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</span> <a href="../www/command-line-options.html#spread">&#x2011;spread</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#stegano">&#x2011;stegano</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#stereo">&#x2011;stereo</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#stretch">&#x2011;stretch</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#strip">&#x2011;strip</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#stroke">&#x2011;stroke</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#strokewidth">&#x2011;strokewidth</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#style">&#x2011;style</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#swap">&#x2011;swap</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#swirl">&#x2011;swirl</a> <span class='bull'>&nbsp;&bull; 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</span> <a href="../www/command-line-options.html#transform">&#x2011;transform</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#transparent">&#x2011;transparent</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#transparent-color">&#x2011;transparent&#x2011;color</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#transpose">&#x2011;transpose</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#transverse">&#x2011;transverse</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#treedepth">&#x2011;treedepth</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#trim">&#x2011;trim</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#type">&#x2011;type</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#undercolor">&#x2011;undercolor</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#unique-colors">&#x2011;unique&#x2011;colors</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#units">&#x2011;units</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#unsharp">&#x2011;unsharp</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#update">&#x2011;update</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#verbose">&#x2011;verbose</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#version">&#x2011;version</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#view">&#x2011;view</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#vignette">&#x2011;vignette</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#virtual-pixel">&#x2011;virtual&#x2011;pixel</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#visual">&#x2011;visual</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#watermark">&#x2011;watermark</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#wave">&#x2011;wave</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#weight">&#x2011;weight</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#white-point">&#x2011;white&#x2011;point</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#white-threshold">&#x2011;white&#x2011;threshold</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#window">&#x2011;window</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#window-group">&#x2011;window&#x2011;group</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#write">&#x2011;write</a> ] </p>
154
155<p>Below is list of command-line options recognized by the ImageMagick <a href="../www/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
156<a href="../www/convert.html">convert</a>, <a href="../www/mogrify.html">mogrify</a>, and .... </p>
157
158<div style="margin: auto;">
159 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
160</div>
161
162<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively blur pixels, with decreasing effect near edges.</td><td style='text-align:right;'></td></tr></table>
163
164<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p>
165
166<div style="margin: auto;">
167 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4>
168</div>
169
170<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize the image using data-dependent triangulation.</td><td style='text-align:right;'></td></tr></table>
171
172<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="#adaptive-resize">-adaptive-resize</a> option defaults to data-dependent triangulation. Use the <a href="#filter">-filter</a> to choose a different resampling algorithm. Offsets, if present in the geometry string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
173
174<div style="margin: auto;">
175 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
176</div>
177
178<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively sharpen pixels, with increasing effect near edges.</td><td style='text-align:right;'></td></tr></table>
179
180<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p>
181
182<div style="margin: auto;">
183 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4>
184</div>
185
186<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join images into a single multi-image file.</td><td style='text-align:right;'></td></tr></table>
187
188<p>This option is enabled by default. An attempt is made to save all
189images of an image sequence into the given output file.
190However, some formats, such as JPEG and PNG, do not support more than one
191image per file, and in that case ImageMagick is forced to write each image as a separate file. As
192such, if more than one image needs to be written, the filename given is
193modified by adding a <a href="#scene">-scene</a> number before the
194suffix, in order to make distinct names for each image. </p>
195
196<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written
197to separate files, whether or not the file format allows multiple images
198per file (for example, GIF, MIFF, and TIFF). </p>
199
200<p>Including a C-style integer format string in the output filename will automagically enable <a href="#adjoin">+adjoin</a> and are used to specify where the <a href="#scene">-scene</a> number is placed in the filenames. These strings, such as '<kbd>%d</kbd>' or '<kbd>%03d</kbd>', are familiar to those who have used the standard <kbd>printf()</kbd>' C-library function. As an example, the command</p>
201
202<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p>
203<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg.
204</p>
205
206<p>In summary, ImageMagick tries to write all images to one file, but will use
207multiple files if either (1) the output image's file format does not allow multi-image files,
208(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is
209present in the output filename. </p>
210
211
212<div style="margin: auto;">
213 <h4><a name="affine" id="affine"></a>-affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em><br/>
214 -affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em></h4>
215</div>
216
217<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the drawing transformation matrix for combined rotating and scaling.</td><td style='text-align:right;'></td></tr></table>
218
219<p>This option sets a transformation matrix, encoded as (<em class="arg">s<sub>x</sub></em>, <em class="arg">r<sub>x</sub></em>, <em class="arg">r<sub>y</sub></em>, <em class="arg">s<sub>y</sub></em>, <em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>), for use by subsequent <a href="#draw">-draw</a> or <a href="#transform">-transform</a> options.</p>
220
221<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p>
222
223<p>Internally, the transformation matrix has 3x3 elements, but three of them are omitted from the input because they are constant. The new (transformed) coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at position (<em class="arg">x</em>, <em class="arg">y</em>) in the original image are calculated using the following matrix equation.</p>
224
225<div class="eqn">
226<img alt="affine transformation" src="../images/affine.png"/>
227</div>
228
229<p>
230The size of the resulting image is that of the smallest rectangle that contains the transformed source image. The parameters <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> subsequently shift the image pixels so that those that are moved out of the image area are cut off.</p>
231
232<p>The transformation matrix complies with the left-handed pixel coordinate system: positive <em class="arg">x</em> and <em class="arg">y</em> directions are rightward and downward, resp.; positive rotation is clockwise.</p>
233
234<p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omotted they default to 0,0. Therefore, four parameters suffice for rotation and scaling without translation.</p>
235
236<p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions, respectively, is accomplished with the following.</p>
237
238<p class="crtsnip">
239 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em>
240</p>
241
242<p>Translation by a displacement (<em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>) is accomplished like so:</p>
243
244<p class="crtsnip">
245 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>
246</p>
247
248<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting
249<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p>
250
251<p class="crtsnip">
252 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em>
253</p>
254
255<p>The cumulative effect of a sequence of <a href="#affine" >-affine</a> transformations can be accomplished by instead by a single <a href="#affine" >-affine</a> operation using the matrix equal to the product of the matrices of the individual transformations.</p>
256
257<p>An attempt is made to detect near-singular transformation matrices. If the matrix determinant has a sufficiently small absolute value it is rejected.</p>
258
259<div style="margin: auto;">
260 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4>
261</div>
262
263<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Gives control of the alpha/matte channel of an image.</td><td style='text-align:right;'></td></tr></table>
264
265<p>Used to set a flag on an image indicating whether or not to use existing alpha
266channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <em class="arg">type</em> from the list below.</p>
267
268
269<table class="doc">
270 <tbody>
271 <tr valign="top">
272 <th align="left" style="width: 8%">type</th>
273 <th align="left">Description</th>
274 </tr>
275
276 <tr valign="top">
277 <td valign="top"><kbd>Off</kbd>&nbsp; or
278 <kbd>Deactivate</kbd></td>
279 <td valign="top">
280 Disables the image's transparency channel. Does not delete or change the
281 existing data, just turns off the use of that data. This is the same as
282 the older <a href="#matte" >+matte</a> operator. </td></tr>
283
284 <tr valign="top">
285 <td valign="top"><kbd>On</kbd>&nbsp; or
286 <kbd>Activate</kbd></td>
287 <td valign="top">
288 Enables the image's use of transparency. If transparency data does not
289 already exist, allocates the data and sets it to opaque. If the image has
290 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT
291 the same as the older <a href="#matte" >-matte</a> operator. </td></tr>
292
293 <tr valign="top">
294 <td valign="top"><kbd>Set</kbd></td>
295 <td valign="top">
296 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously
297 turned off resets the channel to opaque. If the image already had the
298 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr>
299
300 <tr valign="top">
301 <td valign="top"><kbd>Opaque</kbd></td>
302 <td valign="top">
303 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
304 opaque. </td></tr>
305
306 <tr valign="top">
307 <td valign="top"><kbd>Transparent</kbd></td>
308 <td valign="top">
309 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
310 transparent. This effectively creates a fully transparent image the same
311 size as the original and with all its original RGB data still intact. </td></tr>
312
313 <tr valign="top">
314 <td valign="top"><kbd>Extract</kbd></td>
315 <td valign="top">
316 Copies the alpha channel values into all the color channels and turns
317 '<kbd>Off</kbd>' the the image's transparency, so as to generate a
318 gray-scale mask of the image's shape. This is the inverse of
319 '<kbd>Copy</kbd>'. </td></tr>
320
321 <tr valign="top">
322 <td valign="top"><kbd>Copy</kbd></td>
323 <td valign="top">
324 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the
325 gray-scale intensity of the image, as an alpha mask, into the alpha
326 channel, converting a gray-scale mask into a transparent shaped image
327 ready to be colored appropriately. The color channels are not modified.
328 </td></tr>
329
330 <tr valign="top">
331 <td valign="top"><kbd>Shape</kbd></td>
332 <td valign="top">
333 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with
334 the current background color.
335 </td></tr>
336
337 <tr valign="top">
338 <td valign="top"><kbd>Background</kbd></td>
339 <td valign="top">
340 Set any fully-transparent pixel to the background color.
341 </td></tr>
342 </tbody>
343</table>
344
345<p>Note that while the <a href="#matte" >+matte</a> operation is the same as
346"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte"
347>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> set</kbd>" and
348not "<kbd><a href="#alpha" >-alpha</a> on</kbd>".
349That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the
350written image is opaque if the original image had no transparency
351channel enabled, regardless if transparency data is already present. </p>
352
353
354<div style="margin: auto;">
355 <h4><a name="annotate" id="annotate"></a>
356 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br />
357 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br />
358 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> {+-}<em class="arg">t<sub>x</sub></em>{+-}<em class="arg">t<sub>y</sub></em> <em class="arg">text</em></h4>
359</div>
360
361<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with text.</td><td style='text-align:right;'></td></tr></table>
362
363<p>This is a convenience for annotating an image with text. For more precise control over text annotations, use <a href="#draw">-draw</a>.</p>
364
365
366<p>The values <em class="arg">Xdegrees</em> and <em class="arg">Ydegrees</em> control the shears with respect to the , respectively, applied to the text, while <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are offsets that give the location of the text relative to the upper left corner of the image.</p>
367
368<p>Using <a href="#annotate">-annotate</a>&nbsp;<em class="arg">degrees</em> or <a href="#annotate">-annotate</a>&nbsp;<em class="arg">degrees</em>x<em class="arg">degrees</em> produces an unsheared rotation of the text. The direction of the rotation is positive, which means a clockwise rotation if <em class="arg">degrees</em> is positive. (This conforms to the usual mathematical convention once it is realized that the positive <em>y</em>&ndash;direction is conventionally considered to be <em>downward</em> for images.)</p>
369
370<p>The new (transformed) coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at position (<em class="arg">x</em>, <em class="arg">y</em>) in the image are calculated using the following matrix equation.</p>
371<div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"/></div>
372
373<p>If <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omitted, they default to 0. This makes the bottom-left of the text becomes the upper-left corner of the image, which is probably undesirable. Adding a <a href="#gravity" >-gravity</a> option in this case leads to nice results.</p>
374
375<p>Text is any UTF-8 encoded character sequence. If <em class="arg">text</em> is of the form '@mytext.txt', the text is read from the file <kbd>mytext.txt</kbd>. Text in a file is taken literally; no embedded formatting characters are recognized.</p>
376
377<div style="margin: auto;">
378 <h4><a name="antialias" id="antialias"></a>-antialias</h4>
379</div>
380
381<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enable/Disable of the rendering of anti-aliasing pixels when
382drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table>
383
384<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
385drawn. Use <a href="#antialias">+antialias</a> to disable the addition of
386antialiasing edge pixels. This will then reduce the number of colors added to
387an image to just the colors being directly drawn. That is, no mixed colors
388will be added when drawing such objects. </p>
389
390<div style="margin: auto;">
391 <h4><a name="append" id="append"></a>-append</h4>
392</div>
393
394<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join current images vertically or horizontally.</td><td style='text-align:right;'></td></tr></table>
395
396<p>This option creates a single longer image image, by joining all the current
397images in sequence top-to-bottom. Use <a href="#append">+append</a> to
398stack images left-to-right. </p>
399
400<p>If they are not of the same width, narrower images are padded with the
401current <a href="#background">-background</a> color setting, and their
402position relative to each other can be controled by the current <a
403href="#gravity">-gravity</a> setting. </p>
404
405
406<div style="margin: auto;">
407 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4>
408</div>
409
410<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lessen (or intensify) when adding noise to an image.</td><td style='text-align:right;'></td></tr></table>
411
412
413<div style="margin: auto;">
414 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4>
415</div>
416
417<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decrypt a PDF with a password.</td><td style='text-align:right;'></td></tr></table>
418
419<p>Use this option to supply a <em class="arg">password</em> for decrypting a PDF that has been encrypted using Microsoft Crypto API (MSC API). The encrypting using the MSC API is not supported.</p>
420
421<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p>
422
423<div style="margin: auto;">
424 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4>
425</div>
426
427<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust gamma level of image.</td><td style='text-align:right;'></td></tr></table>
428
429<div style="margin: auto;">
430 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4>
431</div>
432
433<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust color levels of image.</td><td style='text-align:right;'></td></tr></table>
434
435<div style="margin: auto;">
436 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
437</div>
438
439<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically orient (rotate) an image created by a digital camera.</td><td style='text-align:right;'></td></tr></table>
440
441<div style="margin: auto;">
442 <h4><a name="average" id="average"></a>-average</h4>
443</div>
444
445<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Average a set of images.</td><td style='text-align:right;'></td></tr></table>
446
447<p>An error results if the images are not identically sized.</p>
448
449<p>The sequence of images is terminated by the appearance of any option. If the <a href="#average">-average</a> option appears after all of the input images, all images are averaged.</p>
450
451<div style="margin: auto;">
452 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
453</div>
454
455<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display the image centered on a backdrop.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
456
457<p>This backdrop covers the entire workstation screen and is useful for hiding other X window activity while viewing the image. The color of the backdrop is specified as the background color. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
458
459<div style="margin: auto;">
460 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
461</div>
462
463<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the background color.</td><td style='text-align:right;'></td></tr></table>
464
465<p>The color is specified using the format described under the <a href="#fill">-fill</a> option. The default background color (if none is specified or found in the image) is white.</p>
466
467<div style="margin: auto;">
468 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
469</div>
470
471<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Measure performance.</td><td style='text-align:right;'></td></tr></table>
472
473<p>Repeat the entire command for the given number of <em class="arg">iterations</em> and report the user-time and elapsed time. For instance, consider the following command and its output.</p>
474
475<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -resize 1000% -bench 5 biglogo.png</span><span class='crtout'>Performance: 5i 0.0539724ips 91.750u 2:33</span></p>
476<p>In this example, 5&nbsp;iterations were completed at 0.0539724&nbsp;iterations per second, using 91.750&nbsp;seconds of the user's allotted time, for a total elapsed time of 2&nbsp;minutes&nbsp;and&nbsp;33&nbsp;seconds.</p>
477
478<div style="margin: auto;">
479 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
480</div>
481
482<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add bias when convolving an image.</td><td style='text-align:right;'></td></tr></table>
483
484<p>This option shifts the output of <a href="../www/command-line-options.html#convolve">&#x2011;convolve</a> so that positive and negative results are relative to the specified bias value. </p>
485
486<p>This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values are clipped at zero.</p>
487
488<p>When using an ImageMagick with the HDRI compile-time setting, <a href="../www/command-line-options.html#bias">&#x2011;bias</a> is not needed, as ImageMagick is able to store/handle any
489negative results without clipping to the color value range
490(0..QuantumRange).</p>
491
492<p>See the discussion on HDRI implementations of ImageMagick on the page
493<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry.
494</p>
495
496<div style="margin: auto;">
497 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
498</div>
499
500<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use black point compensation.</td><td style='text-align:right;'></td></tr></table>
501
502<div style="margin: auto;">
503 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">threshold</em></h4>
504</div>
505
506<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to black all pixels at or below the threshold while leaving all pixels above the threshold unchanged.</td><td style='text-align:right;'></td></tr></table>
507
508
509<div style="margin: auto;">
510 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4>
511</div>
512
513<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>blend an image into another by the given percent.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
514
515<p>Blend will average the images together ('plus') according to the
516percentages given and each pixels transparency. If only a single percentage
517value is given it sets the weight of the composite or 'source' image, while
518the background image is weighted by the exact opposite amount. That is a
519<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the
520'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p>
521
522
523<div style="margin: auto;">
524 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
525</div>
526
527<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the blue chromaticity primary point.</td><td style='text-align:right;'></td></tr></table>
528
529<div style="margin: auto;">
530 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
531</div>
532
533<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</td><td style='text-align:right;'></td></tr></table>
534
535<div style="margin: auto;">
536
537<div style="margin: auto;">
538 <h4><a name="blur" id="blur"></a>-blur <em class="arg">radius</em><br />-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4>
539</div>
540
541<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce image noise and reduce detail levels.</td><td style='text-align:right;'></td></tr></table>
542
543<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
544
545<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
546</div>
547
548<p>Where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. If a radius of 0 is specified, ImageMagick selects a suitable radius for you.</p>
549
550<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply by taking advantage of the separability properties of the distribution. Here we apply a single-dimensional Gaussian matrix in the horizontal direction, then repeat the process in the vertical direction.</p>
551
552<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
553pixels which are outside the image proper are blurred into the final result.
554</p>
555
556
557<div style="margin: auto;">
558 <h4><a name="blur-composite" id="blur"></a>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4>
559</div>
560
561<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Variably blur and image according to the overlay mapping.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
562
563<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
564Average (EWA) of the source image, scaled according to the grayscale
565mapping. </p>
566
567<p>The ellipse is weighted with sigma set to the given <em class="arg"
568>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
569defaults to the <em class="arg" >Width</em> for a normal circular Guassian
570weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
571horizontal clock-wise. </p>
572
573<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
574pixels which are outside the image proper are blurred into the final result.
575</p>
576
577
578<div style="margin: auto;">
579 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
580</div>
581
582<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border of color. </td><td style='text-align:right;'></td></tr></table>
583
584<p>Set the width and height using the <em class="arg">size</em> portion of the <em class="arg">gravity</em> argument. See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are ignored. </p>
585
586<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p>
587
588<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p>
589
590<div style="margin: auto;">
591 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
592</div>
593
594<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border color.</td><td style='text-align:right;'></td></tr></table>
595
596<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
597
598<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
599
600<div style="margin: auto;">
601 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
602</div>
603
604<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border width.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
605
606<div style="margin: auto;">
607 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
608</div>
609
610<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>(This option has been replaced by the <a href='#limit'>-limit</a> option.)</td><td style='text-align:right;'></td></tr></table>
611
612<div style="margin: auto;">
613 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
614</div>
615
616<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a caption to an image.</td><td style='text-align:right;'></td></tr></table>
617
618<div style="margin: auto;">
619 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
620</div>
621
622<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color correct with a color decision list.</td><td style='text-align:right;'></td></tr></table>
623
624<p>Here is an example color correction collection:</p>
625
626<pre class="text">
627&lt;?xml version="1.0" encoding="UTF-8"?>
628&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
629 &lt;ColorCorrection id="cc06668">
630 &lt;SOPNode>
631 &lt;Slope> 0.9 1.2 0.5 &lt;/Slope>
632 &lt;Offset> 0.4 -0.5 0.6 &lt;/Offset>
633 &lt;Power> 1.0 0.8 1.5 &lt;/Power>
634 &lt;/SOPNode>
635 &lt;SATNode>
636 &lt;Saturation> 0.85 &lt;/Saturation>
637 &lt;/SATNode>
638 &lt;/ColorCorrection>
639&lt;/ColorCorrectionCollection>
640</pre>
641
642<div style="margin: auto;">
643 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
644</div>
645
646<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify those image color channels to which subsequent operators are limited.</td><td style='text-align:right;'></td></tr></table>
647
648<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, <kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, <kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, <kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p>
649
650<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p>
651
652<p>The channels above can be specified as a comma-separated list or can be abbreviated as a
653concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', '<kbd>B</kbd>',
654'<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', '<kbd>M</kbd>', '<kbd>Y</kbd>',
655'<kbd>K</kbd>'.
656
657For example, to negate only the alpha channel of an image, use</p>
658<p class="crtsnip">
659 -channel Alpha -negate
660</p>
661
662<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
663'<kbd>RGB</kbd>', which specifies that operators act on all channels except
664the opacity channel. Using the option <a href="#channel" >+channel</a> will reset the value back to this default. </p>
665
666<p>Operators that are affected by the <a href="#channel" >-channel</a>
667setting include the following.
668<a href="#black-threshold">-black-threshold</a>,
669<a href="#blur">-blur</a>,
670<a href="#clut">-clut</a>,
671<a href="#combine">-combine</a>,
672<a href="#contrast-stretch">-contrast-stretch</a>,
673<a href="#evaluate">-evaluate</a>,
674<a href="#function">-function</a>,
675<a href="#fx">-fx</a>,
676<a href="#clut">-hald-clut</a>,
677<a href="#gaussian-blur">-gaussian-blur</a>,
678<a href="#motion-blur">-motion-blur</a>,
679<a href="#negate">-negate</a>,
680<a href="#normalize">-normalize</a>,
681<a href="#ordered-dither">-ordered-dither</a>,
682<a href="#radial-blur">-radial-blur</a>,
683<a href="#random-threshold">-random-threshold</a>,
684<a href="#separate">-separate</a>, and
685<a href="#white-threshold">-white-threshold</a>.
686</p>
687
688
689<div style="margin: auto;">
690 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
691</div>
692
693<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Simulate a charcoal drawing.</td><td style='text-align:right;'></td></tr></table>
694
695<div style="margin: auto;">
696 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
697</div>
698
699<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Remove pixels from the interior of an image.</td><td style='text-align:right;'></td></tr></table>
700
701<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">width</em> and <em class="arg">height</em> given in the of the <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument give the number of columns and rows to remove. The <em class="arg">offset</em> portion of the <em class="arg">geometry</em> argument is influenced by a <a href="#gravity">-gravity</a> setting, if present.</p>
702
703<p>The <a href="#chop">-chop</a> option removes entire rows and columns, and moves the remaining corner blocks leftward and upward to close the gaps.</p>
704
705<div style="margin: auto;">
706 <h4><a name="clip" id="clip"></a>-clip</h4>
707</div>
708
709<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply the clipping path if one is present.</td><td style='text-align:right;'></td></tr></table>
710
711<p>If a clipping path is present, it is applied to subsequent operations.</p>
712
713<p>For example, in the command</p>
714
715<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
716<p>only the pixels within the clipping path are negated.</p>
717
718<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
719
720<div style="margin: auto;">
721 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
722</div>
723
724<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip the image as defined by this mask.</td><td style='text-align:right;'></td></tr></table>
725
726<div style="margin: auto;">
727 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
728</div>
729
730<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip along a named path from the 8BImageMagick profile.</td><td style='text-align:right;'></td></tr></table>
731
732<div style="margin: auto;">
733 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
734</div>
735
736<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make a copy of an image (or images).</td><td style='text-align:right;'></td></tr></table>
737
738<p>Specify the image by its index in the sequence. The first image is index
7390. Negative indexes are relative to the end of the sequence; for example, &minus;1
740represents the last image of the sequence. Specify a range of images with a
741dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
742href="#clone">+clone</a> make a copy of the last image in the image
743sequence.</p>
744
745<div style="margin: auto;">
746 <h4><a name="clut" id="clut"></a>-clut</h4>
747</div>
748
749<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Replace the channel values in the first image using each
750corresponding channel in the second image as a <b>c</b>olor
751<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
752
753<p>The second (LUT) image is ordinarily a gradient image containing the
754histogram mapping of how each channel should be modified. Typically it is a
755either a single row or column image of replacement color values. If larger
756than a single row or column, values are taken from a diagonal line from
757top-left to bottom-right corners.</p>
758
759<p>The lookup is further controlled by the <a
760href="#interpolate">-interpolate</a> setting, which is especially handy for an
761LUT which is not the full length needed by the ImageMagick installed Quality
762(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
763'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
764gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
765lookup of color values. </p>
766
767<p>This operator is especially suited to replacing a grayscale image with a
768specific color gradient from the CLUT image. </p>
769
770<p>Only the channel values defined by the <a href="#channel">-channel</a>
771setting will have their values replaced. In particular, since the default <a
772href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
773transparency (alpha/matte channel) is not affected, unless the <a
774href="#channel">-channel</a> setting is modified. When the alpha channel is
775set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
776as the other channels, implying that alpha/matte values are replaced using the
777alpha/matte values of the original image. </p>
778
779<p>If either the image being modified, or the lookup image, conatins no
780transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
781href="#channel">-channel</a> setting includes alpha replacement, then it is
782assumed that image represents a gray-scale graident which will be used for the
783replacement alpha values. That is you can use a gray-scale CLUT image to
784adjust a existing images alpha channel, or you can color a gray-scale image
785using colors form CLUT containing the desired colors, including transparency.
