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</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; 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</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>
cristy3ed852e2009-09-05 21:47:34 +0000176
cristyb36feb22010-03-26 16:54:37 +0000177<p>Below is list of command-line options recognized by the ImageMagick <a
178href="../www/command-line-tools.html">command-line
179tools</a>. If you want a description of a particular option, click on the
180option name in the navigation bar above and you will go right to it. Unless
cristya8902942010-07-30 00:49:52 +0000181otherwise noted, each option is recognized by the commands <a href="../www/convert.html">convert</a>, <a href="../www/mogrify.html">mogrify</a>.</p>
cristy3ed852e2009-09-05 21:47:34 +0000182
183<div style="margin: auto;">
184 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
185</div>
186
187<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>
cristy3ed852e2009-09-05 21:47:34 +0000188<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>
189
190<div style="margin: auto;">
191 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4>
192</div>
193
194<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>
195
196<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>
197
198<div style="margin: auto;">
199 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
200</div>
201
202<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>
203
204<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>
205
206<div style="margin: auto;">
207 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4>
208</div>
209
210<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>
211
212<p>This option is enabled by default. An attempt is made to save all
213images of an image sequence into the given output file.
214However, some formats, such as JPEG and PNG, do not support more than one
215image per file, and in that case ImageMagick is forced to write each image as a separate file. As
216such, if more than one image needs to be written, the filename given is
217modified by adding a <a href="#scene">-scene</a> number before the
218suffix, in order to make distinct names for each image. </p>
219
220<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written
221to separate files, whether or not the file format allows multiple images
222per file (for example, GIF, MIFF, and TIFF). </p>
223
224<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>
225
226<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p>
227<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg.
228</p>
229
230<p>In summary, ImageMagick tries to write all images to one file, but will use
cristyefb2bdb2010-11-20 19:35:22 +0000231multiple files if either<br>
232 (1) the output image's file format does not allow multi-image files,<br>
233 (2) the <a href="#adjoin">+adjoin</a> option is given, or<br>
234 (3) a C-style integer format string is present in the output filename. </p>
cristy3ed852e2009-09-05 21:47:34 +0000235
236
237<div style="margin: auto;">
238 <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/>
239 -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>
240</div>
241
242<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>
243
244<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>
245
246<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p>
247
248<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>
249
250<div class="eqn">
251<img alt="affine transformation" src="../images/affine.png"/>
252</div>
253
254<p>
255The 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>
256
257<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>
258
259<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>
260
261<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>
262
263<p class="crtsnip">
264 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em>
265</p>
266
267<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>
268
269<p class="crtsnip">
270 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>
271</p>
272
273<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting
274<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p>
275
276<p class="crtsnip">
277 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em>
278</p>
279
280<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>
281
282<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>
283
284<div style="margin: auto;">
285 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4>
286</div>
287
288<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>
289
290<p>Used to set a flag on an image indicating whether or not to use existing alpha
291channel 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>
292
293
294<table class="doc">
295 <tbody>
296 <tr valign="top">
297 <th align="left" style="width: 8%">type</th>
298 <th align="left">Description</th>
299 </tr>
300
301 <tr valign="top">
cristybac7a162010-06-15 19:57:29 +0000302 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td>
cristy83a272e2010-05-07 20:40:35 +0000303 <td valign="top">
cristybac7a162010-06-15 19:57:29 +0000304 Enable the image's transparency channel. Note normally <kbd>Set</kbd>
305 should be used instead of this, unless you specifically need to
306 preserve existing (but specifically turned <kbd>Off</kbd>) transparency
307 channel. </td></tr>
cristy83a272e2010-05-07 20:40:35 +0000308
309 <tr valign="top">
cristybac7a162010-06-15 19:57:29 +0000310 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td>
cristy3ed852e2009-09-05 21:47:34 +0000311 <td valign="top">
312 Disables the image's transparency channel. Does not delete or change the
cristy83a272e2010-05-07 20:40:35 +0000313 existing data, just turns off the use of that data.</td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000314
315 <tr valign="top">
316 <td valign="top"><kbd>Set</kbd></td>
317 <td valign="top">
cristybac7a162010-06-15 19:57:29 +0000318 Activates the alpha/matte channel. If it was previously turned off
319 then it also resets the channel to opaque. If the image already had
320 the alpha channel turned on, it will have no effect.</td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000321
322 <tr valign="top">
323 <td valign="top"><kbd>Opaque</kbd></td>
324 <td valign="top">
cristybac7a162010-06-15 19:57:29 +0000325 Enables the alpha/matte channel and forces it to be fully opaque.
326 </td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000327
328 <tr valign="top">
329 <td valign="top"><kbd>Transparent</kbd></td>
330 <td valign="top">
cristy83a272e2010-05-07 20:40:35 +0000331 Activates the alpha/matte channel and forces it to be fully
cristybac7a162010-06-15 19:57:29 +0000332 transparent. This effectively creates a fully transparent image the
333 same size as the original and with all its original RGB data still
334 intact, but fully transparent. </td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000335
336 <tr valign="top">
337 <td valign="top"><kbd>Extract</kbd></td>
338 <td valign="top">
339 Copies the alpha channel values into all the color channels and turns
cristybac7a162010-06-15 19:57:29 +0000340 '<kbd>Off</kbd>' the the image's transparency, so as to generate
341 a gray-scale mask of the image's shape. The alpha channel data is left
342 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'.
343 </td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000344
345 <tr valign="top">
346 <td valign="top"><kbd>Copy</kbd></td>
347 <td valign="top">
348 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the
cristybac7a162010-06-15 19:57:29 +0000349 gray-scale intensity of the image, into the alpha channel, converting
350 a gray-scale mask into a transparent shaped mask ready to be colored
351 appropriately. The color channels are not modified. </td></tr>
cristy3ed852e2009-09-05 21:47:34 +0000352
353 <tr valign="top">
354 <td valign="top"><kbd>Shape</kbd></td>
355 <td valign="top">
356 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with
cristyb36feb22010-03-26 16:54:37 +0000357 the current background color. That is the RGB color channels is
358 replaced, with appropriate alpha shape.
cristy3ed852e2009-09-05 21:47:34 +0000359 </td></tr>
360
361 <tr valign="top">
362 <td valign="top"><kbd>Background</kbd></td>
363 <td valign="top">
cristyb36feb22010-03-26 16:54:37 +0000364 Set any fully-transparent pixel to the background color, while leaving
365 it fully-transparent. This can make some image file formats, such as
366 PNG, smaller as the RGB values of transparent pixels are more uniform,
367 and thus can compress better.
cristy3ed852e2009-09-05 21:47:34 +0000368 </td></tr>
369 </tbody>
370</table>
371
372<p>Note that while the <a href="#matte" >+matte</a> operation is the same as
cristybac7a162010-06-15 19:57:29 +0000373"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte"
cristyb36feb22010-03-26 16:54:37 +0000374>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a>
cristybac7a162010-06-15 19:57:29 +0000375Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p>
cristy3ed852e2009-09-05 21:47:34 +0000376
377
378<div style="margin: auto;">
379 <h4><a name="annotate" id="annotate"></a>
380 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br />
381 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br />
382 -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>
383</div>
384
385<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>
386
387<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>
388
389
390<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>
391
392<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>
393
394<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>
395<div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"/></div>
396
397<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>
398
399<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>
400
401<div style="margin: auto;">
402 <h4><a name="antialias" id="antialias"></a>-antialias</h4>
403</div>
404
405<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
406drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table>
407
408<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
409drawn. Use <a href="#antialias">+antialias</a> to disable the addition of
410antialiasing edge pixels. This will then reduce the number of colors added to
411an image to just the colors being directly drawn. That is, no mixed colors
cristyd0bd44a2010-09-24 12:38:11 +0000412are added when drawing such objects. </p>
cristy3ed852e2009-09-05 21:47:34 +0000413
414<div style="margin: auto;">
415 <h4><a name="append" id="append"></a>-append</h4>
416</div>
417
418<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>
419
420<p>This option creates a single longer image image, by joining all the current
421images in sequence top-to-bottom. Use <a href="#append">+append</a> to
422stack images left-to-right. </p>
423
424<p>If they are not of the same width, narrower images are padded with the
425current <a href="#background">-background</a> color setting, and their
cristyd0bda5e2010-09-21 16:22:45 +0000426position relative to each other can be controlled by the current <a
cristy3ed852e2009-09-05 21:47:34 +0000427href="#gravity">-gravity</a> setting. </p>
428
429
430<div style="margin: auto;">
431 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4>
432</div>
433
434<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>
435
436
437<div style="margin: auto;">
438 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4>
439</div>
440
441<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>
442
443<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>
444
445<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p>
446
cristyd934d102009-10-10 12:55:13 +0000447
448
cristy3ed852e2009-09-05 21:47:34 +0000449<div style="margin: auto;">
450 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4>
451</div>
452
453<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>
454
cristyd934d102009-10-10 12:55:13 +0000455<p>This calculates the mean values of an image, then applies a calculated <a
456href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the
457image it will get a have a value of 50%. </p>
458
cristyd0bd44a2010-09-24 12:38:11 +0000459<p>This means that any solid 'gray' image becomes 50% gray. </p>
cristyd934d102009-10-10 12:55:13 +0000460
461<p>This works well for real-life images with little or no extreme dark and
462light areas, but tend to fail for images with large amounts of bright sky or
cristyd0bda5e2010-09-21 16:22:45 +0000463dark shadows. It also does not work well for diagrams or cartoon like images.
cristyd934d102009-10-10 12:55:13 +0000464</p>
465
466<p>It uses the <a href="#channel" >-channel</a> setting, (including the
467'<CODE>sync</CODE>' flag for channel syncronization), to determine which color
cristyd0bd44a2010-09-24 12:38:11 +0000468values is used and modified. As the default <a href="#channel"
469>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels are modified
cristyd934d102009-10-10 12:55:13 +0000470together by the same gamma value, preserving colors. </p>
471
472
473
cristy3ed852e2009-09-05 21:47:34 +0000474<div style="margin: auto;">
475 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4>
476</div>
477
478<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>
479
cristyd934d102009-10-10 12:55:13 +0000480<p>This is a 'perfect' image normalization operator. It finds the exact
cristyd0bda5e2010-09-21 16:22:45 +0000481minimum and maximum color values in the image and then applies a <a
cristyd934d102009-10-10 12:55:13 +0000482href="#level" >-level</a> operator to stretch the values to the full range of
483values. </p>
484
cristy83543962009-10-16 19:04:28 +0000485<p>The operator is not typically used for real-life images, image scans, or
cristyd934d102009-10-10 12:55:13 +0000486JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
487for the <a href="#level" >-level</a> operation. On the other hand it is the
488right operator to use for color stretching gradient images being used to
489generate Color lookup tables, distortion maps, or other 'mathematically'
490defined images. </p>
491
492<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a
493href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch"
494>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
495problems that these operators may have. That is <a href="#auto-level"
cristy83543962009-10-16 19:04:28 +0000496>-auto-level</a> is the perfect or ideal version these operators. </p>
cristyd934d102009-10-10 12:55:13 +0000497
498<p>It uses the <a href="#channel" >-channel</a> setting, (including the
499special '<CODE>sync</CODE>' flag for channel syncronization), to determine
cristyd0bd44a2010-09-24 12:38:11 +0000500which color values are used and modified. As the default <a
cristy83543962009-10-16 19:04:28 +0000501href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the
cristyd0bd44a2010-09-24 12:38:11 +0000502'<CODE>sync</CODE>' ensures that the color channels will are modified
cristy83543962009-10-16 19:04:28 +0000503together by the same gamma value, preserving colors, and ignoring
504transparency. </p>
cristyd934d102009-10-10 12:55:13 +0000505
506
cristy3ed852e2009-09-05 21:47:34 +0000507<div style="margin: auto;">
508 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
509</div>
510
511<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>
512
cristy83543962009-10-16 19:04:28 +0000513<p>This operator reads and resets the EXIF image profile setting 'Orientation'
514and then performs the appropriate 90 degree rotation on the image to orient
515the image, for correct viewing. </p>
516
517<p>This EXIF profile setting is usually set using a gravity sensor in digital
518camara, however photos taken directly downward or upward may not have an
519appropriate value. Also images that have been orientation 'corrected' without
520reseting this setting, may be 'corrected' again resulting in a incorrect
521result. If the he EXIF profile was previously stripped, the <a
522href="#auto-orient" >-auto-orient</a> operator will do nothing. </p>
523
524
cristy3ed852e2009-09-05 21:47:34 +0000525<div style="margin: auto;">
526 <h4><a name="average" id="average"></a>-average</h4>
527</div>
528
529<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>
530
531<p>An error results if the images are not identically sized.</p>
532
cristy3ed852e2009-09-05 21:47:34 +0000533
534<div style="margin: auto;">
535 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
536</div>
537
538<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>
539
540<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>
541
542<div style="margin: auto;">
543 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
544</div>
545
546<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>
547
548<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>
549
550<div style="margin: auto;">
551 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
552</div>
553
554<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>
555
cristye6378132009-10-26 20:05:17 +0000556<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. Modify the benchmark with the -duration to run the benchmark for a fixed number of seconds and -concurrent to run the benchmark in parallel (requires the OpenMP feature).</p>
cristy3ed852e2009-09-05 21:47:34 +0000557
cristye6378132009-10-26 20:05:17 +0000558<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -resize 1000% -bench 5 logo.png</span><span class='crtout'>Performance: 5i 0.875657ips 6.880u 0:05.710</span></p>
559<p>In this example, 5 iterations were completed at 0.875657 iterations per second, using 6.88 seconds of the user's allotted time, for a total elapsed time of 5.71 seconds.</p>
cristy3ed852e2009-09-05 21:47:34 +0000560
561<div style="margin: auto;">
562 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
563</div>
564
565<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>
566
567<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>
568
569<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>
570
571<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
572negative results without clipping to the color value range
573(0..QuantumRange).</p>
574
575<p>See the discussion on HDRI implementations of ImageMagick on the page
576<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.
577</p>
578
579<div style="margin: auto;">
580 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
581</div>
582
583<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>
584
585<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +0000586 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
cristy3ed852e2009-09-05 21:47:34 +0000587</div>
588
cristy5cadd612009-09-21 19:33:41 +0000589<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</td><td style='text-align:right;'></td></tr></table>
590
591<p> The threshold value can be given as a percentage or as an absolute integer value within [0,&nbsp;<em class="QR">QuantumRange</em>] corresponding to the desired <a href="../www/command-line-options.html#channel">&#x2011;channel</a> value. See <a href="../www/command-line-options.html#threshold">&#x2011;threshold</a> for more details on thresholds and resulting values.
592</p>
cristy3ed852e2009-09-05 21:47:34 +0000593
594
595<div style="margin: auto;">
cristy83a272e2010-05-07 20:40:35 +0000596 <h4><a name="blend" id="blend"></a>-blend <em class="arg">geometry</em></h4>
cristy3ed852e2009-09-05 21:47:34 +0000597</div>
598
cristy83a272e2010-05-07 20:40:35 +0000599<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 absolute value or percent.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +0000600
601<p>Blend will average the images together ('plus') according to the
602percentages given and each pixels transparency. If only a single percentage
603value is given it sets the weight of the composite or 'source' image, while
604the background image is weighted by the exact opposite amount. That is a
cristy83a272e2010-05-07 20:40:35 +0000605<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the
606'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p>
cristy3ed852e2009-09-05 21:47:34 +0000607
608
609<div style="margin: auto;">
610 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
611</div>
612
613<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>
614
615<div style="margin: auto;">
616 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
617</div>
618
619<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>
620
621<div style="margin: auto;">
622
623<div style="margin: auto;">
624 <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>
625</div>
626
627<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>
628
cristyb15553d2010-07-03 22:53:14 +0000629<p>Convolve the image with a Gaussian or normal distribution using the given
630<em class="arg" >Sigma</em> value. The formula is:</p>
cristy3ed852e2009-09-05 21:47:34 +0000631
632<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
633</div>
634
cristyb15553d2010-07-03 22:53:14 +0000635<p>The <em class="arg" >Sigma</em> value is the important argument, and
cristyefb2bdb2010-11-20 19:35:22 +0000636determines the actual amount of blurring that will take place. </p>
cristy3ed852e2009-09-05 21:47:34 +0000637
cristyb15553d2010-07-03 22:53:14 +0000638<p>The <em class="arg" >Radius</em> is only used to determine the size of the
cristyefb2bdb2010-11-20 19:35:22 +0000639array which will hold the calculated Gaussian distribution. It should be an
cristyd0bda5e2010-09-21 16:22:45 +0000640integer. If not given, or set to zero, IM will calculate the largest possible
cristyb15553d2010-07-03 22:53:14 +0000641radius that will provide meaningful results for the Gaussian distribution.
642</p>
643
644<p>The larger the <em class="arg" >Radius</em> the radius the slower the
645operation is. However too small a <em class="arg" >Radius</em>, and sever
646aliasing effects may result. As a guideline, <em class="arg" >Radius</em>
647should be at least twice the <em class="arg" >Sigma</em> value, though three
648times will produce a more accurite result. </p>
649
650<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply
651by taking advantage of the separability properties of the distribution. Here
652we apply a single-dimensional Gaussian matrix in the horizontal direction,
653then repeat the process in the vertical direction.</p>
cristy3ed852e2009-09-05 21:47:34 +0000654
655<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
656pixels which are outside the image proper are blurred into the final result.
657</p>
658
659
660<div style="margin: auto;">
661 <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>
662</div>
663
664<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>
665
666<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
667Average (EWA) of the source image, scaled according to the grayscale
668mapping. </p>
669
670<p>The ellipse is weighted with sigma set to the given <em class="arg"
671>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
672defaults to the <em class="arg" >Width</em> for a normal circular Guassian
673weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
674horizontal clock-wise. </p>
675
676<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
677pixels which are outside the image proper are blurred into the final result.
678</p>
679
680
681<div style="margin: auto;">
682 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
683</div>
684
685<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>
686
cristybc9539a2010-08-16 18:06:20 +0000687<p>Set the width and height using the <em class="arg">size</em> portion of the
688<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
689ignored. </p>
cristy3ed852e2009-09-05 21:47:34 +0000690
cristybc9539a2010-08-16 18:06:20 +0000691<p>Set the border color by preceding with the <a
692href="#bordercolor">-bordercolor</a> setting.</p>
cristy3ed852e2009-09-05 21:47:34 +0000693
cristybc9539a2010-08-16 18:06:20 +0000694<p>The <a href="#border">-border</a> operation is affected by the current <a
695href="#compose">-compose</a> setting and assumes that this is using the default
696'<kbd>Over</kbd>' composition method. It generates a image of the appropriate
697size colors by the current <a href="#bordercolor">-bordercolor</a> before
698overlaying the original image in the center of this net image. This means that
699with the default compose method of '<kbd>Over</kbd>' any transparent parts may
cristyd0bda5e2010-09-21 16:22:45 +0000700be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p>
cristybc9539a2010-08-16 18:06:20 +0000701<p>See also the <a href="#frame">-frame</a> option, which has more
702functionality.</p>
cristy3ed852e2009-09-05 21:47:34 +0000703
704<div style="margin: auto;">
705 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
706</div>
707
708<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>
709
710<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
711
712<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
713
714<div style="margin: auto;">
715 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
716</div>
717
718<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>
719
720<div style="margin: auto;">
cristy16ff93c2010-01-13 23:18:07 +0000721 <h4><a name="brightness-contrast" id="brightness-contrast"></a>-brightness-contrast <em class="arg">brightness</em><br />-brightness-contrast <em class="arg">brightness</em>{x<em class="arg">contrast</em>}{<em class="arg">%</em>}}</h4>
722</div>
723
724<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the brightness and/or contrast of the image.</td><td style='text-align:right;'></td></tr></table>
725
cristyefb2bdb2010-11-20 19:35:22 +0000726<p>Brightness and Contrast values apply changes to the input image. They are
727not absolute settings. A brightness or contrast value of zero means no change.
728The range of values is -100 to +100 on each. Positive values increase the
729brightness or contrast and negative values decrease the brightness or contrast.
