, otherwise an error occurs.
8475If a visual is not specified, the visual class that can display the most
8476simultaneous colors on the default screen is chosen.</p>
8477
8478
8479<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008480 <h3 class="magick-header"><a id="watermark"></a>-watermark <var>brightness</var>x<var>saturation</var></h3>
cristyd2432012015-05-04 23:15:15 +00008481</div>
8482
8483<p class="magick-description">Watermark an image using the given percentages of brightness and saturation.</p>
8484
8485<p>Take a grayscale image (with alpha mask) and modify the destination image's
8486brightness according to watermark image's grayscale value and the
8487<var>brightness</var> percentage. The destinations color saturation
8488attribute is just direct modified by the <var>saturation</var>
8489percentage, which defaults to 100 percent (no color change). </p>
8490
8491
8492<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008493 <h3 class="magick-header"><a id="wave"></a>-wave <var>amplitude</var><br />-wave <var>amplitude</var>x<var>wavelength</var></h3>
cristyd2432012015-05-04 23:15:15 +00008494</div>
8495
8496<p class="magick-description">Shear the columns of an image into a sine wave.</p>
8497
8498<p>Specify <var>amplitude</var> and <var>wavelength</var>
8499of the wave.</p>
8500
8501<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008502 <h3 class="magick-header"><a id="weight"></a>-weight <var>fontWeight</var></h3>
cristyd2432012015-05-04 23:15:15 +00008503</div>
8504
8505<p class="magick-description">Set a font weight for text.</p>
8506
8507<p>This setting suggests a font weight that ImageMagick should try to apply to
8508the currently selected font family. Use a positive integer for
8509<var>fontWeight</var> or select from the following.</p>
8510
8511<table class="table table-condensed table-striped">
cristy29dc8652015-05-12 16:26:21 +00008512 <col width="25%" />
8513 <col width="75%" />
cristyd2432012015-05-04 23:15:15 +00008514 <thead>
8515 <tr>
8516 <th><var>fontWeight</var></th>
8517 <th>Description</th>
8518 </tr>
8519 </thead>
8520 <tbody>
8521 <tr><td>All </td>
8522 <td>No effect. </td></tr>
8523 <tr><td>Bold </td>
8524 <td>Same as <var>fontWeight</var> = 700.</td></tr>
8525 <tr><td>Bolder </td>
8526 <td>Add 100 to font weight if currently ≤ 800.</td></tr>
8527 <tr><td>Lighter </td>
8528 <td>Subtract 100 to font weight if currently ≤ 100.</td></tr>
8529 <tr><td>Normal </td>
8530 <td>Same as <var>fontWeight</var> = 400.</td></tr>
8531 </tbody>
8532 </table>
8533
8534<p>To print a complete list of weight types, use <a href="command-line-options.html#list">-list
8535weight</a>.</p>
8536
cristy29dc8652015-05-12 16:26:21 +00008537<p>For other settings that affect fonts, see the options <a
8538href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
8539href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#style">-style</a>. </p>
cristyd2432012015-05-04 23:15:15 +00008540
8541<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008542 <h3 class="magick-header"><a id="white-point"></a>-white-point <var>x,y</var></h3>
cristyd2432012015-05-04 23:15:15 +00008543</div>
8544
8545<p class="magick-description">chromaticity white point.</p>
8546
8547<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008548 <h3 class="magick-header"><a id="white-threshold"></a>-white-threshold <var>value</var>{<var>%</var>}</h3>
cristyd2432012015-05-04 23:15:15 +00008549</div>
8550
8551<p class="magick-description">Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</p>
8552
8553<p> The threshold value can be given as a percentage or as an absolute integer
8554value within [0, <var>QuantumRange</var>] corresponding to the
cristy29dc8652015-05-12 16:26:21 +00008555desired <a href="command-line-options.html#channel">&#x2011;channel</a> value. See <a href="command-line-options.html#threshold">&#x2011;threshold</a>for more details on thresholds and resulting values. </p>
cristyd2432012015-05-04 23:15:15 +00008556
8557<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008558 <h3 class="magick-header"><a id="window"></a>-window <var>id</var></h3>
cristyd2432012015-05-04 23:15:15 +00008559</div>
8560
8561<p class="magick-description">Make the image the background of a window.", 'animate', 'display'</p>
8562
8563<p><var>id</var> can be a window id or name. Specify <code>root</code>
8564to select X's root window as the target window.</p>
8565
8566<p>By default the image is tiled onto the background of the target window. If
8567<code>backdrop</code> or <a href="command-line-options.html#geometry">-resize</a> are specified, the
8568image is surrounded by the background color. Refer to <code>X RESOURCES</code>
8569for details.</p>
8570
8571<p>The image will not display on the root window if the image has more unique
cristy29dc8652015-05-12 16:26:21 +00008572colors than the target window colormap allows. Use <a
8573href="command-line-options.html#colors">-colors</a> to reduce the number of colors.</p>
cristyd2432012015-05-04 23:15:15 +00008574
8575<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008576 <h3 class="magick-header"><a id="window-group"></a>-window-group</h3>
cristyd2432012015-05-04 23:15:15 +00008577</div>
8578
8579<p class="magick-description">specify the window group.</p>
8580
8581<div style="margin: auto;">
cristy29dc8652015-05-12 16:26:21 +00008582 <h3 class="magick-header"><a id="write"></a>-write <var>filename</var></h3>
cristyd2432012015-05-04 23:15:15 +00008583</div>
8584
8585<p class="magick-description">write an image sequence.</p>
8586
8587<p>The image sequence preceding the <a href="command-line-options.html#write">-write</a> <var>filename</var> option is written out, and processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the <a href="command-line-options.html#write">+write</a> <var>filename</var> option.</p>
8588
8589<p>Use <a href="command-line-options.html#compress">-compress</a> to specify the type of image compression.</p>
8590</div>
8591</div>
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8597 <a href="links.html">Related</a>
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8601</p>
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