786</p>
787
788<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
789the lookup of the full color RGB value from a 2D representation of a 3D color
790cube. </p>
791
792
793<div style="margin: auto;">
794 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
795</div>
796
797<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</td><td style='text-align:right;'></td></tr></table>
798
799<p>Overlay each image in an image sequence according to its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of an animation at each point in the animation sequence. All images should be the same size, and are assigned appropriate GIF disposal settings for the animation to continue working as expected as a GIF animation. Such frames are more easilly viewed and processed than the highly optimized GIF overlay images. </p>
800
801<p>The animation can be re-optimized after processing using the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', though there is no guarantee that the restored GIF animation optimization is better than the original. </p>
802
803
804<div style="margin: auto;">
805 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
806</div>
807
808<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colorize the image by an amount specified by <em class="arg">value</em> using the color specified by the most recent <a href="#fill" >-fill</a> setting.</td><td style='text-align:right;'></td></tr></table>
809
810<p>Specify the amount of colorization as a percentage. Separate colorization values can be applied to the red, green, and blue channels of the image with a comma-delimited list of colorization values (e.g., <kbd>-colorize 0,0,50</kbd>).</p>
811
812<div style="margin: auto;">
813 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
814</div>
815
816<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the colormap type.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
817
818<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
819
820<p>This option only applies when the default X server visual is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer to <a href="#visual">-visual</a> for more details. By default, a shared colormap is allocated. The image shares colors with other X clients. Some image colors could be approximated, therefore your image may look very different than intended. If <kbd>private</kbd> is chosen, the image colors appear exactly as they are defined. However, other clients may go <em>technicolor</em> when the image colormap is installed.</p>
821
822<div style="margin: auto;">
823 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
824</div>
825
826<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred number of colors in the image.</td><td style='text-align:right;'></td></tr></table>
827
828<p>The actual number of colors in the image may be less than your request, but never more. Note that this a color reduction option. Images with fewer unique colors than specified by <em class="arg">value</em> will have any duplicate or unused colors removed. The ordering of an existing color palette may be altered. When converting an image from color to grayscale, it is more efficient to convert the image to the gray colorspace before reducing the number of colors. Refer to the <a href="../www/quantize.html">color reduction algorithm</a> for more details.</p>
829
830<div style="margin: auto;">
831 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
832</div>
833
834<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image colorspace.</td><td style='text-align:right;'></td></tr></table>
835
836<p>Choices are:</p>
837
838<pre class="text">
839 CMY
840 CMYK
841 Gray
842 HSB
843 HSL
844 HWB
845 Lab
846 Log
847 OHTA
848 Rec601Luma
849 Rec601YCbCr
850 Rec709Luma
851 Rec709YCbCr
852 RGB
853 sRGB
854 Transparent
855 XYZ
856 YCbCr
857 YCC
858 YIQ
859 YPbPr
860 YUV
861</pre>
862
863<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
864
865<p>For a more accurate color conversion to or from the RGB, CMYK, or grayscale colorspaces, use the <a href="#profile">-profile</a> option.</p>
866
867<table class="doc">
868 <caption>Conversion Of RGB To Other Color Spaces</caption>
869 <tr><th align="left" valign="middle">CMY</th></tr>
870 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
871 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
872 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
873 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
874 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
875 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
876 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
877 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
878
879 <tr><th align="left" valign="middle">Gray</th></tr>
880 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
881
882 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
883 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
884 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
885 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
886
887 <tr><th align="left" valign="middle">HSL &mdash; Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
888 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
889 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
890 <tr><td align="left" valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <em>intensity-like</em></td></tr>
891
892 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
893 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
894 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
895 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
896
897 <tr><th align="left" valign="middle">LAB</th></tr>
898 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
899 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
900 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
901
902 <tr><th align="left" valign="middle">LOG</th></tr>
903 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
904 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
905 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
906
907 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
908 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
909 <tr><td align="left" valign="middle">I2=(0.50000*R+0.00000*G&minus;0.50000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
910 <tr><td align="left" valign="middle">I3=(&minus;0.25000*R+0.50000*G&minus;0.25000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
911
912 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
913 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
914
915 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
916 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
917 <tr><td align="left" valign="middle">Cb=(&minus;0.168736*R-0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
918 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
919
920 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
921 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
922
923 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
924 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
925 <tr><td align="left" valign="middle">Cb=(&minus;0.114572*R&minus;0.385428*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
926 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.454153*G&minus;0.045847*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
927
928 <tr><th align="left" valign="middle">sRGB</th></tr>
929 <tr><td align="left" valign="middle">if Rs &le; .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr>
930 <tr><td align="left" valign="middle">if Gs &le; .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr>
931 <tr><td align="left" valign="middle">if Bs &le; .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr>
932
933 <tr><th align="left" valign="middle">XYZ</th></tr>
934 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
935 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
936 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
937
938 <tr><th align="left" valign="middle">YCC</th></tr>
939 <tr><td align="left" valign="middle">Y=(0.29900*R+0.58700*G+0.11400*B) (with complicated scaling); <em>intensity-like</em></td></tr>
940 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
941 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
942
943 <tr><th align="left" valign="middle">YCbCr</th></tr>
944 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
945 <tr><td align="left" valign="middle">Cb=(&minus;0.168736*R&minus;0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
946 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
947
948 <tr><th align="left" valign="middle">YIQ</th></tr>
949 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
950 <tr><td align="left" valign="middle">I=(0.59600*R&minus;0.27400*G&minus;0.32200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
951 <tr><td align="left" valign="middle">Q=(0.21100*R&minus;0.52300*G+0.31200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
952
953 <tr><th align="left" valign="middle">YPbPr</th></tr>
954 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
955 <tr><td align="left" valign="middle">Pb=(&minus;0.168736*R&minus;0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
956 <tr><td align="left" valign="middle">Pr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
957
958 <tr><th align="left" valign="middle">YUV</th></tr>
959 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
960 <tr><td align="left" valign="middle">U=(&minus;0.14740*R&minus;0.28950*G+0.43690*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
961 <tr><td align="left" valign="middle">V=(0.61500*R&minus;0.51500*G&minus;0.10000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
962</table>
963
964<div style="margin: auto;">
965 <h4><a name="combine" id="combine"></a>-combine</h4>
966</div>
967
968<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Combine one or more images into a single image.</td><td style='text-align:right;'></td></tr></table>
969
970<p>The channels (previously set by <a href="#channel">-channel</a>) of the combined image are taken from the grayscale values of each image in the sequence, in order. For the default -channel setting of <kbd>RGB</kbd>, this means the first image is assigned to the <kbd>Red</kbd> channel, the second to the <kbd>Green</kbd> channel, the third to the <kbd>Blue</kbd>.</p>
971
972<p>This option can be thought of as the inverse to <a href="#separate">-separate</a>, so long as the channel settings are the same. Thus, in the following example, the final image should be a copy of the original.
973</p>
974
975<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB -combine imagecopy.png</span></p>
976<div style="margin: auto;">
977 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
978</div>
979
980<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Embed a comment in an image.</td><td style='text-align:right;'></td></tr></table>
981
982<p>This option places comments in a non-pixel portion of the image file. For a comment to be visibly written on the image itself, use the <a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options.</p>
983
984<p>Use this option to assign a specific comment to the image, when writing to an image format that supports comments. You can include the image filename, type, width, height, or other image attribute by embedding special format characters listed under the <a href="#format">-format</a> option. The comment is not drawn on the image, but is embedded in the image datastream via "Comment" tag or similar mechanism. </p>
985
986<p>For example,</p>
987
988<p class="crtsnip">
989 -comment "%m:%f %wx%h"
990</p>
991
992<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> for an image titled <kbd>bird.miff</kbd> and whose width is 512 and height is 480.</p>
993
994<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image comment is read from a file titled by the remaining characters in the string. Comments in a file are literal; no embedded formatting characters are recognized.</p>
995
996<div style="margin: auto;">
997 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
998</div>
999
1000<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the type of image composition.</td><td style='text-align:right;'></td></tr></table>
1001
1002<p>The description of composition uses abstract terminology in order to allow
1003the description to be more precise, while avoiding constant values which are
1004specific to a particular build configuration. Each image pixel is represented
1005by red, green, and blue levels (which are equal for a gray pixel). The
1006build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1007value which may be stored, per pixel, in the red, green, or blue channels of
1008the image. Each image pixel may also optionally (if the image matte channel is
1009enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1010<em>transparent</em>, which may be used to determine the influence of the pixel
1011color when compositing the pixel with another image pixel. If the image matte
1012channel is disabled, then all pixels in the image are treated as opaque. The
1013color of an opaque pixel is fully visible while the color of a transparent
1014pixel color is entirely absent (pixel color is ignored).</p>
1015
1016<p>By definition, raster images have a rectangular shape. All image rows are of
1017equal length, as are all image columns. By treating the alpha channel as a
1018visual "mask" the rectangular image may be given a "shape" by treating the
1019alpha channel as a cookie-cutter for the image. This is done by setting the
1020pixels within the shape to be opaque, with pixels outside the shape set as
1021transparent. Pixels on the boundary of the shape may be between opaque and
1022transparent in order to provide antialiasing (visually smooth edges). The
1023description of the composition operators use this concept of image "shape" in
1024order to make the description of the operators easier to understand. While it
1025is convenient to describe the operators in terms of "shapes" they are by no
1026means limited to mask-style operations since they are based on continuous
1027floating-point mathematics rather than simple boolean operations.</p>
1028
1029<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1030
1031<table class="doc">
1032 <tbody>
1033 <tr valign="top">
1034 <th align="left" style="width: 8%">Method</th>
1035 <th align="left">Description</th>
1036 </tr>
1037
1038 <tr valign="top">
1039 <td valign="top">clear</td>
1040 <td valign="top">Both the color and the alpha of the destination are
1041 cleared. Neither the source nor the destination are used (except for
1042 destinations size and other meta-data which is always preserved.</td>
1043 </tr>
1044
1045 <tr valign="top">
1046 <td valign="top">src</td>
1047 <td valign="top">The source is copied to the destination. The destination
1048 is not used as input, though it is cleared.</td>
1049 </tr>
1050
1051 <tr valign="top">
1052 <td valign="top">dst</td>
1053 <td valign="top">The destination is left untouched. The source image is
1054 completely ignored.</td>
1055 </tr>
1056
1057 <tr valign="top">
1058 <td valign="top">src-over</td>
1059 <td valign="top">The source is composited over the destination. this is
1060 the default alpha blending compose method, when neither the compose
1061 setting is set, nor is set in the image meta-data.</td>
1062 </tr>
1063
1064 <tr valign="top">
1065 <td valign="top">dst-over</td>
1066 <td valign="top">The destination is composited over the source and the
1067 result replaces the destination.</td>
1068 </tr>
1069
1070 <tr valign="top">
1071 <td valign="top">src-in</td>
1072 <td valign="top">The part of the source lying inside of the destination
1073 replaces the destination.</td>
1074 </tr>
1075
1076 <tr valign="top">
1077 <td valign="top">dst-in</td>
1078 <td valign="top">The part of the destination lying inside of the source
1079 replaces the destination. Areas not overlaid are cleared.</td>
1080 </tr>
1081
1082 <tr valign="top">
1083 <td valign="top">src-out</td>
1084 <td valign="top">The part of the source lying outside of the destination
1085 replaces the destination.</td>
1086 </tr>
1087
1088 <tr valign="top">
1089 <td valign="top">dst-out</td>
1090 <td valign="top">The part of the destination lying outside of the source
1091 replaces the destination.</td>
1092 </tr>
1093
1094 <tr valign="top">
1095 <td valign="top">src-atop</td>
1096 <td valign="top">The part of the source lying inside of the destination is
1097 composited onto the destination.</td>
1098 </tr>
1099
1100 <tr valign="top">
1101 <td valign="top">dst-atop</td>
1102 <td valign="top">The part of the destination lying inside of the source is
1103 composited over the source and replaces the destination. Areas not
1104 overlaid are cleared. </td>
1105 </tr>
1106
1107 <tr valign="top">
1108 <td valign="top">xor</td>
1109 <td valign="top">The part of the source that lies outside of the
1110 destination is combined with the part of the destination that lies
1111 outside of the source. Source or Destination, but not both. </td>
1112 </tr>
1113
1114 </tbody>
1115</table>
1116
1117<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1118For example the defaul compose method can be specified as just 'Over'.</p>
1119
1120
1121<p>The following mathemathical composition methods are also available. </p>
1122
1123<p>Typically these use the default 'Over' alpha blending when transparencies
1124are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1125also composes the alpha channel using the same process as the color channels.
1126This allows them to be used for special image masking techniques. </p>
1127
1128<table class="doc">
1129 <tbody>
1130 <tr valign="top">
1131 <th align="left" style="width: 8%">Method</th>
1132 <th align="left">Description</th>
1133 </tr>
1134
1135 <tr valign="top">
1136 <td valign="top">multiply</td>
1137 <td valign="top">The source is multiplied by the destination and replaces the destination. The resultant color is always at least as dark as either of the two constituent colors. Multiplying any color with black produces black. Multiplying any color with white leaves the original color unchanged.</td>
1138 </tr>
1139
1140 <tr valign="top">
1141 <td valign="top">screen</td>
1142 <td valign="top">The source and destination are complemented and then multiplied and then replace the destination. The resultant color is always at least as light as either of the two constituent colors. Screening any color with white produces white. Screening any color with black leaves the original color unchanged.</td>
1143 </tr>
1144
1145 <tr valign="top">
1146 <td valign="top">plus</td>
1147 <td valign="top">The source is added to the destination and replaces the
1148 destination. This operator is useful for averaging or a controled
1149 merger of two images, rather than a direct overlay.</td>
1150 </tr>
1151
1152 <tr valign="top">
1153 <td valign="top">add</td>
1154 <td valign="top">As per 'plus' but transparency data is treated as matte
1155 values. As such any transparent areas in either image remain
1156 transparent. </td>
1157 </tr>
1158
1159 <tr valign="top">
1160 <td valign="top">minus</td>
1161 <td valign="top">Subtract the colors in the source image from the
1162 destination image. When transparency is involved, opaque areas is
1163 subtracted from any destination opaque areas. </td>
1164 </tr>
1165
1166 <tr valign="top">
1167 <td valign="top">subtract</td>
1168 <td valign="top">Subtract the colors in the source image from the
1169 destination image. When transparency is involved transparent areas are
1170 subtracted, so only the opaque areas in the source remain opaque in
1171 the destination image. </td>
1172 </tr>
1173
1174 <tr valign="top">
1175 <td valign="top">difference</td>
1176 <td valign="top">Subtracts the darker of the two constituent colors from
1177 the lighter. Painting with white inverts the destination color.
1178 Painting with black produces no change.</td>
1179 </tr>
1180
1181 <tr valign="top">
1182 <td valign="top">exclusion</td>
1183 <td valign="top">Produces an effect similar to that of 'difference', but
1184 appears as lower contrast. Painting with white inverts the
1185 destination color. Painting with black produces no change.</td>
1186 </tr>
1187
1188 <tr valign="top">
1189 <td valign="top">darken</td>
1190 <td valign="top">Selects the darker of the destination and source colors.
1191 The destination is replaced with the source when the source is darker,
1192 otherwise it is left unchanged.</td>
1193 </tr>
1194
1195 <tr valign="top">
1196 <td valign="top">lighten</td>
1197 <td valign="top">Selects the lighter of the destination and source colors.
1198 The destination is replaced with the source when the source is
1199 lighter, otherwise it is left unchanged. </td>
1200 </tr>
1201
1202 <tr valign="top">
1203 <td valign="top">linear-dodge</td>
1204 <td valign="top">This is equivelent to 'Plus' in that the color channels
1205 are simply added, however it does not 'Plus' the alpha channel, but
1206 uses the normal 'Over' alpha blending, which transparencies are
1207 involved. Produces a sort of additive multiply-like result. Added
1208 ImageMagick version 6.5.4-3. </td>
1209 </tr>
1210
1211 <tr valign="top">
1212 <td valign="top">linear-burn</td>
1213 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1214 Sort of a additive 'Screen' of the images. Added ImageMagick version
1215 6.5.4-3. </td>
1216 </tr>
1217
1218 <tr valign="top">
1219 <td valign="top">color-dodge</td>
1220 <td valign="top">Brightens the destination color to reflect the source
1221 color. Painting with black produces no change.</td>
1222 </tr>
1223
1224 <tr valign="top">
1225 <td valign="top">color-burn</td>
1226 <td valign="top">Darkens the destination color to reflect the source
1227 color. Painting with white produces no change. Fixed in ImageMagick
1228 version 6.5.4-3. </td>
1229 </tr>
1230
1231 <tr valign="top">
1232 <td valign="top">overlay</td>
1233 <td valign="top">Multiplies or screens the colors, dependent on the
1234 destination color. Source colors overlay the destination whilst
1235 preserving its highlights and shadows. The destination color is not
1236 replaced, but is mixed with the source color to reflect the lightness
1237 or darkness of the destination.</td>
1238 </tr>
1239
1240 <tr valign="top">
1241 <td valign="top">hard-light</td>
1242 <td valign="top">Multiplies or screens the colors, dependent on the source
1243 color value. If the source color is lighter than 0.5, the destination
1244 is lightened as if it were screened. If the source color is darker
1245 than 0.5, the destination is darkened, as if it were multiplied. The
1246 degree of lightening or darkening is proportional to the difference
1247 between the source color and 0.5. If it is equal to 0.5 the
1248 destination is unchanged. Painting with pure black or white produces
1249 black or white.</td>
1250 </tr>
1251
1252
1253 <tr valign="top">
1254 <td valign="top">linear-light</td>
1255 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1256 instead. Increases contrast slightly with an impact on the
1257 foreground's tonal values.</td>
1258 </tr>
1259
1260 <tr valign="top">
1261 <td valign="top">soft-light</td>
1262 <td valign="top">Darkens or lightens the colors, dependent on the source
1263 color value. If the source color is lighter than 0.5, the destination
1264 is lightened. If the source color is darker than 0.5, the destination
1265 is darkened, as if it were burned in. The degree of darkening or
1266 lightening is proportional to the difference between the source color
1267 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1268 with pure black or white produces a distinctly darker or lighter area,
1269 but does not result in pure black or white. Fixed in ImageMagick
1270 version 6.5.4-3. </td>
1271 </tr>
1272
1273 <tr valign="top">
1274 <td valign="top">pegtop-light</td>
1275 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1276 continuious mathematical formula rather than two conditionally
1277 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1278 </tr>
1279
1280 <tr valign="top">
1281 <td valign="top">vivid-light</td>
1282 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1283 primary and secondary colors in the image. Added ImageMagick version
1284 6.5.4-3. </td>
1285 </tr>
1286
1287 <tr valign="top">
1288 <td valign="top">pin-light</td>
1289 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1290 to similate the effects of a strong 'pinhole' light source. Added
1291 ImageMagick version 6.5.4-3. </td>
1292 </tr>
1293
1294 </tbody>
1295</table>
1296
1297
1298<p>Also included are these special purpose compose methods:</p>
1299
1300<table class="doc">
1301 <tbody>
1302 <tr valign="top">
1303 <th align="left" style="width: 8%">Method</th>
1304 <th align="left">Description</th>
1305 </tr>
1306
1307 <tr valign="top">
1308 <td valign="top">copy-*</td>
1309 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1310 Magenta, Yellow, Black, or Opacity) in the source image to the
1311 same channel in the destination image. If the channel specified
1312 does not exist in the source image, (which can only happen for methods,
1313 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1314 assumed that the source image is a special grayscale channel image
1315 of the values to be copied. </td>
1316 </tr>
1317
1318 <tr valign="top">
1319 <td valign="top">change-mask</td>
1320 <td valign="top">Replace any destination pixel that is the similar to the source images pixel (as defined by the current <a href="#fuzz">-fuzz</a> factor), with transparency. </td>
1321 </tr>
1322 </tbody>
1323</table>
1324
1325<p>On top of these composed methods are a few special ones that not only require
1326the two images that are being merged or overlaid, but have some extra numerical
1327arguments, which are tabled below. </p>
1328
1329<p>In the "<code>composite</code>" command these composition methods are
1330selected using special options with the arguments needed. They are usually,
1331but not always, the same name as the composte 'method' they use, and replaces
1332the normal use of the <a href="#compose" >-compose</a> setting in the
1333"<code>composite</code>" command. For example... </p>
1334
1335<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1336<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1337these extra arguments to its <a href="#composite" >-composite</a> operator,
1338using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1339these special argumented <a href="#compose" >-compose</a> methods, those the
1340argument and the method both need to be set separatally. For example... </p>
1341
1342<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1343<p>The following is a table of these special 'argumented' compose methods,
1344with a brief summary of what they do. For more details see the equivalent
1345"composite" command option name. </p>
1346
1347<table class="doc">
1348 <tbody>
1349 <tr valign="top">
1350 <th align="left" style="width: 8%">Method</th>
1351 <th align="left">Description</th>
1352 </tr>
1353
1354 <tr valign="top">
1355 <td valign="top">dissolve</td>
1356 <td valign="top">Arguments:
1357 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1358 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1359 <br>Dissolve the 'source' image by the percentage given before overlaying
1360 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1361 greater than 100, it starts dissolving the main image so it will
1362 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1363 both percentages are given, each image are dissolved to the
1364 percentages given.
1365 </td>
1366 </tr>
1367
1368 <tr valign="top">
1369 <td valign="top">blend</td>
1370 <td valign="top">Arguments:
1371 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1372 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1373 <br>Average the images together ('plus') according to the percentages
1374 given and each pixels transparency. If only a single percentage value
1375 is given it sets the weight of the composite or 'source' image, while
1376 the background image is weighted by the exact opposite amount. That is
1377 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1378 the 'destination' image. Thus it is equivalent to <kbd>-blend
1379 30x70</kbd>.
1380 </td>
1381 </tr>
1382
1383 <tr valign="top">
1384 <td valign="top">mathematics</td>
1385 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1386 <br>Not available in "<code>composite</code>" at this time.
1387 <br>Merge the source and destination images according to the formula
1388 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1389 <br>Can be used to generate a custom composition method that would
1390 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1391 DIY image operator. Added to ImageMagick version 6.5.4-3.
1392 </td>
1393 </tr>
1394
1395 <tr valign="top">
1396 <td valign="top">modulate</td>
1397 <td valign="top">Arguments:
1398 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1399 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1400 <br>Take a grayscale image (with alpha mask) and modify the destination
1401 image's brightness according to watermark image's grayscale value and
1402 the <em class="arg">brightness</em> percentage. The destinations
1403 color saturation attribute is just direct modified by the <em
1404 class="arg">saturation</em> percentage, which defaults to 100 percent
1405 (no color change).
1406
1407 </td>
1408 </tr>
1409
1410 <tr valign="top">
1411 <td valign="top">displace</td>
1412 <td valign="top">Arguments:
1413 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1414 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1415 <br>With this option, the 'overlay' image, and optionally the 'mask'
1416 image, is used as a relative displacement map, which is used to
1417 displace the lookup of what part of the destination image is seen at
1418 each point of the overlaid area. Much like the displacement map is a
1419 'lens' that distorts the original 'background' image behind it.
1420 <br><br>
1421 The X-scale is modilated by the 'red' channel of the overlay image
1422 while the Y-scale is modulated by the green channel, (the mask image
1423 if given is rolled into green channel of the overlay image. This
1424 separation allows you to modulate the X and Y lookup displacement
1425 separatally allowing you to di 2 dimentional displacements, rather
1426 than 1 dimentional verctored displacements (using grayscale image).
1427 <br><br>
1428 If the overlay image contains transparency this is used as a mask
1429 of the resulting image to remove 'invalid' pixels.
1430 <br><br>
1431 The '%' flag makes the displacement scale relative to the size of the
1432 overlay image (100% = half width/height of image). Using '!' switches
1433 percentage arguments to refer to the destination image size instead.
1434 <br><br>
1435 Special flags were added Added to ImageMagick version 6.5.3-5.
1436 </td>
1437 </tr>
1438
1439 <tr valign="top">
1440 <td valign="top">distort</td>
1441 <td valign="top">Arguments:
1442 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1443 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1444 <br>Not available in "<code>composite</code>" at this time.
1445 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1446 relative to the center of the overlay (or that given). Basically
1447 allows you to generate absolute distortion maps where 'black' will
1448 look up the left/top edge, and 'white' looks up the bottom/right
1449 edge of the destination image, according to the scale given.
1450 <br><br>
1451 The '!' flag not only switches percentage scaling, to use the
1452 destination image, but also the image the center offset of the lookup.
1453 This means the overlay can lookup a completely different region of the
1454 destination image.
1455 <br><br>
1456 Added to ImageMagick version 6.5.3-5.
1457 </td>
1458 </tr>
1459
1460 <tr valign="top">
1461 <td valign="top">blur</td>
1462 <td valign="top">Arguments:
1463 <em class="arg">Width</em>[x<em class="arg">Height</em
1464 >[+<em class="arg">Angle</em>]]
1465 <br>Equivalent to "<code>composite</code>"
1466 <a href="#blur-composite">-blur</a>
1467 <br>A Variable Blur Mapping Composition method, where each pixel in the
1468 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1469 with an ellipse (typically a circle) of the given sigma size, scaled
1470 according to overlay (source image) grayscale mapping.
1471 <br><br>
1472 As per 'Displace' and 'Distort', the red channel will modulate the
1473 width of the ellipse, while the green channel will modulate the height
1474 of the ellipse. However at this time the ellipse angle is not
1475 modulated though this may be a future posibility (perhaps with a
1476 special flag to enable use of blur channel for this purpose).
1477 <br><br>
1478 Added to ImageMagick version 6.5.4-0.
1479 </td>
1480 </tr>
1481
1482 </tbody>
1483</table>
1484
1485<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1486
1487
1488<div style="margin: auto;">
1489 <h4><a name="composite" id="composite"></a>-composite</h4>
1490</div>
1491
1492<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on the current image sequence.</td><td style='text-align:right;'></td></tr></table>
1493
1494<p>Take the first image 'destination' and overlay the second 'source' image
1495according to the current <a href="#compose">-compose</a> setting. The location
1496of the 'source' or 'overlay' image is controlled according to <a
1497href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1498settings. </p>
1499
1500<p>If a third image is given this is treated as a gray-scale 'mask' image
1501relative to the first 'destination' image. This mask will limit what parts of
1502the destination can be modified by the image composition. However for the
1503'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1504Y-displacement image instead. </p>
1505
1506<p>If a <a href="#compose">-compose</a> method requires extra numerical
1507arguments or flags these can be provided by setting the <a
1508href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1509appropriatally for the compose method. </p>
1510
1511<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1512image outside the overlay area. You can disable this by setting the special <a
1513href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1514to '<kbd>false</kbd>'. </p>
1515
1516
1517<div style="margin: auto;">
1518 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1519</div>
1520
1521<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use pixel compression specified by <em class="arg">type</em> when writing the image.</td><td style='text-align:right;'></td></tr></table>
1522
1523<p>Choices are: <kbd class="arg">None</kbd>, <kbd class="arg">BZip</kbd>, <kbd class="arg">Fax</kbd>, <kbd class="arg">Group4</kbd>, <kbd class="arg">JPEG</kbd>, <kbd class="arg">JPEG2000</kbd>, <kbd class="arg">Lossless</kbd>, <kbd class="arg">LZW</kbd>, <kbd class="arg">RLE</kbd> or <kbd class="arg">Zip</kbd>.</p>
1524
1525<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1526
1527<p>Specify <a href="#compress">+compress</a> to store the binary image in an uncompressed format. The default is the compression type of the specified image file.</p>
1528
1529<p>If <kbd>LZW</kbd> compression is specified but LZW compression has not been enabled, the image data is written in an uncompressed LZW format that can be read by LZW decoders. This may result in larger-than-expected GIF files.</p>
1530
1531<p><kbd>Lossless</kbd> refers to lossless JPEG, which is only available if the JPEG library has been patched to support it. Use of lossless JPEG is generally not recommended.</p>
1532
1533<p>Use the <a href="#quality">-quality</a> option to set the compression level to be used by JPEG, PNG, MIFF, and MPEG encoders. Use the <a href="#sampling-factor">-sampling-factor</a> option to set the sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling the chroma channels.</p>
1534
1535<div style="margin: auto;">
1536 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1537</div>
1538
1539<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enhance or reduce the image contrast.</td><td style='text-align:right;'></td></tr></table>
1540
1541<p>This option enhances the intensity differences between the lighter and darker elements of the image. Use <a href="#contrast">-contrast</a> to enhance the image or <a href="#contrast">+contrast</a> to reduce the image contrast.</p>
1542
1543<p>For a more pronounced effect you can repeat the option:</p>
1544
1545<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1546<div style="margin: auto;">
1547 <h4><a name="contrast-stretch" id="contrast-stretch"></a>-contrast-stretch <em class="arg">black-point</em><br />-contrast-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4>
1548</div>
1549
1550<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table>
1551
1552<p>While performing the stretch, black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">white-point %</em> pixels.</p>
1553
1554<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch">-contrast-stretch</a> will black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">total pixels minus white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">100% minus white-point %</em> pixels.</p>
1555
1556<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that the image's
1557min and max values are stretched to 0 and <em class="QR">QuantumRange</em>, respectively, without any loss of data due to burn-out at either end. This is not the same as <a href="#normalize">-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p>
1558
1559<p>The channels are stretched in concert. Specify <a href="#channel">-channel</a> to normalize the RGB channels individually.</p>
1560
1561
1562<div style="margin: auto;">
1563 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1564</div>
1565
1566<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Convolve an image with a user-supplied convolution kernel.</td><td style='text-align:right;'></td></tr></table>
1567
1568<p>The <em class="arg">kernel</em> is a square matrix specified as a comma-separated list of integers (with no spaces), ordered left-to right, starting with the top row. Presently, only odd-dimensioned kernels are supported, and therefore the number of entries in the specified <em class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 7<sup>2</sup>=49, etc. </p>
1569
1570<p>Note that the <a href="../www/command-line-options.html#convolve">&#x2011;convolve</a> operator supports the <a href="../www/command-line-options.html#bias">&#x2011;bias</a> setting. This option shifts the convolution so that positive and negative results are relative to a user-specified bias value. This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values is clipped at zero.