730To control only contrast, set the brightness=0. To control only brightness,
731set contrast=0 or just leave it off.</p>
cristy16ff93c2010-01-13 23:18:07 +0000732
cristyefb2bdb2010-11-20 19:35:22 +0000733<p>You may also use <a href="#fill">-channel</a> to control which channels to
734apply the brightness and/or contrast change. The default is to apply the same
735transformation to all channels.</p>
cristy16ff93c2010-01-13 23:18:07 +0000736
cristyefb2bdb2010-11-20 19:35:22 +0000737<p>Brightness and Contrast arguments are converted to offset and slope of a
738linear transform and applied
739using <a href="#fill">-function polynomial "slope,offset"</a>.</p>
cristy16ff93c2010-01-13 23:18:07 +0000740
cristyefb2bdb2010-11-20 19:35:22 +0000741<p>The slope varies from 0 at contrast=-100 to almost vertical at
742contrast=+100. For brightness=0 and contrast=-100, the result are totally
743midgray. For brightness=0 and contrast=+100, the result will approach but
744not quite reach a threshold at midgray; that is the linear transformation
745is a very steep vertical line at mid gray.</p>
cristy16ff93c2010-01-13 23:18:07 +0000746
cristyefb2bdb2010-11-20 19:35:22 +0000747<p>Negative slopes, i.e. negating the image, are not possible with this
748function. All achievable slopes are zero or positive.</p>
cristy16ff93c2010-01-13 23:18:07 +0000749
cristyefb2bdb2010-11-20 19:35:22 +0000750<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5
751at brightness=+100. Thus, when contrast=0 and brightness=100, the result is
752totally white. Similarly, when contrast=0 and brightness=-100, the result is
753totally black.</p>
cristy16ff93c2010-01-13 23:18:07 +0000754
cristyefb2bdb2010-11-20 19:35:22 +0000755<p>As the range of values for the arguments are -100 to +100, adding the '%'
756symbol is no different than leaving it off.</p>
cristy16ff93c2010-01-13 23:18:07 +0000757
758<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +0000759 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
760</div>
761
762<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>
763
764<div style="margin: auto;">
765 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
766</div>
767
768<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>
769
cristy71a3f602010-09-15 12:38:16 +0000770<p>This option sets the caption meta-data of an image read in after this
771option has been given. To modify a caption of images already in memory use
772"<kbd><a href="#set">-set</a> caption</kbd>". </p>
773
774<p>The caption can contain special format characters listed in the <a
775href="../www/escape.html">Format and
cristyd0bd44a2010-09-24 12:38:11 +0000776Print Image Properties</a>. These attributes are expanded when the caption
cristy71a3f602010-09-15 12:38:16 +0000777is finally assigned to the individual images. </p>
778
779<p>If the first character of <em class="arg">string</em> is <em
780class="arg">@</em>, the image caption is read from a file titled by the
781remaining characters in the string. Comments read in from a file are literal;
782no embedded formatting characters are recognized.</p>
783
784<p>Caption meta-data ais not visible on the image itself. To do that use the
785<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options
786instead.</p>
787
788<p>For example,</p>
789
790<p class="crtsnip">
791 -caption "%m:%f %wx%h" bird.miff
792</p>
793
794<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming
795that the image <kbd>bird.miff</kbd> has a width of 512 and a height of
796480.</p>
797
798
cristy3ed852e2009-09-05 21:47:34 +0000799<div style="margin: auto;">
800 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
801</div>
802
803<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>
804
805<p>Here is an example color correction collection:</p>
806
807<pre class="text">
cristybac7a162010-06-15 19:57:29 +0000808&lt;?xml version="1.0" encoding="UTF-8"?&gt;
809&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"&gt;
810 &lt;ColorCorrection id="cc06668"&gt;
811 &lt;SOPNode&gt;
812 &lt;Slope&gt; 0.9 1.2 0.5 &lt;/Slope&gt;
813 &lt;Offset&gt; 0.4 -0.5 0.6 &lt;/Offset&gt;
814 &lt;Power&gt; 1.0 0.8 1.5 &lt;/Power&gt;
815 &lt;/SOPNode&gt;
816 &lt;SATNode&gt;
817 &lt;Saturation&gt; 0.85 &lt;/Saturation&gt;
818 &lt;/SATNode&gt;
819 &lt;/ColorCorrection&gt;
820&lt;/ColorCorrectionCollection&gt;
cristy3ed852e2009-09-05 21:47:34 +0000821</pre>
822
823<div style="margin: auto;">
824 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
825</div>
826
827<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>
828
cristyefb2bdb2010-11-20 19:35:22 +0000829<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>,
830<kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>,
831<kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>,
832<kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p>
cristy3ed852e2009-09-05 21:47:34 +0000833
cristy83a272e2010-05-07 20:40:35 +0000834<p>The channels above can also be specified as a comma-separated list or can be
cristyd934d102009-10-10 12:55:13 +0000835abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>',
836'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>',
837'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'.
cristy3ed852e2009-09-05 21:47:34 +0000838
cristy83a272e2010-05-07 20:40:35 +0000839For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels
840you can either use </p>
cristy3ed852e2009-09-05 21:47:34 +0000841<p class="crtsnip">
cristy83a272e2010-05-07 20:40:35 +0000842 -channel Red,Blue
843</p>
844<p>or you can use the short hand form</p>
845<p class="crtsnip">
846 -channel RB
cristy3ed852e2009-09-05 21:47:34 +0000847</p>
848
cristy83a272e2010-05-07 20:40:35 +0000849<p>All the channels that is present in an image can be specified using the
cristybac7a162010-06-15 19:57:29 +0000850special channel type <kbd>All</kbd>. Not all operators are 'channel capable',
851but generally any operators that are generally 'grey-scale' image operators,
852will understand this setting. See individual operator documentation. </p>
853
854<br>
cristy83a272e2010-05-07 20:40:35 +0000855
856<p>On top of the normal channel selection a extra flag can be specified,
857'<kbd>Sync</kbd>'. This is turned on by default and if set means that
cristybac7a162010-06-15 19:57:29 +0000858operators that understand this flag should perform: cross-channel
859syncronization of the channels. If not specified, then most grey-scale
860operators will apply their image processing operations to each individual
861channel (as specified by the rest of the <a href="#channel">-channel</a>
cristyd0bda5e2010-09-21 16:22:45 +0000862setting) completely independently from each other. </p>
cristy83a272e2010-05-07 20:40:35 +0000863
864<p>For example for operators such as <a href="#auto-level">-auto-level</a> and
cristyd0bd44a2010-09-24 12:38:11 +0000865<a href="#auto-gamma">-auto-gamma</a> the color channels are modified
cristy83a272e2010-05-07 20:40:35 +0000866together in exactly the same way so that colors will remain in-sync. Without
cristyd0bd44a2010-09-24 12:38:11 +0000867it being set, then each channel is modified separately and
cristyd0bda5e2010-09-21 16:22:45 +0000868independently, which may produce color distortion. </p>
cristy83a272e2010-05-07 20:40:35 +0000869
cristybac7a162010-06-15 19:57:29 +0000870<p>The <a href="#morphology">-morphology</a> '<kdb>Convolve</kdb>' method
871and the <a href="#compose">-compose</a> mathematical methods, also understands
872the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according
873to the alpha channel (if present). That is to say it will modify the image
874processing with the understanding that fully-transparent colors should not
875contribute to the final result. </p>
876
877Basically, by default, operators work with color channels in syncronous, and
878treats transparency as special, unless the <a href="#channel">-channel</a>
879setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag.
880How each operator does this depends on that operators current implementation.
881Not all operators understands this flag at this time, but that is changing.
882</p>
cristy83a272e2010-05-07 20:40:35 +0000883
884<p>To print a complete list of channel types, use <a href="#list">-list
885channel</a>.</p>
cristy3ed852e2009-09-05 21:47:34 +0000886
cristybac7a162010-06-15 19:57:29 +0000887<br>
cristyd934d102009-10-10 12:55:13 +0000888
889<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
cristybac7a162010-06-15 19:57:29 +0000890'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color
891channels except the transparency channel, and that all the color channels are
892to be modified in exactly the same way, with a understanding of transprancy
893(depending on the operation being applied). The 'plus' form <a
894href="#channel" >+channel</a> will reset the value back to this default. </p>
cristyd934d102009-10-10 12:55:13 +0000895
896<p>Options that are affected by the <a href="#channel" >-channel</a> setting
897include the following.
898
899<a href="#auto-gamma">-auto-gamma</a>,
900<a href="#auto-level">-auto-level</a>,
cristy3ed852e2009-09-05 21:47:34 +0000901<a href="#black-threshold">-black-threshold</a>,
902<a href="#blur">-blur</a>,
cristyb4c03bb2009-09-27 13:55:46 +0000903<a href="#clamp">-clamp</a>,
cristy3ed852e2009-09-05 21:47:34 +0000904<a href="#clut">-clut</a>,
905<a href="#combine">-combine</a>,
cristybac7a162010-06-15 19:57:29 +0000906<a href="#composite">-composite</a> (Mathematical compose methods only),
907<a href="#convolve">-convolve</a>,
cristy3ed852e2009-09-05 21:47:34 +0000908<a href="#contrast-stretch">-contrast-stretch</a>,
909<a href="#evaluate">-evaluate</a>,
910<a href="#function">-function</a>,
911<a href="#fx">-fx</a>,
cristy3ed852e2009-09-05 21:47:34 +0000912<a href="#gaussian-blur">-gaussian-blur</a>,
cristyd934d102009-10-10 12:55:13 +0000913<a href="#hald-clut">-hald-clut</a>,
cristy3ed852e2009-09-05 21:47:34 +0000914<a href="#motion-blur">-motion-blur</a>,
cristybac7a162010-06-15 19:57:29 +0000915<a href="#morphology">-morphology</a>,
cristy3ed852e2009-09-05 21:47:34 +0000916<a href="#negate">-negate</a>,
917<a href="#normalize">-normalize</a>,
918<a href="#ordered-dither">-ordered-dither</a>,
919<a href="#radial-blur">-radial-blur</a>,
920<a href="#random-threshold">-random-threshold</a>,
cristybac7a162010-06-15 19:57:29 +0000921<a href="#separate">-separate</a>,
cristyd934d102009-10-10 12:55:13 +0000922<a href="#threshold">-threshold</a>, and
cristy3ed852e2009-09-05 21:47:34 +0000923<a href="#white-threshold">-white-threshold</a>.
924</p>
925
cristyd0bda5e2010-09-21 16:22:45 +0000926<p>Warning, some operators behave differently when the <a href="#channel"
cristyd934d102009-10-10 12:55:13 +0000927>+channel</a> default setting is in effect, verses ANY user defined <a
cristyd0bda5e2010-09-21 16:22:45 +0000928href="#channel" >-channel</a> setting (including the equivalent of the
cristy83a272e2010-05-07 20:40:35 +0000929default). These operators have yet to be made to understand the newer 'Sync'
930flag. </p>
931
cristybac7a162010-06-15 19:57:29 +0000932<p>For example <a href="#threshold">-threshold</a> will by default gray-scale
933the image before thresholding, if no <a href="#channel" >-channel</a> setting
934has been defined. This is not 'Sync flag controlled, yet. </p>
cristyd934d102009-10-10 12:55:13 +0000935
936<p>Also some operators such as <a href="#blur">-blur</a>, <a
937href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
938color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a
939href="#channel" >-channel</a>. Generally this done to ensure that
940fully-transparent colors are treated as being fully-transparent, and thus any
941underlying 'hidden' color has no effect on the final results. Typically
cristybac7a162010-06-15 19:57:29 +0000942resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a>
cristyd0bda5e2010-09-21 16:22:45 +0000943convolution equivalents however does have a understanding of the 'Sync' flag
cristybac7a162010-06-15 19:57:29 +0000944and will thus handle transparency correctly by default. </p>
cristyd934d102009-10-10 12:55:13 +0000945
cristybac7a162010-06-15 19:57:29 +0000946<p>As a alpha channel is optional within images, some operators will read the
cristyd934d102009-10-10 12:55:13 +0000947color channels of an image as a greyscale alpha mask, when the image has no
cristybac7a162010-06-15 19:57:29 +0000948alpha channel present, and the <a href="#channel" >-channel</a> setting tells
949the operator to apply the operation using alpha channels. The <a
950href="#clut">-clut</a> operator is a good example of this. </p>
cristyd934d102009-10-10 12:55:13 +0000951
cristy3ed852e2009-09-05 21:47:34 +0000952
953<div style="margin: auto;">
cristyb4c03bb2009-09-27 13:55:46 +0000954 <h4><a name="clamp" id="clamp"></a>-clamp</h4>
955</div>
956
957<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Restrict image colors from 0 to the quantum depth.</td><td style='text-align:right;'></td></tr></table>
958
959<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +0000960 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
961</div>
962
963<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>
964
965<div style="margin: auto;">
966 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
967</div>
968
969<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>
970
cristyefb2bdb2010-11-20 19:35:22 +0000971<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>
972and <em class="arg">height</em> given in the of the <em class="arg">size</em>
973portion of the <em class="arg">geometry</em> argument give the number of
974columns and rows to remove. The <em class="arg">offset</em> portion of
975the <em class="arg">geometry</em> argument is influenced by
976a <a href="#gravity">-gravity</a> setting, if present.</p>
cristy3ed852e2009-09-05 21:47:34 +0000977
cristyefb2bdb2010-11-20 19:35:22 +0000978<p>The <a href="#chop">-chop</a> option removes entire rows and columns,
979and moves the remaining corner blocks leftward and upward to close the gaps.</p>
cristy3ed852e2009-09-05 21:47:34 +0000980
981<div style="margin: auto;">
982 <h4><a name="clip" id="clip"></a>-clip</h4>
983</div>
984
985<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>
986
987<p>If a clipping path is present, it is applied to subsequent operations.</p>
988
989<p>For example, in the command</p>
990
991<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
992<p>only the pixels within the clipping path are negated.</p>
993
994<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
995
996<div style="margin: auto;">
997 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
998</div>
999
1000<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>
1001
1002<div style="margin: auto;">
1003 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
1004</div>
1005
1006<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>
1007
1008<div style="margin: auto;">
1009 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
1010</div>
1011
1012<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>
1013
1014<p>Specify the image by its index in the sequence. The first image is index
cristyefb2bdb2010-11-20 19:35:22 +000010150. Negative indexes are relative to the end of the sequence; for
1016example, &minus;1
cristy3ed852e2009-09-05 21:47:34 +00001017represents the last image of the sequence. Specify a range of images with a
cristyefb2bdb2010-11-20 19:35:22 +00001018dash (e.g. 0&minus;4). Separate multiple indexes with commas but no
1019spaces (e.g. 0,2,5). Use <a
cristy3ed852e2009-09-05 21:47:34 +00001020href="#clone">+clone</a> make a copy of the last image in the image
1021sequence.</p>
1022
1023<div style="margin: auto;">
1024 <h4><a name="clut" id="clut"></a>-clut</h4>
1025</div>
1026
1027<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
1028corresponding channel in the second image as a <b>c</b>olor
1029<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
1030
1031<p>The second (LUT) image is ordinarily a gradient image containing the
1032histogram mapping of how each channel should be modified. Typically it is a
1033either a single row or column image of replacement color values. If larger
1034than a single row or column, values are taken from a diagonal line from
1035top-left to bottom-right corners.</p>
1036
1037<p>The lookup is further controlled by the <a
1038href="#interpolate">-interpolate</a> setting, which is especially handy for an
1039LUT which is not the full length needed by the ImageMagick installed Quality
1040(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
1041'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
1042gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
1043lookup of color values. </p>
1044
1045<p>This operator is especially suited to replacing a grayscale image with a
1046specific color gradient from the CLUT image. </p>
1047
1048<p>Only the channel values defined by the <a href="#channel">-channel</a>
1049setting will have their values replaced. In particular, since the default <a
1050href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
1051transparency (alpha/matte channel) is not affected, unless the <a
1052href="#channel">-channel</a> setting is modified. When the alpha channel is
1053set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
1054as the other channels, implying that alpha/matte values are replaced using the
1055alpha/matte values of the original image. </p>
1056
cristyd0bda5e2010-09-21 16:22:45 +00001057<p>If either the image being modified, or the lookup image, contains no
cristy3ed852e2009-09-05 21:47:34 +00001058transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
1059href="#channel">-channel</a> setting includes alpha replacement, then it is
cristyd0bd44a2010-09-24 12:38:11 +00001060assumed that image represents a gray-scale gradient which is used for the
cristy3ed852e2009-09-05 21:47:34 +00001061replacement alpha values. That is you can use a gray-scale CLUT image to
1062adjust a existing images alpha channel, or you can color a gray-scale image
1063using colors form CLUT containing the desired colors, including transparency.
1064</p>
1065
cristyefb2bdb2010-11-20 19:35:22 +00001066<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors
1067according to the lookup of the full color RGB value from a 2D representation
1068of a 3D color cube. </p>
cristy3ed852e2009-09-05 21:47:34 +00001069
1070
1071<div style="margin: auto;">
1072 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
1073</div>
1074
1075<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>
1076
cristyefb2bdb2010-11-20 19:35:22 +00001077<p>Overlay each image in an image sequence according to
1078its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of
1079an animation at each point in the animation sequence. All images should be
1080the same size, and are assigned appropriate GIF disposal settings for the
1081animation to continue working as expected as a GIF animation. Such frames
1082are more easily viewed and processed than the highly optimized GIF overlay
1083images. </p>
cristy3ed852e2009-09-05 21:47:34 +00001084
cristyefb2bdb2010-11-20 19:35:22 +00001085<p>The animation can be re-optimized after processing using
1086the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', although
1087there is no guarantee that the restored GIF animation optimization is
1088better than the original. </p>
cristy3ed852e2009-09-05 21:47:34 +00001089
1090
1091<div style="margin: auto;">
1092 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
1093</div>
1094
1095<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>
1096
cristyefb2bdb2010-11-20 19:35:22 +00001097<p>Specify the amount of colorization as a percentage. Separate colorization
1098values can be applied to the red, green, and blue channels of the image with
1099a comma-delimited list of colorization
1100values (e.g., <kbd>-colorize 0,0,50</kbd>).</p>
cristy3ed852e2009-09-05 21:47:34 +00001101
1102<div style="margin: auto;">
1103 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
1104</div>
1105
1106<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>
1107
1108<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
1109
cristyefb2bdb2010-11-20 19:35:22 +00001110<p>This option only applies when the default X server visual
1111is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer
1112to <a href="#visual">-visual</a> for more details. By default,
1113a shared colormap is allocated. The image shares colors with
1114other X clients. Some image colors could be approximated,
1115therefore your image may look very different than intended.
1116If <kbd>private</kbd> is chosen, the image colors appear exactly
1117as they are defined. However, other clients may go <em>technicolor</em>
1118when the image colormap is installed.</p>
cristy3ed852e2009-09-05 21:47:34 +00001119
1120<div style="margin: auto;">
1121 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
1122</div>
1123
1124<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>
1125
cristyefb2bdb2010-11-20 19:35:22 +00001126<p>The actual number of colors in the image may be less than your request,
1127but never more. Note that this a color reduction option. Images with fewer
1128unique colors than specified by <em class="arg">value</em> will have any
1129duplicate or unused colors removed. The ordering of an existing color
1130palette may be altered. When converting an image from color to grayscale,
1131it is more efficient to convert the image to the gray colorspace before
1132reducing the number of colors. Refer to
1133the <a href="../www/quantize.html">
1134color reduction algorithm</a> for more details.</p>
cristy3ed852e2009-09-05 21:47:34 +00001135
1136<div style="margin: auto;">
cristy2c839602010-04-03 02:32:08 +00001137 <h4><a name="color-matrix" id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4>
1138</div>
1139
1140<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply color correction to the image.</td><td style='text-align:right;'></td></tr></table>
1141
cristyefb2bdb2010-11-20 19:35:22 +00001142<p>This option permits saturation changes, hue rotation, luminance to alpha,
1143and various other effects. Although variable-sized transformation matrices
1144can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6
1145for CMYKA (or RGBA with offsets). The matrix is similar to those used by
1146Adobe Flash except offsets are in column 6 rather than 5 (in support of
1147CMYKA images) and offsets are normalized (divide Flash offset by 255).</p>
cristy2c839602010-04-03 02:32:08 +00001148
1149<p>As an example, to add contrast to an image with offsets, try this command:</p>
1150
1151<pre class="text">
1152convert kittens.jpg -color-matrix \
1153 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \
1154 0.0 1.5 0.0 0.0, 0.0, -0.157 \
1155 0.0 0.0 1.5 0.0, 0.0, -0.157 \
1156 0.0 0.0 0.0 1.0, 0.0, 0.0 \
1157 0.0 0.0 0.0 0.0, 1.0, 0.0 \
1158 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png
1159</pre>
1160<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00001161 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
1162</div>
1163
1164<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>
1165
1166<p>Choices are:</p>
1167
1168<pre class="text">
1169 CMY
1170 CMYK
1171 Gray
1172 HSB
1173 HSL
1174 HWB
1175 Lab
1176 Log
1177 OHTA
1178 Rec601Luma
1179 Rec601YCbCr
1180 Rec709Luma
1181 Rec709YCbCr
1182 RGB
1183 sRGB
1184 Transparent
1185 XYZ
1186 YCbCr
1187 YCC
1188 YIQ
1189 YPbPr
1190 YUV
1191</pre>
1192
1193<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
1194
1195<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>
1196
1197<table class="doc">
1198 <caption>Conversion Of RGB To Other Color Spaces</caption>
1199 <tr><th align="left" valign="middle">CMY</th></tr>
1200 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
1201 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
1202 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
1203 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
1204 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
1205 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
1206 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
1207 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
1208
1209 <tr><th align="left" valign="middle">Gray</th></tr>
1210 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
1211
1212 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
1213 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1214 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
1215 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
1216
1217 <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>
1218 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1219 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
1220 <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>
1221
1222 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
1223 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
1224 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
1225 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
1226
1227 <tr><th align="left" valign="middle">LAB</th></tr>
1228 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1229 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1230 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1231
1232 <tr><th align="left" valign="middle">LOG</th></tr>
1233 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1234 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1235 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1236
1237 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
1238 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
1239 <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>
1240 <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>
1241
1242 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
1243 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
1244
1245 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
1246 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1247 <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>
1248 <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>
1249
1250 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
1251 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
1252
1253 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
1254 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
1255 <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>
1256 <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>
1257
1258 <tr><th align="left" valign="middle">sRGB</th></tr>
1259 <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>
1260 <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>
1261 <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>
1262
1263 <tr><th align="left" valign="middle">XYZ</th></tr>
1264 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
1265 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
1266 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
1267
1268 <tr><th align="left" valign="middle">YCC</th></tr>
1269 <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>
1270 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
1271 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
1272
1273 <tr><th align="left" valign="middle">YCbCr</th></tr>
1274 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1275 <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>
1276 <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>
1277
1278 <tr><th align="left" valign="middle">YIQ</th></tr>
1279 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1280 <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>
1281 <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>
1282
1283 <tr><th align="left" valign="middle">YPbPr</th></tr>
1284 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1285 <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>
1286 <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>
1287
1288 <tr><th align="left" valign="middle">YUV</th></tr>
1289 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1290 <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>
1291 <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>
1292</table>
1293
1294<div style="margin: auto;">
1295 <h4><a name="combine" id="combine"></a>-combine</h4>
1296</div>
1297
1298<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>
1299
1300<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>
1301
1302<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.