1571</p>
1572
1573<p>When using an ImageMagick with the HDRI compile-time setting, <a href="../www/command-line-options.html#bias">&#x2011;bias</a> is not needed,
1574as ImageMagick is able to store/handle any negative results without
1575clipping to the color value range (0..QuantumRange).</p>
1576
1577<p>See the discussion on HDRI implementations of ImageMagick on the page
1578<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry.
1579</p>
1580
1581<div style="margin: auto;">
1582 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1583</div>
1584
1585<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Cut out one or more rectangular regions of the image.</td><td style='text-align:right;'></td></tr></table>
1586
1587<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
1588
1589<p>The <em class="arg">width</em> and <em class="arg">height</em> of the <em class="arg">geometry</em> argument give the size of the image that remains after cropping, and <em class="arg">x</em> and <em class="arg">y</em> in the <em class="arg">offset</em> (if present) gives the location of the top left corner of the cropped image with respect to the original image. To specify the amount to be removed, use <a href="#shave">-shave</a> instead.</p>
1590
1591<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are present, a single image is generated, consisting of the pixels from the cropping region. The offsets specify the location of the upper left corner of the cropping region measured downward and rightward with respect to the upper left corner of the image. If the <a href="#gravity">-gravity</a> option is present with <kbd>NorthEast</kbd>, <kbd>East</kbd>, or <kbd>SouthEast</kbd> gravity, it gives the distance leftward from the right edge of the image to the right edge of the cropping region. Similarly, if the <a href="#gravity">-gravity</a> option is present with <kbd>SouthWest</kbd>, <kbd>South</kbd>, or <kbd>SouthEast</kbd> gravity, the distance is measured upward between the bottom edges.</p>
1592
1593<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are omitted, a set of tiles of the specified geometry, covering the entire input image, is generated. The rightmost tiles and the bottom tiles are smaller if the specified geometry extends beyond the dimensions of the input image.</p>
1594
1595<p>By adding a exclamation character flag to the geometry argument, the
1596cropped images virtual canvas page size and offset is set as if the
1597geometry argument was a viewport or window. This means the canvas page size
1598is set to exactly the same size you specified, the image offset set
1599relative top left corner of the region cropped. </p>
1600
1601<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1602special single pixel transparent 'missed' image is returned, and a 'crop
1603missed' warning given. </p>
1604
1605
1606<div style="margin: auto;">
1607 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1608</div>
1609
1610<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image colormap by amount.</td><td style='text-align:right;'></td></tr></table>
1611
1612<p><em class="arg">Amount</em> defines the number of positions each
1613colormap entry is shifted.</p>
1614
1615
1616<div style="margin: auto;">
1617 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1618</div>
1619
1620<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>enable debug printout.</td><td style='text-align:right;'></td></tr></table>
1621
1622<p>The <kbd>events</kbd> parameter specifies which events are to be logged. It can be either <kbd>None</kbd>, <kbd>All</kbd>, <kbd>Trace</kbd>, or a comma-separated list consisting of one or more of the following domains: <kbd>Annotate</kbd>, <kbd>Blob</kbd>, <kbd>Cache</kbd>, <kbd>Coder</kbd>, <kbd>Configure</kbd>, <kbd>Deprecate</kbd>, <kbd>Exception</kbd>, <kbd>Locale</kbd>, <kbd>Render</kbd>, <kbd>Resource</kbd>, <kbd>Security</kbd>, <kbd>TemporaryFile</kbd>, <kbd>Transform</kbd>, <kbd>X11</kbd>, or <kbd>User</kbd>. </p>
1623
1624
1625<p>For example, to log cache and blob events, use.</p>
1626
1627<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1628<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1629
1630<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1631
1632<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1633
1634<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1635
1636<p>Debugging may also be set using the <kbd>MAGICK_DEBUG</kbd> <a href="../www/resources.html#environment">environment variable</a>. The allowed values for the <kbd>MAGICK_DEBUG</kbd> environment variable are the same as for the <a href="#debug">-debug</a> option.</p>
1637
1638
1639<div style="margin: auto;">
1640 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1641</div>
1642
1643<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decipher and restore pixels that were previously transformed by <a href="#encipher">-encipher</a>.</td><td style='text-align:right;'></td></tr></table>
1644
1645<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1646
1647<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1648
1649
1650<div style="margin: auto;">
1651 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1652</div>
1653
1654<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>find areas that has changed between images </td><td style='text-align:right;'></td></tr></table>
1655
1656<p>Given a sequence of images all the same size, such as produced by <a href="#coalesce">-coalesce</a>, replace the second and later images, with a smaller image of just the area that changed relative to the previous image. </p>
1657
1658<p>The resulting sequence of images can be used to optimize an animation sequence, though will not work correctly for GIF animations when parts of the animation can go from opaque to transparent. </p>
1659
1660<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1661
1662
1663<div style="margin: auto;">
1664 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1665</div>
1666
1667<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add coder/decoder specific options.</td><td style='text-align:right;'></td></tr></table>
1668
1669<p>This option creates one or more definitions for coders and decoders to use while reading and writing image data. Definitions may be passed to coders and decoders to control options that are specific to certain image formats. If <em class="arg">value</em> is missing for a definition, an empty-valued definition of a flag is created with that name. This used to control on/off options. Use <a href="#define">+define key</a> to remove definitions previously created. Use <a href="#define">+define "*"</a> to remove all existing definitions.</p>
1670
1671<p>The following definitions may be created:</p>
1672
1673<ul>
1674<dt>jp2:rate=value</dt>
1675 <dd>Specify the compression factor to use while writing JPEG-2000 files. The compression factor is the reciprocal of the compression ratio. The valid range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, this value overrides the -quality setting. A quality setting of 75 results in a rate value of 0.06641.</dd><br />
1676<dt>mng:need-cacheoff</dt>
1677 <dd>turn playback caching off for streaming MNG.</dd><br />
1678<dt>png:bit-depth=value</dt>
1679<dt>png:color-type=value</dt>
1680 <dd>desired bit-depth and color-type for PNG output. You can force the PNG encoder to use a different bit-depth and color-type than it would have normally selected, but only if this does not cause any loss of image quality. Any attempt to reduce image quality is treated as an error and no PNG file is written. E.g., if you have a 1-bit black-and-white image, you can use these "defines" to cause it to be written as an 8-bit grayscale, indexed, or even a 64-bit RGBA. But if you have a 16-million color image, you cannot force it to be written as a grayscale or indexed PNG. If you wish to do this, you must use the appropriate <a href="#depth">-depth</a>, <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to reduce the image quality prior to using the PNG encoder. Note that in indexed PNG files, "bit-depth" refers to the number of bits per index, which can range from 1 to 8. In such files, the color samples always have 8-bit depth.</dd><br />
1681<dt>ps:imagemask</dt>
1682 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create Postscript files that render bilevel images with the Postscript imagemask operator instead of the image operator.</dd>
1683</ul>
1684
1685<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1686
1687<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1688<p>Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>. For example, to set a temporary path to put work files, use:</p>
1689
1690<p class="crtsnip">
1691-define registry:temporary-path=/data/tmp
1692</p>
1693
1694<div style="margin: auto;">
1695 <h4><a name="delay" id="delay"></a>-delay <em class="arg">ticks</em> <br />-delay <em class="arg">ticks</em>x<em class="arg">ticks-per-second</em> {<em class="arg">&lt;</em>} {<em class="arg">&gt;</em>}</h4>
1696</div>
1697
1698<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display the next image after pausing.</td><td style='text-align:right;'></td></tr></table>
1699
1700<p>This option is useful for regulating the animation of image sequences <em>ticks/ticks-per-second</em> seconds must expire before the display of the next image. The default is no delay between each showing of the image sequence. The default ticks-per-second is 100.</p>
1701
1702<p>Use <kbd>&gt;</kbd> to change the image delay <em>only</em> if its current value exceeds the given delay. <kbd>&lt;</kbd> changes the image delay <em>only</em> if current value is less than the given delay. For example, if you specify <kbd>30&gt;</kbd> and the image delay is 20, the image delay does not change. However, if the image delay is 40 or 50, the delay it is changed to 30. Enclose the given delay in quotation marks to prevent the <kbd>&lt;</kbd> or <kbd>&gt;</kbd> from being interpreted by your shell as a file redirection.</p>
1703
1704
1705<div style="margin: auto;">
1706 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1707</div>
1708
1709<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>delete the image, specified by its index, from the image sequence.</td><td style='text-align:right;'></td></tr></table>
1710
1711<p>Specify the image by its index in the sequence. The first image is index 0. Negative indexes are relative to the end of the sequence, for example, -1 represents the last image of the sequence. Specify a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use <kbd>+delete</kbd> to delete the last image in the current image sequence.</p>
1712
1713
1714<div style="margin: auto;">
1715 <h4><a name="density" id="density"></a>-density <em class="arg">width</em><br />-density <em class="arg">width</em>x<em class="arg">height</em></h4>
1716</div>
1717
1718<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the horizontal and vertical resolution of an image for rendering to devices.</td><td style='text-align:right;'></td></tr></table>
1719
1720<p>This option specifies the image resolution to store while encoding a raster image or the canvas resolution while rendering (reading) vector formats such as Postscript, PDF, WMF, and SVG into a raster image. Image resolution provides the unit of measure to apply when rendering to an output device or raster image. The default unit of measure is in dots per inch (DPI). The <a href="#units">-units</a> option may be used to select dots per centimeter instead.</p>
1721
1722<p>The default resolution is 72 dots per inch, which is equivalent to one point per pixel (Macintosh and Postscript standard). Computer screens are normally 72 or 96 dots per inch, while printers typically support 150, 300, 600, or 1200 dots per inch. To determine the resolution of your display, use a ruler to measure the width of your screen in inches, and divide by the number of horizontal pixels (1024 on a 1024x768 display).</p>
1723
1724<p>If the file format supports it, this option may be used to update the stored image resolution. Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile is not stripped from the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p>
1725
1726<p>The <a href="#density">-density</a> option sets an <em>attribute</em> and does not alter the underlying raster image. It may be used to adjust the rendered size for desktop publishing purposes by adjusting the scale applied to the pixels. To resize the image so that it is the same size at a different resolution, use the <a href="#resample">-resample</a> option.</p>
1727
1728<div style="margin: auto;">
1729 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1730</div>
1731
1732<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>depth of the image.</td><td style='text-align:right;'></td></tr></table>
1733
1734<p>This the number of bits in a color sample within a pixel. Use this option to specify the depth of raw images whose depth is unknown such as GRAY, RGB, or CMYK, or to change the depth of any image after it has been read.</p>
1735
1736<div style="margin: auto;">
1737 <h4><a name="descend" id="descend"></a>-descend</h4>
1738</div>
1739
1740<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>obtain image by descending window hierarchy.</td><td style='text-align:right;'></td></tr></table>
1741
1742<div style="margin: auto;">
1743 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1744</div>
1745
1746<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>straighten an image. A threshold of 40% works for most images.</td><td style='text-align:right;'></td></tr></table>
1747
1748<p>Use <a href="#set">-set</a> <kbd>option:deskew:auto-crop <em>width</em></kbd> to auto crop the image. The set argument is the pixel width of the image background (e.g 40).</p>
1749
1750<div style="margin: auto;">
1751 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1752</div>
1753
1754<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the speckles within an image.</td><td style='text-align:right;'></td></tr></table>
1755
1756<div style="margin: auto;">
1757 <h4><a name="displace" id="displace"></a>-displace <em class="arg">horizontal-scale</em><br />-displace <em class="arg">horizontal-scale</em>x<em class="arg">vertical-scale</em></h4>
1758</div>
1759
1760<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shift image pixels as defined by a displacement map.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
1761
1762<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1763will be used as a displacement map, which is used to displace the lookup of
1764what part of the 'background' image is seen at each point of the overlaid
1765area. Much like the displacement map is a 'lens' that redirects light shining
1766through it so as to present a distorted view the original 'background' image
1767behind it. </p>
1768
1769<p>Any perfect grey areas of the displacement map produce a zero
1770displacement of the image. Black areas produce the given maximum negative
1771displacement of the lookup point, while white produce a maximum positive
1772displacement of the lookup. </p>
1773
1774<p>Note that it is the lookup of the 'background' that is displaced, not a
1775displacement of the image itself. As such an area of the displacement map
1776containing 'white' will have the lookup point 'shifted' by a positive amount,
1777and thus generating a copy of the destination image to the right/downward from
1778the correct position. That is the image will look like it may have been
1779'shifted' in a negative left/upward direction. Understanding this is a very
1780important in understanding how displacement maps work. </p>
1781
1782<p>The given arguments define the maximum amount of displacement in pixels
1783that a particular map can produce. If the displacement scale is large enough
1784it is also posible to lookup parts of the 'background' image that lie well
1785outside the bounds of the displacement map itself. That is you could very
1786easilly copy a section of the original image from outside the overlay area
1787into the overlay area. </p>
1788
1789<p>The '%' flag makes the displacement scale relative to the size of the
1790overlay image (100% = half width/height of image). Using '!' switches
1791percentage arguments to refer to the destination image size instead.
1792these flags were added as of IM v6.5.3-5.</p>
1793
1794<p>Normally a single grayscale displacement map is provided, which with the
1795given scaling values will determine a single direction (vector) in which
1796displacements can occur (positivally or negativally). However, if you also
1797specify a third image which is normally used as a <em class="arg">mask</em>,
1798then the <em class="arg">composite image</em> will be used for horizontal X
1799displacement, while the <em class="arg">mask image</em> is used for vertical Y
1800displacement. This allows you to define completely different displacement
1801values for the X and Y directions, and allowing you to lookup any point within
1802the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1803any other nearby pixel, producing complex 2 dimentional displacements, rather
1804than a simple 1 dimentional vector displacements. </p>
1805
1806<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1807you can use the 'red' channel of the overlay image to specify the horizontal
1808or X displacement, and the 'green' channel for the vertical or Y displacement.
1809</p>
1810
1811<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1812mask the transparency of the destination image. However areas outside the
1813overlaid areas will not be effected. </p>
1814
1815
1816<div style="margin: auto;">
1817 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1818</div>
1819
1820<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies the X server to contact.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
1821
1822<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1823
1824<div style="margin: auto;">
1825 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1826</div>
1827
1828<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>define the GIF disposal image setting for images that are being created or read in. </td><td style='text-align:right;'></td></tr></table>
1829
1830<p>The layer disposal method defines the way each the displayed image is to be
1831modified after the current 'frame' of an animation has finished being
1832displayed (after its 'delay' period), but before the next frame on an
1833animation is to be overlaid onto the display. </p>
1834
1835<p>Here are the valid methods:</p>
1836
1837<pre class="text">
1838Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1839None 1 Do not dispose, just overlay next frame image.
1840Background 2 Clear the frame area with the background color.
1841Previous 3 Clear to the image prior to this frames overlay.
1842</pre>
1843
1844<p>You can also use the numbers given above, which is what the GIF format
1845uses internally to represent the above settings. </p>
1846
1847<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1848
1849<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1850resetting the layer disposal methods of images being read in. </p>
1851
1852<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1853disposal method for images already in memory.</p>
1854
1855<div style="margin: auto;">
1856 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1857</div>
1858
1859<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>maximum RMSE for subimage match (default 0.2).</td><td style='text-align:right;'>[<a href="../www/compare.html">compare</a>]</td></tr></table>
1860
1861
1862<div style="margin: auto;">
1863 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
1864</div>
1865
1866<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dissolve an image into another by the given percent.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
1867
1868<p>The opacity of the composite image is multiplied by the given percent, then
1869it is composited 'over' the main image. If <em class="arg">src_percent</em>
1870is greater than 100, start dissolving the main image so it will become
1871transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
1872are given, each image are dissolved to the percentages given. </p>
1873
1874<p>Note that dissolve percentages do not add, two opaque images dissolved
1875'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
1876images, you would need to use dissolve values of '50,100'. </p>
1877
1878<div style="margin: auto;">
1879 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
1880</div>
1881
1882<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>distort an image, using the given <em class="arg">method</em> and its required <em class="arg">arguments</em>.</td><td style='text-align:right;'></td></tr></table>
1883
1884<p>The <em class="arg">arguments</em> is a single string containing a list
1885of floating point numbers separated by commas or spaces. The number of
1886and meaning of the floating point values depends on the distortion <em
1887class="arg">method</em> being used. </p>
1888
1889<p>Choose from these distortion types:</p>
1890
1891<table class="doc">
1892 <tr valign="top">
1893 <th align="left" style="width: 8%">Method</th>
1894 <th align="left">Description</th>
1895 </tr>
1896
1897 <tr valign="top">
1898 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
1899 <br/>or &nbsp; <kbd>SRT</kbd></td>
1900 <td valign="top">
1901 Distort image by first scaling and rotating about a given 'center',
1902 before translating that 'center' to the new location, in that order. It
1903 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
1904 distortion, but without shearing effects. It also provides a good way
1905 of rotating and displacing a smaller image for tiling onto a larger
1906 background (IE 2-dimensional animations). <br/>
1907
1908 The number of arguments determine the specific meaning of each
1909 argument for the scales, rotation, and translation operations. <br/>
1910
1911 <table style="margin-left:auto; margin-right:auto;">
1912 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
1913 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
1914 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
1915 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1916 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
1917 <tr><td>5:</td>
1918 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1919 <tr><td>6:</td>
1920 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
1921 <tr><td>7:</td>
1922 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
1923 &nbsp; NewX,NewY</em></td></tr>
1924 </table>
1925
1926 This is actually an alternative way of specifing a 2 dimensional linear
1927 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
1928
1929 <tr valign="top">
1930 <td valign="top"><kbd>Affine</kbd></td>
1931 <td valign="top">
1932 Distort the image linearly by moving a list of at least 3 or more sets
1933 of control points (as defined below). Idealy 3 sets or 12 floating
1934 point values are given allowing the image to be linearly scaled,
1935 rotated, sheared, and translated, according to those three points. See
1936 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
1937 distortions. <br/>
1938
1939 More than 3 sets given control point pairs (12 numbers) is least
1940 squares fitted to best match a lineary affine distortion. If only 2
1941 control point pairs (8 numbers) are given a two point image translation
1942 rotation and scaling is performed, without any posible shearing,
1943 flipping or changes in aspect ratio to the resulting image. If only one
1944 control point pair is provides the image is only translated, (which may
1945 be a floating point non-integer translation). <br/>
1946
1947 This distortion does not include any form of perspective distortion.
1948 </td>
1949
1950 </tr>
1951
1952 <tr valign="top">
1953 <td valign="top"><kbd>AffineProjection</kbd></td>
1954 <td valign="top">
1955 Linearly distort an image using the given Affine Matrix of 6
1956 pre-calculated coefficients forming a set of Affine Equations to map
1957 the source image to the destination image.
1958
1959 <div style="text-align: center"><em>
1960 s<sub>x</sub>, r<sub>x</sub>,
1961 r<sub>y</sub>, s<sub>y</sub>,
1962 t<sub>x</sub>, t<sub>y</sub>
1963 </em></div>
1964
1965 See <a href="#affine" >-affine</a> setting for more detail, and
1966 meanings of these coefficients. <br/>
1967
1968 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
1969 alternative methods of defining this distortion, with ImageMagick doing the
1970 calculations needed to generate the required coefficients. You can see
1971 the internally generated coefficients, by using a <a href="#verbose"
1972 >-verbose</a> setting. </td>
1973
1974 </tr>
1975
1976<!-- still under development, do not display - Anthony
1977 <tr valign="top">
1978 <td valign="top"><kbd>Bilinear</kbd></td>
1979 <td valign="top">
1980 Bilinear (reversed) Distortion, given a minimum of 4 sets of
1981 coordinate pairs, or 16 values (see below). Not that lines may not
1982 appear straight after distortion, though the distance between
1983 coordinates will remain consistant. </td>
1984 </tr>
1985-->
1986
1987 <tr valign="top">
1988 <td valign="top"><kbd>Perspective</kbd></td>
1989 <td valign="top">
1990 Perspective distort the images, using a list of 4 or more sets of
1991 control points (as defined below). More that 4 sets (16 numbers) of
1992 control points provide least squares fitting for more accurate
1993 distortions (for the purposes of image registration and panarama
1994 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
1995 linear distortion. <br/>
1996
1997 Perspective Distorted images ensures that straight lines remain
1998 straight, but the scale of the distorted image will vary. The horizon
1999 is anti-aliased, and the 'sky' color may be set using the
2000 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2001 </tr>
2002
2003 <tr valign="top">
2004 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2005 <td valign="top">
2006 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2007 pre-calculated coefficients. You can get these coefficients by looking
2008 at the <a href="#verbose" >-verbose</a> output of a
2009 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2010 If the last two perspective scaling coefficients are zero, the
2011 remaining 6 represents a transposed 'Affine Matrix'. </td>
2012
2013 </tr>
2014
2015 <tr valign="top">
2016 <td valign="top"><kbd>Arc</kbd></td>
2017 <td valign="top">
2018 Arc the image (variation of polar mapping) over the angle given around
2019 a circle. <br/>
2020 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2021 <tr valign="top"><td>Argument</td>
2022 <td>Meaning</td></tr>
2023 <tr valign="top"><td><em>arc_angle</em></td>
2024 <td>The angle over which to arc the image side-to-side</td></tr>
2025 <tr valign="top"><td><em>rotate_angle</em></td>
2026 <td>Angle to rotate resulting image from vertical center</td></tr>
2027 <tr valign="top"><td><em>top_radius</em></td>
2028 <td>Set top edge of source image at this radius</td></tr>
2029 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2030 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2031 </table>
2032
2033 The resulting image is always resized to best fit the resulting image,
2034 (as if using <a href="#distort" >+distort</a>) while attempting to
2035 preserve scale and aspect ratio of the original image as much as
2036 possible with the arguments given by the user. All four arguments will
2037 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2038
2039 This a variation of a polar distortion designed to try to preserve the
2040 aspect ratio of the image rather than direct Cartesian to Polar
2041 conversion. </td>
2042 </tr>
2043
2044 <tr valign="top">
2045 <td valign="top"><kbd>Polar</kbd></td>
2046 <td valign="top">
2047 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2048 the image. that is the height of the input image is mapped to the
2049 radius limits, while the width is wrapped around between the
2050 angle limits. <br/>
2051
2052 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2053
2054 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2055 center to the center of the image, and the angles going from -180 (top)
2056 to +180 (top). If <em>Rmax</em> is given the special value of
2057 '<code>0</code>', the the distance from the center to the nearest edge
2058 is used for the radius of the output image, which will ensure the whole
2059 image is visible (though scaled smaller). However a special value of
2060 '<code>-1</code>' will use the distance from the center to the furthest
2061 corner, This may 'clip' the corners from the input rectangular image,
2062 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2063 the same arguments. <br/>
2064
2065 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2066 output image center will default to <code>0,0</code> of the virtual
2067 canvas, and the image size adjusted to ensure the whole input image is
2068 made visible in the output image on the virtual canvas. </td>
2069
2070 </tr>
2071
2072 <tr valign="top">
2073 <td valign="top"><kbd>DePolar</kbd></td>
2074 <td valign="top">
2075 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2076 but generates the reverse Polar to Cartesian distortion. <br/>
2077
2078 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2079 the corners of the input image. However using the special
2080 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2081 distance) will ensure the whole distorted image is preserved in the
2082 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2083 reverse the distortion re-producing the original.
2084
2085 Note that as this distortion requires the area resampling of a circular
2086 arc, which can not be handled by the builtin EWA resampling function.
2087 As such the normal EWA filters are turned off. It is recomended some
2088 form of 'super-sampling' image processing technique be used to produce
2089 a high quality result. </td>
2090
2091 </tr>
2092
2093 <tr valign="top">
2094 <td valign="top"><kbd>Barrel</kbd></td>
2095 <td valign="top">
2096 Given the four coefficients (A,B,C,D) as defined by <a
2097 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2098 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2099 correct radial lens distortions. That is in photographs, make straight
2100 lines straight again. <br/>
2101
2102 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2103 <em>X</em> , <em>Y</em> ] ] <br/>
2104 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2105 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2106 [ <em>X</em> , <em>Y</em> ] <br/>
2107 So that it forms the function <br/>
2108 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2109 <em>C</em>*r + <em>D</em> )<br/>
2110
2111 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2112 (defaulting to the center of the image). <br/>
2113 The second form is typically used to distort images, rather than
2114 correct lens distortions. <br/>
2115 </td>
2116
2117 </tr>
2118
2119 <tr valign="top">
2120 <td valign="top"><kbd>BarrelInverse</kbd></td>
2121 <td valign="top">
2122 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2123 arguments, and argument handling. However it uses the inverse
2124 of the radial polynomial,
2125 so that it forms the function <br/>
2126 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2127 <em>C</em>*r + <em>D</em> )
2128 </td>
2129 </tr>
2130
2131 <tr valign="top">
2132 <td valign="top"><kbd>Shepards</kbd></td>
2133 <td valign="top">
2134 Distort the given list control points (any number) using an Inverse
2135 Squared Distance Interpolation Method (<a
2136 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2137 >Shepards Method</a>). The control points in effect do 'localized'
2138 distortions of the image around the given control point. For best
2139 results extra control points should be added to 'lock' the positions of
2140 the corners and other unchanging parts of the image. <br/>
2141
2142 The distortion has been likened to 'taffy pulling' using nails, pins or
2143 sticks. It basically uses the <a href="#sparse-color"
2144 >-sparse-color</a> method of the same name to generate separate X and Y
2145 displacement maps (see <a href="#displace" >-displace</a>) for source
2146 image color look-up. </td>
2147
2148 </tr>
2149
2150</table>
2151
2152<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2153
2154<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2155'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2156defining how these points in the given image should be distorted in the
2157destination image. Each set of four floating point values represent a source
2158image coordinate, followed immediately by the destination image coordinate.
2159This produces a list of values such as...</p>
2160<div style="text-align: center"><em>
2161 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2162 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2163 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2164 ... &nbsp;
2165 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2166</em></div>
2167<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2168destination image. </p>
2169
2170<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2171needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2172perspective distortion of the built-in "rose:" image. Note how spaces were
2173used to group the 4 sets of coordinate pairs, to make it easier to read and
2174understand.</p>
2175
2176<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2177 convert rose: -virtual-pixel black \ <br/>
2178 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2179 rose_3d_rotated.gif</span></p>
2180<p>If more that the required number of coordinate pairs are given for a
2181distortion, the distortion method is 'least squares' fitted to
2182produce the best result for all the coordinate pairs given. If less than the
2183ideal number of points are given, the distort will generally fall back to a
2184simpler form of distortion that can handles the smaller number of coordinates
2185(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2186
2187<p>By using more coodinates you can make use of image registration tool to
2188find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2189of the distortion. Of course a bad coordinate pair can also make the 'fit'
2190worse. Caution is always advised. </p>
2191
2192<p>Colors are acquired from the source image according to the <a
2193href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2194magnified. However if the viewed image is minified (image becomes smaller), a
2195special area resampling function (added ImageMagick v6.3.5-9), is used to
2196produce a higher quality image. For example you can use a
2197'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2198way to the horizon. </p>
2199
2200<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2201 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2202 checks_tiled.jpg</span></p>
2203<p>Note that a infinitely tiled perspective images involving the horizon can
2204be very slow to generate due to the use of the high quality 'area resampling'
2205function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2206using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2207(recommended if you plan to use super-sampling instead). </p>
2208
2209<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2210'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2211will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2212pixels. If you do not what these pixels to be visible, set the color to match
2213the rest of the ground. </p>
2214
2215<p>The output image size will by default be the same as the input image. This
2216means that if the part of the distorted image falls outside the viewed area of
2217the 'distorted space', those parts is clipped and lost. However if you
2218use the plus form of the operator (<a href="#distort" >+distort</a>) the
2219operator will attempt (if posible) to show the whole of the distorted image,
2220while retaining a correct 'virtual canvas' offset, for image layering. This
2221offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2222if it is unwanted. </p>
2223
2224<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2225option:distort:viewport {geometry_string}</kbd>" setting which will specify
2226the size and the offset of the generated 'viewport' image of the distorted
2227image space.</p>
2228
2229<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2230{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2231that factor without changing the viewed contents of the distorted image. This
2232can be used either for 'super-sampling' the image for a higher quality result,
2233or for panning and zooming around the image (with appropriate viewport
2234changes, or post-distort cropping and resizing). </p>
2235
2236<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2237href="#distort" >-distort</a> to attempt to output the internal coefficients,
2238and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2239and debugging purposes. This many not be available for all distorts. </p>
2240
2241<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2242produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2243and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2244above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2245</p>
2246
2247
2248<div style="margin: auto;">
2249 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2250</div>
2251
2252<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a Riemersma or Floyd-Steinberg error diffusion dither to images when general color reduction is applied via an option, or automagically when saving to specific formats. This enabled by default. </td><td style='text-align:right;'></td></tr></table>
2253
2254<p>Dithering places two or more colors in neighbouring pixels so that to the eye a closer approximation of the images original color is reproduced. This reduces the number of colors needed to reproduce the image but at the cost of a lower level pattern of colors. Error diffusion dithers can use any set of colors (generated or user defined) to an image. </p>
2255
2256<p>Dithering is turned on by default, to turn it off use the plus form of the
2257setting, <a href="#dither">+dither</a>. This will also also render PostScript
2258without text or graphic aliasing. Disabling dithering often (but not always)
2259leads to faster process, a smaller number of colors, but more cartoon like
2260image coloring. Generally resulting in 'color banding' effects in areas with
2261color gradients. </p>
2262
2263<p>The color reduction operators <a href="#colors">-colors</a>, <a
2264href="#monochrome">-monochrome</a>, <a href="#remap ">-remap</a>, and <a href="#posterize">-posterize</a>, apply dithering to images using the reduced color set they created. These operators are also used as part of automatic color reduction when saving images to formats with limited color support, such as <kbd>GIF:</kbd>, <kbd>XBM:</kbd>, and others, so dithering may also be used in these cases. </p>
2265
2266<p>Alternatively you can use <a href="#random-threshold">-random-threshold</a> to generate purely random dither. Or use <a href="#ordered-dither">-ordered-dither</a> to apply threshold mapped dither patterns, using uniform color maps, rather than specific color maps. </p>
2267
2268
2269<div style="margin: auto;">
2270 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2271</div>
2272
2273<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with one or more graphic primitives.</td><td style='text-align:right;'></td></tr></table>
2274
2275<p>Use this option to annotate or decorate an image with one or more graphic primitives. The primitives include shapes, text, transformations, and pixel operations.</p>
2276
2277<p>The shape primitives:</p>
2278
2279<pre class="text">
2280 point x,y
2281 line x0,y0 x1,y1
2282 rectangle x0,y0 x1,y1
2283 roundRectangle x0,y0 x1,y1 wc,hc
2284 arc x0,y0 x1,y1 a0,a1
2285 ellipse x0,y0 rx,ry a0,a1
2286 circle x0,y0 x1,y1
2287 polyline x0,y0 ... xn,yn
2288 polygon x0,y0 ... xn,yn
2289 bezier x0,y0 ... xn,yn
2290 path path specification
2291 image operator x0,y0 w,h filename
2292</pre>
2293
2294<p>The text primitive:</p>
2295
2296<pre class="text">
2297 text x0,y0 string
2298</pre>
2299<p>The text gravity primitive:</p>
2300
2301<pre class="text">
2302 gravity NorthWest, North, NorthEast, West, Center,
2303 East, SouthWest, South, or SouthEast
2304</pre>
2305
2306<p>The text gravity primitive only affects the placement of text and does not interact with the other primitives. It is equivalent to using the <a href="#gravity">-gravity</a> command-line option, except that it is limited in scope to the <a href="#draw">-draw</a> option in which it appears.</p>
2307
2308<p>The transformation primitives:</p>
2309
2310<pre class="text">
2311 rotate degrees
2312 translate dx,dy
2313 scale sx,sy
2314 skewX degrees
2315 skewY degrees
2316</pre>
2317
2318<p>The pixel operation primitives:</p>
2319
2320<pre class="text">
2321 color x0,y0 method
2322 matte x0,y0 method
2323</pre>
2324
2325<p>The shape primitives are drawn in the color specified by the preceding <a href="#fill">-fill</a> setting. For unfilled shapes, use <a href="#fill">-fill none</a>. You can optionally control the stroke (the "outline" of a shape) with the <a href="#stroke">-stroke</a> and <a href="#strokewidth">-strokewidth</a> settings.</p>
2326
2327<p>A <kbd>point</kbd> primitive is specified by a single <em>point</em> in the pixel plane, that is, by an ordered pair of integer coordinates, <em>x</em>,<em>y</em>. (As it involves only a single pixel, a <kbd>point</kbd> primitive is not affected by <a href="#stroke">-stroke</a> or <a href="#strokewidth">-strokewidth</a>.)</p>
2328
2329<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2330
2331<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2332
2333<p>A <kbd>roundRectangle</kbd> primitive takes the same corner points as a <kbd>rectangle</kbd> followed by the width and height of the rounded corners to be removed.</p>
2334
2335<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2336
2337<p>The <kbd>arc</kbd> primitive is used to inscribe an elliptical segment in to a given rectangle. An <kbd>arc</kbd> requires the two corners used for <kbd>rectangle</kbd> (see above) followed by the start and end angles of the arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end points produced are then joined with a line segment and the resulting segment of an ellipse is filled.</p>
2338
2339<p>Use <kbd>ellipse</kbd> to draw a partial (or whole) ellipse. Give the center point, the horizontal and vertical "radii" (the <em>semi-axes</em> of the ellipse) and start and end angles in degrees (e.g. 100,100 100,150 0,360).</p>
2340
2341<p>The <kbd>polyline</kbd> and <kbd>polygon</kbd> primitives require three or more points to define their perimeters. A <kbd>polyline</kbd> is simply a <kbd>polygon</kbd> in which the final point is not stroked to the start point. When unfilled, this is a <em>polygonal line</em>. If the <a href="#stroke">-stroke</a> setting is <kbd>none</kbd> (the default), then a <kbd>polyline</kbd> is identical to a <kbd>polygon</kbd>.
2342</p>
2343
2344<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2345
2346<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2347
2348<p class="crtsnip">
2349 -draw 'circle 100,100 150,150'
2350</p>
2351
2352<p>The <kbd>Bezier</kbd> primitive creates a spline curve and requires three or points to define its shape. The first and last points are the <em>knots</em> and these points are attained by the curve, while any intermediate coordinates are <em>control points</em>. If two control points are specified, the line between each end knot and its sequentially respective control point determines the tangent direction of the curve at that end. If one control point is specified, the lines from the end knots to the one control point determines the tangent directions of the curve at each end. If more than two control points are specified, then the additional control points act in combination to determine the intermediate shape of the curve. In order to
2353draw complex curves, it is highly recommended either to use the <kbd>path</kbd> primitive or to draw multiple four-point bezier segments with the start and end knots of each successive segment repeated. For example:</p>
2354
2355<p class="crtsnip">
2356 -draw 'bezier 20,50 45,100 45,0 70,50'
2357</p>
2358<p class="crtsnip">
2359 -draw 'bezier 70,50 95,100 95,0 120,50'
2360</p>
2361
2362
2363<p>A <kbd>path</kbd> represents an outline of an object, defined in terms of moveto (set a new current point), lineto (draw a straight line), curveto (draw a Bezier curve), arc (elliptical or circular arc) and closepath (close the current shape by drawing a line to the last moveto) elements. Compound paths (i.e., a path with subpaths, each consisting of a single moveto followed by one or more line or curve operations) are possible to allow effects such as <em>donut holes</em> in objects. (See <a href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
2364
2365<p>Use <kbd>image</kbd> to composite an image with another image. Follow the image keyword with the composite operator, image location, image size, and filename:</p>
2366
2367<p class="crtsnip">
2368 -draw 'image SrcOver 100,100 225,225 image.jpg'
2369</p>
2370
2371<p>You can use 0,0 for the image size, which means to use the actual dimensions found in the image header. Otherwise, it is scaled to the given dimensions. See <a href="#compose">-compose</a> for a description of the composite operators.</p>
2372
2373<p>Use <kbd>text</kbd> to annotate an image with text. Follow the text coordinates with a string. If the string has embedded spaces, enclose it in single or double quotes.</p>
2374
2375<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2376
2377<p class="crtsnip">
2378 -draw 'text 100,100 "Works like magick!"'
2379</p>
2380
2381<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2382
2383<p>The <kbd>rotate</kbd> primitive rotates subsequent shape primitives and text primitives about the origin of the main image. If the <a href="#region">-region</a> option precedes the <a href="#draw">-draw</a> option, the origin for transformations is the upper left corner of the region.</p>
2384
2385<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2386
2387<p>The <kbd>scale</kbd> primitive scales them.</p>
2388
2389<p>The <kbd>skewX</kbd> and <kbd>skewY</kbd> primitives skew them with respect to the origin of the main image or the region.</p>
2390
2391<p>The transformations modify the current affine matrix, which is initialized from the initial affine matrix defined by the <a href="#affine">-affine</a> option. Transformations are cumulative within the <a href="#draw">-draw</a> option. The initial affine matrix is not affected; that matrix is only changed by the appearance of another <a href="#affine">-affine</a> option. If another <a href="#draw">-draw</a> option appears, the current affine matrix is reinitialized from the initial affine
2392matrix.</p>
2393
2394<p>Use the <kbd>color</kbd> primitive to change the color of a pixel to the fill color (see <a href="#fill">-fill</a>). Follow the pixel coordinate with a method:</p>
2395
2396<pre class="text">
2397 point
2398 replace
2399 floodfill
2400 filltoborder
2401 reset
2402</pre>
2403
2404<p>Consider the target pixel as that specified by your coordinate. The <kbd>point</kbd> method recolors the target pixel. The <kbd>replace</kbd> method recolors any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> recolors any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> recolors any neighbor pixel that is not the border color. Finally, <kbd>reset</kbd> recolors all pixels.</p>
2405
2406<p>Use <kbd>matte</kbd> to the change the pixel matte value to transparent. Follow the pixel coordinate with a method (see the <kbd>color</kbd> primitive for a description of methods). The <kbd>point</kbd> method changes the matte value of the target pixel. The <kbd>replace</kbd> method changes the matte value of any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> changes the matte value of any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> changes the matte value of any neighbor pixel that is not the border color (<a href="#bordercolor">-bordercolor</a>). Finally <kbd>reset</kbd> changes the matte value of all pixels.</p>
2407
2408<p>You can set the primitive color, font, and font bounding box color with <a href="#fill">-fill</a>, <a href="#font">-font</a>, and <a href="#box">-box</a> respectively. Options are processed in command line order so be sure to use these options <em>before</em> the <a href="#draw">-draw</a> option.</p>
2409
2410<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2411
2412<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2413
2414
2415<div style="margin: auto;">
2416 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2417</div>
2418
2419<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect edges within an image.</td><td style='text-align:right;'></td></tr></table>
2420
2421<div style="margin: auto;">
2422 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2423</div>
2424
2425<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>emboss an image.</td><td style='text-align:right;'></td></tr></table>
2426
2427<div style="margin: auto;">
2428 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2429</div>
2430
2431<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Encipher pixels for later deciphering by <a href="#decipher">-decipher</a>.</td><td style='text-align:right;'></td></tr></table>
2432
2433<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2434
2435<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2436
2437<div style="margin: auto;">
2438 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2439</div>
2440
2441<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the text encoding.</td><td style='text-align:right;'></td></tr></table>
2442
2443<p>Choose from <kbd>AdobeCustom</kbd>, <kbd>AdobeExpert</kbd>, <kbd>AdobeStandard</kbd>, <kbd>AppleRoman</kbd>, <kbd>BIG5</kbd>, <kbd>GB2312</kbd>, <kbd>Latin 2</kbd>, <kbd>None</kbd>, <kbd>SJIScode</kbd>, <kbd>Symbol</kbd>, <kbd>Unicode</kbd>, <kbd>Wansung</kbd>.</p>
2444
2445<div style="margin: auto;">
2446 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2447</div>
2448
2449<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify endianness (<kbd>MSB</kbd> or <kbd>LSB</kbd>) of the image.</td><td style='text-align:right;'></td></tr></table>
2450
2451<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2452
2453<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2454
2455
2456<div style="margin: auto;">
2457 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2458</div>
2459
2460<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a digital filter to enhance a noisy image.</td><td style='text-align:right;'></td></tr></table>
2461
2462
2463<div style="margin: auto;">
2464 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2465</div>
2466
2467<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform histogram equalization on the image channel-by-channel.</td><td style='text-align:right;'></td></tr></table>
2468
2469<p>To perform histogram equalization on all channels in concert, transform the image into some other color space, such as HSL, OHTA, YIQ or YUV, then equalize the appropriate intensity-like channel, then convert back to RGB.</p>
2470
2471<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2472
2473<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal components transformation that puts most of the information in the first channel. Here we have ... <kbd>-colorspace OHTA -channel red -equalize -colorspace RGB</kbd> ...</p>
2474
2475<div style="margin: auto;">
2476 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2477</div>
2478
2479<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</td><td style='text-align:right;'></td></tr></table>
2480
2481<p>(See the <a href="#function" >-function</a> operator for some multi-parameter functions. See the <a href="#fx" >-fx</a> operator if more elaborate calculations are needed.)</p>
2482
2483<p>The behaviors of each <em class="arg">operator</em> are summarized in the following list. For brevity, the numerical value of a "pixel" referred to below is the value of the corresponding channel of that pixel, while a "normalized pixel" is that number divided by the maximum (installation-dependent) value <em class="QR">QuantumRange</em>. (If normalized pixels are used, they are restored, following the other calculations, to the full range by multiplying by <em class="QR">QuantumRange</em>.)</p>
2484
2485<table class="doc">
2486 <col width="25%" />
2487 <col width="75%" />
2488 <thead>
2489 <tr>
2490 <th><em class="arg">operator</em></th>
2491 <th>Summary (see further below for details)</th>
2492 </tr>
2493 </thead>
2494 <tbody>
2495
2496 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2497 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2498 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2499 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2500 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2501 <tr><td>LeftShift </td> <td>Shift the pixel values left by <em class="arg">value</em> bits (i.e., multiply pixels by 2<sup><em class="arg">value</em></sup>).</td></tr>
2502 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2503 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2504 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2505 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2506 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2507 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2508 <tr><td>RightShift </td> <td>Shift the pixel values right by <em class="arg">value</em> bits (i.e., divide pixels by 2<sup><em class="arg">value</em></sup>).</td></tr>
2509 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2510 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2511 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2512 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2513
2514 <tr><td>&nbsp;</td></tr>
2515
2516 <tr><td>Gaussian-noise</td></tr>
2517 <tr><td>Impulse-noise</td></tr>
2518 <tr><td>Laplacian-noise</td></tr>
2519 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2520 <tr><td>PoissonNoise</td></tr>
2521 <tr><td>Uniform-noise</td></tr>
2522
2523 <tr><td>&nbsp;</td></tr>
2524
2525 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2526 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2527 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2528 </tbody>
2529 </table>
2530
2531<p>The specified functions are applied only to each previously set <a
2532href="#channel" >-channel</a> in the image. If necessary, the results of the
2533calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2534class="QR">QuantumRange</em>]. The transparency channel of the image is
2535represented as a 'alpha' values (0 = fully transparent), so, for example, a
2536<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2537semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2538as a percentage of the <em class="QR">QuantumRange</em>.</p>
2539
2540<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2541<a href="#list">-list evaluate</a>.</p>
2542
2543<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2544<kbd>Multiply</kbd> methods can also be achieved using either the <a
2545href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2546appropriate argument, to linearly modify the overall range of color values.
2547Please note, however, that <a href="#level" >-level</a> treats transparency as
2548'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2549'alpha' values.</p>
2550
2551<p><kbd>AddModulus</kbd> has been added as of ImageMagick 6.4.8-4 and provides addition modulo the <em class="QR">QuantumRange</em>. It is therefore equivalent to <kbd>Add</kbd> unless the resulting pixel value is outside the interval [0,&nbsp;<em class="QR">QuantumRange</em>]. </p>
2552
2553<p><kbd>Log</kbd> has been added as of ImageMagick 6.4.2-1 and works on normalized pixel values. This a <em>scaled</em> log function. The <em class="arg">value</em> used with <kbd>Log</kbd> provides a <em>scaling factor</em> that adjusts the curvature in the graph of the log function. The formula applied to a normalized value <b><em>u</em></b> is below. </p>
2554
2555 <div style="text-align:center;">
2556 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2557 </div>
2558
2559<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2560normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2561href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2562to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2563with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2564with <kbd>Pow</kbd>.</p>
2565
2566<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2567converts the image values into a value according to a (co)sine wave function.
2568The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2569is biased 50% and normalized by 50% so as to fit in the respective color value
2570range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2571function (its frequency), and thus determines the number of 'waves' that will
2572be generated over the input color range. For example, if the <em
2573class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2574class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2575then the effective period is the <em>half</em> the <em
2576class="QR">QuantumRange</em>.
2577
2578 <div style="text-align:center;">
2579 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2580 </div>
2581
2582See also the <a href="#function" >-function</a> operator, which is a
2583multi-value version of evaluate. </P>
2584
2585
2586<div style="margin: auto;">
2587 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2588</div>
2589
2590<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image size and offset.</td><td style='text-align:right;'></td></tr></table>
2591
2592<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting.</p>
2593
2594<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
2595
2596<div style="margin: auto;">
2597 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2598</div>
2599
2600<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Extract the specified area from image.</td><td style='text-align:right;'></td></tr></table>
2601
2602<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2603
2604<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' image.rgb image.png</span></p><p>If you omit the offsets, as in</p>
2605
2606<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p>
2607<p>then the image will be <em>resized</em> to the specified dimensions instead,
2608equivalent to:</p>
2609
2610<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p>
2611<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
2612
2613<div style="margin: auto;">
2614 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2615</div>
2616
2617<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font family for text.</td><td style='text-align:right;'></td></tr></table>
2618
2619<p>This setting suggests a font family that ImageMagick should try to use for rendering text. If the family can be found it is used; if not, a default font (e.g., "Arial") or a family known to be similar is substituted (e.g., "Courier" might be used if "System" is requested but not found).
2620</p>
2621
2622<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>.
2623</p>
2624
2625<div style="margin: auto;">
2626 <h4><a name="fft" id="fft"></a>-fft</h4>
2627</div>
2628
2629<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the forward discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table>
2630
2631<p>This option is new as of ImageMagick 6.5.4-3 and transforms an image from the normal (spatial) domain to the frequency domain. In the frequency domain, an image is represented as a superposition of complex sinusoidal waves of varying amplitudes. The image x and y coordinates are the possible frequencies along the x and y directions, respectively, and the pixel intensity values are complex numbers that correspond to the sinusoidal wave amplitudes. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p>
2632
2633<p>A single image name is provided as output for this option. However, the output result will have two components. It will be either a two-frame image or two separate images, depending upon whether the image format specified supports multi-frame images. The reason that we get a dual output result is because the frequency domain represents an image using complex numbers, which cannot be visualized directly. Therefore, the complex values are automagically separated into a two-component image representation. The first component is the magnitude of the complex number and the second is the phase of the complex number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers" target="_blank">Complex Numbers</a>.<p>
2634
2635<p>The magnitude and phase component images must be specified using image formats that do not limit the color or compress the image. Thus, MIFF, TIF, PFM, EXR and PNG are the recommended image formats to use. All of these formats, except PNG support multi-frame images. So for example,</p>
2636
2637<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2638<p>generates a magnitude image as <kbd>fft_image.miff[0]</kbd> and a phase image as <kbd>fft_image.miff[1]</kbd>. Similarly,</p>
2639
2640<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2641<p>generates a magnitude image as <kbd>fft_image-0.png</kbd> and a phase image as <kbd>fft_image-1.png</kbd>. If you prefer this representation, then you can force any of the other formats to produce two output images by including <a href="#adjoin">+adjoin</a> following -fft in the command line.</p>
2642
2643<p>The input image can be any size, but if not square and even-dimensioned, it will be padded automagically to the larger of the width or height of the input image and to an even number of pixels. The padding will occur at the bottom and/or right sides of the input image. The resulting output magnitude and phase images will be square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p>
2644
2645<p>Both output components will have dynamic ranges that fit within [0,&nbsp;<em class="QR">QuantumRange</em>], so that HDRI need not be enabled. Phase values nominally range from 0 to 2*&pi;, but for non-HDRI compilations of ImageMagick, the phase image is scaled to span the full dynamic range. The magnitude image is not scaled and thus generally will contain very small values. As such, the image normally will appear totally black. In order to view any detail, the magnitude image typically is enhanced with a log function into what is usually called the spectrum. A log function is used to enhance the darker values more in comparison to the lighter values. This can be done, for example, as follows:</p>
2646
2647<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2648 -evaluate log 1000 fft_image_spectrum.png</span></p>
2649<p>where the <a href="#contrast-stretch">-contrast-stretch</a> 0 is used to scale the image to full dynamic range, first. The argument to the <a href="#evaluate">-evaluate</a> log typically is specified between 100 and 10,000, depending upon the amount of detail that one wants to bring out in the spectrum. Larger values produce more visible detail. Too much detail, however, may hide the important features.</p>
2650
2651<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2652
2653<p>Use <a href="#fft">+fft</a> to produce two output images that are the real and imaginary components of the complex valued Fourier transform.</p>
2654
2655<p>However, as the real and imaginary components can contain negative values, this requires that IM be configured with HDRI enabled. In this case, you must use either MIFF, TIF or PFM formats for the real and imaginary component results, since they are formats that preserve both negative and fractional values without clipping them or truncating the fractional part.</p>
2656
2657<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> also will be square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a>
2658
2659<p>See the discussion on HDRI implementations of ImageMagick on the page
2660<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry.
2661</p>
2662
2663
2664<div style="margin: auto;">
2665 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2666</div>
2667
2668<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when filling a graphic primitive.</td><td style='text-align:right;'></td></tr></table>
2669
2670<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA, HSL, HSLA, CMYK, or CMYKA specification. See <a href="../www/color.html">Color Names</a> for a description of how to properly specify the color argument.</p>
2671
2672<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2673
2674<p>For example,</p>
2675
2676<p class="crtsnip">
2677 -fill blue
2678</p>
2679<p class="crtsnip">
2680 -fill "#ddddff"
2681</p>
2682<p class="crtsnip">
2683 -fill "rgb(255,255,255)"
2684</p>
2685
2686<p>See <a href="#draw">-draw</a> for further details.</p>
2687
2688<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2689
2690<div style="margin: auto;">
2691 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2692</div>
2693
2694<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use this <em class="arg">type</em> of filter when resizing an image.</td><td style='text-align:right;'></td></tr></table>
2695
2696<p>Use this option to affect the resizing operation of an image (see <a
2697href="#resize">-resize</a>). For example you can use a simple resize filter
2698such as:</p>
2699
2700<pre class="text">
2701 Point Hermite Cubic
2702 Box Gaussian Catrom
2703 Triangle Quadratic Mitchell
2704</pre>
2705
2706<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2707by default <kbd>blackman</kbd>-windowed. However these filters define a
2708windowing filter for the Sinc or Bessel filter function, as appropriate for
2709the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2710>-resize</a>). Windowed filters include: </p>
2711
2712<pre class="text">
2713 Lanczos Hamming Parzen
2714 Blackman Kaiser Welsh
2715 Hanning Bartlett Bohman
2716</pre>
2717
2718<p>Also one special self-windowing filter is also provided
2719<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2720on the current 'support' or 'lobes' expert settings (see below).</p>
2721
2722<p>If you do not select a filter with this option, the filter defaults to <kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or if the image is enlarged. Otherwise the filter default to <kbd>Lanczos</kbd>.</p>
2723
2724<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2725
2726<p>You can modify how the filter behaves as it scales your image through the
2727use of these expert settings:</p>
2728
2729<dl class="doc">
2730<dt>-set filter:blur <em>factor</em></dt>
2731<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2732 blurry or &lt; 1.0 for sharp.</dd>
2733
2734<dt>-set filter:support <em>radius</em></dt>
2735<dd>Set the filter support radius.</dd>
2736
2737<dt>-set filter:lobes <em>count</em></dt>
2738<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2739 alternative way of specifying the 'support' range of the filter.</dd>
2740
2741<dt>-set filter:b <em>b-spline_factor</em></dt>
2742<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2743<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2744 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2745 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2746 are defined, the other is set so as to generate a 'Keys' type cubic
2747 filter.