1303</p>
1304
cristy4949d522010-03-12 18:41:34 +00001305<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 \ <br/> -combine imagecopy.png</span></p>
cristy3ed852e2009-09-05 21:47:34 +00001306<div style="margin: auto;">
1307 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
1308</div>
1309
1310<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>
1311
cristyd0bda5e2010-09-21 16:22:45 +00001312<p>This option sets the comment meta-data of an image read in after this
cristy71a3f602010-09-15 12:38:16 +00001313option has been given. To modify a comment of images already in memory use
1314"<kbd><a href="#set">-set</a> comment</kbd>". </p>
cristy3ed852e2009-09-05 21:47:34 +00001315
cristy71a3f602010-09-15 12:38:16 +00001316<p>The comment can contain special format characters listed in the <a
1317href="../www/escape.html">Format and
cristyd0bd44a2010-09-24 12:38:11 +00001318Print Image Properties</a>. These attributes are expanded when the comment
cristy71a3f602010-09-15 12:38:16 +00001319is finally assigned to the individual images. </p>
1320
1321<p>If the first character of <em class="arg">string</em> is <em
1322class="arg">@</em>, the image comment is read from a file titled by the
1323remaining characters in the string. Comments read in from a file are literal;
1324no embedded formatting characters are recognized.</p>
1325
1326<p>Comment meta-data are not visible on the image itself. To do that use the
1327<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options
1328instead.</p>
cristy3ed852e2009-09-05 21:47:34 +00001329
1330<p>For example,</p>
1331
1332<p class="crtsnip">
cristy71a3f602010-09-15 12:38:16 +00001333 -comment "%m:%f %wx%h" bird.miff
cristy3ed852e2009-09-05 21:47:34 +00001334</p>
1335
cristy71a3f602010-09-15 12:38:16 +00001336<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming
1337that the image <kbd>bird.miff</kbd> has a width of 512 and a height of
1338480.</p>
cristy3ed852e2009-09-05 21:47:34 +00001339
1340<div style="margin: auto;">
1341 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1342</div>
1343
1344<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>
1345
cristybc9539a2010-08-16 18:06:20 +00001346<p>See <a href="../www/compose.html">Alpha Compositing</a> for
1347a detailed discussion of alpha compositing.</p>
cristy3ed852e2009-09-05 21:47:34 +00001348
cristybc9539a2010-08-16 18:06:20 +00001349<p>This setting effects image processing operators that merge two (or more)
1350images together in some way. This includes the operators,
1351<a href="#composite">-composite</a>,
1352<a href="#layers">-layers</a> composite,
1353<a href="#flatten">-flatten</a>,
1354<a href="#mosaic">-mosaic</a>,
1355<a href="#layers">-layers</a> merge,
1356<a href="#border">-border</a>,
1357<a href="#frame">-frame</a>,
1358and <a href="#extent">-extent</a>. </p>
cristy3ed852e2009-09-05 21:47:34 +00001359
cristybc9539a2010-08-16 18:06:20 +00001360<p>It is also one of the primary options for the "<kbd>composite</kbd>"
1361command. </p>
cristy3ed852e2009-09-05 21:47:34 +00001362
1363
1364<div style="margin: auto;">
1365 <h4><a name="composite" id="composite"></a>-composite</h4>
1366</div>
1367
cristybc9539a2010-08-16 18:06:20 +00001368<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on two images and an optional mask</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00001369
1370<p>Take the first image 'destination' and overlay the second 'source' image
1371according to the current <a href="#compose">-compose</a> setting. The location
1372of the 'source' or 'overlay' image is controlled according to <a
1373href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1374settings. </p>
1375
1376<p>If a third image is given this is treated as a gray-scale 'mask' image
1377relative to the first 'destination' image. This mask will limit what parts of
1378the destination can be modified by the image composition. However for the
1379'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1380Y-displacement image instead. </p>
1381
1382<p>If a <a href="#compose">-compose</a> method requires extra numerical
1383arguments or flags these can be provided by setting the <a
1384href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
cristyd0bda5e2010-09-21 16:22:45 +00001385appropriately for the compose method. </p>
cristy3ed852e2009-09-05 21:47:34 +00001386
1387<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1388image outside the overlay area. You can disable this by setting the special <a
1389href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1390to '<kbd>false</kbd>'. </p>
1391
1392
1393<div style="margin: auto;">
1394 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1395</div>
1396
1397<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>
1398
1399<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>
1400
1401<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1402
1403<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>
1404
1405<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>
1406
1407<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>
1408
1409<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>
1410
1411<div style="margin: auto;">
1412 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1413</div>
1414
1415<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>
1416
1417<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>
1418
1419<p>For a more pronounced effect you can repeat the option:</p>
1420
1421<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1422<div style="margin: auto;">
1423 <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>
1424</div>
1425
1426<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>
1427
cristyd934d102009-10-10 12:55:13 +00001428<p>While performing the stretch, black-out at most <em
1429class="arg" >black-point</em> pixels and white-out at most <em
1430class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most
1431<em class="arg" >black-point %</em> pixels and white-out at most <em
1432class="arg" >white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001433
cristyd934d102009-10-10 12:55:13 +00001434<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch"
1435>-contrast-stretch</a> will black-out at most <em class="arg"
1436>black-point</em> pixels and white-out at most <em class="arg" >total pixels
1437minus white-point</em> pixels. Or, if percent is used, black-out at most <em
1438class="arg">black-point %</em> pixels and white-out at most <em class="arg"
1439>100% minus white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001440
cristyd934d102009-10-10 12:55:13 +00001441<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that
1442the image's min and max values are stretched to 0 and <em class="QR"
1443>QuantumRange</em>, respectively, without any loss of data due to burn-out or
1444clipping at either end. This is not the same as <a href="#normalize"
cristyd4d64ed2010-08-22 22:19:33 +00001445>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or
cristyd934d102009-10-10 12:55:13 +00001446prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p>
cristy3ed852e2009-09-05 21:47:34 +00001447
cristyd934d102009-10-10 12:55:13 +00001448<p>Internally operator works by creating a histogram bin, and then uses that
1449bin to modify the image. As such some colors may be merged together when they
1450originally fell into the same 'bin'. </p>
1451
1452<p>All the channels are normalized in concert by the came amount so as to
1453preserve color integrity, when the default <a href="#channel" >+channel</a>
cristyd0bda5e2010-09-21 16:22:45 +00001454setting is in use. Specifying any other <a href="#channel" >-channel</a>
cristyd934d102009-10-10 12:55:13 +00001455setting will normalize the RGB channels independently.</p>
1456
1457<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
1458normalization of mathematical images. </p>
1459
1460<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00001461
1462
1463<div style="margin: auto;">
1464 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1465</div>
1466
1467<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>
1468
cristy16ff93c2010-01-13 23:18:07 +00001469<p>The <em class="arg">kernel</em> is a matrix specified as
cristyd934d102009-10-10 12:55:13 +00001470a comma-separated list of integers (with no spaces), ordered left-to right,
1471starting with the top row. Presently, only odd-dimensioned kernels are
1472supported, and therefore the number of entries in the specified <em
1473class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
14747<sup>2</sup>=49, etc. </p>
cristy3ed852e2009-09-05 21:47:34 +00001475
cristyd934d102009-10-10 12:55:13 +00001476<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
1477positive and negative results are relative to a user-specified bias value.
1478This is important for non-HDRI compilations of ImageMagick when dealing with
1479convolutions that contain negative as well as positive values. This is
1480especially the case with convolutions involving high pass filters or edge
1481detection. Without an output bias, the negative values is clipped at zero.
cristy3ed852e2009-09-05 21:47:34 +00001482</p>
1483
cristyd934d102009-10-10 12:55:13 +00001484<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
1485negative results without clipping to the color value range (0..QuantumRange).
1486See the discussion on HDRI implementations of ImageMagick on the page <a
1487href="/www/high-dynamic-range.html">High
1488Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a
1489href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1490<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1491entry. </p>
cristy3ed852e2009-09-05 21:47:34 +00001492
cristy3ed852e2009-09-05 21:47:34 +00001493
1494<div style="margin: auto;">
1495 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1496</div>
1497
1498<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>
1499
1500<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>
1501
1502<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>
1503
1504<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>
1505
1506<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>
1507
1508<p>By adding a exclamation character flag to the geometry argument, the
1509cropped images virtual canvas page size and offset is set as if the
1510geometry argument was a viewport or window. This means the canvas page size
1511is set to exactly the same size you specified, the image offset set
1512relative top left corner of the region cropped. </p>
1513
1514<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1515special single pixel transparent 'missed' image is returned, and a 'crop
1516missed' warning given. </p>
1517
cristy739df912009-10-24 16:10:18 +00001518<p>It might be necessary to <a href="#repage" >+repage</a> the image prior to cropping the image to ensure the crop coordinate frame is relocated to the upper-left corner of the visible image.</p>
cristy3ed852e2009-09-05 21:47:34 +00001519
1520<div style="margin: auto;">
1521 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1522</div>
1523
1524<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>
1525
1526<p><em class="arg">Amount</em> defines the number of positions each
1527colormap entry is shifted.</p>
1528
1529
1530<div style="margin: auto;">
1531 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1532</div>
1533
1534<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>
1535
1536<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>
1537
1538
1539<p>For example, to log cache and blob events, use.</p>
1540
1541<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1542<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1543
1544<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1545
1546<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1547
1548<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1549
1550<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>
1551
1552
1553<div style="margin: auto;">
1554 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1555</div>
1556
1557<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>
1558
1559<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1560
1561<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1562
1563
1564<div style="margin: auto;">
1565 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1566</div>
1567
1568<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>
1569
1570<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>
1571
1572<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>
1573
1574<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1575
1576
1577<div style="margin: auto;">
1578 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1579</div>
1580
cristyd0bd44a2010-09-24 12:38:11 +00001581<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add specific global settings generally used to control
cristyd0bda5e2010-09-21 16:22:45 +00001582coders and image processing operations.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00001583
cristyd0bda5e2010-09-21 16:22:45 +00001584<p>This option creates one or more definitions for coders and decoders to use
1585while reading and writing image data. Definitions are generally used to
1586control image file format coder modules, and image processing operations,
1587beyond what is provided by normal means. Defined settings are listed in <a
1588href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format)
1589as "Artifacts". </p>
cristy3ed852e2009-09-05 21:47:34 +00001590
cristyd0bda5e2010-09-21 16:22:45 +00001591<p>If <em class="arg">value</em> is missing for a definition, an empty-valued
1592definition of a flag is created with that name. This used to control on/off
1593options. Use <a href="#define">+define key</a> to remove definitions
1594previously created. Use <a href="#define">+define "*"</a> to remove all
1595existing definitions.</p>
1596
cristyd0bd44a2010-09-24 12:38:11 +00001597<p>The same 'artifact' settings can also be defined using the <a
cristyd0bda5e2010-09-21 16:22:45 +00001598href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg"
cristyd0bd44a2010-09-24 12:38:11 +00001599>value</em>"</a> option, which also allows the use of <a href="../www/escape.html" >Format and Print Image
cristyd0bda5e2010-09-21 16:22:45 +00001600Properties</a> in the defined value. </p>
1601
cristyefb2bdb2010-11-20 19:35:22 +00001602<p>The <em>option</em> and <em>key</em> are case-independent (they are
1603converted to lowercase for use within the decoders) while the <em>value</em>
1604is case-dependent.</p>
1605
cristyd0bda5e2010-09-21 16:22:45 +00001606<p>Such settings are global in scope, and effect all images and operations. </p>
1607
1608<p>The following definitions are just some of the artifacts that are
1609available:</p>
cristy3ed852e2009-09-05 21:47:34 +00001610
1611<ul>
cristyd0bda5e2010-09-21 16:22:45 +00001612
cristy045bd902010-01-30 18:56:24 +00001613<dt>dcm:display-range=reset</dt>
cristyd0bda5e2010-09-21 16:22:45 +00001614<dd>Set the display range to the minimum and maximum pixel values for the
1615 DCM image format.</dd><br />
1616
cristy045bd902010-01-30 18:56:24 +00001617<dt>dot:layout-engine=<em class="arg">value</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001618<dd>Set the specify the layout engine for the DOT image format (e.g.
1619 <kbd>neato</kbd>).</dd><br />
1620
cristy045bd902010-01-30 18:56:24 +00001621<dt>jpeg:extent=<em class="arg">value</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001622<dd>Restrict the maximum JPEG file size, for example <kbd>-define
1623 jpeg:extent=400kb</kbd>.</dd><br />
1624
cristy045bd902010-01-30 18:56:24 +00001625<dt>jpeg:size=<em class="arg">geometry</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001626<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128.
1627 It is most useful for increasing performance and reducing the memory
1628 requirements when reducing the size of a large JPEG image.</dd><br />
1629
cristy045bd902010-01-30 18:56:24 +00001630<dt>jp2:rate=<em class="arg">value</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001631<dd>Specify the compression factor to use while writing JPEG-2000 files. The
1632 compression factor is the reciprocal of the compression ratio. The valid
1633 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined,
1634 this value overrides the -quality setting. A quality setting of 75
1635 results in a rate value of 0.06641.</dd><br />
1636
cristy3ed852e2009-09-05 21:47:34 +00001637<dt>mng:need-cacheoff</dt>
1638 <dd>turn playback caching off for streaming MNG.</dd><br />
cristyd0bda5e2010-09-21 16:22:45 +00001639
cristy045bd902010-01-30 18:56:24 +00001640<dt>png:bit-depth=<em class="arg">value</em></dt>
1641<dt>png:color-type=<em class="arg">value</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001642<dd>desired bit-depth and color-type for PNG output. You can force the PNG
1643 encoder to use a different bit-depth and color-type than it would have
1644 normally selected, but only if this does not cause any loss of image
1645 quality. Any attempt to reduce image quality is treated as an error and no
1646 PNG file is written. E.g., if you have a 1-bit black-and-white image, you
1647 can use these "defines" to cause it to be written as an 8-bit grayscale,
1648 indexed, or even a 64-bit RGBA. But if you have a 16-million color image,
1649 you cannot force it to be written as a grayscale or indexed PNG. If you
1650 wish to do this, you must use the appropriate <a href="#depth">-depth</a>,
1651 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to
1652 reduce the image quality prior to using the PNG encoder. Note that in
1653 indexed PNG files, "bit-depth" refers to the number of bits per index,
cristyefb2bdb2010-11-20 19:35:22 +00001654 which can be 1, 2, 4, or 8. In such files, the color samples always have
cristyd0bda5e2010-09-21 16:22:45 +00001655 8-bit depth.</dd><br />
1656
cristy3ed852e2009-09-05 21:47:34 +00001657<dt>ps:imagemask</dt>
cristyd0bda5e2010-09-21 16:22:45 +00001658<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create
1659 Postscript files that render bilevel images with the Postscript imagemask
1660 operator instead of the image operator.</dd><br />
1661
cristy045bd902010-01-30 18:56:24 +00001662<dt>quantum:format=<em class="arg">type</em></dt>
cristyd0bda5e2010-09-21 16:22:45 +00001663<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point
1664 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode
1665 to preserve negative values. If <a href="#depth">-depth</a> 16 is
cristyd0bd44a2010-09-24 12:38:11 +00001666 included, the result is a single precision floating point format.
1667 If <a href="#depth">-depth</a> 32 is included, the result is
cristyd0bda5e2010-09-21 16:22:45 +00001668 double precision floating point format.</dd>
1669
cristy3ed852e2009-09-05 21:47:34 +00001670</ul>
1671
cristyd0bda5e2010-09-21 16:22:45 +00001672<p>For example, to create a postscript file that will render only the black
1673pixels of a bilevel image, use:</p>
cristy3ed852e2009-09-05 21:47:34 +00001674
1675<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
cristyd0bda5e2010-09-21 16:22:45 +00001676<p>Set attributes of the image registry by prefixing the value with
1677<kbd>registry:</kbd>. For example, to set a temporary path to put work files,
1678use:</p>
cristy3ed852e2009-09-05 21:47:34 +00001679
1680<p class="crtsnip">
1681-define registry:temporary-path=/data/tmp
1682</p>
1683
cristyd0bda5e2010-09-21 16:22:45 +00001684
1685
cristy3ed852e2009-09-05 21:47:34 +00001686<div style="margin: auto;">
1687 <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>
1688</div>
1689
1690<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>
1691
1692<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>
1693
1694<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>
1695
1696
1697<div style="margin: auto;">
1698 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1699</div>
1700
1701<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>
1702
1703<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>
1704
1705
1706<div style="margin: auto;">
1707 <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>
1708</div>
1709
1710<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>
1711
1712<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>
1713
1714<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>
1715
1716<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>
1717
1718<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>
1719
1720<div style="margin: auto;">
1721 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1722</div>
1723
1724<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>
1725
1726<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>
1727
1728<div style="margin: auto;">
1729 <h4><a name="descend" id="descend"></a>-descend</h4>
1730</div>
1731
1732<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>
1733
1734<div style="margin: auto;">
1735 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1736</div>
1737
1738<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>
1739
1740<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>
1741
1742<div style="margin: auto;">
1743 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1744</div>
1745
1746<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>
1747
1748<div style="margin: auto;">
cristy2c839602010-04-03 02:32:08 +00001749 <h4><a name="direction" id="direction"></a>-direction <em class="arg">type</em></h4>
1750</div>
1751
1752<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render text right-to-left or left-to-right.</td><td style='text-align:right;'></td></tr></table>
1753
1754<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00001755 <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>
1756</div>
1757
1758<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>
1759
1760<p>With this option, the 'overlay' image, and optionally the 'mask' image,
cristyd0bd44a2010-09-24 12:38:11 +00001761is used as a displacement map, which is used to displace the lookup of
cristy3ed852e2009-09-05 21:47:34 +00001762what part of the 'background' image is seen at each point of the overlaid
1763area. Much like the displacement map is a 'lens' that redirects light shining
1764through it so as to present a distorted view the original 'background' image
1765behind it. </p>
1766
1767<p>Any perfect grey areas of the displacement map produce a zero
1768displacement of the image. Black areas produce the given maximum negative
1769displacement of the lookup point, while white produce a maximum positive
1770displacement of the lookup. </p>
1771
1772<p>Note that it is the lookup of the 'background' that is displaced, not a
1773displacement of the image itself. As such an area of the displacement map
1774containing 'white' will have the lookup point 'shifted' by a positive amount,
1775and thus generating a copy of the destination image to the right/downward from
1776the correct position. That is the image will look like it may have been
1777'shifted' in a negative left/upward direction. Understanding this is a very
1778important in understanding how displacement maps work. </p>
1779
1780<p>The given arguments define the maximum amount of displacement in pixels
1781that a particular map can produce. If the displacement scale is large enough
cristyd0bda5e2010-09-21 16:22:45 +00001782it is also possible to lookup parts of the 'background' image that lie well
cristy3ed852e2009-09-05 21:47:34 +00001783outside the bounds of the displacement map itself. That is you could very
cristyd0bda5e2010-09-21 16:22:45 +00001784easily copy a section of the original image from outside the overlay area
cristy3ed852e2009-09-05 21:47:34 +00001785into the overlay area. </p>
1786
1787<p>The '%' flag makes the displacement scale relative to the size of the
1788overlay image (100% = half width/height of image). Using '!' switches
1789percentage arguments to refer to the destination image size instead.
1790these flags were added as of IM v6.5.3-5.</p>
1791
1792<p>Normally a single grayscale displacement map is provided, which with the
1793given scaling values will determine a single direction (vector) in which
cristyd0bda5e2010-09-21 16:22:45 +00001794displacements can occur (positively or negatively). However, if you also
cristy3ed852e2009-09-05 21:47:34 +00001795specify a third image which is normally used as a <em class="arg">mask</em>,
cristyd0bd44a2010-09-24 12:38:11 +00001796the <em class="arg">composite image</em> is used for horizontal X
cristy3ed852e2009-09-05 21:47:34 +00001797displacement, while the <em class="arg">mask image</em> is used for vertical Y
1798displacement. This allows you to define completely different displacement
1799values for the X and Y directions, and allowing you to lookup any point within
1800the <em class="arg">scale</em> bounds. In other words each pixel can lookup
cristyd0bda5e2010-09-21 16:22:45 +00001801any other nearby pixel, producing complex 2 dimensional displacements, rather
1802than a simple 1 dimensional vector displacements. </p>
cristy3ed852e2009-09-05 21:47:34 +00001803
cristyd0bda5e2010-09-21 16:22:45 +00001804<p>Alteratively rather than suppling two separate images, as of IM v6.4.4-0,
cristy3ed852e2009-09-05 21:47:34 +00001805you can use the 'red' channel of the overlay image to specify the horizontal
1806or X displacement, and the 'green' channel for the vertical or Y displacement.