2748
2749<dt>-set filter:filter <em>filter</em></dt>
2750<dd>Use this function directly as the scaling filter. This will allow
2751 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2752 rather than as its normal usage as a windowing function for 'Sinc' or
2753 'Bessel'. If defined, no windowing function is used, unless the following
2754 expert setting is also defined.</dd>
2755
2756<dt>-set filter:window <em>filter</em></dt>
2757<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2758 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2759 support range) with the given filter. This allows you to use a filter that
2760 is not normally used as a windowing function, such as <kbd>box</kbd>,
2761 (which effectivally turns off the windowing function). </dd>
2762
2763</dl>
2764
2765<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2766
2767<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2768 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2769 -resize 150% image.jpg</span></p>
2770<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2771
2772<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2773 -resize 150% image.jpg</span></p>
2774<p>Note that the use of expert options (except for 'blur' with simple resize
2775filters), are provided for image processing experts who have studied and
2776understood how resize filters work. Without this knowledge, and an
2777understanding of the defination of the actual filters involved, using expert
2778settings are more likely to be detremental to your image resizing.</p>
2779
2780
2781<div style="margin: auto;">
2782 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2783</div>
2784
2785<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>This is a simple alias for the <a href="#layers" >-layers</a> method "flatten".</td><td style='text-align:right;'></td></tr></table>
2786
2787
2788<div style="margin: auto;">
2789 <h4><a name="flip" id="flip"></a>-flip</h4>
2790</div>
2791
2792<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table>
2793
2794<p>reflect the scanlines in the vertical direction.</p>
2795
2796<div style="margin: auto;">
2797 <h4><a name="floodfill" id="floodfill"></a>-floodfill {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em> <em class="arg">color</em></h4>
2798</div>
2799
2800<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>floodfill the image with color at the specified offset. Using <a href="#fuzz" >-fuzz</a> to floodfill pixels which only change by a small amount.</td><td style='text-align:right;'></td></tr></table>
2801
2802<div style="margin: auto;">
2803 <h4><a name="flop" id="flop"></a>-flop</h4>
2804</div>
2805
2806<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table>
2807
2808<p>reflect the scanlines in the horizontal direction.</p>
2809
2810
2811<div style="margin: auto;">
2812 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2813</div>
2814
2815<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the font to use when annotating images with text, or creating labels.</td><td style='text-align:right;'></td></tr></table>
2816
2817<p>To print a complete list of fonts, use the <a href="#list">-list font</a> option (for versions prior to 6.3.6, use 'type' instead of 'font').</p>
2818
2819<p>In addition to the fonts specified by the above pre-defined list, you can
2820also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2821is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2822<kbd>x:fixed</kbd> is X11 font.</p>
2823
2824<p>For other settings that affect fonts, see the options <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p>
2825
2826
2827<div style="margin: auto;">
2828 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2829</div>
2830
2831<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the foreground color.</td><td style='text-align:right;'></td></tr></table>
2832
2833<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2834
2835<p>The default foreground color is black.</p>
2836
2837<div style="margin: auto;">
2838 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2839</div>
2840
2841<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image format type.</td><td style='text-align:right;'></td></tr></table>
2842
2843<p>When used with the <kbd>mogrify</kbd> utility, this option converts any image to the image <a href="/www/formats.html">format</a> you specify. For a list of image format types supported by ImageMagick, use <a href="#list">-list format</a>.</p>
2844
2845<p>By default the file is written to its original name. However, if the filename extension matches a supported format, the extension is replaced with the image format type specified with <a href="#format">-format</a>. For example, if you specify <em class="arg">tiff</em> as the format type and the input image filename is <em class="arg">image.gif</em>, the output image filename becomes <em class="arg">image.tiff</em>.</p>
2846
2847<div style="margin: auto;">
2848 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2849</div>
2850
2851<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>output formatted image characteristics.</td><td style='text-align:right;'>[<a href="../www/identify.html">identify</a>]</td></tr></table>
2852
2853<p>See <a href="../www/escape.html">Format and Print Image Properties</a> for an explanation on how to specify the argument to this option.</p>
2854
2855<div style="margin: auto;">
2856 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2857</div>
2858
2859<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border or beveled frame.</td><td style='text-align:right;'></td></tr></table>
2860
2861<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
2862
2863<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument indicates the amount of extra width and height that is added to the dimensions of the image. If no offsets are given in the <em class="arg">geometry</em> argument, then the border added is a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that the width and height of the border is partitioned to form an outer bevel of thickness <em>x</em>&nbsp;pixels and an inner bevel of thickness <em>y</em>&nbsp;pixels. (Negative offsets make no sense here.) The <a href="#frame">-frame</a> option is not affected by the <a href="#gravity">-gravity</a> option.</p>
2864
2865
2866<div style="margin: auto;">
2867 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
2868</div>
2869
2870<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>include the X window frame in the imported image.</td><td style='text-align:right;'>[<a href="../www/import.html">import</a>]</td></tr></table>
2871
2872<div style="margin: auto;">
2873 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
2874</div>
2875
2876<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a function to channel values.</td><td style='text-align:right;'></td></tr></table>
2877
2878<p>This operator performs calculations based on the given arguments to modify each of the color values for each previously set <a href="#channel">-channel</a> in the image. See <a href="#evaluate">-evaluate</a> for details concerning how the results of the calculations are handled.</p>
2879
2880<p>This is can be considered a multi-argument version of the <a href="#evaluate">-evaluate</a> operator. (Added in ImageMagick&nbsp;6.4.8&minus;8.)</p>
2881
2882<p>Here, <em class="arg">parameters</em> is a comma-separated list of numerical values. The number of values varies depending on which <em class="arg">function</em> is selected. Choose the <em class="arg">function</em> from:</p>
2883
2884<pre class="text">
2885 Polynomial
2886 Sinusoid
2887 Arcsin
2888 Arctan
2889</pre>
2890
2891<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
2892
2893<dl class="doc">
2894<dt><kbd>Polynomial</kbd></dt>
2895<dd>
2896<p>The <kbd>Polynomial</kbd> function takes an arbitrary number of parameters, these being the coefficients of a polynomial, in decreasing order of degree. That is, entering</p>
2897
2898<div style="text-align: center">
2899 -function Polynomial <em>a</em><sub><em>n</em></sub>,<em>a</em><sub><em>n</em>-1</sub>,...<em>a</em><sub>1</sub>,<em>a</em><sub>0</sub>
2900</div>
2901
2902<p>will invoke a polynomial function given by</p>
2903
2904<div style="text-align: center">
2905 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
2906 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
2907 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
2908</div>
2909
2910<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
2911
2912<p>The <kbd>Polynomial</kbd> function can be used in place of <kbd>Set</kbd> (the <em>constant</em> polynomial) and <kbd>Add</kbd>, <kbd>Divide</kbd>, <kbd>Multiply</kbd>, and <kbd>Subtract</kbd> (some <em>linear</em> polynomials) of the <a href="#evaluate">-evaluate</a> operator. The <a href="#level">-level</a> operator also affects channels linearly. Some correspondences follow.</p>
2913
2914<table class="doc">
2915 <col width="35%" />
2916 <col width="35%" />
2917 <col width="30%" />
2918 <tr>
2919 <td>-evaluate Set <em class="arg">value</em> </td>
2920 <td>-function Polynomial <em class="arg">value</em></td>
2921 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
2922 </tr>
2923 <tr>
2924 <td>-evaluate Add <em class="arg">value</em> </td>
2925 <td>-function Polynomial 1,<em class="arg">value</em></td>
2926 </tr>
2927 <tr>
2928 <td>-evaluate Subtract <em class="arg">value</em> </td>
2929 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
2930 </tr>
2931 <tr>
2932 <td>-evaluate Multiply <em class="arg">value</em> </td>
2933 <td>-function Polynomial <em class="arg">value</em>,0</td>
2934 </tr>
2935 <tr>
2936 <td>+level black% x white%</td>
2937 <td>-function Polynomial A,B</td>
2938 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
2939 </tr>
2940</table>
2941
2942<p>The <kbd>Polynomial</kbd> function gives great versatility, since polynomials can be used to fit any continuous curve to any degree of accuracy desired.</p>
2943</dd>
2944
2945<dt><kbd>Sinusoid</kbd></dt>
2946<dd>
2947<p>The <kbd>Sinusoid</kbd> function can be used to vary the channel values sinusoidally by setting frequency, phase shift, amplitude, and a bias. These values are given as one to four parameters, as follows,</p>
2948
2949<div style="text-align: center">
2950 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
2951</div>
2952
2953<p>where <em>phase</em> is in degrees. (The domain [0,1] of the function corresponds to 0 through <em class="arg">freq</em>&times;360&nbsp;degrees.) The result is that if a pixel's normalized channel value is originally <b><em>u</em></b>, its resulting normalized value is given by </p>
2954
2955<div style="text-align: center">
2956<em class="arg">amp</em> * sin(2*&pi;* (<em class="arg">freq</em> * <b><em>u</em></b> + <em class="arg">phase</em> / 360)) + <em class="arg">bias</em>
2957</div>
2958
2959<p> For example, the following generates a curve that starts and ends at 0.9 (when <b><em>u</em></b>=0 and 1, resp.), oscillating three times between .7&minus;.2=.5 and .7+.2=.9. </p>
2960
2961<p class="crtsnip">
2962 -function Sinusoid 3,-90,.2,.7
2963</p>
2964
2965<p>The default values of <em class="arg">amp</em> and <em class="arg">bias</em> are both .5. The default for <em class="arg">phase</em> is 0.</p>
2966
2967<p>The <kbd>Sinusoid</kbd> function generalizes <kbd>Sin</kbd> and <kbd>Cos</kbd> of the <a href="#evaluate">-evaluate</a> operator by allowing varying amplitude, phase and bias. The correspondence is as follows.</p>
2968
2969<table class="doc">
2970 <tr>
2971 <td>-evaluate Sin <em class="arg">freq</em> </td>
2972 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
2973 </tr>
2974 <tr>
2975 <td>-evaluate Cos <em class="arg">freq</em> </td>
2976 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
2977 </tr>
2978</table>
2979</dd>
2980
2981<dt><kbd>ArcSin</kbd></dt>
2982<dd>
2983<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
2984and can be used to generate cylindrical distortion and displacement maps.
2985The curve can be adjusted relative to both the input values and output range
2986of values.
2987
2988<div style="text-align: center">
2989 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
2990</div>
2991
2992<p>with all values given in terms of noramlize color values (0.0 for black,
29931.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
2994for bout input (<em class="arg">width</em>), and output (<em
2995class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
2996
2997<div style="text-align: center">
2998<em class="arg">range</em>/&pi; * asin( 2/<em class="arg">width</em> * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
2999</div>
3000
3001</dd>
3002
3003<dt><kbd>ArcTan</kbd></dt>
3004<dd>
3005<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3006limit values at infinities, though a center using the given slope value.
3007All these values can be adjusted via the arguments.
3008
3009<div style="text-align: center">
3010 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3011</div>
3012
3013<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3014</p>
3015
3016<div style="text-align: center">
3017<em class="arg">range</em>/&pi; * atan( <em class="arg">slope</em>*&pi; * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
3018</div>
3019
3020</dd>
3021
3022</dl>
3023
3024
3025<div style="margin: auto;">
3026 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3027</div>
3028
3029<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colors within this <em class="arg">distance</em> are considered equal.</td><td style='text-align:right;'></td></tr></table>
3030
3031<p>A number of algorithms search for a target color. By default the color must be exact. Use this option to match colors that are close to the target color in RGB space. For example, if you want to automagically trim the edges of an image with <a href="#trim">-trim</a> but the image was scanned and the target background color may differ by a small amount. This option can account for these differences.</p>
3032
3033<p>The <em class="arg">distance</em> can be in absolute intensity units or, by appending <kbd>%</kbd> as a percentage of the maximum possible intensity (255, 65535, or 4294967295).</p>
3034
3035
3036<div style="margin: auto;">
3037 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3038</div>
3039
3040<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a mathematical expression to an image or image channels.</td><td style='text-align:right;'></td></tr></table>
3041
3042<p>If the first character of <em class="arg">expression</em> is <kbd>@</kbd>, the expression is read from a file titled by the remaining characters in the string.</p>
3043
3044<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3045
3046
3047<div style="margin: auto;">
3048 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3049</div>
3050
3051<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>level of gamma correction.</td><td style='text-align:right;'></td></tr></table>
3052
3053<p>The same color image displayed on two different workstations may look different due to differences in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values extend from <kbd>0.8</kbd> to <kbd>2.3</kbd>. Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it. Large adjustments to image gamma may result in the loss of some image information if the pixel quantum size is only eight bits (quantum range 0 to 255).</p>
3054
3055<p>Gamma adjusts the image's channel values pixel-by-pixel according to a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the normalized or 0 to 1 color value. For example, using a value of gamma=2 is the same as taking the square root of the image.</p>
3056
3057<p>You can apply separate gamma values to the red, green, and blue channels of the image with a gamma value list delimited with commas (e.g., <kbd>1.7,2.3,1.2</kbd>).</p>
3058
3059<p>Use <a href="#gamma">+gamma <em class="arg">value</em></a> to set the image gamma level without actually adjusting the image pixels. This option is useful if the image is of a known gamma but not set as an image attribute (e.g. PNG images).</p>
3060
3061<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3062
3063<div style="margin: auto;">
3064 <h4><a name="gaussian-blur" id="gaussian-blur"></a>-gaussian-blur <em class="arg">radius</em><br />-gaussian-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4>
3065</div>
3066
3067<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur the image with a Gaussian operator.</td><td style='text-align:right;'></td></tr></table>
3068
3069<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3070
3071<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3072</div>
3073
3074<p>where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. Specify a radius of 0 and ImageMagick selects a suitable radius for you.</p>
3075
3076<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3077full 2-dimentional convolution is used to generate the weighted average of the
3078neighbouring pixels. </p>
3079
3080<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3081pixels which are outside the image proper are blurred into the final result.
3082</p>
3083
3084
3085<div style="margin: auto;">
3086 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3087</div>
3088
3089<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred size and location of the image.</td><td style='text-align:right;'></td></tr></table>
3090
3091<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3092
3093<div style="margin: auto;">
3094 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3095</div>
3096
3097<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Sets the current gravity suggestion for various other settings and options.</td><td style='text-align:right;'></td></tr></table>
3098
3099<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3100<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3101<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3102list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3103installation.</p>
3104
3105<p>The direction you choose specifies where to position text or subimages. For example, a gravity of <kbd>Center</kbd> forces the text to be centered within the image. By default, the image gravity is <kbd>NorthWest</kbd>. See <a href="#draw">-draw</a> for more details about graphic primitives. Only the text primitive of <a href="#draw">-draw</a> affected by the <a href="#gravity">-gravity</a> option.</p>
3106
3107<p>The <a href="#gravity">-gravity</a> option is also used in concert with the <a href="#geometry">-geometry</a> setting and other settings or options that take <em class="arg">geometry</em> as an argument, such as the <a href="#crop">-crop</a> option. </p>
3108
3109<p>If a <a href="#gravity">-gravity</a> setting occurs before another option or setting having a <em class="arg">geometry</em> argument that specifies an offset, the offset is usually applied to the point within the image suggested by the <a href="#gravity">-gravity</a> argument. Thus, in the following command, for example, suppose the file <kbd>image.png</kbd> has dimensions 200x100. The offset specified by the argument to <a href="#region">-region</a> is (&minus;40,+20). The argument to <a href="#gravity">-gravity</a> is <kbd>Center</kbd>, which suggests the midpoint of the image, at the point (100,50). The offset (&minus;40,20) is applied to that point, giving (100&minus;40,50+20)=(60,70), so the specified 10x10&nbsp;region is located at that point. (In addition, the <a href="#gravity">-gravity</a> affects the region itself, which is <em>centered</em> at the pixel coordinate&nbsp;(60,70). (See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p>
3110
3111<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p>
3112<p>When used as an option to <a href="../www/composite.html">composite</a>, <a href="#gravity">-gravity</a> gives the direction that the image gravitates within the composite.</p>
3113
3114<p>When used as an option to <a href="../www/montage.html">montage</a>, <a href="#gravity">-gravity</a> gives the direction that an image gravitates within a tile. The default gravity is <kbd>Center</kbd> for this purpose.</p>
3115
3116
3117<div style="margin: auto;">
3118 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3119</div>
3120
3121<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>green chromaticity primary point.</td><td style='text-align:right;'></td></tr></table>
3122
3123
3124<div style="margin: auto;">
3125 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3126</div>
3127
3128<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a Hald color lookup table to the image.</td><td style='text-align:right;'></td></tr></table>
3129
3130<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3131dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3132can apply any color transformation to the Hald image and then use this option
3133to apply the transform to the image. </p>
3134
3135<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3136<p>This option provides a convenient method for you to use Gimp or Photoshop
3137to make color corrections to the Hald CLUT image and subsequently apply them
3138to multiple images using an ImageMagick script. </p>
3139
3140<p>Note that the representation is only of the normal RGB color space and that
3141the whole color value triplet is used for the interpolated lookup of the
3142represented Hald color cube image. Because of this the operation is not <a
3143href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3144images transparency or alpha/matte channel.</p>
3145
3146<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3147of the individual color channels, usally involving a simplier gray-scale
3148image. E.g: gray-scale to color replacement, or modification by a histogram
3149mapping. </p>
3150
3151
3152<div style="margin: auto;">
3153 <h4><a name="help" id="help"></a>-help</h4>
3154</div>
3155
3156<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print usage instructions.</td><td style='text-align:right;'></td></tr></table>
3157
3158<div style="margin: auto;">
3159 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3160</div>
3161
3162<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table>
3163
3164<div style="margin: auto;">
3165 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3166</div>
3167
3168<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the icon geometry.</td><td style='text-align:right;'></td></tr></table>
3169
3170<p>Offsets, if present in the geometry specification, are handled in the same manner as the <a href="#geometry">-geometry</a> option, using X11 style to handle negative offsets.</p>
3171
3172<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3173
3174<div style="margin: auto;">
3175 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3176</div>
3177
3178<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>iconic animation.</td><td style='text-align:right;'></td></tr></table>
3179
3180<div style="margin: auto;">
3181 <h4><a name="identify" id="identify"></a>-identify</h4>
3182</div>
3183
3184<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>identify the format and characteristics of the image.</td><td style='text-align:right;'></td></tr></table>
3185
3186<p>This information is printed: image scene number; image name; image size; the image class (<em class="arg">DirectClass</em> or <em class="arg">PseudoClass</em>); the total number of unique colors; and the number of seconds to read and transform the image. Refer to <a href="../www/miff.html">MIFF</a> for a description of the image class.</p>
3187
3188<p>If <a href="#colors">-colors</a> is also specified, the total unique colors in the image and color reduction error values are printed. Refer to <a href="/www/quantize.html">color reduction algorithm</a> for a description of these values.</p>
3189
3190<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3191amounts of image properties are displayed including image statistics, profiles,
3192image histogram, and others.</p>
3193
3194<div style="margin: auto;">
3195 <h4><a name="ift" id="ift"></a>-ift</h4>
3196</div>
3197
3198<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the inverse discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table>
3199
3200<p>This option is new as of ImageMagick 6.5.4-3 and transforms a pair of magnitude and phase images from the frequency domain to a single image in the normal or spatial domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p>
3201
3202<p>For example, depending upon the image format used to store the result of the <a href="#fft">-fft</a>, one would use either</p>
3203
3204<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3205<p>or</p>
3206
3207<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png</span></p>
3208
3209<p>The resulting image may need to be cropped due to padding introduced when the original image, prior to the <a href="#fft">-fft</a> or <a href="#fft">+fft</a>, was not square or even dimensioned. Any padding will be at the right and/or bottom sides of the image.
3210
3211<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3212
3213<p>Use <a href="#ift">+ift</a> (with HDRI enabled) to transform a pair of real and imaginary images from the frequency domain to a single image in the normal (spatial) domain.
3214
3215<div style="margin: auto;">
3216 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3217</div>
3218
3219<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make image immutable.</td><td style='text-align:right;'></td></tr></table>
3220
3221<div style="margin: auto;">
3222 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3223</div>
3224
3225<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implode image pixels about the center.</td><td style='text-align:right;'></td></tr></table>
3226
3227<div style="margin: auto;">
3228 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3229</div>
3230
3231<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>insert the last image into the image sequence.</td><td style='text-align:right;'></td></tr></table>
3232
3233<p>This option takes last image in the current image sequence and inserts it at the given index. If a negative index is used, the insert position is calculated before the last image is removed from the sequence. As such <kbd>-insert -1</kbd> will result in no change to the image sequence.</p>
3234
3235<p>The <kbd>+insert</kbd> option is equivalent to <kbd>-insert -1</kbd>. In other words, insert the last image, at the end of the current image sequence. Consequently this has no effect on the image sequence order.</p>
3236
3237<div style="margin: auto;">
3238 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3239</div>
3240
3241<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use this type of rendering intent when managing the image color.</td><td style='text-align:right;'></td></tr></table>
3242
3243<p>Use this option to affect the color management operation of an image (see <a href="#profile">-profile</a>). Choose from these intents: <kbd>Absolute, Perceptual, Relative, Saturation</kbd>.</p>
3244
3245<p>The default intent is undefined.</p>
3246
3247<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3248
3249<div style="margin: auto;">
3250 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3251</div>
3252
3253<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the type of interlacing scheme.</td><td style='text-align:right;'></td></tr></table>
3254
3255<p>Choose from:</p>
3256
3257<pre class="text">
3258 none
3259 line
3260 plane
3261 partition
3262 JPEG
3263 GIF
3264 PNG
3265</pre>
3266
3267<p>This option is used to specify the type of interlacing scheme for raw image formats such as <kbd>RGB</kbd> or <kbd>YUV</kbd>.</p>
3268
3269<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3270
3271<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3272
3273<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3274
3275<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3276image.G, and image.B).</p>
3277
3278<p>Use <kbd>Line</kbd> or <kbd>Plane</kbd> to create an <kbd>interlaced PNG</kbd> or <kbd>GIF</kbd> or <kbd>progressive JPEG</kbd>
3279image.</p>
3280
3281<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3282
3283<div style="margin: auto;">
3284 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3285</div>
3286
3287<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</td><td style='text-align:right;'></td></tr></table>
3288
3289<p>When looking up the color of a pixel using a non-interger floating point
3290value, you typically fall in between the pixel colors defined by the source
3291image. This setting determines how the color is determined from the colors of
3292the pixels surrounding that point. That is how to determine the color of a
3293point that falls between two, or even four different colored pixels. </p>
3294
3295<pre class="text">
3296 integer: The color of the top-left pixel (floor function)
3297 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3298 average: The average color of the surrounding four pixels
3299 bilinear A double linear interpolation of pixels (the default)
3300 mesh Divide area into two flat triangular interpolations
3301 bicubic Fitted bicubic-spines of surrounding 16 pixels
3302 spline Direct spline curves (colors are blurred)
3303 filter Use resize <a href="#filter">-filter</a> settings
3304</pre>
3305
3306<p>This most important for distortion operators such as <a href="#distort"
3307>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3308>-transform</a> and <a href="#fx" >-fx</a>. </p>
3309
3310<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3311
3312<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3313lookup for positions outside the boundaries of the image. </p>
3314
3315
3316<div style="margin: auto;">
3317 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3318</div>
3319
3320<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two words.</td><td style='text-align:right;'></td></tr></table>
3321
3322<div style="margin: auto;">
3323 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3324</div>
3325
3326<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two letters.</td><td style='text-align:right;'></td></tr></table>
3327
3328<div style="margin: auto;">
3329 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3330</div>
3331
3332<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>assign a label to an image.</td><td style='text-align:right;'></td></tr></table>
3333
3334<p>Use this option to assign a specific label to the image, as it is read in or created. You can use the <a href="#set" >-set</a> operation to re-assign a the labels of images already read in. Image formats such as TIFF, PNG, MIFF, supports saving the label information with the image.</p>
3335
3336<p>When saving an image to a <em class="arg">PostScript</em> file, any label assigned to an image is used as a header string to print above the postscript image. </p>
3337
3338<p>You can include the image filename, type, width, height, or other image attribute by embedding special format character. See <a href="#format">-format</a> for details of the percent escape codes.</p>
3339
3340<p>For example,</p>
3341
3342<p class="crtsnip">
3343 -label "%m:%f %wx%h" bird.miff
3344</p>
3345
3346<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the "<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it is read in. If a <a href="#label">+label</a> option was used instead, any existing label present in the image would be used. You can remove all labels from an image by assigning the empty string. </p>
3347
3348<p>A label is not drawn on the image, but is embedded in the image datastream via <em>Label</em> tag or similar mechanism. If you want the label to be visible on the image itself, use the <a href="#draw">-draw</a> option, or during the final processing in the creation of a image montage.</p>
3349
3350<p>The label font can be specified with <a href="#font">-font</a>, and the
3351other font attribute settings.</p>
3352
3353<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image label is read from a file titled by the remaining characters in the string. Labels in a file are literal, no embedded formatting characters are recognized.</p>
3354
3355
3356<div style="margin: auto;">
3357 <h4><a name="lat" id="lat"></a>-lat <em class="arg">width</em><br />-lat <em class="arg">width</em>x<em class="arg">height</em>{<em class="arg">+-</em>}<em class="arg">offset</em>{<em class="arg">%</em>}</h4>
3358</div>
3359
3360<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform local adaptive threshold.</td><td style='text-align:right;'></td></tr></table>
3361
3362<p>Adaptively threshold each pixel based on the value of pixels in a
3363surrounding window. If the current pixel is lighter than this average plus
3364the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3365black. Small variations in pixel values such as found in scanned documents
3366can be ignored if offset is positive. A negative offset will make it more
3367sensitive to those small variations. </p>
3368
3369<p>This is commonly used to threshold images with an uneven background. It is
3370based on the assumption that average color of the small window is the
3371the local background color, from which to separate the forground color. </p>
3372
3373
3374<div style="margin: auto;">
3375 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3376</div>
3377
3378<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>handle multiple images forming a set of image layers or animation frames.</td><td style='text-align:right;'></td></tr></table>
3379
3380<p>Perform various image operation methods to a ordered sequence of images
3381which may represent either a set of overlaid 'image layers', a GIF disposal
3382animation, or a fully-'coalesced' animation sequence. </p>
3383
3384<table class="doc">
3385 <tbody>
3386 <tr valign="top">
3387 <th align="left" style="width: 8%">Method</th>
3388 <th align="left">Description</th>
3389 </tr>
3390
3391 <tr valign="top">
3392 <td valign="top">compare-any</td>
3393 <td valign="top">Crop the second and later frames to the smallest rectangle
3394 that contains all the differences between the two images. No GIF <a
3395 href="#dispose" >-dispose</a> methods are taken into account. </td>
3396 </tr>
3397
3398 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3399 >-deconstruct</a> operator, and does not preserve animations normal
3400 working, especially when animation used layer disposal methods such as
3401 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3402 </tr>
3403
3404 <tr valign="top">
3405 <td valign="top">compare-clear</td>
3406 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3407 opaque pixels which become transparent in the second frame. That is the
3408 smallest image needed to mask or erase pixels for the next frame. </td>
3409 </tr>
3410
3411 <tr valign="top">
3412 <td valign="top">compare-overlay</td>
3413 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3414 extra color to the next image, as a result of overlaying color pixels.