1807</p>
1808
cristyd0bd44a2010-09-24 12:38:11 +00001809<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a
cristy3ed852e2009-09-05 21:47:34 +00001810mask the transparency of the destination image. However areas outside the
1811overlaid areas will not be effected. </p>
1812
1813
1814<div style="margin: auto;">
1815 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1816</div>
1817
1818<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>
1819
1820<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1821
1822<div style="margin: auto;">
1823 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1824</div>
1825
1826<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>
1827
1828<p>The layer disposal method defines the way each the displayed image is to be
1829modified after the current 'frame' of an animation has finished being
1830displayed (after its 'delay' period), but before the next frame on an
1831animation is to be overlaid onto the display. </p>
1832
1833<p>Here are the valid methods:</p>
1834
1835<pre class="text">
1836Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1837None 1 Do not dispose, just overlay next frame image.
1838Background 2 Clear the frame area with the background color.
1839Previous 3 Clear to the image prior to this frames overlay.
1840</pre>
1841
1842<p>You can also use the numbers given above, which is what the GIF format
1843uses internally to represent the above settings. </p>
1844
cristyd0bda5e2010-09-21 16:22:45 +00001845<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p>
cristy3ed852e2009-09-05 21:47:34 +00001846
1847<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1848resetting the layer disposal methods of images being read in. </p>
1849
1850<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1851disposal method for images already in memory.</p>
1852
1853<div style="margin: auto;">
1854 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1855</div>
1856
1857<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>
1858
1859
1860<div style="margin: auto;">
1861 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
1862</div>
1863
1864<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>
1865
1866<p>The opacity of the composite image is multiplied by the given percent, then
1867it is composited 'over' the main image. If <em class="arg">src_percent</em>
cristyd0bd44a2010-09-24 12:38:11 +00001868is greater than 100, start dissolving the main image so it becomes
cristy3ed852e2009-09-05 21:47:34 +00001869transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
1870are given, each image are dissolved to the percentages given. </p>
1871
1872<p>Note that dissolve percentages do not add, two opaque images dissolved
1873'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
1874images, you would need to use dissolve values of '50,100'. </p>
1875
1876<div style="margin: auto;">
1877 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
1878</div>
1879
1880<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>
1881
1882<p>The <em class="arg">arguments</em> is a single string containing a list
1883of floating point numbers separated by commas or spaces. The number of
1884and meaning of the floating point values depends on the distortion <em
1885class="arg">method</em> being used. </p>
1886
1887<p>Choose from these distortion types:</p>
1888
1889<table class="doc">
1890 <tr valign="top">
1891 <th align="left" style="width: 8%">Method</th>
1892 <th align="left">Description</th>
1893 </tr>
1894
1895 <tr valign="top">
1896 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
1897 <br/>or &nbsp; <kbd>SRT</kbd></td>
1898 <td valign="top">
1899 Distort image by first scaling and rotating about a given 'center',
1900 before translating that 'center' to the new location, in that order. It
1901 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
1902 distortion, but without shearing effects. It also provides a good way
1903 of rotating and displacing a smaller image for tiling onto a larger
1904 background (IE 2-dimensional animations). <br/>
1905
1906 The number of arguments determine the specific meaning of each
1907 argument for the scales, rotation, and translation operations. <br/>
1908
1909 <table style="margin-left:auto; margin-right:auto;">
1910 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
1911 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
1912 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
1913 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1914 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
1915 <tr><td>5:</td>
1916 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1917 <tr><td>6:</td>
1918 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
1919 <tr><td>7:</td>
1920 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
1921 &nbsp; NewX,NewY</em></td></tr>
1922 </table>
1923
cristyd0bda5e2010-09-21 16:22:45 +00001924 This is actually an alternative way of specifying a 2 dimensional linear
cristy3ed852e2009-09-05 21:47:34 +00001925 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
1926
1927 <tr valign="top">
1928 <td valign="top"><kbd>Affine</kbd></td>
1929 <td valign="top">
1930 Distort the image linearly by moving a list of at least 3 or more sets
cristyd0bda5e2010-09-21 16:22:45 +00001931 of control points (as defined below). Ideally 3 sets or 12 floating
cristy3ed852e2009-09-05 21:47:34 +00001932 point values are given allowing the image to be linearly scaled,
1933 rotated, sheared, and translated, according to those three points. See
1934 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
1935 distortions. <br/>
1936
1937 More than 3 sets given control point pairs (12 numbers) is least
1938 squares fitted to best match a lineary affine distortion. If only 2
1939 control point pairs (8 numbers) are given a two point image translation
cristyd0bda5e2010-09-21 16:22:45 +00001940 rotation and scaling is performed, without any possible shearing,
cristy3ed852e2009-09-05 21:47:34 +00001941 flipping or changes in aspect ratio to the resulting image. If only one
1942 control point pair is provides the image is only translated, (which may
1943 be a floating point non-integer translation). <br/>
1944
1945 This distortion does not include any form of perspective distortion.
1946 </td>
1947
1948 </tr>
1949
1950 <tr valign="top">
1951 <td valign="top"><kbd>AffineProjection</kbd></td>
1952 <td valign="top">
1953 Linearly distort an image using the given Affine Matrix of 6
1954 pre-calculated coefficients forming a set of Affine Equations to map
1955 the source image to the destination image.
1956
1957 <div style="text-align: center"><em>
1958 s<sub>x</sub>, r<sub>x</sub>,
1959 r<sub>y</sub>, s<sub>y</sub>,
1960 t<sub>x</sub>, t<sub>y</sub>
1961 </em></div>
1962
1963 See <a href="#affine" >-affine</a> setting for more detail, and
1964 meanings of these coefficients. <br/>
1965
1966 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
cristyd0bd44a2010-09-24 12:38:11 +00001967 alternative methods of defining this distortion, with ImageMagick doing
1968 the calculations needed to generate the required coefficients. You can
1969 see the internally generated coefficients, by using a <a
1970 href="#verbose" >-verbose</a> setting with those other varients. </td>
cristy3ed852e2009-09-05 21:47:34 +00001971
1972 </tr>
1973
cristy3ed852e2009-09-05 21:47:34 +00001974 <tr valign="top">
cristyd0bd44a2010-09-24 12:38:11 +00001975 <td valign="top"><kbd>BilinearForward</kbd><br/>
1976 <kbd>BilinearReverse</kbd></td>
cristy3ed852e2009-09-05 21:47:34 +00001977 <td valign="top">
cristyd0bd44a2010-09-24 12:38:11 +00001978 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
1979 16 values (see below). Not that lines may not appear straight after
1980 distortion, though the distance between coordinates will remain
1981 consistent. <br/>
1982
1983 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any
1984 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any
1985 quadrilateral to a rectangle, while preserving the straigth line edges
1986 in each case. <br/>
1987
1988 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels
1989 which will be colored using the <a href="#mattecolor" >-mattecolor</a>
1990 color setting. Also if the quadraterial becomes 'flipped' the image
1991 may dissappear. <br/>
1992
1993 There are future plans to produce a true Bilinear distortion that will
1994 attempt to map any quadrilateral to any other quadrilateral, while
1995 preserving edges (and edge distance ratios).
1996
1997 </td>
cristy3ed852e2009-09-05 21:47:34 +00001998 </tr>
cristy3ed852e2009-09-05 21:47:34 +00001999
2000 <tr valign="top">
2001 <td valign="top"><kbd>Perspective</kbd></td>
2002 <td valign="top">
2003 Perspective distort the images, using a list of 4 or more sets of
2004 control points (as defined below). More that 4 sets (16 numbers) of
2005 control points provide least squares fitting for more accurate
2006 distortions (for the purposes of image registration and panarama
2007 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2008 linear distortion. <br/>
2009
2010 Perspective Distorted images ensures that straight lines remain
2011 straight, but the scale of the distorted image will vary. The horizon
2012 is anti-aliased, and the 'sky' color may be set using the
2013 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2014 </tr>
2015
2016 <tr valign="top">
2017 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2018 <td valign="top">
cristyd0bda5e2010-09-21 16:22:45 +00002019 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8
cristy3ed852e2009-09-05 21:47:34 +00002020 pre-calculated coefficients. You can get these coefficients by looking
2021 at the <a href="#verbose" >-verbose</a> output of a
2022 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2023 If the last two perspective scaling coefficients are zero, the
2024 remaining 6 represents a transposed 'Affine Matrix'. </td>
2025
2026 </tr>
2027
2028 <tr valign="top">
2029 <td valign="top"><kbd>Arc</kbd></td>
2030 <td valign="top">
2031 Arc the image (variation of polar mapping) over the angle given around
2032 a circle. <br/>
2033 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2034 <tr valign="top"><td>Argument</td>
2035 <td>Meaning</td></tr>
2036 <tr valign="top"><td><em>arc_angle</em></td>
2037 <td>The angle over which to arc the image side-to-side</td></tr>
2038 <tr valign="top"><td><em>rotate_angle</em></td>
2039 <td>Angle to rotate resulting image from vertical center</td></tr>
2040 <tr valign="top"><td><em>top_radius</em></td>
2041 <td>Set top edge of source image at this radius</td></tr>
2042 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2043 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2044 </table>
2045
2046 The resulting image is always resized to best fit the resulting image,
2047 (as if using <a href="#distort" >+distort</a>) while attempting to
2048 preserve scale and aspect ratio of the original image as much as
2049 possible with the arguments given by the user. All four arguments will
2050 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2051
2052 This a variation of a polar distortion designed to try to preserve the
2053 aspect ratio of the image rather than direct Cartesian to Polar
2054 conversion. </td>
2055 </tr>
2056
2057 <tr valign="top">
2058 <td valign="top"><kbd>Polar</kbd></td>
2059 <td valign="top">
2060 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2061 the image. that is the height of the input image is mapped to the
2062 radius limits, while the width is wrapped around between the
2063 angle limits. <br/>
2064
2065 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2066
2067 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2068 center to the center of the image, and the angles going from -180 (top)
2069 to +180 (top). If <em>Rmax</em> is given the special value of
2070 '<code>0</code>', the the distance from the center to the nearest edge
2071 is used for the radius of the output image, which will ensure the whole
2072 image is visible (though scaled smaller). However a special value of
2073 '<code>-1</code>' will use the distance from the center to the furthest
2074 corner, This may 'clip' the corners from the input rectangular image,
2075 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2076 the same arguments. <br/>
2077
2078 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2079 output image center will default to <code>0,0</code> of the virtual
2080 canvas, and the image size adjusted to ensure the whole input image is
2081 made visible in the output image on the virtual canvas. </td>
2082
2083 </tr>
2084
2085 <tr valign="top">
2086 <td valign="top"><kbd>DePolar</kbd></td>
2087 <td valign="top">
2088 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2089 but generates the reverse Polar to Cartesian distortion. <br/>
2090
2091 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2092 the corners of the input image. However using the special
2093 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2094 distance) will ensure the whole distorted image is preserved in the
2095 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2096 reverse the distortion re-producing the original.
2097
2098 Note that as this distortion requires the area resampling of a circular
2099 arc, which can not be handled by the builtin EWA resampling function.
cristyd0bda5e2010-09-21 16:22:45 +00002100 As such the normal EWA filters are turned off. It is recommended some
cristy3ed852e2009-09-05 21:47:34 +00002101 form of 'super-sampling' image processing technique be used to produce
2102 a high quality result. </td>
2103
2104 </tr>
2105
2106 <tr valign="top">
2107 <td valign="top"><kbd>Barrel</kbd></td>
2108 <td valign="top">
2109 Given the four coefficients (A,B,C,D) as defined by <a
2110 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
cristyd0bda5e2010-09-21 16:22:45 +00002111 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to
cristy3ed852e2009-09-05 21:47:34 +00002112 correct radial lens distortions. That is in photographs, make straight
2113 lines straight again. <br/>
2114
2115 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2116 <em>X</em> , <em>Y</em> ] ] <br/>
2117 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2118 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2119 [ <em>X</em> , <em>Y</em> ] <br/>
2120 So that it forms the function <br/>
2121 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2122 <em>C</em>*r + <em>D</em> )<br/>
2123
2124 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2125 (defaulting to the center of the image). <br/>
2126 The second form is typically used to distort images, rather than
2127 correct lens distortions. <br/>
2128 </td>
2129
2130 </tr>
2131
2132 <tr valign="top">
2133 <td valign="top"><kbd>BarrelInverse</kbd></td>
2134 <td valign="top">
2135 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2136 arguments, and argument handling. However it uses the inverse
2137 of the radial polynomial,
2138 so that it forms the function <br/>
2139 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
cristyd0bd44a2010-09-24 12:38:11 +00002140 <em>C</em>*r + <em>D</em> )<br/>
2141 Note that this is not the reverse of the '<kbd>Barrel</kbd>'
2142 distortion, just a different barrel-like radial distortion method.
2143
cristy3ed852e2009-09-05 21:47:34 +00002144 </td>
2145 </tr>
2146
2147 <tr valign="top">
2148 <td valign="top"><kbd>Shepards</kbd></td>
2149 <td valign="top">
2150 Distort the given list control points (any number) using an Inverse
2151 Squared Distance Interpolation Method (<a
cristyd0bd44a2010-09-24 12:38:11 +00002152 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards
2153 Method</a>). The control points in effect do 'localized' displacement
2154 of the image around the given control point (preserving the look and
2155 the rotation of the area near the control points. For best results
2156 extra control points should be added to 'lock' the positions of the
2157 corners, edges and other unchanging parts of the image, to prevent
2158 their movement. <br/>
cristy3ed852e2009-09-05 21:47:34 +00002159
cristyd0bd44a2010-09-24 12:38:11 +00002160 The distortion has been likened to 'taffy pulling' using nails, or
2161 pins' stuck in a block of 'jelly' which is then moved to the new
2162 position, distorting te surface of the jelly. <br/>
cristy3ed852e2009-09-05 21:47:34 +00002163
cristyd0bd44a2010-09-24 12:38:11 +00002164 Internally it is equivelent to generating a displacement map (see <a
2165 href="#displace" >-displace</a>) for source image color look-up using
2166 the <a href="#sparse-color" >-sparse-color</a> method of the same name.
2167
2168 </td>
cristy3ed852e2009-09-05 21:47:34 +00002169 </tr>
2170
2171</table>
2172
cristyd0bd44a2010-09-24 12:38:11 +00002173<p>To print a complete list of distortion methods, use <a href="#list">-list
2174distort</a>.</p>
cristy3ed852e2009-09-05 21:47:34 +00002175
2176<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2177'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2178defining how these points in the given image should be distorted in the
2179destination image. Each set of four floating point values represent a source
2180image coordinate, followed immediately by the destination image coordinate.
2181This produces a list of values such as...</p>
2182<div style="text-align: center"><em>
2183 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2184 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2185 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2186 ... &nbsp;
2187 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2188</em></div>
2189<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2190destination image. </p>
2191
2192<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2193needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2194perspective distortion of the built-in "rose:" image. Note how spaces were
2195used to group the 4 sets of coordinate pairs, to make it easier to read and
2196understand.</p>
2197
2198<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
cristyd0bd44a2010-09-24 12:38:11 +00002199convert rose: -virtual-pixel black \<br/>
2200 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/>
2201 rose_3d_rotated.gif</span></p>
2202<p>If more that the required number of coordinate pairs are given for
2203a distortion, the distortion method is 'least squares' fitted to produce the
2204best result for all the coordinate pairs given. If less than the ideal number
2205of points are given, the distort will generally fall back to a simpler form of
2206distortion that can handles the smaller number of coordinates (usally a linear
2207'<kbd>Affine</kbd>' distortion). </p>
cristy3ed852e2009-09-05 21:47:34 +00002208
cristyd0bda5e2010-09-21 16:22:45 +00002209<p>By using more coordinates you can make use of image registration tool to
cristyd0bd44a2010-09-24 12:38:11 +00002210find matching coordinate pairs in overlapping images, so as to improve the
2211'fit' of the distortion. Of course a bad coordinate pair can also make the
2212'fit' worse. Caution is always advised. </p>
cristy3ed852e2009-09-05 21:47:34 +00002213
2214<p>Colors are acquired from the source image according to the <a
2215href="#interpolate" >-interpolate</a> color lookup setting, when the image is
cristyd0bd44a2010-09-24 12:38:11 +00002216magnified. However if the viewed image is minified (image becomes smaller),
2217a special area resampling function (added ImageMagick v6.3.5-9), is used to
2218produce a higher quality image. For example you can use
2219a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all
2220the way to the horizon. </p>
cristy3ed852e2009-09-05 21:47:34 +00002221
cristyd0bd44a2010-09-24 12:38:11 +00002222<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2223convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/>
2224 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/>
2225 checks_tiled.jpg</span></p>
cristy3ed852e2009-09-05 21:47:34 +00002226<p>Note that a infinitely tiled perspective images involving the horizon can
2227be very slow to generate due to the use of the high quality 'area resampling'
2228function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2229using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2230(recommended if you plan to use super-sampling instead). </p>
2231
2232<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2233'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2234will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2235pixels. If you do not what these pixels to be visible, set the color to match
2236the rest of the ground. </p>
2237
2238<p>The output image size will by default be the same as the input image. This
2239means that if the part of the distorted image falls outside the viewed area of
cristyd0bd44a2010-09-24 12:38:11 +00002240the 'distorted space', those parts is clipped and lost. However if you use
2241the plus form of the operator (<a href="#distort" >+distort</a>) the operator
2242will attempt (if possible) to show the whole of the distorted image, while
2243retaining a correct 'virtual canvas' offset, for image layering. This offset
2244may need to be removed using <a href="#repage" >+repage</a>, to remove if it
2245is unwanted. </p>
cristy3ed852e2009-09-05 21:47:34 +00002246
2247<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2248option:distort:viewport {geometry_string}</kbd>" setting which will specify
2249the size and the offset of the generated 'viewport' image of the distorted
2250image space.</p>
2251
2252<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2253{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2254that factor without changing the viewed contents of the distorted image. This
2255can be used either for 'super-sampling' the image for a higher quality result,
2256or for panning and zooming around the image (with appropriate viewport
2257changes, or post-distort cropping and resizing). </p>
2258
2259<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2260href="#distort" >-distort</a> to attempt to output the internal coefficients,
2261and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2262and debugging purposes. This many not be available for all distorts. </p>
2263
2264<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2265produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2266and/or <a href="#shear" >-shear</a> operation, with more control of due to the
cristyd0bd44a2010-09-24 12:38:11 +00002267above settings. It is algorithmically slower however, though that may not be
2268the case in ImageMagick's implementation. </p>
cristy3ed852e2009-09-05 21:47:34 +00002269
2270
2271<div style="margin: auto;">
2272 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2273</div>
2274
2275<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>
2276
cristyd0bda5e2010-09-21 16:22:45 +00002277<p>Dithering places two or more colors in neighboring 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>
cristy3ed852e2009-09-05 21:47:34 +00002278
2279<p>Dithering is turned on by default, to turn it off use the plus form of the
2280setting, <a href="#dither">+dither</a>. This will also also render PostScript
2281without text or graphic aliasing. Disabling dithering often (but not always)
2282leads to faster process, a smaller number of colors, but more cartoon like
2283image coloring. Generally resulting in 'color banding' effects in areas with
2284color gradients. </p>
2285
2286<p>The color reduction operators <a href="#colors">-colors</a>, <a
2287href="#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>
2288
2289<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>
2290
2291
2292<div style="margin: auto;">
2293 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2294</div>
2295
2296<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>
2297
2298<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>
2299
2300<p>The shape primitives:</p>
2301
2302<pre class="text">
2303 point x,y
2304 line x0,y0 x1,y1
2305 rectangle x0,y0 x1,y1
2306 roundRectangle x0,y0 x1,y1 wc,hc
2307 arc x0,y0 x1,y1 a0,a1
2308 ellipse x0,y0 rx,ry a0,a1
2309 circle x0,y0 x1,y1
2310 polyline x0,y0 ... xn,yn
2311 polygon x0,y0 ... xn,yn
2312 bezier x0,y0 ... xn,yn
2313 path path specification
2314 image operator x0,y0 w,h filename
2315</pre>
2316
2317<p>The text primitive:</p>
2318
2319<pre class="text">
2320 text x0,y0 string
2321</pre>
2322<p>The text gravity primitive:</p>
2323
2324<pre class="text">
2325 gravity NorthWest, North, NorthEast, West, Center,
2326 East, SouthWest, South, or SouthEast
2327</pre>
2328
2329<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>
2330
2331<p>The transformation primitives:</p>
2332
2333<pre class="text">
2334 rotate degrees
2335 translate dx,dy
2336 scale sx,sy
2337 skewX degrees
2338 skewY degrees
2339</pre>
2340
2341<p>The pixel operation primitives:</p>
2342
2343<pre class="text">
2344 color x0,y0 method
2345 matte x0,y0 method
2346</pre>
2347
2348<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>
2349
2350<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>
2351
2352<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2353
2354<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2355
2356<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>
2357
2358<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2359
2360<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>
2361
2362<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>
2363
2364<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>.