3415 That is the smallest single overlaid image to add or change colors. </td>
3416 </tr>
3417
3418 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3419 composition method '<kbd>change-mask</kbd>', to reduce the image to
3420 just the pixels that need to be overlaid. </td>
3421 </tr>
3422
3423 <tr valign="top">
3424 <td valign="top">coalesce</td>
3425 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3426 >-coalesce</a> operator. Apply the layer disposal methods set in the
3427 current image sequence to form a fully defined animation sequence, as
3428 it should be displayed. Effectively converting a GIF animation into a
3429 'film strip'-like animation. </td>
3430 </tr>
3431
3432 <tr valign="top">
3433 <td valign="top">composite</td>
3434 <td valign="top">Alpha Composition of two image lists, separated by a
3435 "<kbd>null:</kbd>" image, with the destination image list first, and
3436 the source images last. An image from each list are composited
3437 together until one list is finished. The separator image and source
3438 image lists are removed. </td>
3439 </tr>
3440
3441
3442 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3443 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3444 size of the first image in each list. Unlike a normal <a
3445 href="#composite" >-composite</a> operation, the canvas offset is also
3446 added to the final composite positioning of each image. </td>
3447 </tr>
3448
3449 <tr><td></td><td>If one of the image lists only contains one image, that image is
3450 applied to all the images in the other image list, regardless of which
3451 list it is. In this case it is the image meta-data of the list which
3452 preserved. </td>
3453 </tr>
3454
3455
3456 <tr valign="top">
3457 <td valign="top">dispose</td>
3458 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3459 the animation after the layer disposal method has been applied, before
3460 the next sub-frame image is overlaid. That is the 'dispose' image that
3461 results from the application of the GIF <a href="#dispose"
3462 >-dispose</a> method. This allows you to check what
3463 is going wrong with a particular animation you may be developing.
3464 </td>
3465 </tr>
3466
3467 <tr valign="top">
3468 <td valign="top">flatten</td>
3469 <td valign="top">Create a canvas the size of the first images virtual
3470 canvas using the current <a href="#background" >-background</a> color,
3471 and <a href="#compose" >-compose</a> each image in turn onto that
3472 canvas. Images falling outside that canvas is clipped. Final
3473 image will have a zero virtual canvas offset. </td>
3474 </tr>
3475
3476 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3477 overlaying all the prepared image layers into a final image. </td>
3478 </tr>
3479
3480 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3481 canvas with real pixels, or to underlay a opaque color to remove
3482 transparency from an image.</td>
3483 </tr>
3484
3485
3486 <tr valign="top">
3487 <td valign="top">merge</td>
3488 <td valign="top">As 'flatten' method but merging all the given image
3489 layers into a new layer image just large enough to hold all the image
3490 without clipping or extra space. The new images virtual offset will
3491 prevere the position of the new layer, even if this offset is
3492 negative. the virtual canvas size of the first image is preserved.
3493 </td>
3494 </tr>
3495
3496 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3497 as few image file formats handle them correctly. </td>
3498 </tr>
3499
3500 <tr valign="top">
3501 <td valign="top">mosaic</td>
3502 <td valign="top">As 'flatten' method but expanding the initial canvas size
3503 of the first image so as to hold all the image layers. However as a
3504 virtual canvas is 'locked' to the origin, by defination, image layers
3505 with a negative offsets will still be clipped by the top and left
3506 edges.</td>
3507 </tr>
3508
3509 <tr><td></td><td>This method is commonly used to layout individual image using various
3510 offset but without knowning the final canvas size. The resulting image
3511 will, like 'flatten' not have any virtual offset, so can be saved to
3512 any image file format. </td>
3513 </tr>
3514
3515
3516 <tr valign="top">
3517 <td valign="top">optimize</td>
3518 <td valign="top">Optimize a coalesced animation, into GIF animation using
3519 a number of general techniques. This currently a short cut to
3520 apply both the '<kbd>optimize-frame</kbd>', and
3521 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3522 include other optimization methods as they are developed. </td>
3523 </tr>
3524
3525 <tr valign="top">
3526 <td valign="top">optimize-frame</td>
3527 <td valign="top">Optimize a coalesced animation, into GIF animation by
3528 reducing the number of pixels per frame as much as possible by
3529 attempting to pick the best layer disposal method to use, while ensuring
3530 the result will continue to animate properly. </td>
3531 </tr>
3532
3533 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3534 then no reasonably fast GIF optimization algorithm can do this.
3535 However this does seem to do better than most other GIF frame
3536 optimizers seen. </td>
3537 </tr>
3538
3539 <tr valign="top">
3540 <td valign="top">optimize-plus</td>
3541 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3542 overall optimization by adding extra frames to the animation, without
3543 changing the final look or timing of the animation. The frames are
3544 added to attempt to separate the clearing of pixels from the
3545 overlaying of new additional pixels from one animation frame to the
3546 next. If this does not improve the optimization (for the next frame
3547 only), it will fall back to the results of the previous normal
3548 '<kbd>optimize-frame</kbd>' technique. </td>
3549 </tr>
3550
3551 <tr><td></td><td>There is the possibility that the change in the disposal style will
3552 result in a worsening in the optimization of later frames, though this
3553 is unlikely. In other words there no guarantee that it is better than
3554 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3555 however you can get a vast improvment in the final animation size. </td>
3556 </tr>
3557
3558 <tr valign="top">
3559 <td valign="top">optimize-transparency</td>
3560 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3561 overlay images with transparency, if it does not change the resulting
3562 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3563 </td>
3564 </tr>
3565
3566 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3567 into a smaller file size due to larger areas of one (transparent)
3568 color rather than a pattern of multiple colors repeating the current
3569 disposed image of the last frame. </td>
3570 </tr>
3571
3572 <tr valign="top">
3573 <td valign="top">remove-dups</td>
3574 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3575 images, so as to simplify layer overlays of coalesced animations.
3576 </td>
3577 </tr>
3578
3579 <tr><td></td><td>Usually this a result of using a constant time delay across the
3580 whole animation, or after a larger animation was split into smaller
3581 sub-animations. The duplicate frames could also have been used as
3582 part of some frame optimization methods. </td>
3583 </tr>
3584
3585 <tr valign="top">
3586 <td valign="top">remove-zero</td>
3587 <td valign="top">Remove any image with a zero time delay, unless ALL the
3588 images have a zero time delay (and is not a proper timed animation, a
3589 warning is then issued). </td>
3590 </tr>
3591
3592 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3593 partial intermediary updates between the frames that are actually
3594 displayed to users. These frames are usally added for improved frame
3595 optimization in GIF animations. </td>
3596 </tr>
3597
3598 <tr valign="top">
3599 <td valign="top">trim-bounds</td>
3600 <td valign="top">Find the bounds of all the images in the current
3601 image sequence, then adjust the offsets so all images are contained on
3602 a minimal positive canvas. None of the image data is modified, only
3603 there virtual canvas size and offset. The all the image is given
3604 the same canvas size, and and will have a positive offset, but will
3605 remain in the same position relative to each other. As a result of the
3606 minimal canvas size at least one image will touch every edge of that
3607 canvas. The image data however may be transparent.
3608 </td>
3609 </tr>
3610
3611 </tbody>
3612</table>
3613
3614<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3615
3616<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3617>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3618>-mosaic</a> are only aliases for the above methods. Also see <a
3619href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3620href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3621>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3622
3623
3624<div style="margin: auto;">
3625 <h4><a name="level" id="level"></a>-level <em class="arg">black_point</em>{,<em class="arg">white_point</em>}{<em class="arg">%</em>}{,<em class="arg">gamma</em>}</h4>
3626</div>
3627
3628<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of image channels.</td><td style='text-align:right;'></td></tr></table>
3629
3630<p>Given one, two or three values delimited with commas: black-point,
3631white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3632white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3633point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3634contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3635both black and white points are percentages of the full color range. Gamma
3636will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3637omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3638
3639<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3640the given '<kbd>black_point</kbd>' value in the original image is set to
3641zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3642<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3643to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3644adjusted. </p>
3645
3646<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3647adding the special '!' flag anywhere in the argument list, will cause the
3648operator to do the reverse of the level adjustment. That is a zero, or
3649<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3650adjusted to the given level values, allowing you to de-contrast, or compress
3651the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3652
3653<p>Only the channels defined by the current <a href="#channel">-channel</a>
3654setting are adjusted (defaults to RGB color channels only), allowing you to
3655limit the effect of this operator. </p>
3656
3657<p>Please note that the transparency channel is treated as 'matte'
3658values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3659
3660
3661<div style="margin: auto;">
3662 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3663 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3664</div>
3665
3666<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash seperated colors.</td><td style='text-align:right;'></td></tr></table>
3667
3668<p>This function is exactly like <a href="#level">-level</a>, except that the
3669value value for each color channel is determined by the
3670'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3671described under the <a href="#fill">-fill</a> option). </p>
3672
3673<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3674is mapped to become 'black' and 'white' respectivally, with all the other
3675colors linearly adjusted (or clipped) to match that change. Each channel is
3676adjusted separatally using the channel values of the colors specified. </p>
3677
3678<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3679will map the image color 'black' and 'white' to the given colors
3680respectivally, resulting in a gradient (de-contrasting) tint of the image to
3681those colors. This can also be used to convert a plain gray-scale image into a
3682one using the gradient of colors specified. </p>
3683
3684<p>By supplying a single color with a comma separator either before or after
3685that color, will just replace the respective 'black' or 'white' point
3686respectivally. But if no comma separator is provided, the given color is
3687used for both the black and white color points, making the operator either
3688threshold the images around that color (- form) or set all colors to that
3689color (+ form). </p>
3690
3691
3692<div style="margin: auto;">
3693 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3694</div>
3695
3696<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel cache resource limit.</td><td style='text-align:right;'></td></tr></table>
3697
3698<p>Choose from: <kbd>area</kbd>, <kbd>disk</kbd>, <kbd>file</kbd>, <kbd>map</kbd>, <kbd>memory</kbd>, <kbd>threads</kbd>, or <kbd>time</kbd>.</p>
3699
3700<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2gb of image area, 1.5gb memory, 8gb memory map, and 16tb of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p>
3701
3702<p class="crtsnip">
3703 -limit memory 32mb -limit map 64mb
3704</p>
3705
3706<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3707
3708<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list resource</span><span class='crtout'><pre>File Area Memory Map Disk Thread Time
3709-------------------------------------------------------------------
3710 768 3.8187gb 2.864gb 7.6375gb 16eb 2 unlimited</pre>
3711</span></p>
3712<p>Requests for pixel storage to keep intermediate images are satisfied by one of three resource categories: in-memory pool, memory-mapped files pool, and disk pool (in that order) depending on the <a href="../www/command-line-options.html#limit">&#x2011;limit</a> settings and whether the system honors a resource request. If the total size of allocated pixel storage in the given pool reaches the corresponding limit, the request is passed to the next pool. Additionally, requests that exceed the <kbd>area</kbd> limit automagically are allocated on disk.</p>
3713
3714<p>To illustrate how ImageMagick utilizes resource limits, consider a typical image resource request. First, ImageMagick tries to allocate the pixels in memory. The request might be denied if the resource request exceeds the <kbd>memory</kbd> limit or if the system does not honor the request. If a memory request is not honored, the pixels are allocated to disk and the file is memory-mapped. However, if the allocation request exceeds the <kbd>map</kbd> limit, the resource allocation goes to disk. In all cases, if the resource request exceeds the <kbd>area</kbd> limit, the pixels are automagically cached to disk. If the disk has a hard limit, the program fails.</p>
3715
3716<p>In most cases you simply do not need to concern yourself with resource limits. ImageMagick chooses reasonable defaults and most images do not tax your computer resources. Where limits do come in handy is when you process images that are large or on shared systems where ImageMagick can consume all or most of the available memory. In this case, the ImageMagick workflow slows other processes or, in extreme cases, brings the system to a halt. Under these circumstances, setting limits give some assurances that the ImageMagick workflow will not interfere with other concurrent uses of the computer. For example, assume you have a web interface that processes images uploaded from the Internet. To assure ImageMagick does not exceed 10mb of memory you can simply set the area limit to 10mb:</p>
3717
3718<p class="crtsnip">
3719-limit area 10mb
3720</p>
3721
3722<p>Now whenever a large image is processed, the pixels are automagically cached to disk instead of memory. This of course implies that large images typically process very slowly, simply because pixel processing in memory can be an order of magnitude faster than on disk. Because your web site users might inadvertedly upload a huge image to process, you should set a disk limit as well:</p>
3723
3724<p class="crtsnip">
3725-limit area 10mb -limit disk 500mb
3726</p>
3727
3728<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3729
3730<p>In addition to command-line resource limit option, resources can be set with <a href="../www/resources.html#environment">environment variables</a>. Set the environment variables <kbd>MAGICK_AREA_LIMIT</kbd>, <kbd>MAGICK_DISK_LIMIT</kbd>, <kbd>MAGICK_FILE_LIMIT</kbd>, <kbd>MAGICK_MEMORY_LIMIT</kbd>, <kbd>MAGICK_MAP_LIMIT</kbd>, <kbd>MAGICK_THREAD_LIMIT</kbd>, <kbd>MAGICK_TIME_LIMIT</kbd> for limits of image area, disk space, open files, heap memory, memory map, number of threads of execution, and maximum elapsed time in seconds respectively.</p>
3731
3732<p> Inquisitive users can try adding <a href="#debug">-debug cache</a> to their commands and then scouring the generated output for references to the pixel cache, in order to determine how the pixel cache was allocated and how resources were consumed. Advanced Unix/Linux users can pipe that output through <kbd>grep memory|open|destroy|disk</kbd> for more readable sifting.
3733</p>
3734
3735<p>For more about ImageMagick's use of resources, see the section <b>Cache Storage and Resource Requirements</b> on the <a href="../www/architecture.html#cache">Architecture</a> page.
3736</p>
3737
3738<div style="margin: auto;">
3739 <h4><a name="linear-stretch" id="linear-stretch"></a>-linear-stretch <em class="arg">black-point</em><br />-linear-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4>
3740</div>
3741
3742<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Linear with saturation stretch.</td><td style='text-align:right;'></td></tr></table>
3743
3744<div style="margin: auto;">
3745 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3746</div>
3747
3748<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the line width for subsequent draw operations.</td><td style='text-align:right;'></td></tr></table>
3749
3750<div style="margin: auto;">
3751 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3752</div>
3753
3754<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>rescale image with seam-carving.</td><td style='text-align:right;'></td></tr></table>
3755
3756<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3757
3758<div style="margin: auto;">
3759 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3760</div>
3761
3762<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Print a list of supported arguments for various options or settings. Choose from these list types:</td><td style='text-align:right;'></td></tr></table>
3763
3764<pre class="text">
3765 coder
3766 color
3767 configure
3768 delegate
3769 font
3770 format
3771 list
3772 log
3773 magic
3774 module
3775 resource
3776 threshold
3777</pre>
3778
3779<p>The above lists are only some of the many lists available. These lists vary depending on your version of ImageMagick. For example use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p>
3780
3781<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3782<div style="margin: auto;">
3783 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3784</div>
3785
3786<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify format for debug log.</td><td style='text-align:right;'></td></tr></table>
3787
3788<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3789
3790<p>You can display the following components by embedding special format characters:</p>
3791
3792<pre class="text">
3793 %d domain
3794 %e event
3795 %f function
3796 %l line
3797 %m module
3798 %p process ID
3799 %r real CPU time
3800 %t wall clock time
3801 %u user CPU time
3802 %% percent sign
3803 \n newline
3804 \r carriage return
3805</pre>
3806
3807<p>For example:</p>
3808
3809<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug coders -log "%u %m:%l %e" in.gif out.png</span></p>
3810<p>The default behavior is to print all of the components.</p>
3811
3812<div style="margin: auto;">
3813 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3814</div>
3815
3816<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add Netscape loop extension to your GIF animation.</td><td style='text-align:right;'></td></tr></table>
3817
3818<p>Set iterations to zero to repeat the animation an infinite number of times, otherwise the animation repeats itself up to <em class="arg">iterations</em> times.</p>
3819
3820<div style="margin: auto;">
3821 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3822</div>
3823
3824<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, de-emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table>
3825
3826<div style="margin: auto;">
3827 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
3828</div>
3829
3830<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>magnify the image.</td><td style='text-align:right;'></td></tr></table>
3831
3832
3833<div style="margin: auto;">
3834 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
3835</div>
3836
3837<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display image using this <em class="arg">type</em>.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
3838
3839<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
3840
3841<pre class="text">
3842 best
3843 default
3844 gray
3845 red
3846 green
3847 blue
3848</pre>
3849
3850<p>The <em class="arg">X server</em> must support the <em class="arg">Standard Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as the type and <kbd>display</kbd> searches the list of colormap types in <kbd>top-to-bottom</kbd> order until one is located. See <em class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p>
3851
3852
3853<div style="margin: auto;">
3854 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
3855</div>
3856
3857<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel map.</td><td style='text-align:right;'>[<a href="../www/stream.html">stream</a>]</td></tr></table>
3858
3859<p>Here are the valid components of a map:</p>
3860
3861<pre class="text">
3862 r red pixel component
3863 g green pixel component
3864 b blue pixel component
3865 a alpha pixel component (0 is transparent)
3866 o opacity pixel component (0 is opaque)
3867 i grayscale intensity pixel component
3868 c cyan pixel component
3869 m magenta pixel component
3870 y yellow pixel component
3871 k black pixel component
3872 p pad component (always 0)
3873</pre>
3874
3875<p>You can specify as many of these components as needed in any order (e.g. bgr). The components can repeat as well (e.g. rgbr).</p>
3876
3877<div style="margin: auto;">
3878 <h4><a name="mask" id="mask"></a>-mask
3879<em class="arg">filename</em></h4>
3880</div>
3881
3882<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Composite the image pixels as defined by the mask.</td><td style='text-align:right;'></td></tr></table>
3883
3884<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
3885
3886<div style="margin: auto;">
3887 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
3888</div>
3889
3890<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the color to be used with the <a href="#frame">-frame</a> option.</td><td style='text-align:right;'></td></tr></table>
3891
3892<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
3893
3894<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
3895
3896<div style="margin: auto;">
3897 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
3898</div>
3899
3900<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a median filter to the image.</td><td style='text-align:right;'></td></tr></table>
3901
3902<div style="margin: auto;">
3903 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
3904</div>
3905
3906<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Output to STDERR a measure of the differences between images according to the <em class="arg">type</em> given metric.</td><td style='text-align:right;'></td></tr></table>
3907
3908<p>Choose from:</p>
3909
3910<pre class="text">
3911 AE absolute number of differnet pixels
3912 MAE mean absolute error (normalized), average channel error distance
3913 MEPP mean error per pixel (normalized mean error, normalized peak error)
3914 MSE mean error squared, average of the channel error squared
3915 PAE peak absolute (normalize peak absolute)
3916 PSNR peak signal to noise ratio
3917 RMSE root mean squared (normalized root mean squared)
3918</pre>
3919
3920<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
3921controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
3922only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
3923size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
3924'similar'. </p>
3925
3926<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
3927('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
3928normalized) from the single comparision run. </p>
3929
3930<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
3931
3932
3933<div style="margin: auto;">
3934 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
3935</div>
3936
3937<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mode of operation.</td><td style='text-align:right;'>[<a href="../www/montage.html">montage</a>]</td></tr></table>
3938
3939<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
3940
3941<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
3942argument for a list of <a href="#mode" >-mode</a> arguments available
3943in your ImageMagick installation.</p>
3944
3945
3946<div style="margin: auto;">
3947 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
3948</div>
3949
3950<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Vary the <em class="arg">brightness</em>, <em class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table>
3951
3952<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
3953missing values are taken to mean 100.</p>
3954
3955<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
3956means pure black, 50 is half as bright, 200 is twice as bright. To invert its
3957meaning <a href="#negate">-negate</a> the image before and after. </p>
3958
3959<p>The <em class="arg">saturation</em> controls the amount of color in an image. For example, 0 produce a grayscale image, while a large value such as 200 produce a very colorful, 'cartoonish' color.</p>
3960
3961<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors within the image by the amount specified. For example, 50 results in a counter-clockwise rotation of 90, mapping red
3962shades to purple, and so on. A value of either 0 or 200 results in a complete
3963180 degree rotation of the image. Using a value of 300 is a 360 degree
3964rotation resulting in no change to the original image. </p>
3965
3966<p>For example, to increase the color brightness by 20% and decrease the color saturation by 10% and leave the hue unchanged, use <a href="#modulate">-modulate 120,90</a>.</p>
3967
3968<p>Use <a href="#set">-set</a> attribute of '<kbd class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or <kbd>HWB</kbd>. For example,</p>
3969
3970<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png</span></p>
3971<div style="margin: auto;">
3972 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
3973</div>
3974
3975<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>monitor progress.</td><td style='text-align:right;'></td></tr></table>
3976
3977
3978<div style="margin: auto;">
3979 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
3980</div>
3981
3982<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image to black and white.</td><td style='text-align:right;'></td></tr></table>
3983
3984
3985<div style="margin: auto;">
3986 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
3987</div>
3988
3989<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>morphs an image sequence.</td><td style='text-align:right;'></td></tr></table>
3990
3991<p>Both the image pixels and size are linearly interpolated to give the
3992appearance of a meta-morphosis from one image to the next, over all the images
3993in the current image list. The added images are the equivalent of a <a
3994href="#blend">-blend</a> composition. The <em class="arg">frames</em>
3995argument determine how many images to interpolate between each image. </p>
3996
3997
3998<div style="margin: auto;">
3999 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4000</div>
4001
4002<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>an simple alias for the <a href="#layers" >-layers</a> method "mosaic"</td><td style='text-align:right;'></td></tr></table>
4003
4004
4005<div style="margin: auto;">
4006 <h4><a name="motion-blur" id="motion-blur"></a>-motion-blur <em class="arg">radius</em><br />-motion-blur <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4>
4007</div>
4008
4009<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate motion blur.</td><td style='text-align:right;'></td></tr></table>
4010
4011<p>Blur with the given radius, standard deviation (sigma), and angle. The
4012angle given is the angle toward which the image is blurred. That is the
4013direction people would consider the object is coming from. </p>
4014
4015<p>Note that the blur is not uniform distribution, giving the motion a
4016definate sense of direction of movement. </p>
4017
4018<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4019pixels which are outside the image proper are blurred into the final result.
4020</p>
4021
4022<div style="margin: auto;">
4023 <h4><a name="name" id="name"></a>-name</h4>
4024</div>
4025
4026<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name an image.</td><td style='text-align:right;'></td></tr></table>
4027<div style="margin: auto;">
4028 <h4><a name="negate" id="negate"></a>-negate</h4>
4029</div>
4030
4031<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace every pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table>
4032
4033<p>The red, green, and blue intensities of an image are negated. White becomes black, yellow becomes blue, etc. Use <a href="#negate">+negate</a> to only negate the grayscale pixels of the image.</p>
4034
4035<div style="margin: auto;">
4036 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4037 +noise <em class="arg">type</em></h4>
4038</div>
4039
4040<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add or reduce noise in an image.</td><td style='text-align:right;'></td></tr></table>
4041
4042<p>The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired structures. The central idea of the algorithm is to replace a pixel with its next neighbor in value within a pixel window, if this pixel has been found to be noise. A pixel is defined as noise if and only if this pixel is a maximum or minimum within the pixel window.</p>
4043
4044<p>Use <kbd><a href="#noise">-noise</a> <em class="arg">radius</em></kbd> to specify the width of the neighborhood when reducing noise.</p>
4045
4046<p>Use <a href="#noise">+noise</a> followed by a noise <em class="arg">type</em> to add noise to an image. Choose from these noise types:</p>
4047
4048<pre class="text">
4049Gaussian
4050Impulse
4051Laplacian
4052Multiplicative
4053Poisson
4054Random
4055Uniform
4056</pre>
4057
4058<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4059
4060
4061<div style="margin: auto;">
4062 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4063</div>
4064
4065<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table>
4066
4067<p>The intensity values are stretched to cover the entire range of possible values. While doing so, black-out at most <em>2%</em> of the pixels and white-out at most <em>1%</em> of the pixels.</p>
4068
4069<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. (Before this
4070version, it was equivalent to <a href="#contrast-stretch">-contrast-stretch 2%x99%)</a></p>
4071
4072<p>All the channels are normalized in concert by the came amount so as to preserve color integrity. Specify <a href="#channel">-channel</a> to normalize the RGB channels independently.</p>
4073
4074
4075<div style="margin: auto;">
4076 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4077</div>
4078
4079<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dither the image using a pre-defined ordered dither <em class="arg">threshold map</em> specified, and a uniform color map with the number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table>
4080
4081<p>You can choose from these standard threshold maps:</p>
4082
4083<pre class="text">
4084 checks
4085 o2x2
4086 o3x3
4087 o4x4
4088 o8x8
4089 h4x4a
4090 h6x6a
4091 h8x8a
4092 h4x4o
4093 h6x6o
4094 h8x8o
4095 h16x16o
4096</pre>
4097
4098<p>The '<kbd>o</kbd>' are ordered diffused pixel threshold maps, while the
4099'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled,
4100or 'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord
4101dither pattern. Or you can define your own <em class="arg">threshold
4102map</em> in a personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
4103
4104<p>To print a complete list of threshold, use the <a href="#list">-list threshold</a> option.</p>
4105
4106<p>It is recommended that the <a href="#map">+map</a> operator be used after
4107applying <a href="#ordered-dither">-ordered-dither</a> to reduce the number of
4108colors an animated image sequence, to less that 256 colors. This ensures that
4109a common or global color table is used when saving the result to a color
4110limited file format such as GIF. </p>
4111
4112<p>Note that at this time the exact same map is used for all color channels, no
4113attempt is made to offset or rotate the dither map for different channels is
4114made, at this point in time. (possible future expansion) </p>
4115
4116
4117<div style="margin: auto;">
4118 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4119</div>
4120
4121<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>change this color to the fill color within the image.</td><td style='text-align:right;'></td></tr></table>
4122
4123<p>The <em class="arg">color</em> argument is defined using the format
4124described under the <a href="#fill">-fill</a> option.