2365</p>
2366
2367<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2368
2369<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2370
2371<p class="crtsnip">
2372 -draw 'circle 100,100 150,150'
2373</p>
2374
2375<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
2376draw 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>
2377
2378<p class="crtsnip">
2379 -draw 'bezier 20,50 45,100 45,0 70,50'
2380</p>
2381<p class="crtsnip">
2382 -draw 'bezier 70,50 95,100 95,0 120,50'
2383</p>
2384
2385
2386<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>
2387
2388<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>
2389
2390<p class="crtsnip">
2391 -draw 'image SrcOver 100,100 225,225 image.jpg'
2392</p>
2393
cristybc9539a2010-08-16 18:06:20 +00002394<p>You can use 0,0 for the image size, which means to use the actual
2395dimensions found in the image header. Otherwise, it is scaled to the given
2396dimensions. See <a href="../www/compose.html">Alpha Compositing</a> for
2397a detailed discussion of alpha composition methods that are available. </p>
cristy3ed852e2009-09-05 21:47:34 +00002398
2399<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>
2400
2401<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2402
2403<p class="crtsnip">
2404 -draw 'text 100,100 "Works like magick!"'
2405</p>
2406
2407<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2408
2409<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>
2410
2411<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2412
2413<p>The <kbd>scale</kbd> primitive scales them.</p>
2414
2415<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>
2416
2417<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
2418matrix.</p>
2419
2420<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>
2421
2422<pre class="text">
2423 point
2424 replace
2425 floodfill
2426 filltoborder
2427 reset
2428</pre>
2429
2430<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>
2431
2432<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>
2433
2434<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>
2435
2436<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2437
2438<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2439
2440
2441<div style="margin: auto;">
2442 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2443</div>
2444
2445<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>
2446
2447<div style="margin: auto;">
2448 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2449</div>
2450
2451<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>
2452
2453<div style="margin: auto;">
2454 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2455</div>
2456
2457<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>
2458
2459<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2460
2461<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2462
cristyd0bda5e2010-09-21 16:22:45 +00002463
2464
cristy3ed852e2009-09-05 21:47:34 +00002465<div style="margin: auto;">
2466 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2467</div>
2468
2469<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>
2470
2471<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>
2472
2473<div style="margin: auto;">
2474 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2475</div>
2476
2477<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>
2478
2479<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2480
2481<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2482
2483
2484<div style="margin: auto;">
2485 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2486</div>
2487
2488<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>
2489
2490
2491<div style="margin: auto;">
2492 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2493</div>
2494
2495<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>
2496
2497<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>
2498
2499<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2500
2501<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>
2502
2503<div style="margin: auto;">
2504 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2505</div>
2506
2507<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>
2508
2509<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>
2510
2511<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>
2512
2513<table class="doc">
2514 <col width="25%" />
2515 <col width="75%" />
2516 <thead>
2517 <tr>
2518 <th><em class="arg">operator</em></th>
2519 <th>Summary (see further below for details)</th>
2520 </tr>
2521 </thead>
2522 <tbody>
2523
cristy3c98a4f2010-08-13 20:09:41 +00002524 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr>
cristy3ed852e2009-09-05 21:47:34 +00002525 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2526 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2527 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2528 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2529 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
cristy5063d812010-10-19 16:28:10 +00002530 <tr><td>Exp </td> <td>base-e exponential function</td></tr>
2531 <tr><td>Exponential </td> <td>base-e exponential function</td></tr>
cristy3ed852e2009-09-05 21:47:34 +00002532 <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>
2533 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2534 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
cristy63fed272010-03-07 19:08:45 +00002535 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr>
cristy3ed852e2009-09-05 21:47:34 +00002536 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2537 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2538 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2539 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2540 <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>
2541 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2542 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2543 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2544 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2545
2546 <tr><td>&nbsp;</td></tr>
2547
2548 <tr><td>Gaussian-noise</td></tr>
2549 <tr><td>Impulse-noise</td></tr>
2550 <tr><td>Laplacian-noise</td></tr>
2551 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2552 <tr><td>PoissonNoise</td></tr>
2553 <tr><td>Uniform-noise</td></tr>
2554
2555 <tr><td>&nbsp;</td></tr>
2556
2557 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2558 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2559 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2560 </tbody>
2561 </table>
2562
2563<p>The specified functions are applied only to each previously set <a
2564href="#channel" >-channel</a> in the image. If necessary, the results of the
2565calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2566class="QR">QuantumRange</em>]. The transparency channel of the image is
2567represented as a 'alpha' values (0 = fully transparent), so, for example, a
2568<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2569semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2570as a percentage of the <em class="QR">QuantumRange</em>.</p>
2571
2572<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2573<a href="#list">-list evaluate</a>.</p>
2574
2575<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2576<kbd>Multiply</kbd> methods can also be achieved using either the <a
2577href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2578appropriate argument, to linearly modify the overall range of color values.
2579Please note, however, that <a href="#level" >-level</a> treats transparency as
2580'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2581'alpha' values.</p>
2582
2583<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>
2584
cristyce66ab12010-10-21 23:36:32 +00002585<p><kbd>Exp or Exponential</kbd> has been added as of ImageMagick 6.6.5-1 and works on normalized pixel values. The <em class="arg">value</em> used with <kbd>Exp</kbd> should be negative so as to produce a decaying exponential function. Non-negative values will always produce results larger unity and thus outside the interval [0,&nbsp;<em class="QR">QuantumRange</em>]. The formula is expressed below. </p>
2586
2587 <div style="text-align:center;">
2588 exp(<em class="arg">value</em> &times; <b><em>u</em></b>)
2589 </div>
2590
2591<p> If the input image is squared, for example, using <a
2592href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p>
2593
cristy3ed852e2009-09-05 21:47:34 +00002594<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>
2595
2596 <div style="text-align:center;">
2597 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2598 </div>
2599
2600<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2601normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2602href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2603to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2604with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2605with <kbd>Pow</kbd>.</p>
2606
2607<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2608converts the image values into a value according to a (co)sine wave function.
2609The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2610is biased 50% and normalized by 50% so as to fit in the respective color value
2611range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2612function (its frequency), and thus determines the number of 'waves' that will
2613be generated over the input color range. For example, if the <em
2614class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2615class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2616then the effective period is the <em>half</em> the <em
2617class="QR">QuantumRange</em>.
2618
2619 <div style="text-align:center;">
2620 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2621 </div>
2622
2623See also the <a href="#function" >-function</a> operator, which is a
2624multi-value version of evaluate. </P>
2625
cristy63fed272010-03-07 19:08:45 +00002626<div style="margin: auto;">
2627 <h4><a name="evaluate-sequence" id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4>
2628</div>
2629
2630<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 over a sequence of images.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00002631
2632<div style="margin: auto;">
2633 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2634</div>
2635
2636<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>
2637
cristy3e2860c2010-01-24 01:36:30 +00002638<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. To specify how to compose the image with the background, use <a href="#compose" >-compose</a>.</p>
cristy549177c2010-11-11 13:51:21 +00002639<p>This command reduces or expands a JPEG image to fit on an 800x600
2640display. If the aspect ratio of the input image isn't exactly 4:3, then the
2641image is centered on an 800x600 black canvas: </p>
2642
2643<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert input.jpg -resize 800x600 -background black -compose Copy \ <br /> -gravity center -extent 800x600 -quality 92 output.jpg</span></p>
2644
cristy3ed852e2009-09-05 21:47:34 +00002645
2646<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>
2647
2648<div style="margin: auto;">
2649 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2650</div>
2651
2652<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>
2653
2654<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2655
cristy4949d522010-03-12 18:41:34 +00002656<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br/> 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]' \ <br/> image.rgb image.png</span></p><p>If you omit the offsets, as in</p>
cristy3ed852e2009-09-05 21:47:34 +00002657
cristy4949d522010-03-12 18:41:34 +00002658<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 \ <br/> image.rgb image.png</span></p>
cristyd0bd44a2010-09-24 12:38:11 +00002659<p>the image is <em>resized</em> to the specified dimensions instead,
cristy3ed852e2009-09-05 21:47:34 +00002660equivalent to:</p>
2661
2662<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>
2663<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>
2664
2665<div style="margin: auto;">
2666 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2667</div>
2668
2669<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>
2670
2671<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).
2672</p>
2673
2674<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>.
2675</p>
2676
2677<div style="margin: auto;">
cristy7396d882010-01-27 02:37:56 +00002678 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4>
2679</div>
2680
2681<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</td><td style='text-align:right;'></td></tr></table>
2682
2683<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00002684 <h4><a name="fft" id="fft"></a>-fft</h4>
2685</div>
2686
2687<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>
2688
cristyb36feb22010-03-26 16:54:37 +00002689<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It 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>
cristy3ed852e2009-09-05 21:47:34 +00002690
cristyd0bd44a2010-09-24 12:38:11 +00002691<p>A single image name is provided as output for this option. However, the output result will have two components. It is 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>
cristy3ed852e2009-09-05 21:47:34 +00002692
2693<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>
2694
2695<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2696<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>
2697
2698<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2699<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>
2700
cristyd0bd44a2010-09-24 12:38:11 +00002701<p>The input image can be any size, but if not square and even-dimensioned, it is 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 is square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p>
cristy3ed852e2009-09-05 21:47:34 +00002702
2703<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>
2704
2705<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2706 -evaluate log 1000 fft_image_spectrum.png</span></p>
2707<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>
2708
2709<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2710
2711<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>
2712
2713<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>
2714
cristyd0bd44a2010-09-24 12:38:11 +00002715<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> is also square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a>
cristy3ed852e2009-09-05 21:47:34 +00002716
2717<p>See the discussion on HDRI implementations of ImageMagick on the page
2718<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.
2719</p>
2720
2721
2722<div style="margin: auto;">
2723 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2724</div>
2725
2726<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>
2727
2728<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>
2729
2730<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2731
2732<p>For example,</p>
2733
2734<p class="crtsnip">
2735 -fill blue
2736</p>
2737<p class="crtsnip">
2738 -fill "#ddddff"
2739</p>
2740<p class="crtsnip">
2741 -fill "rgb(255,255,255)"
2742</p>
2743
2744<p>See <a href="#draw">-draw</a> for further details.</p>
2745
2746<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2747
2748<div style="margin: auto;">
2749 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2750</div>
2751
cristyd0bda5e2010-09-21 16:22:45 +00002752<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 or
2753distorting an image.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00002754
cristyd0bda5e2010-09-21 16:22:45 +00002755<p>Use this option to affect the resizing operation of an image during
2756operations such as <a href="#resize">-resize</a> and <a href="#distort"
2757>-distort</a>. For example you can use a simple resize filter such as:</p>
cristy3ed852e2009-09-05 21:47:34 +00002758
2759<pre class="text">
2760 Point Hermite Cubic
2761 Box Gaussian Catrom
2762 Triangle Quadratic Mitchell
2763</pre>
2764
cristyd0bda5e2010-09-21 16:22:45 +00002765<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well
cristyd0bd44a2010-09-24 12:38:11 +00002766as a faster <kbd>SincFast</kbd> equivalent form). However these filters are
2767generally useless on their own as they are infinite filters that are being
2768clipped to the filters support size. Their direct use is not recommended
2769except via expert settings (see below). </p>
cristyd0bda5e2010-09-21 16:22:45 +00002770
2771Instead these special filter functions are typically windowed by a windowing
2772function that the <a href="#filter" >-filter</a> setting defines. That is
2773using these functions will define a 'Windowed' filter, appropriate to the
2774operator involved. Windowed filters include: </p>
cristy3ed852e2009-09-05 21:47:34 +00002775
2776<pre class="text">
2777 Lanczos Hamming Parzen
2778 Blackman Kaiser Welsh
2779 Hanning Bartlett Bohman
2780</pre>
2781
2782<p>Also one special self-windowing filter is also provided
2783<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2784on the current 'support' or 'lobes' expert settings (see below).</p>
2785
cristyd0bda5e2010-09-21 16:22:45 +00002786<p>If you do not select a filter with this option, the filter defaults to
2787<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or
2788if the image is enlarged. Otherwise the filter default to
2789<kbd>Lanczos</kbd>.</p>
cristy3ed852e2009-09-05 21:47:34 +00002790
cristyd0bda5e2010-09-21 16:22:45 +00002791<p>To print a complete list of resize filters, use the <a href="#list">-list
2792filter</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00002793
2794<p>You can modify how the filter behaves as it scales your image through the
cristyd0bda5e2010-09-21 16:22:45 +00002795use of these expert settings (see also <a href="#define" >-define</a> and <a
2796href="#set" >-set</a>):-</p>
cristy3ed852e2009-09-05 21:47:34 +00002797
2798<dl class="doc">
cristyd0bda5e2010-09-21 16:22:45 +00002799<dt>-define filter:blur=<em>factor</em></dt>
cristy3ed852e2009-09-05 21:47:34 +00002800<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
cristyd0bda5e2010-09-21 16:22:45 +00002801 blurry or &lt; 1.0 for sharp. This should only be used with Gaussian and
2802 Gaussian-like filters simple filters, or you may not get the expected
2803 results. </dd>
cristy3ed852e2009-09-05 21:47:34 +00002804
cristyd0bda5e2010-09-21 16:22:45 +00002805<dt>-define filter:support=<em>radius</em></dt>
2806<dd>Set the filter support radius. Defines how large the filter should be and
2807 thus directly defines how slow the filtered resampling process is. All
2808 filters have a default 'prefered' support size. Some filters like
2809 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on
2810 this value. With simple filters this value either does nothing (but slow
2811 the resampling), or will clip the filter function in a detrimental way.
2812 </dd>
cristy3ed852e2009-09-05 21:47:34 +00002813
cristyd0bda5e2010-09-21 16:22:45 +00002814<dt>-define filter:lobes=<em>count</em></dt>
cristy3ed852e2009-09-05 21:47:34 +00002815<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
cristyd0bda5e2010-09-21 16:22:45 +00002816 alternative way of specifying the 'support' range of the filter, that is
2817 designed to be more suited to windowed filters, especially when used for
2818 image distorts.</dd>
cristy3ed852e2009-09-05 21:47:34 +00002819
cristyd0bda5e2010-09-21 16:22:45 +00002820<dt>-define filter:b=<em>b-spline_factor</em></dt>
2821<dt>-define filter:c=<em>keys_alpha_factor</em></dt>
cristy3ed852e2009-09-05 21:47:34 +00002822<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2823 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2824 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2825 are defined, the other is set so as to generate a 'Keys' type cubic
cristyd0bda5e2010-09-21 16:22:45 +00002826 filter. Values meaning was defined by a research paper by
2827 Mitchell-Netravali.
cristy3ed852e2009-09-05 21:47:34 +00002828
cristyd0bda5e2010-09-21 16:22:45 +00002829<dt>-define filter:filter=<em>filter_function</em></dt>
cristy3ed852e2009-09-05 21:47:34 +00002830<dd>Use this function directly as the scaling filter. This will allow
cristyd0bda5e2010-09-21 16:22:45 +00002831 you to directly use a windowing filter such as <kbd>Blackman</kbd>,
cristy3ed852e2009-09-05 21:47:34 +00002832 rather than as its normal usage as a windowing function for 'Sinc' or
cristyd0bda5e2010-09-21 16:22:45 +00002833 'Bessel' functions. If defined, no windowing function is used, unless the
2834 following expert setting is also defined.</dd>
cristy3ed852e2009-09-05 21:47:34 +00002835
cristyd0bda5e2010-09-21 16:22:45 +00002836<dt>-define filter:window=<em>filter_function</em></dt>
2837<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and
2838 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined
2839 support range) with the given filter. This allows you to specify a filter
2840 function that is not normally used as a windowing function, such as
2841 <kbd>Box</kbd>, (which effectively turns off the windowing function),
2842 to window a <kbd>Sinc</kbd>, or the function the previous setting defined.
2843 </dd>
2844
2845<dt>-define filter:verbose=<em>1</em></dt>
2846<dd>This causes IM to print information on the final internal filter
2847 selection to standard output. This includes a commented header on the
2848 filter settings being used, and data allowing the filter weights to be
2849 easily graphed. </dd>
2850
2851<dd>Note however that some filters are internally defined in terms of other
2852 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of
2853 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while
2854 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific
2855 'B' and 'C' settings. </dd>
cristy3ed852e2009-09-05 21:47:34 +00002856
2857</dl>
2858
cristyd0bda5e2010-09-21 16:22:45 +00002859<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p>
cristy3ed852e2009-09-05 21:47:34 +00002860
2861<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2862 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2863 -resize 150% image.jpg</span></p>
2864<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2865
2866<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2867 -resize 150% image.jpg</span></p>
2868<p>Note that the use of expert options (except for 'blur' with simple resize
cristyd0bda5e2010-09-21 16:22:45 +00002869filters, and 'verbose' for viewing the internal filter selection), are
2870provided for image processing experts who have studied and understood how
2871resize filters work. Without this knowledge, and an understanding of the
2872definition of the actual filters involved, using expert settings are more
2873likely to be detrimental to your image resizing.</p>
cristy3ed852e2009-09-05 21:47:34 +00002874
2875
2876<div style="margin: auto;">
2877 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2878</div>
2879
2880<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>
2881
2882
2883<div style="margin: auto;">
2884 <h4><a name="flip" id="flip"></a>-flip</h4>
2885</div>
2886
2887<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>
2888
2889<p>reflect the scanlines in the vertical direction.</p>
2890
2891<div style="margin: auto;">
2892 <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>
2893</div>
2894
2895<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>
2896
2897<div style="margin: auto;">
2898 <h4><a name="flop" id="flop"></a>-flop</h4>
2899</div>
2900
2901<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>
2902
2903<p>reflect the scanlines in the horizontal direction.</p>
2904
2905
2906<div style="margin: auto;">
2907 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2908</div>
2909
2910<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>
2911
2912<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>
2913
2914<p>In addition to the fonts specified by the above pre-defined list, you can
2915also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2916is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2917<kbd>x:fixed</kbd> is X11 font.</p>
2918
2919<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>
2920
2921
2922<div style="margin: auto;">
2923 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2924</div>
2925
2926<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>
2927
2928<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2929
2930<p>The default foreground color is black.</p>
2931
2932<div style="margin: auto;">
2933 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2934</div>
2935
2936<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>
2937
2938<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>
2939
2940<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>
2941
2942<div style="margin: auto;">
2943 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2944</div>
2945
2946<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>
2947
2948<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>
2949
2950<div style="margin: auto;">
2951 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2952</div>
2953
2954<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>
2955
cristybc9539a2010-08-16 18:06:20 +00002956<p>The color of the border is specified with the <a href="#mattecolor"
2957>-mattecolor</a> command line option. </p>
cristy3ed852e2009-09-05 21:47:34 +00002958
cristybc9539a2010-08-16 18:06:20 +00002959<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
2960class="arg">geometry</em> argument indicates the amount of extra width and
2961height that is added to the dimensions of the image. If no offsets are given
2962in the <em class="arg">geometry</em> argument, then the border added is
2963a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that
2964the width and height of the border is partitioned to form an outer bevel of
2965thickness <em>x</em>&nbsp;pixels and an inner bevel of thickness
2966<em>y</em>&nbsp;pixels. Negative offsets make no sense as frame arguments.
2967</p>
2968
2969<p>The <a href="#frame">-frame</a> option is affected by the current <a
2970href="#compose">-compose</a> setting and assumes that this is using the default
cristyd0bda5e2010-09-21 16:22:45 +00002971'<kbd>Over</kbd>' composition method. It generates a image of the appropriate
cristybc9539a2010-08-16 18:06:20 +00002972size with the current <a href="#bordercolor">-bordercolor</a> setting, and then
2973draws the frame of four distinct colors close to the current <a
2974href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto
2975center of this image. This means that with the default compose method of
2976'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a
2977href="#bordercolor">-bordercolor</a> setting.</p>
2978
2979<p>The image composition is not
2980affected by the <a href="#gravity">-gravity</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00002981
2982
2983<div style="margin: auto;">
2984 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
2985</div>
2986
2987<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>
2988
2989<div style="margin: auto;">
2990 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
2991</div>
2992
2993<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>
2994
2995<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>
2996
2997<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>
2998
2999<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>
3000
3001<pre class="text">
3002 Polynomial
3003 Sinusoid
3004 Arcsin
3005 Arctan
3006</pre>
3007
3008<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
3009
3010<dl class="doc">
3011<dt><kbd>Polynomial</kbd></dt>
3012<dd>
3013<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>
3014
3015<div style="text-align: center">
3016 -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>
3017</div>
3018
3019<p>will invoke a polynomial function given by</p>
3020
3021<div style="text-align: center">
3022 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
3023 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
3024 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
3025</div>
3026
3027<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
3028
3029<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>
3030
3031<table class="doc">
3032 <col width="35%" />
3033 <col width="35%" />
3034 <col width="30%" />
3035 <tr>
3036 <td>-evaluate Set <em class="arg">value</em> </td>
3037 <td>-function Polynomial <em class="arg">value</em></td>
3038 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
3039 </tr>
3040 <tr>
3041 <td>-evaluate Add <em class="arg">value</em> </td>
3042 <td>-function Polynomial 1,<em class="arg">value</em></td>
3043 </tr>
3044 <tr>
3045 <td>-evaluate Subtract <em class="arg">value</em> </td>
3046 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
3047 </tr>
3048 <tr>
3049 <td>-evaluate Multiply <em class="arg">value</em> </td>
3050 <td>-function Polynomial <em class="arg">value</em>,0</td>
3051 </tr>
3052 <tr>
3053 <td>+level black% x white%</td>
3054 <td>-function Polynomial A,B</td>
3055 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3056 </tr>
3057</table>
3058
3059<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>
3060</dd>
3061
3062<dt><kbd>Sinusoid</kbd></dt>
3063<dd>
3064<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>
3065
3066<div style="text-align: center">
3067 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
3068</div>
3069
3070<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>
3071
3072<div style="text-align: center">
3073<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>
3074</div>
3075
3076<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>
3077
3078<p class="crtsnip">
3079 -function Sinusoid 3,-90,.2,.7
3080</p>
3081
3082<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>
3083
3084<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>
3085
3086<table class="doc">
3087 <tr>
3088 <td>-evaluate Sin <em class="arg">freq</em> </td>
3089 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
3090 </tr>
3091 <tr>
3092 <td>-evaluate Cos <em class="arg">freq</em> </td>
3093 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
3094 </tr>
3095</table>
3096</dd>
3097
3098<dt><kbd>ArcSin</kbd></dt>
3099<dd>
3100<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
3101and can be used to generate cylindrical distortion and displacement maps.
3102The curve can be adjusted relative to both the input values and output range
3103of values.
3104
3105<div style="text-align: center">
3106 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3107</div>
3108
3109<p>with all values given in terms of noramlize color values (0.0 for black,
31101.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3111for bout input (<em class="arg">width</em>), and output (<em
3112class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3113
3114<div style="text-align: center">
3115<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>
3116</div>
3117
3118</dd>
3119
3120<dt><kbd>ArcTan</kbd></dt>
3121<dd>
3122<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3123limit values at infinities, though a center using the given slope value.
3124All these values can be adjusted via the arguments.
3125
3126<div style="text-align: center">
3127 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3128</div>
3129
3130<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3131</p>
3132
3133<div style="text-align: center">
3134<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>
3135</div>
3136
3137</dd>
3138
3139</dl>
3140
3141
3142<div style="margin: auto;">
3143 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3144</div>
3145
3146<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>
3147
3148<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>
3149
3150<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>
3151
3152
3153<div style="margin: auto;">
3154 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3155</div>
3156
3157<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>
3158
3159<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>
3160
3161<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3162
3163
3164<div style="margin: auto;">
3165 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3166</div>
3167
3168<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>
3169
3170<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>
3171
3172<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>
3173
3174<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>
3175
3176<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>
3177
3178<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3179
3180<div style="margin: auto;">
3181 <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>
3182</div>
3183
3184<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>
3185
cristyb15553d2010-07-03 22:53:14 +00003186<p>Convolve the image with a Gaussian or normal distribution using the given
3187<em class="arg" >Sigma</em> value. The formula is:</p>
cristy3ed852e2009-09-05 21:47:34 +00003188
3189<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3190</div>
3191
cristyb15553d2010-07-03 22:53:14 +00003192<p>The <em class="arg" >Sigma</em> value is the important argument, and
cristyefb2bdb2010-11-20 19:35:22 +00003193determines the actual amount of blurring that will take place. </p>
cristyb15553d2010-07-03 22:53:14 +00003194
3195<p>The <em class="arg" >Radius</em> is only used to determine the size of the
cristyefb2bdb2010-11-20 19:35:22 +00003196array which will hold the calculated Gaussian distribution. It should be an
cristyd0bda5e2010-09-21 16:22:45 +00003197integer. If not given, or set to zero, IM will calculate the largest possible
cristyb15553d2010-07-03 22:53:14 +00003198radius that will provide meaningful results for the Gaussian distribution.
3199</p>
3200
3201<p>The larger the <em class="arg" >Radius</em> the radius the slower the
3202operation is. However too small a <em class="arg" >Radius</em>, and sever
3203aliasing effects may result. As a guideline, <em class="arg" >Radius</em>
3204should be at least twice the <em class="arg" >Sigma</em> value, though three
3205times will produce a more accurite result. </p>
cristy3ed852e2009-09-05 21:47:34 +00003206
3207<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
cristyd0bda5e2010-09-21 16:22:45 +00003208full 2-dimensional convolution is used to generate the weighted average of the
3209neighboring pixels. </p>
cristy3ed852e2009-09-05 21:47:34 +00003210
3211<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3212pixels which are outside the image proper are blurred into the final result.
3213</p>
3214
3215
3216<div style="margin: auto;">
3217 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3218</div>
3219
3220<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>
3221
3222<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>
3223
3224<div style="margin: auto;">
3225 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3226</div>
3227
3228<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>
3229
3230<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3231<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3232<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3233list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3234installation.</p>
3235
3236<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>
3237
3238<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>
3239
3240<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>
3241
cristy4949d522010-03-12 18:41:34 +00003242<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 \ <br/> -negate output.png</span></p>
cristy3ed852e2009-09-05 21:47:34 +00003243<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>
3244
3245<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>
3246
3247
3248<div style="margin: auto;">
3249 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3250</div>
3251
3252<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>
3253
3254
3255<div style="margin: auto;">
3256 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3257</div>
3258
3259<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>
3260
3261<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3262dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3263can apply any color transformation to the Hald image and then use this option
3264to apply the transform to the image. </p>
3265
3266<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3267<p>This option provides a convenient method for you to use Gimp or Photoshop
3268to make color corrections to the Hald CLUT image and subsequently apply them
3269to multiple images using an ImageMagick script. </p>
3270
3271<p>Note that the representation is only of the normal RGB color space and that
3272the whole color value triplet is used for the interpolated lookup of the
3273represented Hald color cube image. Because of this the operation is not <a
3274href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3275images transparency or alpha/matte channel.</p>
3276
3277<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3278of the individual color channels, usally involving a simplier gray-scale
3279image. E.g: gray-scale to color replacement, or modification by a histogram
3280mapping. </p>
3281
3282
3283<div style="margin: auto;">
3284 <h4><a name="help" id="help"></a>-help</h4>
3285</div>
3286
3287<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>
3288
3289<div style="margin: auto;">
3290 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3291</div>
3292
3293<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>
3294
3295<div style="margin: auto;">
3296 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3297</div>
3298
3299<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>
3300
3301<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>
3302
3303<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>
3304
3305<div style="margin: auto;">
3306 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3307</div>
3308
3309<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>
3310
3311<div style="margin: auto;">
3312 <h4><a name="identify" id="identify"></a>-identify</h4>
3313</div>
3314
3315<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>
3316
3317<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>
3318
3319<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>
3320
cristyd0bda5e2010-09-21 16:22:45 +00003321<p>If <a href="#verbose">-verbose</a> precedes this option, copious
cristy3ed852e2009-09-05 21:47:34 +00003322amounts of image properties are displayed including image statistics, profiles,
3323image histogram, and others.</p>
3324
3325<div style="margin: auto;">
3326 <h4><a name="ift" id="ift"></a>-ift</h4>
3327</div>
3328
3329<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>
3330
cristyb36feb22010-03-26 16:54:37 +00003331<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It 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>
cristy3ed852e2009-09-05 21:47:34 +00003332
3333<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>
3334
3335<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3336<p>or</p>
3337
3338<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>
3339
cristyd0bd44a2010-09-24 12:38:11 +00003340<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 is at the right and/or bottom sides of the image.
cristy3ed852e2009-09-05 21:47:34 +00003341
3342<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3343
3344<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.
3345
3346<div style="margin: auto;">
3347 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3348</div>
3349
3350<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>
3351
3352<div style="margin: auto;">
3353 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3354</div>
3355
3356<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>
3357
3358<div style="margin: auto;">
3359 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3360</div>
3361
3362<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>
3363
3364<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>
3365
3366<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>
3367
3368<div style="margin: auto;">
3369 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3370</div>
3371
3372<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>
3373
3374<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>
3375
3376<p>The default intent is undefined.</p>
3377
3378<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3379
3380<div style="margin: auto;">
3381 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3382</div>
3383
3384<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>
3385
3386<p>Choose from:</p>
3387
3388<pre class="text">
3389 none
3390 line
3391 plane
3392 partition
3393 JPEG
3394 GIF
3395 PNG
3396</pre>
3397
3398<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>
3399
3400<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3401
3402<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3403
3404<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3405
3406<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3407image.G, and image.B).</p>
3408
3409<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>
3410image.</p>
3411
3412<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3413
3414<div style="margin: auto;">
3415 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3416</div>
3417
3418<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>
3419
cristyd0bda5e2010-09-21 16:22:45 +00003420<p>When looking up the color of a pixel using a non-integer floating point
cristy3ed852e2009-09-05 21:47:34 +00003421value, you typically fall in between the pixel colors defined by the source
3422image. This setting determines how the color is determined from the colors of
3423the pixels surrounding that point. That is how to determine the color of a
3424point that falls between two, or even four different colored pixels. </p>
3425
3426<pre class="text">
3427 integer: The color of the top-left pixel (floor function)
3428 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3429 average: The average color of the surrounding four pixels
3430 bilinear A double linear interpolation of pixels (the default)
3431 mesh Divide area into two flat triangular interpolations
3432 bicubic Fitted bicubic-spines of surrounding 16 pixels
3433 spline Direct spline curves (colors are blurred)
3434 filter Use resize <a href="#filter">-filter</a> settings
3435</pre>
3436
3437<p>This most important for distortion operators such as <a href="#distort"
3438>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3439>-transform</a> and <a href="#fx" >-fx</a>. </p>
3440
3441<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3442
3443<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3444lookup for positions outside the boundaries of the image. </p>
3445
3446
3447<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003448 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3449</div>
3450
3451<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two text lines.</td><td style='text-align:right;'></td></tr></table>
3452
3453<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003454 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3455</div>
3456
3457<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>
3458
3459<div style="margin: auto;">
3460 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3461</div>
3462
3463<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>
3464
3465<div style="margin: auto;">
3466 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3467</div>
3468
3469<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>
3470
cristy71a3f602010-09-15 12:38:16 +00003471<p>Use this option to assign a specific label to the image, as it is read in
3472or created. You can use the <a href="#set" >-set</a> operation to re-assign
3473a the labels of images already read in. Image formats such as TIFF, PNG,
3474MIFF, supports saving the label information with the image.</p>
cristy3ed852e2009-09-05 21:47:34 +00003475
cristy71a3f602010-09-15 12:38:16 +00003476<p>When saving an image to a <em class="arg">PostScript</em> file, any label
3477assigned to an image is used as a header string to print above the postscript
3478image. </p>
cristy3ed852e2009-09-05 21:47:34 +00003479
cristybc9539a2010-08-16 18:06:20 +00003480<p>You can include the image filename, type, width, height, or other image
3481attribute by embedding special format character. See <a href="../www/escape.html">Format and Print Image
3482Properties</a> for details of the percent escape codes.</p>
cristy3ed852e2009-09-05 21:47:34 +00003483
3484<p>For example,</p>
3485
3486<p class="crtsnip">
3487 -label "%m:%f %wx%h" bird.miff
3488</p>
3489
cristy71a3f602010-09-15 12:38:16 +00003490<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the
3491"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it
3492is read in. If a <a href="#label">+label</a> option was used instead, any
3493existing label present in the image would be used. You can remove all labels
3494from an image by assigning the empty string. </p>
cristy3ed852e2009-09-05 21:47:34 +00003495
cristy71a3f602010-09-15 12:38:16 +00003496<p>A label is not drawn on the image, but is embedded in the image datastream
3497via <em>Label</em> tag or similar mechanism. If you want the label to be
3498visible on the image itself, use the <a href="#draw">-draw</a> option, or
3499during the final processing in the creation of a image montage.</p>
cristy3ed852e2009-09-05 21:47:34 +00003500
cristy71a3f602010-09-15 12:38:16 +00003501<p>If the first character of <em class="arg">string</em> is <em
3502class="arg">@</em>, the image label is read from a file titled by the
3503remaining characters in the string. Labels in a file are literal, no embedded
3504formatting characters are recognized.</p>
cristy3ed852e2009-09-05 21:47:34 +00003505
3506
3507<div style="margin: auto;">
3508 <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>
3509</div>
3510
3511<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>
3512
3513<p>Adaptively threshold each pixel based on the value of pixels in a
3514surrounding window. If the current pixel is lighter than this average plus
3515the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3516black. Small variations in pixel values such as found in scanned documents
3517can be ignored if offset is positive. A negative offset will make it more
3518sensitive to those small variations. </p>
3519
3520<p>This is commonly used to threshold images with an uneven background. It is
3521based on the assumption that average color of the small window is the
3522the local background color, from which to separate the forground color. </p>
3523
3524
3525<div style="margin: auto;">
3526 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3527</div>
3528
3529<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>
3530
3531<p>Perform various image operation methods to a ordered sequence of images
3532which may represent either a set of overlaid 'image layers', a GIF disposal
3533animation, or a fully-'coalesced' animation sequence. </p>
3534
3535<table class="doc">
3536 <tbody>
3537 <tr valign="top">
3538 <th align="left" style="width: 8%">Method</th>
3539 <th align="left">Description</th>
3540 </tr>
3541
3542 <tr valign="top">
3543 <td valign="top">compare-any</td>
3544 <td valign="top">Crop the second and later frames to the smallest rectangle
3545 that contains all the differences between the two images. No GIF <a
3546 href="#dispose" >-dispose</a> methods are taken into account. </td>
3547 </tr>
3548
3549 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3550 >-deconstruct</a> operator, and does not preserve animations normal
3551 working, especially when animation used layer disposal methods such as
3552 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3553 </tr>
3554
3555 <tr valign="top">
3556 <td valign="top">compare-clear</td>
3557 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3558 opaque pixels which become transparent in the second frame. That is the
3559 smallest image needed to mask or erase pixels for the next frame. </td>
3560 </tr>
3561
3562 <tr valign="top">
3563 <td valign="top">compare-overlay</td>
3564 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3565 extra color to the next image, as a result of overlaying color pixels.
3566 That is the smallest single overlaid image to add or change colors. </td>
3567 </tr>
3568
3569 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3570 composition method '<kbd>change-mask</kbd>', to reduce the image to
3571 just the pixels that need to be overlaid. </td>
3572 </tr>
3573
3574 <tr valign="top">
3575 <td valign="top">coalesce</td>
3576 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3577 >-coalesce</a> operator. Apply the layer disposal methods set in the
3578 current image sequence to form a fully defined animation sequence, as
3579 it should be displayed. Effectively converting a GIF animation into a
3580 'film strip'-like animation. </td>
3581 </tr>
3582
3583 <tr valign="top">
3584 <td valign="top">composite</td>
3585 <td valign="top">Alpha Composition of two image lists, separated by a
3586 "<kbd>null:</kbd>" image, with the destination image list first, and
3587 the source images last. An image from each list are composited
3588 together until one list is finished. The separator image and source
3589 image lists are removed. </td>
3590 </tr>
3591
3592
cristybac7a162010-06-15 19:57:29 +00003593 <tr><td></td>
3594 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according
3595 to <a href="#gravity" >-gravity</a> in accordance of the virtual
3596 canvas size of the first image in each list. Unlike a normal <a
cristy3ed852e2009-09-05 21:47:34 +00003597 href="#composite" >-composite</a> operation, the canvas offset is also
cristybac7a162010-06-15 19:57:29 +00003598 added to the final composite positioning of each image. </td> </tr>
cristy3ed852e2009-09-05 21:47:34 +00003599
cristybac7a162010-06-15 19:57:29 +00003600 <tr><td></td>
3601 <td>If one of the image lists only contains one image, that image is
cristy3ed852e2009-09-05 21:47:34 +00003602 applied to all the images in the other image list, regardless of which
3603 list it is. In this case it is the image meta-data of the list which
3604 preserved. </td>
3605 </tr>
3606
3607
3608 <tr valign="top">
3609 <td valign="top">dispose</td>
3610 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3611 the animation after the layer disposal method has been applied, before
3612 the next sub-frame image is overlaid. That is the 'dispose' image that
3613 results from the application of the GIF <a href="#dispose"
3614 >-dispose</a> method. This allows you to check what
3615 is going wrong with a particular animation you may be developing.
3616 </td>
3617 </tr>
3618
3619 <tr valign="top">
3620 <td valign="top">flatten</td>
3621 <td valign="top">Create a canvas the size of the first images virtual
3622 canvas using the current <a href="#background" >-background</a> color,
3623 and <a href="#compose" >-compose</a> each image in turn onto that
3624 canvas. Images falling outside that canvas is clipped. Final
3625 image will have a zero virtual canvas offset. </td>
3626 </tr>
3627
cristybac7a162010-06-15 19:57:29 +00003628 <tr><td></td>
3629 <td>This usally used as one of the final 'image layering' operations
cristy3ed852e2009-09-05 21:47:34 +00003630 overlaying all the prepared image layers into a final image. </td>
3631 </tr>
3632
cristybac7a162010-06-15 19:57:29 +00003633 <tr><td></td>
3634 <td>For a single image this method can also be used to fillout a virtual
cristy3ed852e2009-09-05 21:47:34 +00003635 canvas with real pixels, or to underlay a opaque color to remove
3636 transparency from an image.</td>
3637 </tr>
3638
3639
3640 <tr valign="top">
3641 <td valign="top">merge</td>
3642 <td valign="top">As 'flatten' method but merging all the given image
3643 layers into a new layer image just large enough to hold all the image
3644 without clipping or extra space. The new images virtual offset will
3645 prevere the position of the new layer, even if this offset is
3646 negative. the virtual canvas size of the first image is preserved.
3647 </td>
3648 </tr>
3649
3650 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3651 as few image file formats handle them correctly. </td>
3652 </tr>
3653
3654 <tr valign="top">
3655 <td valign="top">mosaic</td>
3656 <td valign="top">As 'flatten' method but expanding the initial canvas size
3657 of the first image so as to hold all the image layers. However as a
cristyd0bda5e2010-09-21 16:22:45 +00003658 virtual canvas is 'locked' to the origin, by definition, image layers
cristy3ed852e2009-09-05 21:47:34 +00003659 with a negative offsets will still be clipped by the top and left
3660 edges.</td>
3661 </tr>
3662
3663 <tr><td></td><td>This method is commonly used to layout individual image using various
cristyd0bda5e2010-09-21 16:22:45 +00003664 offset but without knowing the final canvas size. The resulting image
cristy3ed852e2009-09-05 21:47:34 +00003665 will, like 'flatten' not have any virtual offset, so can be saved to
3666 any image file format. </td>
3667 </tr>
3668
3669
3670 <tr valign="top">
3671 <td valign="top">optimize</td>
3672 <td valign="top">Optimize a coalesced animation, into GIF animation using
3673 a number of general techniques. This currently a short cut to
3674 apply both the '<kbd>optimize-frame</kbd>', and
3675 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3676 include other optimization methods as they are developed. </td>
3677 </tr>
3678
3679 <tr valign="top">
3680 <td valign="top">optimize-frame</td>
3681 <td valign="top">Optimize a coalesced animation, into GIF animation by
3682 reducing the number of pixels per frame as much as possible by
3683 attempting to pick the best layer disposal method to use, while ensuring
3684 the result will continue to animate properly. </td>
3685 </tr>
3686
3687 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3688 then no reasonably fast GIF optimization algorithm can do this.
3689 However this does seem to do better than most other GIF frame
3690 optimizers seen. </td>
3691 </tr>
3692
3693 <tr valign="top">
3694 <td valign="top">optimize-plus</td>
3695 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3696 overall optimization by adding extra frames to the animation, without
3697 changing the final look or timing of the animation. The frames are
3698 added to attempt to separate the clearing of pixels from the
3699 overlaying of new additional pixels from one animation frame to the
3700 next. If this does not improve the optimization (for the next frame
3701 only), it will fall back to the results of the previous normal
3702 '<kbd>optimize-frame</kbd>' technique. </td>
3703 </tr>
3704
3705 <tr><td></td><td>There is the possibility that the change in the disposal style will
3706 result in a worsening in the optimization of later frames, though this
3707 is unlikely. In other words there no guarantee that it is better than
3708 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
cristyd0bda5e2010-09-21 16:22:45 +00003709 however you can get a vast improvement in the final animation size. </td>
cristy3ed852e2009-09-05 21:47:34 +00003710 </tr>
3711
3712 <tr valign="top">
3713 <td valign="top">optimize-transparency</td>
3714 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3715 overlay images with transparency, if it does not change the resulting
3716 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3717 </td>
3718 </tr>
3719
3720 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3721 into a smaller file size due to larger areas of one (transparent)
3722 color rather than a pattern of multiple colors repeating the current
3723 disposed image of the last frame. </td>
3724 </tr>
3725
3726 <tr valign="top">
3727 <td valign="top">remove-dups</td>
3728 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3729 images, so as to simplify layer overlays of coalesced animations.