4125The <a href="#fuzz">-fuzz</a> setting can be used to match and replace colors similar
4126to the one given.</p>
4127
4128<p>The <a href="#transparent">-transparent</a> operator is exactly the same
4129as <a href="#opaque">-opaque</a> but makes the matching color transparent,
4130rather than the same as the current <a href="#fill">-fill</a> color. </p>
4131
4132<p>Use <em class="arg">+opaque</em> to paint any pixel that does not match the target color.</p>
4133
4134<div style="margin: auto;">
4135 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4136</div>
4137
4138<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify orientation of a digital camera image.</td><td style='text-align:right;'></td></tr></table>
4139
4140<p>Choose from these orientations:</p>
4141
4142<pre class="text">
4143 bottom-left
4144 bottom-right
4145 left-bottom
4146 left-top
4147 right-bottom
4148 right-top
4149 top-left
4150 top-right
4151 undefined
4152</pre>
4153
4154<p>To print a complete list of orientations, use the <a href="#list">-list orientation</a> option.</p>
4155
4156
4157<div style="margin: auto;">
4158 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4159 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4160 +page
4161 </h4>
4162</div>
4163
4164<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the size and location of an image on the larger virtual canvas.</td><td style='text-align:right;'></td></tr></table>
4165
4166<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4167
4168<p>For convenience you can specify the page size using <em class="arg">media</em> (see below). Offsets can then be added as with other <em class="arg">geometry</em> arguments (e.g. <a href="#page">-page</a>&nbsp;<kbd>Letter+43+43</kbd>).</p>
4169
4170<p>Use <em class="arg">media</em> as shorthand to specify the dimensions (<em class="arg">width</em>x<em class="arg">height</em>) of the <em class="arg">PostScript</em> page in dots per inch or a TEXT page in pixels. The choices for a PostScript page are:</p>
4171<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4172<thead>
4173 <tr valign="top">
4174 <th align="center"><em class="arg">media</em></th>
4175 <th align="center"><em class="arg">width</em></th>
4176 <th align="center"><em class="arg">height</em></th>
4177 </tr>
4178</thead>
4179<tbody>
4180<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4181<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4182<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4183<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4184<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4185<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4186<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4187<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4188<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4189<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4190<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4191<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4192<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4193<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4194<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4195<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4196<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4197<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4198<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4199<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4200<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4201<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4202<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4203<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4204<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4205<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4206<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4207<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4208<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4209<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4210<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4211<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4212<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4213<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4214<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4215<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4216<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4217<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4218</tbody>
4219</table>
4220
4221
4222
4223
4224<p>This option is also used to place subimages when writing to a multi-image format that supports offsets, such as GIF89 and MNG. When used for this purpose the offsets are always measured from the top left corner of the canvas and are not affected by the <a href="#gravity">-gravity</a> option. To position a GIF or MNG image, use <a href="#page">-page</a><em class="arg">{+-}x{+-}y</em> (e.g. -page +100+200). When writing to a MNG file, a <a href="#page">-page</a> option appearing ahead of the first image in the sequence with nonzero width and height defines the width and height values that are written in the <kbd>MHDR</kbd> chunk. Otherwise, the MNG width and height are computed from the bounding box that contains all images in the sequence. When writing a GIF89 file, only the bounding box method is used to determine its dimensions.</p>
4225
4226<p>For a PostScript page, the image is sized as in <a href="#geometry">-geometry</a> but positioned relative to the <em>lower left-hand corner</em> of the page by {+-}<kbd>x</kbd><em class="arg">offset</em>{+-}<kbd>y</kbd> <em class="arg">offset</em>. Use <a href="#page">-page 612x792</a>, for example, to center the image within the page. If the image size exceeds the PostScript page, it is reduced to fit the page. The default gravity for the <a href="#page">-page</a> option is <em class="arg">NorthWest</em>, i.e., positive <kbd>x</kbd> and <kbd>y</kbd> <em class="arg">offset</em> are measured rightward and downward from the top left corner of the page, unless the <a href="#gravity">-gravity</a> option is present with a value other than <em class="arg">NorthWest</em>.</p>
4227
4228<p>The default page dimensions for a TEXT image is 612x792.</p>
4229
4230<p>This option is used in concert with <a href="#density">-density</a>.</p>
4231
4232<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4233
4234<div style="margin: auto;">
4235 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4236</div>
4237
4238<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an oil painting.</td><td style='text-align:right;'></td></tr></table>
4239
4240<p>Each pixel is replaced by the most frequent color in a circular neighborhood whose width is specified with <em class="arg">radius</em>.</p>
4241
4242<div style="margin: auto;">
4243 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4244
4245<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write images to this path on disk.</td><td style='text-align:right;'></td></tr></table>
4246
4247<div style="margin: auto;">
4248 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4249</div>
4250
4251<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between animation loops.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>]</td></tr></table>
4252
4253<p>Pause for the specified number of seconds before repeating the animation.</p>
4254
4255<div style="margin: auto;">
4256 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4257</div>
4258
4259<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between snapshots.</td><td style='text-align:right;'>[<a href="../www/import.html">import</a>]</td></tr></table>
4260
4261<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4262
4263<div style="margin: auto;">
4264 <h4><a name="ping" id="ping"></a>-ping</h4>
4265</div>
4266
4267<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>efficiently determine image characteristics.</td><td style='text-align:right;'></td></tr></table>
4268
4269<div style="margin: auto;">
4270 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4271</div>
4272
4273<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pointsize of the PostScript, OPTION1, or TrueType font.</td><td style='text-align:right;'></td></tr></table>
4274
4275<div style="margin: auto;">
4276 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4277</div>
4278
4279<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a Polaroid picture.</td><td style='text-align:right;'></td></tr></table>
4280
4281<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4282
4283<div style="margin: auto;">
4284 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4285</div>
4286
4287<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the image to a limited number of color levels.</td><td style='text-align:right;'></td></tr></table>
4288
4289<div style="margin: auto;">
4290 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4291</div>
4292
4293<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>image preview type.</td><td style='text-align:right;'></td></tr></table>
4294
4295<p>Use this option to affect the preview operation of an image (e.g. <kbd>convert file.png -preview Gamma Preview:gamma.png</kbd>). Choose from these previews:</p>
4296
4297<pre class="text">
4298 Rotate
4299 Shear
4300 Roll
4301 Hue
4302 Saturation
4303 Brightness
4304 Gamma
4305 Spiff
4306 Dull
4307 Grayscale
4308 Quantize
4309 Despeckle
4310 ReduceNoise
4311 Add Noise
4312 Sharpen
4313 Blur
4314 Threshold
4315 EdgeDetect
4316 Spread
4317 Shade
4318 Raise
4319 Segment
4320 Solarize
4321 Swirl
4322 Implode
4323 Wave
4324 OilPaint
4325 CharcoalDrawing
4326 JPEG
4327</pre>
4328
4329<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4330
4331<p>The default preview is <kbd>JPEG</kbd>.</p>
4332
4333<div style="margin: auto;">
4334 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4335</div>
4336
4337<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>interpret string and print to console.</td><td style='text-align:right;'></td></tr></table>
4338
4339<div style="margin: auto;">
4340 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4341</div>
4342
4343<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>process the image with a custom image filter.</td><td style='text-align:right;'></td></tr></table>
4344
4345<p>The command arguments has the form <kbd>"module arg1 arg2 arg3 ... argN"</kbd> where <kbd>module</kbd> is the name of the module to invoke (e.g. "Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to pass to the process module.</p>
4346
4347<div style="margin: auto;">
4348 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4349 +profile <em class="arg">profile_name</em></h4>
4350</div>
4351
4352<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Manage ICM, IPTC, or generic profiles in an image.</td><td style='text-align:right;'></td></tr></table>
4353
4354<p>Using <a href="#profile">-profile</a> <em class="arg">filename</em> adds an ICM (ICC color management), IPTC (newswire information), or a generic profile to the image.</p>
4355
4356<p>Use <a href="#profile">+profile <em class="arg">profile_name</em></a> to remove the indicated profile. ImageMagick uses standard filename globbing, so wildcard expressions may be used to remove more than one profile. Here we remove all profiles from the image except for the XMP profile: <kbd>+profile "!xmp,*"</kbd>. </p>
4357
4358<p>Use <kbd>identify -verbose</kbd> to find out which profiles are in the image file. Use <a href="#strip">-strip</a> to remove all profiles (and comments).</p>
4359
4360<p>To extract a profile, the <a href="#profile">-profile</a> option is not used. Instead, simply write the file to an image format such as <em class="arg">APP1, 8BImageMagick, ICM,</em> or <em class="arg">IPTC</em>.</p>
4361
4362<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4363
4364<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4365<p>It is important to note that results may depend on whether or not the original image already has an included profile. Also, keep in mind that <a href="#profile">-profile</a> is an "operator" (as opposed to a "setting") and therefore a conversion is made each time it is encountered, in order, in the command-line. For instance, in the following example, if the original image is CMYK with profile, a CMYK-CMYK-RGB conversion results.</p>
4366
4367<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p>
4368<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4369CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4370</p>
4371
4372<div style="margin: auto;">
4373 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4374</div>
4375
4376<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>JPEG/MIFF/PNG compression level.</td><td style='text-align:right;'></td></tr></table>
4377
4378<p>For the JPEG and MPEG image formats, quality is 0 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default is to use the estimate quality of your input image otherwise 85. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p>
4379
4380<p>For the MIFF image format, quality/10 is the zlib compression level, which is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect on the image appearance, since the compression is always lossless.</p>
4381
4382<p>For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 85 results in a request for 16:1 compression. The quality value 100 results in a request for non-lossy compression.</p>
4383
4384<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). Compression levels range from 0 (fastest compression) to 100 (best but slowest). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.</p>
4385
4386<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4387
4388<pre class="text">
4389 0: none
4390 1: sub
4391 2: up
4392 3: average
4393 4: Paeth
4394</pre>
4395
4396<p>If filter-type is 5, adaptive filtering is used when quality is greater than 50 and the image does not have a color map, otherwise no filtering is used.</p>
4397
4398<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4399
4400<p>Only if the output is MNG, if filter-type is 7, the LOCO color transformation and adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> are used.</p>
4401
4402<p>The default is quality is 85, which means nearly the best compression with adaptive filtering. The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p>
4403
4404<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4405
4406<p>When writing a JNG image with transparency, two quality values are required, one for the main image and one for the grayscale image that conveys the alpha channel. These are written as a single integer equal to the main image quality plus 1000 times the opacity quality. For example, if you want to use quality 85 for the main image and quality 90 to compress the opacity data, use <a href="#quality">-quality 90085</a>.</p>
4407
4408<div style="margin: auto;">
4409 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4410</div>
4411
4412<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors in this colorspace.</td><td style='text-align:right;'></td></tr></table>
4413
4414<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4415
4416
4417<div style="margin: auto;">
4418 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4419</div>
4420
4421<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>suppress all warning messages. Error messages are still reported.</td><td style='text-align:right;'></td></tr></table>
4422
4423<div style="margin: auto;">
4424 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4425</div>
4426
4427<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur around the center of the image.</td><td style='text-align:right;'></td></tr></table>
4428
4429<p>Note that this is actually a rotational blur rather than a radial and as
4430such actually mis-named. </p>
4431
4432<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4433pixels which are outside the image proper are blurred into the final result.
4434</p>
4435
4436
4437<div style="margin: auto;">
4438 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4439</div>
4440
4441<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lighten or darken image edges.</td><td style='text-align:right;'></td></tr></table>
4442
4443<p>This will create a 3-D effect. Use <a href="#raise">-raise</a> to create a raised effect, otherwise use <a href="#raise">+raise</a>.
4444</p>
4445
4446<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4447
4448<div style="margin: auto;">
4449 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4450</div>
4451
4452<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a random threshold to the image.</td><td style='text-align:right;'></td></tr></table>
4453
4454<div style="margin: auto;">
4455 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4456</div>
4457
4458<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Translate, scale, shear, or rotate image colors.</td><td style='text-align:right;'></td></tr></table>
4459
4460<p>Although variable-sized matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA. Populate the last row with normalized values to translate.
4461</p>
4462
4463<div style="margin: auto;">
4464 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4465</div>
4466
4467<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the red chromaticity primary point.</td><td style='text-align:right;'></td></tr></table>
4468
4469<div style="margin: auto;">
4470 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4471</div>
4472
4473<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pay attention to warning messages.</td><td style='text-align:right;'></td></tr></table>
4474
4475<div style="margin: auto;">
4476 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4477</div>
4478
4479<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce the number of colors in an image to the colors used by this image.</td><td style='text-align:right;'></td></tr></table>
4480
4481<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4482the given colors are dithered over the image as necessary, otherwise the closest
4483color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4484
4485<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4486images in the current image sequence, all the images will have the same color
4487table. That means that when saved to a file format such as GIF, it will use
4488that color table as a single common or global color table, for all the images,
4489without requiring extra local color tables. </p>
4490
4491<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4492sequence to use a common color map over all the images. This equivalent to
4493appending all the images together (without extra background colors) and color
4494reducing those images using <a href="#colors">-colors</a> with a 256 color
4495limit, then <a href="#remap">-remap</a> those colors over the original list of
4496images. This ensures all the images follow a single color map. </p>
4497
4498<p>If the number of colors over all the images is less than 256, then <a
4499href="#remap">+remap</a> should not perform any color reduction or dithering, as
4500no color changes are needed. In that case, its only effect is to force the use
4501of a global color table. This recommended after using either <a
4502href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4503reduce the number of colors in an animated image sequence. </p>
4504
4505<div style="margin: auto;">
4506 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4507</div>
4508
4509<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a region in which subsequent operations apply.</td><td style='text-align:right;'></td></tr></table>
4510
4511<p>The <em class="arg">x</em> and <em class="arg">y</em> offsets are treated in the same manner as in <a href="#crop">-crop</a>.</p>
4512
4513<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4514
4515<div style="margin: auto;">
4516 <h4><a name="remote" id="remote"></a>-remote</h4>
4517</div>
4518
4519<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform a remote operation.</td><td style='text-align:right;'></td></tr></table>
4520
4521<p>The only command recognized is the name of an image file to load.</p>
4522
4523<p>If you have more than one <a href="../www/display.html">display</a> application running simultaneously, use the <a href="#window"> window</a> option to specify which application to control.</p>
4524
4525<div style="margin: auto;">
4526 <h4><a name="render" id="render"></a>-render</h4>
4527</div>
4528
4529<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render vector operations.</td><td style='text-align:right;'></td></tr></table>
4530
4531<p>Use <a href="#render">+render</a> to turn off rendering vector operations. This useful when saving the result to vector formats such as MVG or SVG.</p>
4532
4533<div style="margin: auto;">
4534<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4535</div>
4536
4537<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the canvas and offset information of the image.</td><td style='text-align:right;'></td></tr></table>
4538
4539<p>This option is like <a href="#page">-page</a> but acts as an image operator
4540rather than a setting. You can separately set the canvas size or the offset
4541of the image on that canvas by only providing those components. </p>
4542
4543<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4544
4545<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4546offset to move the image relative to its previous position. This useful for
4547animation sequences. </p>
4548
4549<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4550recalculate the canvas size so the image (at its current offset) will appear
4551completely on that canvas (unless it has a negative offset).</p>
4552
4553<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4554canvas meta-data from the images. </p>
4555
4556<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4557directly assign virtual canvas meta-data. </p>
4558
4559
4560<div style="margin: auto;">
4561 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4562</div>
4563
4564<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resample image to specified horizontal and vertical resolution.</td><td style='text-align:right;'></td></tr></table>
4565
4566<p>Resize the image so that its rendered size remains the same as the original at the specified target resolution. For example, if a 300 DPI image renders at 3 inches by 2 inches on a 300 DPI device, when the image has been resampled to 72 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of storing the image resolution. For formats which do not support an image resolution, the original resolution of the image must be specified via <a href="#density">-density</a> on the command line prior to specifying the resample resolution.</p>
4567
4568<p>Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile exists in the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p>
4569
4570<div style="margin: auto;">
4571 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4572</div>
4573
4574<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize an image.</td><td style='text-align:right;'></td></tr></table>
4575
4576<p>See <a href="../www/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 ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
4577
4578<p>If the <a href="#filter">-filter</a> option precedes the <a href="#resize">-resize</a> option, the image is resized with the specified filter.</p>
4579
4580<div style="margin: auto;">
4581 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4582</div>
4583
4584<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>settings remain in effect until parenthesis boundary.</td><td style='text-align:right;'></td></tr></table>
4585
4586<div style="margin: auto;">
4587 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4588</div>
4589
4590<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reverse the order of images in the current image list.</td><td style='text-align:right;'></td></tr></table>
4591
4592
4593<div style="margin: auto;">
4594 <h4><a name="roll" id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4>
4595</div>
4596
4597<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>roll an image vertically or horizontally by the amount given.</td><td style='text-align:right;'></td></tr></table>
4598
4599<p>A negative <em class="arg">x</em> offset rolls the image left-to-right. A negative <em class="arg">y</em> offset rolls the image top-to-bottom.</p>
4600
4601
4602<div style="margin: auto;">
4603 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4604</div>
4605
4606<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply Paeth image rotation (using shear operations) to the image.</td><td style='text-align:right;'></td></tr></table>
4607
4608<p>Use <kbd>&gt;</kbd> to rotate the image only if its width exceeds the height. <kbd>&lt;</kbd> rotates the image <em>only</em> if its width is less than the height. For example, if you specify <kbd>-rotate "-90&gt;"</kbd> and the image size is 480x640, the image is not rotated. However, if the image is 640x480, it is rotated by -90 degrees. If you use <kbd>&gt;</kbd> or <kbd>&lt;</kbd>, enclose it in quotation marks to prevent it from being misinterpreted as a file redirection.</p>
4609
4610<p>Empty triangles in the corners, left over from rotating the image, are
4611filled with the <kbd>background</kbd> color. </p>
4612
4613<p>See also the <a href="#distort">-distort</a> operator and specifically the
4614'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4615
4616
4617<div style="margin: auto;">
4618 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4619</div>
4620
4621<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale image using pixel sampling.</td><td style='text-align:right;'></td></tr></table>
4622
4623<p><a href="#sample">-sample</a> ignores the current <a href="#resize">-resize</a> <a href="#filter">-filter</a> setting. The results are equivalent to using <a href="#resize">-resize</a> with a <a href="#filter">-filter</a> setting of <kbd>point</kbd>, though <a href="#sample">-sample</a> is a lot faster. </p>
4624
4625<p>See <a href="../www/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 ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
4626
4627
4628<div style="margin: auto;">
4629 <h4><a name="sampling-factor" id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4>
4630</div>
4631
4632<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</td><td style='text-align:right;'></td></tr></table>
4633
4634<p>This option specifies the sampling factors to be used by the JPEG encoder for chroma downsampling. If this option is omitted, the JPEG library will use its own default values. When reading or writing the YUV format and when writing the M2V (MPEG-2) format, use <a href="#sampling-factor">-sampling-factor 2x1</a> or <a href="#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2 downsampling method.</p>
4635
4636<div style="margin: auto;">
4637 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4638</div>
4639
4640<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale the image.</td><td style='text-align:right;'></td></tr></table>
4641
4642<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="#scale">-scale</a> option uses a simpler, faster algorithm than <a href="#resize">-resize</a>, and it ignores the <a href="#filter">-filter</a> setting if one is present. Offsets, if present in the <em class="arg">geometry</em> string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
4643
4644<div style="margin: auto;">
4645 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4646</div>
4647
4648<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set scene number.</td><td style='text-align:right;'></td></tr></table>
4649
4650<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4651
4652<div style="margin: auto;">
4653 <h4><a name="screen" id="screen"></a>-screen</h4>
4654</div>
4655
4656<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the screen to capture.</td><td style='text-align:right;'></td></tr></table>
4657
4658<p>This option indicates that the GetImage request used to obtain the image should be done on the root window, rather than directly on the specified window. In this way, you can obtain pieces of other windows that overlap the specified window, and more importantly, you can capture menus or other popups that are independent windows but appear over the specified window.</p>
4659
4660<div style="margin: auto;">
4661 <h4><a name="seed" id="seed"></a>-seed</h4>
4662</div>
4663
4664<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>seed a new sequence of pseudo-random numbers</td><td style='text-align:right;'></td></tr></table>
4665
4666<div style="margin: auto;">
4667 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4668</div>
4669
4670<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>segment the colors of an image.</td><td style='text-align:right;'></td></tr></table>
4671
4672<p>Segment an image by analyzing the histograms of the color components and identifying units that are homogeneous with the fuzzy c-means technique. This is part of the ImageMagick color quantization routines. </p>
4673
4674<p>Specify <em class="arg">cluster threshold</em> as the number of pixels in each cluster that must exceed the cluster threshold to be considered valid. <em class="arg">Smoothing threshold</em> eliminates noise in the second derivative of the histogram. As the value is increased, you can expect a smoother second derivative. The default is 1.5.</p>
4675
4676<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4677of the color clusters is returned.</p>
4678
4679
4680<div style="margin: auto;">
4681 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4682</div>
4683
4684<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Selectively blur pixels within a contrast threshold.</td><td style='text-align:right;'></td></tr></table>
4685
4686<div style="margin: auto;">
4687 <h4><a name="separate" id="separate"></a>-separate</h4>
4688</div>
4689
4690<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>separate an image channel into a grayscale image. Specify the channel with <a href="#channel">-channel</a>.</td><td style='text-align:right;'></td></tr></table>
4691
4692<div style="margin: auto;">
4693 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4694</div>
4695
4696<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a sepia-toned photo.</td><td style='text-align:right;'></td></tr></table>
4697
4698<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4699
4700<p>This option applies a special effect to the image, similar to the effect achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <em class="QR">QuantumRange</em> and is a measure of the extent of the sepia toning. A threshold of 80% is a good starting point for a reasonable tone.</p>
4701
4702<div style="margin: auto;">
4703 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4704</div>
4705
4706<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set an image attribute for all images in the current image sequence, after they have been created or read in. </td><td style='text-align:right;'></td></tr></table>
4707
4708<p>Attributes of interest include <a href="#comment">-comment</a>, <a href="#delay">-delay</a>, <a href="#dispose">-dispose</a>, and <a href="#page">-page</a>. For example:</p>
4709
4710<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p>
4711<p>The <a href="#repage">-repage</a> operator will also set the
4712'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4713separately set the virtual canvas's size and offset components, and also allows
4714relative offset changes, and automatic canvas size re-calculating. The above
4715<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4716virtual canvas (page) meta-data. </p>
4717
4718<p>Set image options by prefixing the value with <kbd>option:</kbd>. Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>.</p>
4719
4720<div style="margin: auto;">
4721 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4722</div>
4723
4724<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shade the image using a distant light source.</td><td style='text-align:right;'></td></tr></table>
4725
4726<p>Specify <em class="arg">azimuth</em> and <em class="arg">elevation</em> as the position of the light source. Use <a href="#shade">+shade</a> to return the shading results as a grayscale image.</p>
4727
4728<div style="margin: auto;">
4729 <h4><a name="shadow" id="shadow"></a>-shadow <em class="arg">percent-opacity</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4>
4730</div>
4731
4732<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an image shadow.</td><td style='text-align:right;'></td></tr></table>
4733
4734<div style="margin: auto;">
4735 <h4><a name="shared-memory"
4736id="shared-memory"></a>-shared-memory</h4>
4737</div>
4738
4739<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use shared memory.</td><td style='text-align:right;'></td></tr></table>
4740
4741<p>This option specifies whether the utility should attempt to use shared memory for pixmaps. ImageMagick must be compiled with shared memory support, and the display must support the <em class="arg">MIT-SHM</em> extension. Otherwise, this option is ignored. The default is <kbd>True</kbd>.</p>
4742
4743<div style="margin: auto;">
4744 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4745</div>
4746
4747<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image.</td><td style='text-align:right;'></td></tr></table>
4748
4749<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4750
4751<div style="margin: auto;">
4752 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4753</div>
4754
4755<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shave pixels from the image edges.</td><td style='text-align:right;'></td></tr></table>
4756
4757<p>The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument specifies the width of the region to be removed from both sides of the image and the height of the regions to be removed from top and bottom. Offsets are ignored.</p>
4758
4759<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4760
4761<div style="margin: auto;">
4762 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4763</div>
4764
4765<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the image along the x-axis and/or y-axis.</td><td style='text-align:right;'></td></tr></table>
4766
4767<p>The shear angles may be positive, negative, or zero. When <em class="arg">Ydegrees</em> is omitted it defaults to 0. When both angles are given, the horizontal component of the shear is performed before the vertical component.</p>
4768
4769<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e., horizontally or vertically, respectively),creating a parallelogram. The amount of each is controlled by the respective shear angle. For horizontal shears, <em class="arg">Xdegrees</em> is measured clockwise relative to "up" (the negative y-axis), sliding the top edge to the right when 0&deg;&lt;<em class="arg">Xdegrees</em>&lt;90&deg; and to the left when 90&deg;&lt;<em class="arg">Xdegrees</em>&lt;180&deg;. For vertical shears <em class="arg">Ydegrees</em> is measured clockwise relative to "right" (the positive x-axis), sliding the right edge down when 0&deg;&lt;<em class="arg">Ydegrees</em>&lt;90&deg; and up when 90&deg;&lt;<em class="arg">Ydegrees</em>&lt;180&deg;.</p>
4770
4771<p>Empty triangles left over from shearing the image are filled with the color defined by the <a href="#fill">-background</a> option. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4772
4773<p>The horizontal shear is performed before the vertical part. This is important to note, since horizontal and vertical shears do not <em>commute</em>, i.e., the order matters in a sequence of shears. For example, the following two commands are not equivalent.</p>
4774
4775<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x0 -shear 0x60 logo-sheared.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 0x60 -shear 20x0 logo-sheared.png</span></p>
4776<p>The first of the two commands above is equivalent to the following, except for the amount of empty space created; the command that follows generates a smaller image, and so is a better choice in terms of time and space.</p>
4777
4778<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4779<div style="margin: auto;">
4780 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4781</div>
4782
4783<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>increase the contrast without saturating highlights or shadows.</td><td style='text-align:right;'></td></tr></table>
4784
4785<p>Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. <em class="arg">Contrast</em> indicates how much to increase the contrast (0 is none; 3 is typical; 20 is a lot); <em class="arg">mid-point</em> indicates where midtones fall in the resultant image (0 is white; 50% is middle-gray; 100% is black). By default the image contrast is increased, use <em class="arg">+sigmoidal-contrast</em> to decrease the contrast.</p>
4786
4787<div style="margin: auto;">
4788 <h4><a name="silent" id="silent"></a>-silent</h4>
4789</div>
4790
4791<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>operate silently.</td><td style='text-align:right;'></td></tr></table>
4792
4793<div style="margin: auto;">
4794 <h4><a name="size" id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4>
4795</div>
4796
4797<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the width and height of the image.</td><td style='text-align:right;'></td></tr></table>
4798
4799<p>Use this option to specify the width and height of raw images whose dimensions are unknown such as <kbd>GRAY</kbd>, <kbd>RGB</kbd>, or <kbd>CMYK</kbd>. In addition to width and height, use <a href="#size">-size</a> with an offset to skip any header information in the image or tell the number of colors in a <kbd>MAP</kbd> image file, (e.g. -size 640x512+256).</p>
4800
4801<p>For Photo CD images, choose from these sizes:</p>
4802
4803<pre class="text">
4804 192x128
4805 384x256
4806 768x512
4807 1536x1024
4808 3072x2048
4809</pre>
4810
4811<p>Finally, use this option to choose a particular resolution layer of a JBIG or JPEG image (e.g. -size 1024x768).</p>
4812
4813<div style="margin: auto;">
4814 <h4><a name="sketch" id="sketch"></a>-sketch <em class="arg">radius</em><br />-sketch <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4>
4815</div>
4816
4817<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a pencil sketch.</td><td style='text-align:right;'></td></tr></table>
4818
4819<p>Sketch with the given radius, standard deviation (sigma), and angle. The angle given is the angle toward which the image is sketched. That is the direction people would consider the object is coming from. </p>
4820
4821<div style="margin: auto;">
4822 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
4823</div>
4824
4825<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the number of screen snapshots.</td><td style='text-align:right;'>[<a href="../www/import.html">import</a>]</td></tr></table>
4826
4827<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
4828
4829<div style="margin: auto;">
4830 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
4831</div>
4832
4833<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>negate all pixels above the threshold level.</td><td style='text-align:right;'></td></tr></table>
4834
4835<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4836
4837<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
4838
4839<div style="margin: auto;">
4840 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
4841 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
4842</div>
4843
4844<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </td><td style='text-align:right;'></td></tr></table>
4845
4846
4847<table class="doc">
4848 <tbody>
4849 <tr valign="top">
4850 <th align="left" style="width: 8%">Method</th>
4851 <th align="left">Description</th>
4852 </tr>
4853
4854 <tr valign="top">
4855 <td valign="top">voronoi</td>
4856 <td valign="top">Simply map each pixel to the to nearest color point
4857 given. The result are polygonal 'cells' of solid color. </td>
4858 </tr>
4859
4860 <tr valign="top">
4861 <td valign="top">shepards</td>
4862 <td valign="top">Colors points basied on the ratio of inverse distance
4863 squared. Generating spots of color in a sea of the average of
4864 colors. </td>
4865 </tr>
4866
4867 <tr valign="top">
4868 <td valign="top">barycentric</td>
4869 <td valign="top">three point triangle of color given 3 points.