3730 </td>
3731 </tr>
3732
3733 <tr><td></td><td>Usually this a result of using a constant time delay across the
3734 whole animation, or after a larger animation was split into smaller
3735 sub-animations. The duplicate frames could also have been used as
3736 part of some frame optimization methods. </td>
3737 </tr>
3738
3739 <tr valign="top">
3740 <td valign="top">remove-zero</td>
3741 <td valign="top">Remove any image with a zero time delay, unless ALL the
3742 images have a zero time delay (and is not a proper timed animation, a
3743 warning is then issued). </td>
3744 </tr>
3745
3746 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3747 partial intermediary updates between the frames that are actually
3748 displayed to users. These frames are usally added for improved frame
3749 optimization in GIF animations. </td>
3750 </tr>
3751
3752 <tr valign="top">
3753 <td valign="top">trim-bounds</td>
3754 <td valign="top">Find the bounds of all the images in the current
3755 image sequence, then adjust the offsets so all images are contained on
3756 a minimal positive canvas. None of the image data is modified, only
3757 there virtual canvas size and offset. The all the image is given
3758 the same canvas size, and and will have a positive offset, but will
3759 remain in the same position relative to each other. As a result of the
3760 minimal canvas size at least one image will touch every edge of that
3761 canvas. The image data however may be transparent.
3762 </td>
3763 </tr>
3764
3765 </tbody>
3766</table>
3767
3768<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3769
3770<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3771>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3772>-mosaic</a> are only aliases for the above methods. Also see <a
3773href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3774href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3775>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3776
3777
3778<div style="margin: auto;">
3779 <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>
3780</div>
3781
3782<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>
3783
3784<p>Given one, two or three values delimited with commas: black-point,
3785white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3786white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3787point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3788contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3789both black and white points are percentages of the full color range. Gamma
3790will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3791omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3792
3793<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3794the given '<kbd>black_point</kbd>' value in the original image is set to
3795zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3796<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3797to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3798adjusted. </p>
3799
3800<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3801adding the special '!' flag anywhere in the argument list, will cause the
3802operator to do the reverse of the level adjustment. That is a zero, or
3803<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3804adjusted to the given level values, allowing you to de-contrast, or compress
3805the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3806
3807<p>Only the channels defined by the current <a href="#channel">-channel</a>
3808setting are adjusted (defaults to RGB color channels only), allowing you to
3809limit the effect of this operator. </p>
3810
3811<p>Please note that the transparency channel is treated as 'matte'
3812values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3813
3814
3815<div style="margin: auto;">
3816 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3817 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3818</div>
3819
cristyd0bda5e2010-09-21 16:22:45 +00003820<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 separated colors.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00003821
3822<p>This function is exactly like <a href="#level">-level</a>, except that the
3823value value for each color channel is determined by the
3824'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3825described under the <a href="#fill">-fill</a> option). </p>
3826
cristyd0bda5e2010-09-21 16:22:45 +00003827<p>This effectually means the colors provided to <kbd>-level-colors</kbd>
3828is mapped to become 'black' and 'white' respectively, with all the other
cristy3ed852e2009-09-05 21:47:34 +00003829colors linearly adjusted (or clipped) to match that change. Each channel is
cristyd0bda5e2010-09-21 16:22:45 +00003830adjusted separately using the channel values of the colors specified. </p>
cristy3ed852e2009-09-05 21:47:34 +00003831
3832<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3833will map the image color 'black' and 'white' to the given colors
cristyd0bda5e2010-09-21 16:22:45 +00003834respectively, resulting in a gradient (de-contrasting) tint of the image to
cristy3ed852e2009-09-05 21:47:34 +00003835those colors. This can also be used to convert a plain gray-scale image into a
3836one using the gradient of colors specified. </p>
3837
3838<p>By supplying a single color with a comma separator either before or after
3839that color, will just replace the respective 'black' or 'white' point
cristyd0bda5e2010-09-21 16:22:45 +00003840respectively. But if no comma separator is provided, the given color is
cristy3ed852e2009-09-05 21:47:34 +00003841used for both the black and white color points, making the operator either
3842threshold the images around that color (- form) or set all colors to that
3843color (+ form). </p>
3844
3845
3846<div style="margin: auto;">
3847 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3848</div>
3849
3850<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>
3851
3852<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>
3853
cristy6b636652009-12-05 17:16:11 +00003854<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, 1.5GiB memory, 8GiB memory map, and 18.45EB 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>
cristy3ed852e2009-09-05 21:47:34 +00003855
3856<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +00003857 -limit memory 32MiB -limit map 64MiB
cristy3ed852e2009-09-05 21:47:34 +00003858</p>
3859
3860<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3861
cristy6b636652009-12-05 17:16:11 +00003862<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
3863------------------------------------------------------------------------------
3864 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre>
cristy3ed852e2009-09-05 21:47:34 +00003865</span></p>
3866<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>
3867
3868<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>
3869
3870<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>
3871
3872<p class="crtsnip">
3873-limit area 10mb
3874</p>
3875
cristyd0bda5e2010-09-21 16:22:45 +00003876<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 inadvertently upload a huge image to process, you should set a disk limit as well:</p>
cristy3ed852e2009-09-05 21:47:34 +00003877
3878<p class="crtsnip">
3879-limit area 10mb -limit disk 500mb
3880</p>
3881
3882<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3883
3884<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>
3885
3886<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.
3887</p>
3888
3889<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.
3890</p>
3891
3892<div style="margin: auto;">
3893 <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>
3894</div>
3895
3896<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>
3897
cristyd934d102009-10-10 12:55:13 +00003898<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>,
3899and uses a 'histogram bin' to determine the range of color values that needs to
3900be stretched. However it then stretchs those colors using the <a
3901href="#level" >-level</a> operator.</p>
3902
3903<p>As such while the initial determination may have 'binning' round off
3904effects, the image colors are stretched mathematically, rather than using the
3905histogram bins. This makes the operator more accurate. </p>
3906
3907<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of
3908'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near
3909perfect stretch of the color range. </p>
3910
3911<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
3912normalization of mathematical images. </p>
3913
3914<p>This operator is under review for re-development. </p>
3915
3916
cristy3ed852e2009-09-05 21:47:34 +00003917<div style="margin: auto;">
3918 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3919</div>
3920
3921<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>
3922
3923<div style="margin: auto;">
3924 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3925</div>
3926
3927<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>
3928
3929<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>
3930
3931<div style="margin: auto;">
3932 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3933</div>
3934
3935<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>
3936
3937<pre class="text">
cristyc1aee832010-05-08 00:36:47 +00003938 Align
3939 Alpha
3940 Boolean
3941 Channel
3942 Class
3943 ClipPath
3944 Coder
3945 Color
3946 Colorspace
3947 Command
3948 Compose
3949 Compress
3950 Configure
3951 DataType
3952 Debug
3953 Decoration
3954 Delegate
3955 Direction
3956 Dispose
3957 Distort
3958 Dither
3959 Endian
3960 Evaluate
3961 FillRule
3962 Filter
3963 Font
3964 Format
3965 Function
3966 Gravity
3967 ImageList
3968 Intent
3969 Interlace
3970 Interpolate
3971 Kernel
cristy787d4352010-03-06 13:55:58 +00003972 Layers
3973 LineCap
3974 LineJoin
3975 List
3976 Locale
3977 LogEvent
3978 Log
3979 Magic
3980 Method
3981 Metric
3982 Mime
3983 Mode
3984 Morphology
3985 Module
3986 Noise
3987 Orientation
3988 Policy
3989 PolicyDomain
3990 PolicyRights
3991 Preview
3992 Primitive
3993 QuantumFormat
3994 Resource
3995 SparseColor
3996 Storage
3997 Stretch
3998 Style
3999 Threshold
4000 Type
4001 Units
4002 Validate
4003 VirtualPixel
cristy3ed852e2009-09-05 21:47:34 +00004004</pre>
4005
cristybac7a162010-06-15 19:57:29 +00004006<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list
4007list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments
4008available:</p>
cristy3ed852e2009-09-05 21:47:34 +00004009
4010<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
4011<div style="margin: auto;">
4012 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
4013</div>
4014
4015<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>
4016
cristybac7a162010-06-15 19:57:29 +00004017<p>This option specifies the format for the log printed when the <a
4018href="#debug">-debug</a> option is active.</p>
cristy3ed852e2009-09-05 21:47:34 +00004019
cristybac7a162010-06-15 19:57:29 +00004020<p>You can display the following components by embedding special format
4021characters:</p>
cristy3ed852e2009-09-05 21:47:34 +00004022
4023<pre class="text">
4024 %d domain
4025 %e event
4026 %f function
4027 %l line
4028 %m module
4029 %p process ID
4030 %r real CPU time
4031 %t wall clock time
4032 %u user CPU time
4033 %% percent sign
4034 \n newline
4035 \r carriage return
4036</pre>
4037
4038<p>For example:</p>
4039
4040<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>
4041<p>The default behavior is to print all of the components.</p>
4042
4043<div style="margin: auto;">
4044 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
4045</div>
4046
4047<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>
4048
cristybac7a162010-06-15 19:57:29 +00004049<p>Set iterations to zero to repeat the animation an infinite number of times,
4050otherwise the animation repeats itself up to <em class="arg">iterations</em>
4051times.</p>
cristy3ed852e2009-09-05 21:47:34 +00004052
4053<div style="margin: auto;">
4054 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
4055</div>
4056
4057<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>
4058
4059<div style="margin: auto;">
4060 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
4061</div>
4062
4063<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>
4064
4065
4066<div style="margin: auto;">
4067 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
4068</div>
4069
4070<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>
4071
4072<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
4073
4074<pre class="text">
4075 best
4076 default
4077 gray
4078 red
4079 green
4080 blue
4081</pre>
4082
cristybac7a162010-06-15 19:57:29 +00004083<p>The <em class="arg">X server</em> must support the <em class="arg">Standard
4084Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as
4085the type and <kbd>display</kbd> searches the list of colormap types in
4086<kbd>top-to-bottom</kbd> order until one is located. See <em
4087class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p>
cristy3ed852e2009-09-05 21:47:34 +00004088
4089
4090<div style="margin: auto;">
4091 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
4092</div>
4093
4094<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>
4095
4096<p>Here are the valid components of a map:</p>
4097
4098<pre class="text">
4099 r red pixel component
4100 g green pixel component
4101 b blue pixel component
4102 a alpha pixel component (0 is transparent)
4103 o opacity pixel component (0 is opaque)
4104 i grayscale intensity pixel component
4105 c cyan pixel component
4106 m magenta pixel component
4107 y yellow pixel component
4108 k black pixel component
4109 p pad component (always 0)
4110</pre>
4111
cristybac7a162010-06-15 19:57:29 +00004112<p>You can specify as many of these components as needed in any order (e.g.
4113bgr). The components can repeat as well (e.g. rgbr).</p>
4114
cristy3ed852e2009-09-05 21:47:34 +00004115
4116<div style="margin: auto;">
4117 <h4><a name="mask" id="mask"></a>-mask
4118<em class="arg">filename</em></h4>
4119</div>
4120
4121<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>
4122
4123<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
4124
4125<div style="margin: auto;">
4126 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
4127</div>
4128
4129<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>
4130
4131<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4132
cristybac7a162010-06-15 19:57:29 +00004133<p>The default matte color is <kbd>#BDBDBD</kbd>, <span
4134style="background-color: #bdbdbd;">this shade of gray</span>.</p>
cristy3ed852e2009-09-05 21:47:34 +00004135
4136<div style="margin: auto;">
cristyd2baf7d2010-03-06 04:26:44 +00004137 <h4><a name="maximum" id="maximum"></a>-maximum</h4>
4138</div>
4139
4140<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the maximum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table>
4141
4142<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00004143 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
4144</div>
4145
4146<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>
4147
4148<div style="margin: auto;">
4149 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
4150</div>
4151
4152<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>
4153
4154<p>Choose from:</p>
4155
4156<pre class="text">
cristybac7a162010-06-15 19:57:29 +00004157 AE absolute error count, number of different pixels (-fuzz effected)
4158 MAE mean absolute error (normalized), average channel error distance
4159 MEPP mean error per pixel (normalized mean error, normalized peak error)
4160 MSE mean error squared, average of the channel error squared
cristy771f7a72010-11-27 21:42:59 +00004161 NCC normalized cross correlation
cristybac7a162010-06-15 19:57:29 +00004162 PAE peak absolute (normalize peak absolute)
4163 PSNR peak signal to noise ratio
4164 RMSE root mean squared (normalized root mean squared)
cristy3ed852e2009-09-05 21:47:34 +00004165</pre>
4166
cristy771f7a72010-11-27 21:42:59 +00004167<p>Control the '<kbd>AE</kbd>', or absolute count of pixels that are different,
4168with the <a href="#fuzz" >-fuzz</a> factor (ignore pixels which
4169only changed by a small amount). Use '<kbd>PAE</kbd>' to find the
cristy3ed852e2009-09-05 21:47:34 +00004170size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
cristy771f7a72010-11-27 21:42:59 +00004171'similar', while '<kbd>MAE</kbd>' dtermines the factor needed
cristybac7a162010-06-15 19:57:29 +00004172for about half the pixels to be similar. </p>
cristy3ed852e2009-09-05 21:47:34 +00004173
4174<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
4175('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
cristyd0bda5e2010-09-21 16:22:45 +00004176normalized) from a single comparison run. </p>
cristy3ed852e2009-09-05 21:47:34 +00004177
cristybac7a162010-06-15 19:57:29 +00004178<p>To print a complete list of metrics, use the <a href="#list">-list
4179metrics</a> option.</p>
4180
cristy3ed852e2009-09-05 21:47:34 +00004181
cristyd2baf7d2010-03-06 04:26:44 +00004182<div style="margin: auto;">
4183 <h4><a name="minimum" id="minimum"></a>-minimum</h4>
4184</div>
4185
4186<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the minimum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table>
4187
cristy3ed852e2009-09-05 21:47:34 +00004188
4189<div style="margin: auto;">
4190 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
4191</div>
4192
4193<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>
4194
cristybac7a162010-06-15 19:57:29 +00004195<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame,
4196Unframe, or Concatenate</kbd></p>
cristy3ed852e2009-09-05 21:47:34 +00004197
cristybac7a162010-06-15 19:57:29 +00004198<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument
4199for a list of <a href="#mode" >-mode</a> arguments available in your
4200ImageMagick installation.</p>
cristy3ed852e2009-09-05 21:47:34 +00004201
4202
4203<div style="margin: auto;">
4204 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
4205</div>
4206
cristybac7a162010-06-15 19:57:29 +00004207<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
4208class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004209
cristyb36feb22010-03-26 16:54:37 +00004210<p>The arguments are given as a percentages of variation. A value of 100 means
4211no change, and any missing values are taken to mean 100.</p>
cristy3ed852e2009-09-05 21:47:34 +00004212
cristyb36feb22010-03-26 16:54:37 +00004213<p>The <em class="arg">brightness</em> is a multiplier of the overall
4214brightness of the image, so 0 means pure black, 50 is half as bright, 200 is
4215twice as bright. To invert its meaning <a href="#negate">-negate</a> the image
4216before and after. </p>
cristy3ed852e2009-09-05 21:47:34 +00004217
cristyb36feb22010-03-26 16:54:37 +00004218<p>The <em class="arg">saturation</em> controls the amount of color in an
4219image. For example, 0 produce a grayscale image, while a large value such as
4220200 produce a very colorful, 'cartoonish' color.</p>
cristy3ed852e2009-09-05 21:47:34 +00004221
cristyb36feb22010-03-26 16:54:37 +00004222<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors
4223within the image by the amount specified. For example, 50 results in
4224a counter-clockwise rotation of 90, mapping red shades to purple, and so on.
4225A value of either 0 or 200 results in a complete 180 degree rotation of the
4226image. Using a value of 300 is a 360 degree rotation resulting in no change to
4227the original image. </p>
cristy3ed852e2009-09-05 21:47:34 +00004228
cristyb36feb22010-03-26 16:54:37 +00004229<p>For example, to increase the color brightness by 20% and decrease the color
4230saturation by 10% and leave the hue unchanged, use <a
4231href="#modulate">-modulate 120,90</a>.</p>
cristy3ed852e2009-09-05 21:47:34 +00004232
cristyb36feb22010-03-26 16:54:37 +00004233<p>Use <a href="#set">-set</a> attribute of '<kbd
4234class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to
4235modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or
4236<kbd>HWB</kbd>. For example,</p>
cristy3ed852e2009-09-05 21:47:34 +00004237
4238<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>
cristyb36feb22010-03-26 16:54:37 +00004239
cristy3ed852e2009-09-05 21:47:34 +00004240<div style="margin: auto;">
4241 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
4242</div>
4243
4244<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>
4245
4246
4247<div style="margin: auto;">
4248 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
4249</div>
4250
4251<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>
4252
4253
4254<div style="margin: auto;">
4255 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4256</div>
4257
4258<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>
4259
4260<p>Both the image pixels and size are linearly interpolated to give the
4261appearance of a meta-morphosis from one image to the next, over all the images
4262in the current image list. The added images are the equivalent of a <a
4263href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4264argument determine how many images to interpolate between each image. </p>
4265
4266
4267<div style="margin: auto;">
cristy488844c2010-01-22 14:02:05 +00004268 <h4><a name="morphology" id="morphology"></a>-morphology</h4>
4269 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4>
4270</div>
4271
cristy2c839602010-04-03 02:32:08 +00004272<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a morphology method to the image.</td><td style='text-align:right;'></td></tr></table>
cristy488844c2010-01-22 14:02:05 +00004273
cristy83a272e2010-05-07 20:40:35 +00004274Until I get around to writing a option summary for this, see <A
4275HREF="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples,
4276Morphology</A>. </P>
4277
4278
cristy488844c2010-01-22 14:02:05 +00004279<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00004280 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4281</div>
4282
4283<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>
4284
4285
4286<div style="margin: auto;">
4287 <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>
4288</div>
4289
4290<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>
4291
4292<p>Blur with the given radius, standard deviation (sigma), and angle. The
4293angle given is the angle toward which the image is blurred. That is the
4294direction people would consider the object is coming from. </p>
4295
4296<p>Note that the blur is not uniform distribution, giving the motion a
cristyd0bda5e2010-09-21 16:22:45 +00004297definite sense of direction of movement. </p>
cristy3ed852e2009-09-05 21:47:34 +00004298
4299<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4300pixels which are outside the image proper are blurred into the final result.
4301</p>
4302
4303<div style="margin: auto;">
4304 <h4><a name="name" id="name"></a>-name</h4>
4305</div>
4306
4307<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>
4308<div style="margin: auto;">
4309 <h4><a name="negate" id="negate"></a>-negate</h4>
4310</div>
4311
cristyb29bc032010-02-01 20:29:43 +00004312<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004313
4314<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>
4315
4316<div style="margin: auto;">
4317 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4318 +noise <em class="arg">type</em></h4>
4319</div>
4320
4321<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>
4322
4323<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>
4324
4325<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>
4326
4327<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>
4328
4329<pre class="text">
4330Gaussian
4331Impulse
4332Laplacian
4333Multiplicative
4334Poisson
4335Random
4336Uniform
4337</pre>
4338
4339<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4340
cristy83543962009-10-16 19:04:28 +00004341<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos
4342the use of a controlling value to specify teh amount of noise that should be
4343added to an image. </p>
4344
cristy3ed852e2009-09-05 21:47:34 +00004345
4346<div style="margin: auto;">
4347 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4348</div>
4349
4350<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>
4351
cristyd934d102009-10-10 12:55:13 +00004352<p>The intensity values are stretched to cover the entire range of possible
4353values. While doing so, black-out at most <em>2%</em> of the pixels and
4354white-out at most <em>1%</em> of the pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00004355
cristyd934d102009-10-10 12:55:13 +00004356<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a>
4357is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>.
4358(Before this version, it was equivalent to <a href="#contrast-stretch"
4359>-contrast-stretch 2%x99%</a>).</p>
cristy3ed852e2009-09-05 21:47:34 +00004360
cristyd934d102009-10-10 12:55:13 +00004361<p>All the channels are normalized in concert by the came amount so as to
4362preserve color integrity, when the default <a href="#channel" >+channel</a>
cristyd0bda5e2010-09-21 16:22:45 +00004363setting is in use. Specifying any other <a href="#channel" >-channel</a>
cristyd934d102009-10-10 12:55:13 +00004364setting will normalize the RGB channels independently.</p>
4365
4366<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details.