4870 Giving only 2 points will form a linear gradient between those points.
4871 Gradient is however not restricted to just the triangle or line. </td>
4872 </tr>
4873
4874 <tr valign="top">
4875 <td valign="top">bilinear</td>
4876 <td valign="top">Like barycentric but for 4 points. Less than 4 points
4877 fall back to barycentric. </td>
4878 </tr>
4879
4880 </tbody>
4881</table>
4882
4883<p>The points are placed according to the images location on the virtual
4884canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
4885offset), and do not actually have to exist on the given image, but may be
4886some point beyond the edge of the image. All points are floating point values.
4887</p>
4888
4889<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
4890modified, whcih means the matte/alpha transparency channel is not effected by
4891default. If enabled, the image also needs a the matte/alpha channel to be
4892enabled for this operator to effect an images transparency. This is typical
4893transparency handling for images. </p>
4894
4895<p>All the above methods when given a single point of color will replace all
4896the colors in the image with the color given, regardless of the point. This is
4897logical, and provides an alternative technique to recolor a image to some
4898default value. </p>
4899
4900
4901<div style="margin: auto;">
4902 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
4903</div>
4904
4905<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Splice the current background color into the image.</td><td style='text-align:right;'></td></tr></table>
4906
4907<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. See <a href="#background">-background</a> to reset the background color.</p>
4908
4909<div style="margin: auto;">
4910 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
4911</div>
4912
4913<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image pixels by a random amount.</td><td style='text-align:right;'></td></tr></table>
4914
4915<p>The argument <em class="arg">amount</em> defines the size of the neighborhood around each pixel from which to choose a candidate pixel to swap.</p>
4916
4917<div style="margin: auto;">
4918 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
4919</div>
4920
4921<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>hide watermark within an image.</td><td style='text-align:right;'></td></tr></table>
4922
4923<p>Use an offset to start the image hiding some number of pixels from the beginning of the image. Note this offset and the image size. You will need this information to recover the steganographic image (e.g. display -size 320x256+35 stegano:image.png).</p>
4924
4925<div style="margin: auto;">
4926 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
4927</div>
4928
4929<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>composite two images to create a stereo anaglyph.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
4930
4931<p>The left side of the stereo pair is saved as the red channel of the output image. The right side is saved as the green channel. Red-green stereo glasses are required to properly view the stereo image.</p>
4932
4933<div style="margin: auto;">
4934 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
4935</div>
4936
4937<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel storage type. Here are the valid types:</td><td style='text-align:right;'></td></tr></table>
4938
4939<pre class="text">
4940 char store pixels as unsigned characters
4941 double store pixels as doubles
4942 float store pixels as floats
4943 integer store pixels as integers
4944 long store pixels as longs
4945 quantum store pixels in the native depth of your ImageMagick distribution
4946 short store pixels as unsigned shorts
4947</pre>
4948
4949<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
4950values range from 0 to the maximum value the storage type can support.</p>
4951
4952<div style="margin: auto;">
4953 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
4954</div>
4955
4956<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a type of stretch style for fonts.</td><td style='text-align:right;'></td></tr></table>
4957
4958<p>This setting suggests a type of stretch that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStretch</em> from the following.</p>
4959
4960<pre class="text">
4961 Any
4962 Condensed
4963 Expanded
4964 ExtraCondensed
4965 ExtraExpanded
4966 Normal
4967 SemiCondensed
4968 SemiExpanded
4969 UltraCondensed
4970 UltraExpanded
4971</pre>
4972
4973<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
4974
4975<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p>
4976
4977<div style="margin: auto;">
4978 <h4><a name="strip" id="strip"></a>-strip</h4>
4979</div>
4980
4981<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>strip the image of any profiles or comments.</td><td style='text-align:right;'></td></tr></table>
4982
4983<div style="margin: auto;">
4984 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
4985</div>
4986
4987<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when stroking a graphic primitive.</td><td style='text-align:right;'></td></tr></table>
4988
4989<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4990
4991<p>See <a href="#draw">-draw</a> for further details.</p>
4992
4993<div style="margin: auto;">
4994 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
4995</div>
4996
4997<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the stroke width.</td><td style='text-align:right;'></td></tr></table>
4998
4999<p>See <a href="#draw">-draw</a> for further details.</p>
5000
5001<div style="margin: auto;">
5002 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5003</div>
5004
5005<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font style for text.</td><td style='text-align:right;'></td></tr></table>
5006
5007<p>This setting suggests a font style that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStyle</em> from the following.</p>
5008
5009<pre class="text">
5010 Any
5011 Italic
5012 Normal
5013 Oblique
5014</pre>
5015
5016<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#weight">-weight</a>. </p>
5017
5018<div style="margin: auto;">
5019 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5020</div>
5021
5022<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Swap the positions of two images in the image sequence.</td><td style='text-align:right;'></td></tr></table>
5023
5024<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third images in the current image sequence. Use <a href="#swap">+swap</a> to switch the last two images in the sequence.</p>
5025
5026<div style="margin: auto;">
5027 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5028</div>
5029
5030<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>swirl image pixels about the center.</td><td style='text-align:right;'></td></tr></table>
5031
5032<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5033
5034<div style="margin: auto;">
5035 <h4><a name="taint" id="taint"></a>-taint</h4>
5036</div>
5037
5038<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified even if it isn't.</td><td style='text-align:right;'></td></tr></table>
5039
5040<div style="margin: auto;">
5041 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5042</div>
5043
5044<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>font for writing fixed-width text.</td><td style='text-align:right;'></td></tr></table>
5045
5046<p>Specifies the name of the preferred font to use in fixed (typewriter style) formatted text. The default is 14 point <em class="arg">Courier</em>.</p>
5047
5048<p>You can tag a font to specify whether it is a PostScript, TrueType, or OPTION1 font. For example, <kbd>Courier.ttf</kbd> is a TrueType font and <kbd>x:fixed</kbd> is OPTION1.</p>
5049
5050<div style="margin: auto;">
5051 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5052</div>
5053
5054<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name of texture to tile onto the image background.</td><td style='text-align:right;'></td></tr></table>
5055
5056<div style="margin: auto;">
5057 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5058</div>
5059
5060<!-- {<em class="arg">green,blue,opacity</em>}
5061<p>If the green or blue value is omitted, these channels use the same value as the first one provided. If all three color values are the same, the result is a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used and any partially transparent pixel becomes fully transparent.</p>
5062-->
5063
5064<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply simultaneous black/white threshold to the image.</td><td style='text-align:right;'></td></tr></table>
5065
5066<p>Any pixel values (more specifically, those channels set using <a href="../www/command-line-options.html#channel">&#x2011;channel</a>) that exceed the specified threshold are reassigned the maximum channel value, while all other values are assigned the minimum.</p>
5067
5068<p> The threshold value can be given as a percentage or as an absolute integer value corresponding to the desired channel value. When given as an integer, the minimum attainable value is 0 (corresponding to black when all channels are affected), but the maximum value (corresponding to white) is that of the <kbd>quantum depth</kbd> of the particular build of ImageMagick, and is therefore dependent on the installation. For that reason, a reasonable recommendation for most applications is to specify the threshold values as a percentage.
5069</p>
5070
5071<p> The following would force pixels with red values above 50% to have 100% red values, while those at or below 50% red would be set to 0 in the red channel. The green, blue, and alpha channels (if present) would be unchanged. </p>
5072
5073<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5074<p>As (possibly) impractical but instructive examples, the following would generate an all-black and an all-white image with the same dimensions as the input image.</p>
5075
5076
5077<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -threshold 100% black.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -threshold -1 white.png</span></p>
5078<p>Note that the values of the transparency channel is treated as 'matte'
5079values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5080
5081<p> See also <a href="../www/command-line-options.html#black-threshold">&#x2011;black&#x2011;threshold</a> and <a href="../www/command-line-options.html#white-threshold">&#x2011;white&#x2011;threshold</a>.
5082</p>
5083
5084<div style="margin: auto;">
5085 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5086</div>
5087
5088<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Create a thumbnail of the image.</td><td style='text-align:right;'></td></tr></table>
5089
5090<p>This is similar to <a href="#resize">-resize</a>, except it is optimized for speed and any image profile, other than a color profile, is removed to reduce the thumbnail size. To strip the color profiles as well, add <a href="#strip">-strip</a> just before of after this option.</p>
5091
5092<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5093
5094<div style="margin: auto;">
5095 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5096</div>
5097
5098<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the tile image used for filling a subsequent graphic primitive.</td><td style='text-align:right;'></td></tr></table>
5099
5100<div style="margin: auto;">
5101 <h4>-tile <em class="arg">geometry</em></h4>
5102</div>
5103
5104<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the layout of images .</td><td style='text-align:right;'>[<a href="../www/montage.html">montage</a>]</td></tr></table>
5105
5106<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5107
5108<div style="margin: auto;">
5109 <h4>-tile</h4>
5110</div>
5111
5112<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies that a subsequent composite operation is repeated across and down image.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5113
5114<div style="margin: auto;">
5115 <h4><a name="tile-offset" id="tile-offset"></a>-tile-offset {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4>
5116</div>
5117
5118<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the offset for tile images, relative to the background image it is tiled on.</td><td style='text-align:right;'></td></tr></table>
5119
5120<p>This should be set before the tiling image is set by <a href="#tile" >-tile</a> or <a href="#texture" >-texture</a>, or directly applied for creating a tiled canvas using <kbd>TILE:</kbd> or <kbd>PATTERN:</kbd> input formats. </p>
5121
5122<p>Internally ImageMagick does a <a href="#roll" >-roll</a> of the tile image by the arguments given when the tile image is set. </p>
5123
5124<div style="margin: auto;">
5125 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5126</div>
5127
5128<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Tint the image with the fill color.</td><td style='text-align:right;'></td></tr></table>
5129
5130<p>Tint the image with the fill color.</p>
5131
5132<p>Specify the amount of tinting as a percentage. Pure colors like black, white red, yellow, will not be affected by -tint. Only mid-range colors such as the various shades of grey.</p>
5133
5134<div style="margin: auto;">
5135 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5136</div>
5137
5138<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a title to displayed image.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>, <a href="../www/montage.html">montage</a>]</td></tr></table>
5139
5140<p>Use this option to assign a specific title to the image. This assigned to the image window and is typically displayed in the window title bar. Optionally you can include the image filename, type, width, height, Exif data, or other image attribute by embedding special format characters described under the <a href="#format">-format</a> option.</p>
5141
5142<p>For example,</p>
5143
5144<p class="crtsnip">
5145 -title "%m:%f %wx%h"
5146</p>
5147
5148<p>produces an image title of <kbd>MIFF:bird.miff 512x480</kbd> for an image titled <kbd>bird.miff</kbd> and whose width is 512 and height is 480.</p>
5149
5150
5151<div style="margin: auto;">
5152 <h4><a name="transform" id="transform"></a>-transform</h4>
5153</div>
5154
5155<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image.</td><td style='text-align:right;'></td></tr></table>
5156
5157<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5158
5159<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg</span></p>
5160<div style="margin: auto;">
5161 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5162</div>
5163
5164<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make this color transparent within the image.</td><td style='text-align:right;'></td></tr></table>
5165
5166<p>The <em class="arg">color</em> argument is defined using the format
5167described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5168>-fuzz</a> setting can be used to match and replace colors similar to the one
5169given. </p>
5170
5171<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5172href="#transparent" >-transparent</a> but replaces the matching color same as
5173the current <a href="#fill">-fill</a> color setting. </p>
5174
5175<p>This does not define the 'transparency color' used for color-mapped image
5176formats, such as GIF. For that use <a href="#transparent-color"
5177>-transparent-color</a> </p>
5178
5179<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5180paint any pixel that does not match the target color, with the fill color.</p>
5181
5182
5183<div style="margin: auto;">
5184 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5185</div>
5186
5187<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the transparent color.</td><td style='text-align:right;'></td></tr></table>
5188
5189<p>Sometimes this is used for saving to image formats such as
5190GIF and PNG8 which uses this color to represent boolean transparency. This
5191does not make a color transparent, it only defines what color the transparent
5192color is in the color palette of the saved image. Use <a
5193href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5194
5195<p>This option allows you to have both an opaque visible color, as well as a
5196transparent color of the same color value without conflict. That is, you can
5197use the same color for both the transparent and opaque color areas within an
5198image. This, in turn, frees to you to select a transparent color that is
5199appropriate when an image is displayed by an application that does not handle a
5200transparent color index, while allowing ImageMagick to correctly handle images of this
5201type. </p>
5202
5203<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5204
5205<div style="margin: auto;">
5206 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5207</div>
5208
5209<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the top-left to bottom-right diagonal.</td><td style='text-align:right;'></td></tr></table>
5210
5211<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5212</p>
5213
5214<div style="margin: auto;">
5215 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5216</div>
5217
5218<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <kbd>-flop -rotate 90</kbd>.</td><td style='text-align:right;'></td></tr></table>
5219
5220
5221<div style="margin: auto;">
5222 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5223</div>
5224
5225<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>tree depth for the color reduction algorithm.</td><td style='text-align:right;'></td></tr></table>
5226
5227<p>Normally, this integer value is zero or one. A value of zero or one causes the use of an optimal tree depth for the color reduction algorithm.</p>
5228
5229<p>An optimal depth generally allows the best representation of the source image with the fastest computational speed and the least amount of memory. However, the default depth is inappropriate for some images. To assure the best representation, try values between 2 and 8 for this parameter. Refer to the <a href="../www/quantize.html">color reduction algorithm</a> for more details.</p>
5230
5231<p>The <a href="#colors">-colors</a> or <a href="#monochrome">-monochrome</a> option, or writing to an image format which requires color reduction, is required for this option to take effect.</p>
5232
5233<div style="margin: auto;">
5234 <h4><a name="trim" id="trim"></a>-trim</h4>
5235</div>
5236
5237<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>trim an image.</td><td style='text-align:right;'></td></tr></table>
5238
5239<p>This option removes any edges that are exactly the same color as the corner pixels. Use <a href="#fuzz">-fuzz</a> to make <a href="#trim">-trim</a> remove edges that are nearly the same color as the corner pixels.</p>
5240
5241<p>The page or virtual canvas information of the image is preserved allowing
5242you to extract the result of the <a href="#trim">-trim</a> operation from the
5243image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5244information if it is unwanted.</p>
5245
5246<p>If the trimmed image 'disappears' an warning is produced, and a special
5247single pixel transparent 'missed' image is returned, in the same way as when a
5248<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5249
5250
5251<div style="margin: auto;">
5252 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5253</div>
5254
5255<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image type.</td><td style='text-align:right;'></td></tr></table>
5256 <p>Choose from: <kbd>Bilevel</kbd>, <kbd>Grayscale</kbd>, <kbd>GrayscaleMatte</kbd>, <kbd>Palette</kbd>, <kbd>PaletteMatte</kbd>, <kbd>TrueColor</kbd>, <kbd>TrueColorMatte</kbd>, <kbd>ColorSeparation</kbd>, <kbd>ColorSeparationMatte</kbd>, or <kbd>Optimize</kbd>.</p>
5257
5258<p>Normally, when a format supports different subformats such as grayscale and truecolor, the encoder will try to choose an efficient subformat. The <a href="#type">-type</a> option can be used to overrride this behavior. For example, to prevent a JPEG from being written in grayscale format even though only gray pixels are present, use.</p>
5259
5260<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5261<p>Similarly, use <a href="#type">-type TrueColorMatte</a> to force the encoder to write an alpha channel even though the image is opaque, if the output format supports transparency.</p>
5262
5263<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5264
5265<div style="margin: auto;">
5266 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5267</div>
5268
5269<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the color of the annotation bounding box.</td><td style='text-align:right;'></td></tr></table>
5270
5271<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5272
5273<p>See <a href="#draw">-draw</a> for further details.</p>
5274
5275
5276<div style="margin: auto;">
5277 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5278</div>
5279
5280<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect when image file is modified and redisplay.</td><td style='text-align:right;'></td></tr></table>
5281
5282<p>Suppose that while you are displaying an image the file that is currently displayed is over-written. <kbd>display</kbd> will automagically detect that the input file has been changed and update the displayed image accordingly.</p>
5283
5284
5285<div style="margin: auto;">
5286 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5287</div>
5288
5289<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>discard all but one of any pixel color.</td><td style='text-align:right;'></td></tr></table>
5290
5291
5292<div style="margin: auto;">
5293 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5294</div>
5295
5296<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the units of image resolution.</td><td style='text-align:right;'></td></tr></table>
5297
5298<p>Choose from: <kbd>Undefined</kbd>, <kbd>PixelsPerInch</kbd>, or <kbd>PixelsPerCentimeter</kbd>. This option is normally used in conjunction with the <a href="#density">-density</a> option.</p>
5299
5300
5301<div style="margin: auto;">
5302 <h4><a name="unsharp" id="unsharp"></a>-unsharp <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+amount</em>}{<em class="arg">+threshold</em>}</h4>
5303</div>
5304
5305<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image with an unsharp mask operator.</td><td style='text-align:right;'></td></tr></table>
5306
5307<p>The <a href="#unsharp">-unsharp</a> option sharpens an image. The image is convolved with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 to have the method select a suitable radius.</p>
5308
5309<p>The parameters are:</p>
5310
5311<pre class="text">
5312 radius: The radius of the Gaussian, in pixels, not counting the center
5313 pixel (default 0).
5314 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5315 amount: The fraction of the difference between the original and the blur
5316 image that is added back into the original (default 1.0).
5317 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5318 difference amount (default 0.05).
5319</pre>
5320
5321
5322<div style="margin: auto;">
5323 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5324</div>
5325
5326<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print detailed information about the image when this option preceds the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table>
5327
5328
5329<div style="margin: auto;">
5330 <h4><a name="version" id="version"></a>-version</h4>
5331</div>
5332
5333<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print ImageMagick version string and exit.</td><td style='text-align:right;'></td></tr></table>
5334
5335
5336<div style="margin: auto;">
5337 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5338</div>
5339
5340<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>FlashPix viewing parameters.</td><td style='text-align:right;'></td></tr></table>
5341
5342
5343<div style="margin: auto;">
5344 <h4><a name="vignette" id="vignette"></a>-vignette <em class="arg">radius</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4>
5345</div>
5346
5347<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>soften the edges of the image in vignette style.</td><td style='text-align:right;'></td></tr></table>
5348
5349
5350<div style="margin: auto;">
5351 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5352</div>
5353
5354<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify contents of <em>virtual pixels</em>.</td><td style='text-align:right;'></td></tr></table>
5355
5356<p>This option defines what color source should be used if and when a color
5357lookup completely 'misses' the source image. The color(s) that appear to
5358surround the source image. Generally this color is derived from the source
5359image, but could also be set to a specify background color. </p>
5360
5361<p>Choose from these methods:</p>
5362
5363<pre class="text">
5364 background: the area surrounding the image is the background color
5365 black: the area surrounding the image is black
5366 checker-tile: alternate squares with image and background color
5367 dither: non-random 32x32 dithered pattern
5368 edge: extend the edge pixel toward infinity
5369 gray: the area surrounding the image is gray
5370 horizontal-tile: horizontally tile the image, background color above/below
5371 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5372 mirror: mirror tile the image
5373 random: choose a random pixel from the image
5374 tile: tile the image (default)
5375 transparent: the area surrounding the image is transparent blackness
5376 vertical-tile: vertically tile the image, sides are background color
5377 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5378 white: the area surrounding the image is white
5379</pre>
5380
5381<p>The default value is "edge".</p>
5382
5383<p>This most important for distortion operators such as <a href="#distort"
5384>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5385However it also effects operations that may access pixels just outside the
5386image proper, such as <a href="#convolve">-convolve</a>, <a
5387href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5388
5389<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5390
5391
5392<div style="margin: auto;">
5393 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5394</div>
5395
5396<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Animate images using this X visual type.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
5397
5398<p>Choose from these visual classes:</p>
5399
5400<pre class="text">
5401 StaticGray
5402 GrayScale
5403 StaticColor
5404 PseudoColor
5405 TrueColor
5406 DirectColor
5407 default
5408 visual id
5409</pre>
5410
5411<p>The X server must support the visual you choose, otherwise an error occurs. If a visual is not specified, the visual class that can display the most simultaneous colors on the default screen is chosen.</p>
5412
5413
5414<div style="margin: auto;">
5415 <h4><a name="watermark" id="watermark"></a>-watermark <em
5416 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5417</div>
5418
5419<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Watermark an image using the given percentages of brightness and
5420saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5421
5422<p>Take a grayscale image (with alpha mask) and modify the destination image's
5423brightness according to watermark image's grayscale value and the <em
5424class="arg">brightness</em> percentage. The destinations color saturation
5425attribute is just direct modified by the <em class="arg">saturation</em>
5426percentage, which defaults to 100 percent (no color change). </p>
5427
5428
5429<div style="margin: auto;">
5430 <h4><a name="wave" id="wave"></a>-wave <em class="arg">amplitude</em><br />-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4>
5431</div>
5432
5433<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the columns of an image into a sine wave.</td><td style='text-align:right;'></td></tr></table>
5434
5435<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5436
5437<div style="margin: auto;">
5438 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5439</div>
5440
5441<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font weight for text.</td><td style='text-align:right;'></td></tr></table>
5442
5443<p>This setting suggests a font weight that ImageMagick should try to apply to the currently selected font family. Use a positive integer for <em class="arg">fontWeight</em> or select from the following.</p>
5444
5445<table class="doc">
5446 <col width="25%" />
5447 <col width="75%" />
5448 <thead>
5449 <tr>
5450 <th><em class="arg">fontWeight</em></th>
5451 <th>Description</th>
5452 </tr>
5453 </thead>
5454 <tbody>
5455 <tr><td>All </td> <td>No effect. </td></tr>
5456 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5457 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5458 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5459 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5460 </tbody>
5461 </table>
5462
5463<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5464
5465<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#style">-style</a>. </p>
5466
5467<div style="margin: auto;">
5468 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5469</div>
5470
5471<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>chromaticity white point.</td><td style='text-align:right;'></td></tr></table>
5472
5473<div style="margin: auto;">
5474 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">threshold</em></h4>
5475</div>
5476
5477<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to white all pixels at or above the threshold.</td><td style='text-align:right;'></td></tr></table>
5478
5479<div style="margin: auto;">
5480 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5481</div>
5482
5483<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make the image the background of a window.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>, <a href="../www/display.html">display</a>]</td></tr></table>
5484
5485<p><em class="arg">id</em> can be a window id or name. Specify <kbd>root</kbd> to select X's root window as the target window.</p>
5486
5487<p>By default the image is tiled onto the background of the target window. If <kbd>backdrop</kbd> or <a href="#geometry">-resize</a> are specified, the image is surrounded by the background color. Refer to <kbd>X RESOURCES</kbd> for details.</p>
5488
5489<p>The image will not display on the root window if the image has more unique colors than the target window colormap allows. Use <a href="#colors">-colors</a> to reduce the number of colors.</p>
5490
5491<div style="margin: auto;">
5492 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5493</div>
5494
5495<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the window group.</td><td style='text-align:right;'></td></tr></table>
5496
5497<div style="margin: auto;">
5498 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5499</div>
5500
5501<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write an image sequence.</td><td style='text-align:right;'></td></tr></table>
5502 <p>The image sequence preceding the <a href="#write">-write</a> <em class="arg">filename</em> 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="#write">+write</a> <em class="arg">filename</em> option.</p>
5503
5504<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5505
5506
5507</div>
5508
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