4367Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization
cristy83543962009-10-16 19:04:28 +00004368that is better suited to mathematically generated images. </p>
cristyd934d102009-10-10 12:55:13 +00004369
4370<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00004371
4372
4373<div style="margin: auto;">
4374 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4375</div>
4376
cristyd934d102009-10-10 12:55:13 +00004377<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
4378class="arg">threshold map</em> specified, and a uniform color map with the
4379given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004380
4381<p>You can choose from these standard threshold maps:</p>
4382
4383<pre class="text">
cristya6d7cf72010-11-07 15:58:34 +00004384threshold 1x1 Threshold 1x1 (non-dither)
4385checks 2x1 Checkerboard 2x1 (dither)
4386o2x2 2x2 Ordered 2x2 (dispersed)
4387o3x3 3x3 Ordered 3x3 (dispersed)
4388o4x4 4x4 Ordered 4x4 (dispersed)
4389o8x8 8x8 Ordered 8x8 (dispersed)
4390h4x4a 4x1 Halftone 4x4 (angled)
4391h6x6a 6x1 Halftone 6x6 (angled)
4392h8x8a 8x1 Halftone 8x8 (angled)
4393h4x4o Halftone 4x4 (orthogonal)
4394h6x6o Halftone 6x6 (orthogonal)
4395h8x8o Halftone 8x8 (orthogonal)
4396h16x16o Halftone 16x16 (orthogonal)
4397c5x5b c5x5 Circles 5x5 (black)
4398c5x5w Circles 5x5 (white)
4399c6x6b c6x6 Circles 6x6 (black)
4400c6x6w Circles 6x6 (white)
4401c7x7b c7x7 Circles 7x7 (black)
4402c7x7w Circles 7x7 (white)
cristy3ed852e2009-09-05 21:47:34 +00004403</pre>
4404
cristyde368992010-11-05 14:32:14 +00004405<p> The <kbd>checks</kbd> pattern produces a 3 level checkerbord dither
cristyd934d102009-10-10 12:55:13 +00004406pattern. Or you can define your own <em class="arg" >threshold map</em> in a
cristyde368992010-11-05 14:32:14 +00004407personal or system <kbd>thresholds.xml</kbd> XML file. </p>
cristy3ed852e2009-09-05 21:47:34 +00004408
cristyd934d102009-10-10 12:55:13 +00004409<p>To print a complete list of threshold, use the <a href="#list" >-list
4410threshold</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004411
cristyd934d102009-10-10 12:55:13 +00004412<p>It is recommended that the <a href="#map" >+map</a> operator be used after
4413applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of
cristy3ed852e2009-09-05 21:47:34 +00004414colors an animated image sequence, to less that 256 colors. This ensures that
4415a common or global color table is used when saving the result to a color
4416limited file format such as GIF. </p>
4417
cristyd934d102009-10-10 12:55:13 +00004418<p>Note that at this time the exact same threshold dithering map is used for
4419all color channels, no attempt is made to offset or rotate the map for
4420different channels is made, to create an offset printing effect. (possible
4421future expansion) </p>
cristy3ed852e2009-09-05 21:47:34 +00004422
4423
4424<div style="margin: auto;">
4425 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4426</div>
4427
4428<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>
4429
cristyc54f5d42009-11-27 21:36:31 +00004430<p>The <em class="arg">color</em> argument is defined using the format
cristyd934d102009-10-10 12:55:13 +00004431described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz"
4432>-fuzz</a> setting can be used to match and replace colors similar to the one
4433given.</p>
cristy3ed852e2009-09-05 21:47:34 +00004434
cristyb36feb22010-03-26 16:54:37 +00004435<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match
4436the target color. </p>
cristy3ed852e2009-09-05 21:47:34 +00004437
cristyb36feb22010-03-26 16:54:37 +00004438<p>The <a href="#transparent">-transparent</a> operator is exactly the same
4439as <a href="#opaque" >-opaque</a> but replaces the matching color with
4440transparency rather than the current <a href="#fill">-fill</a> color setting.
4441To ensure that it can do this it also ensures that the image has an alpha
4442channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for
4443the new transparent colors, and does not require you to modify the <a
4444href="#channel">-channel</a> to enable alpha channel handling. </p>
cristyd934d102009-10-10 12:55:13 +00004445
cristy3ed852e2009-09-05 21:47:34 +00004446
4447<div style="margin: auto;">
4448 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4449</div>
4450
4451<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>
4452
4453<p>Choose from these orientations:</p>
4454
4455<pre class="text">
4456 bottom-left
4457 bottom-right
4458 left-bottom
4459 left-top
4460 right-bottom
4461 right-top
4462 top-left
4463 top-right
4464 undefined
4465</pre>
4466
cristyd934d102009-10-10 12:55:13 +00004467<p>To print a complete list of orientations, use the <a href="#list" >-list
4468orientation</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004469
4470
4471<div style="margin: auto;">
4472 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4473 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4474 +page
4475 </h4>
4476</div>
4477
4478<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>
4479
4480<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>
4481
4482<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>
4483
4484<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>
4485<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4486<thead>
4487 <tr valign="top">
4488 <th align="center"><em class="arg">media</em></th>
4489 <th align="center"><em class="arg">width</em></th>
4490 <th align="center"><em class="arg">height</em></th>
4491 </tr>
4492</thead>
4493<tbody>
4494<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4495<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4496<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4497<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4498<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4499<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4500<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4501<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4502<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4503<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4504<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4505<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4506<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4507<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4508<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4509<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4510<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4511<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4512<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4513<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4514<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4515<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4516<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4517<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4518<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4519<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4520<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4521<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4522<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4523<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4524<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4525<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4526<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4527<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4528<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4529<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4530<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4531<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4532</tbody>
4533</table>
4534
4535
4536
4537
4538<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>
4539
4540<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>
4541
4542<p>The default page dimensions for a TEXT image is 612x792.</p>
4543
4544<p>This option is used in concert with <a href="#density">-density</a>.</p>
4545
4546<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4547
4548<div style="margin: auto;">
4549 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4550</div>
4551
4552<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>
4553
4554<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>
4555
4556<div style="margin: auto;">
4557 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4558
4559<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>
4560
4561<div style="margin: auto;">
4562 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4563</div>
4564
4565<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>
4566
4567<p>Pause for the specified number of seconds before repeating the animation.</p>
4568
4569<div style="margin: auto;">
4570 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4571</div>
4572
4573<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>
4574
4575<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4576
4577<div style="margin: auto;">
4578 <h4><a name="ping" id="ping"></a>-ping</h4>
4579</div>
4580
4581<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>
4582
4583<div style="margin: auto;">
4584 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4585</div>
4586
4587<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>
4588
4589<div style="margin: auto;">
4590 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4591</div>
4592
4593<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>
4594
4595<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4596
4597<div style="margin: auto;">
4598 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4599</div>
4600
4601<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>
4602
4603<div style="margin: auto;">
cristyd43a46b2010-01-21 02:13:41 +00004604 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4>
4605</div>
4606
4607<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the maximum number of significant digits to be printed.</td><td style='text-align:right;'></td></tr></table>
4608
4609<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00004610 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4611</div>
4612
4613<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>
4614
4615<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>
4616
4617<pre class="text">
4618 Rotate
4619 Shear
4620 Roll
4621 Hue
4622 Saturation
4623 Brightness
4624 Gamma
4625 Spiff
4626 Dull
4627 Grayscale
4628 Quantize
4629 Despeckle
4630 ReduceNoise
4631 Add Noise
4632 Sharpen
4633 Blur
4634 Threshold
4635 EdgeDetect
4636 Spread
4637 Shade
4638 Raise
4639 Segment
4640 Solarize
4641 Swirl
4642 Implode
4643 Wave
4644 OilPaint
4645 CharcoalDrawing
4646 JPEG
4647</pre>
4648
4649<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4650
4651<p>The default preview is <kbd>JPEG</kbd>.</p>
4652
4653<div style="margin: auto;">
4654 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4655</div>
4656
4657<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>
4658
4659<div style="margin: auto;">
4660 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4661</div>
4662
4663<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>
4664
4665<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>
4666
4667<div style="margin: auto;">
4668 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4669 +profile <em class="arg">profile_name</em></h4>
4670</div>
4671
4672<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>
4673
4674<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>
4675
4676<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>
4677
4678<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>
4679
4680<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>
4681
4682<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4683
4684<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4685<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>
4686
4687<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>
4688<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4689CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4690</p>
4691
4692<div style="margin: auto;">
4693 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4694</div>
4695
4696<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>
4697
cristy851dbce2010-08-06 21:40:00 +00004698<p>For the JPEG and MPEG image formats, quality is 1 (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 92. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p>
cristy3ed852e2009-09-05 21:47:34 +00004699
4700<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>
4701
cristy851dbce2010-08-06 21:40:00 +00004702<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 100, a request for non-lossy compression. A quality of 75 results in a request for 16:1 compression.</p>
cristy3ed852e2009-09-05 21:47:34 +00004703
cristy3c98a4f2010-08-13 20:09:41 +00004704<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression. The default PNG compression is 75.</p>
cristy3ed852e2009-09-05 21:47:34 +00004705
4706<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4707
4708<pre class="text">
4709 0: none
4710 1: sub
4711 2: up
4712 3: average
4713 4: Paeth
4714</pre>
4715
4716<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>
4717
4718<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4719
4720<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>
4721
cristy3c98a4f2010-08-13 20:09:41 +00004722<p>The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p>
cristy3ed852e2009-09-05 21:47:34 +00004723
4724<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4725
cristy3ed852e2009-09-05 21:47:34 +00004726<div style="margin: auto;">
4727 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4728</div>
4729
cristy3c98a4f2010-08-13 20:09:41 +00004730<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors using this colorspace.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004731
cristy3c98a4f2010-08-13 20:09:41 +00004732<p>This setting defines the colorspace used to sort out and reduce the number
4733of colors needed by an image (for later dithering) by operators such as <a
4734href="#colors" >-colors</a>, Note that color reducion also happens
4735automatically when saving images to color-limited image file formats, such as
4736GIF, and PNG8.</p>
cristy3ed852e2009-09-05 21:47:34 +00004737
4738
4739<div style="margin: auto;">
4740 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4741</div>
4742
4743<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>
4744
4745<div style="margin: auto;">
4746 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4747</div>
4748
4749<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>
4750
4751<p>Note that this is actually a rotational blur rather than a radial and as
4752such actually mis-named. </p>
4753
4754<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4755pixels which are outside the image proper are blurred into the final result.
4756</p>
4757
4758
4759<div style="margin: auto;">
4760 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4761</div>
4762
4763<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>
4764
4765<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>.
4766</p>
4767
4768<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4769
4770<div style="margin: auto;">
4771 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4772</div>
4773
4774<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>
4775
4776<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00004777 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4778</div>
4779
4780<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>
4781
4782<div style="margin: auto;">
4783 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4784</div>
4785
4786<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>
4787
4788<div style="margin: auto;">
4789 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4790</div>
4791
4792<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>
4793
4794<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4795the given colors are dithered over the image as necessary, otherwise the closest
4796color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4797
4798<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4799images in the current image sequence, all the images will have the same color
4800table. That means that when saved to a file format such as GIF, it will use
4801that color table as a single common or global color table, for all the images,
4802without requiring extra local color tables. </p>
4803
4804<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4805sequence to use a common color map over all the images. This equivalent to
4806appending all the images together (without extra background colors) and color
4807reducing those images using <a href="#colors">-colors</a> with a 256 color
4808limit, then <a href="#remap">-remap</a> those colors over the original list of
4809images. This ensures all the images follow a single color map. </p>
4810
4811<p>If the number of colors over all the images is less than 256, then <a
4812href="#remap">+remap</a> should not perform any color reduction or dithering, as
4813no color changes are needed. In that case, its only effect is to force the use
4814of a global color table. This recommended after using either <a
4815href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4816reduce the number of colors in an animated image sequence. </p>
4817
4818<div style="margin: auto;">
4819 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4820</div>
4821
4822<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>
4823
4824<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>
4825
4826<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>
4827
4828<div style="margin: auto;">
4829 <h4><a name="remote" id="remote"></a>-remote</h4>
4830</div>
4831
4832<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>
4833
4834<p>The only command recognized is the name of an image file to load.</p>
4835
4836<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>
4837
4838<div style="margin: auto;">
4839 <h4><a name="render" id="render"></a>-render</h4>
4840</div>
4841
4842<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>
4843
4844<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>
4845
4846<div style="margin: auto;">
4847<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4848</div>
4849
4850<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>
4851
4852<p>This option is like <a href="#page">-page</a> but acts as an image operator
4853rather than a setting. You can separately set the canvas size or the offset
4854of the image on that canvas by only providing those components. </p>
4855
4856<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>
4857
4858<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4859offset to move the image relative to its previous position. This useful for
4860animation sequences. </p>
4861
4862<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4863recalculate the canvas size so the image (at its current offset) will appear
4864completely on that canvas (unless it has a negative offset).</p>
4865
4866<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4867canvas meta-data from the images. </p>
4868
4869<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4870directly assign virtual canvas meta-data. </p>
4871
4872
4873<div style="margin: auto;">
4874 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4875</div>
4876
4877<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>
4878
4879<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>
4880
4881<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>
4882
4883<div style="margin: auto;">
4884 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4885</div>
4886
4887<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>
4888
4889<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>
4890
4891<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>
4892
cristy13538962010-02-26 17:53:04 +00004893<p>Many image processing algorithms assume your image is in a linear-light coding. If your image is gamma-corrected, you can remove the nonlinear gamma correction, apply the transform, then restore it like this:</p>
4894
cristy4949d522010-03-12 18:41:34 +00004895<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br/> -quality 92 passport.jpg</span></p>
cristy3ed852e2009-09-05 21:47:34 +00004896<div style="margin: auto;">
4897 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4898</div>
4899
4900<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>
4901
4902<div style="margin: auto;">
4903 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4904</div>
4905
4906<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>
4907
4908
4909<div style="margin: auto;">
4910 <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>
4911</div>
4912
4913<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>
4914
4915<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>
4916
4917
4918<div style="margin: auto;">
4919 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4920</div>
4921
4922<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>
4923
4924<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>
4925
4926<p>Empty triangles in the corners, left over from rotating the image, are
4927filled with the <kbd>background</kbd> color. </p>
4928
4929<p>See also the <a href="#distort">-distort</a> operator and specifically the
4930'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4931
4932
4933<div style="margin: auto;">
4934 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4935</div>
4936
cristyd0bd44a2010-09-24 12:38:11 +00004937<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel subsampling and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004938
cristyd0bd44a2010-09-24 12:38:11 +00004939<p>Change the image size simply by directly sampling the pixels original
4940image. When magnifying, pixels are replicated in blocks. When minifying,
4941pixels are sub-sampled (i.e., some rows and columns are skipped over). </p>
cristy3ed852e2009-09-05 21:47:34 +00004942
cristyd0bd44a2010-09-24 12:38:11 +00004943<p>The results are thus equivalent to using <a href="#resize">-resize</a> with
4944a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest
4945neighbour), though <a href="#sample">-sample</a> is a lot faster, as it
4946avoids all the filter processing of the image. As such it completely ignores
4947the current <a href="#filter">-filter</a> setting. </p>
4948
4949<p>The key feature of the <a href="#sample">-sample</a> is that no new colors
4950will be added to the resulting image, though some colors may disappear. </p>
4951
4952<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
4953ignored, unlike <a href="#resize">-resize</a>. </p>
cristy3ed852e2009-09-05 21:47:34 +00004954
4955
4956<div style="margin: auto;">
4957 <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>
4958</div>
4959
4960<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>
4961
4962<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>
4963
4964<div style="margin: auto;">
4965 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4966</div>
4967
cristyd0bd44a2010-09-24 12:38:11 +00004968<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel block averaging and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00004969
cristyd0bd44a2010-09-24 12:38:11 +00004970<p>Change the image size simply by replacing pixels by averaging pixels
4971together when minifying, or replacing pixels when magnifing. </p>
4972
4973<p>The results are thus equivalent to using <a href="#resize">-resize</a> with
4974a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot
4975faster, as it avoids all the filter processing of the image. As such it
4976completely ignores the current <a href="#filter">-filter</a> setting. </p>
4977
4978<p>If when shrinking (minifying) images the original image is some integer
4979multiple of the new image size, the number of pixels avergaed together to
4980produce the new pixel color is the same across the whole image. This is
4981a special case known as 'binning' and is often used as a method of reducing
4982noise in image such as those generated by digital cameras, especially in low
4983light conditions. </p>
4984
cristy3ed852e2009-09-05 21:47:34 +00004985
4986<div style="margin: auto;">
4987 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4988</div>
4989
4990<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>
4991
4992<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4993
4994<div style="margin: auto;">
4995 <h4><a name="screen" id="screen"></a>-screen</h4>
4996</div>
4997
4998<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>
4999
5000<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>
5001
5002<div style="margin: auto;">
5003 <h4><a name="seed" id="seed"></a>-seed</h4>
5004</div>
5005
5006<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>
5007
5008<div style="margin: auto;">
5009 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
5010</div>
5011
5012<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>
5013
5014<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>
5015
5016<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>
5017
5018<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
5019of the color clusters is returned.</p>
5020
5021
5022<div style="margin: auto;">
5023 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
5024</div>
5025
cristy2e2662a2010-10-09 14:29:37 +00005026<div style="margin: auto;">
5027 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4>
5028</div>
5029
cristy3ed852e2009-09-05 21:47:34 +00005030<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>
5031
cristy2e2662a2010-10-09 14:29:37 +00005032<p>Blurs those pixels that are less than or equal to the threshold in contrast. The threshold may be expressed as a fraction of <em class="QR">QuantumRange</em> or as a percentage.</p>
5033
cristy3ed852e2009-09-05 21:47:34 +00005034<div style="margin: auto;">
5035 <h4><a name="separate" id="separate"></a>-separate</h4>
5036</div>
5037
5038<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>
5039
5040<div style="margin: auto;">
5041 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
5042</div>
5043
5044<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>
5045
5046<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
5047
5048<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>
5049
cristyd0bda5e2010-09-21 16:22:45 +00005050
5051
cristy3ed852e2009-09-05 21:47:34 +00005052<div style="margin: auto;">
cristyd0bd44a2010-09-24 12:38:11 +00005053 <h4><a name="set" id="set"></a>-set <em class="arg">key value</em></h4>
5054 <h4><a name="set" id="set"></a>+set <em class="arg">key</em></h4>
cristy3ed852e2009-09-05 21:47:34 +00005055</div>
5056
cristyd0bd44a2010-09-24 12:38:11 +00005057<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sets image attributes and properties for images in the current
cristyd0bda5e2010-09-21 16:22:45 +00005058image sequence.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00005059
cristyd0bd44a2010-09-24 12:38:11 +00005060<p>This will assign (or modify) specific settings attached to all the images
5061in the current image sequence. Using the <a href="#set">+set</a> form of the
5062option will either remove, or reset that setting to a default state, as
5063appropriate. </p>
cristy3ed852e2009-09-05 21:47:34 +00005064
cristyd0bd44a2010-09-24 12:38:11 +00005065<p>For example, it will modify specific well known image meta-data
5066'attributes' such as those normally overridden by: the options <a
5067href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a
5068href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally
5069assigned before the image is read in, by using a <em class="arg">key</em> of
5070the same name. </p>
cristy3ed852e2009-09-05 21:47:34 +00005071
cristyd0bd44a2010-09-24 12:38:11 +00005072<p>If the given <em class="arg">key</em> does not match a specific known
5073'attribute ', such as shown above, the setting is stored as a a free form
cristyd0bda5e2010-09-21 16:22:45 +00005074'properity' string. Such settings are listed in <a href="#verbose"
5075>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties".
5076</p>
5077
cristyd0bd44a2010-09-24 12:38:11 +00005078<p>This includes string 'properities' that are set by and assigned to images
5079using the options <a href="#comment" >-comment</a>, <a href="#label"
5080>-label</a>, <a href="#caption" >-caption</a>. These options actually assign
5081a global 'artifact' which are automatically assigned (and any <a href="../www/escape.html" >Format Percent
5082Escapes</a> expanded) to images as they are read in. For example:</p>
cristyd0bda5e2010-09-21 16:22:45 +00005083
cristyd0bd44a2010-09-24 12:38:11 +00005084<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'>identify -format %c rose.png</span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>Rose is a rose is a rose is a rose</span></p>
5085<p>The set value can also make use of <a href="../www/escape.html" >Format and Print Image
5086Properties</a> in the defined value. For example:</p>
5087
5088<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -set origsize '%wx%h' -resize 50% \</span><span class='crtout'> -format 'Old size = %[origsize] New size = %wx%h' info:</span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>Old size = 70x46 New size = 35x23</span></p>
5089<p>Other well known 'properities' that can be include:
5090'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and
5091'<kbd>signature</kbd>'. </p>
5092
5093<p>The <a href="#repage">-repage</a> operator will also allow you to modify
5094the '<kbd>page</kbd>' attribute of an image for images already in memory (also
5095see <a href="#repage">-page</a>). However it is designed to provide a finer
5096control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a>
5097option will only provide a direct, unmodified assignment of '<kbd>page</kbd>'
5098attribute. </p>
5099
5100<p>This option can also associate a colorspace or profile with your image.
5101For example,</p>
5102
5103<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd</span></p>
cristyd0bda5e2010-09-21 16:22:45 +00005104<p>Some 'properties' must be defined in a specific way to be used. For
5105example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to
5106modify the output filename of an image. For example</p>
5107
5108<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p>
5109<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will
5110be saved as a global "Artifact" exactly as if it was set using the <a
cristyd0bd44a2010-09-24 12:38:11 +00005111href="#define" >-define</a> option. As such settings are globel in scope, they
5112can be used to pass 'attributes' and 'properities' of one specific image,
5113in a way that allows you to use them in a completely different image, even if
5114the original image has long since been modified or destroyed. For example: </p>
5115
5116<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -set option:rosesize '%wx%h' -delete 0 \</span><span class='crtout'> label:'%[rosesize]' label_size_of_rose.gif</span></p>
5117<p>Note that <a href="../www/escape.html" >Format Percent Escapes</a> will only match
5118a 'artifact' if the given <em class="arg">key</em> does not match an existing
5119'attribute' or 'properity'. </p>
cristyd0bda5e2010-09-21 16:22:45 +00005120
5121<p>You can set the attributes of the image registry by prefixing the value
5122with <kbd>registry:</kbd>.</p>
5123
5124
cristy3ed852e2009-09-05 21:47:34 +00005125
5126<div style="margin: auto;">
5127 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
5128</div>
5129
5130<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>
5131
5132<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>
5133
5134<div style="margin: auto;">
5135 <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>
5136</div>
5137
5138<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>
5139
5140<div style="margin: auto;">
5141 <h4><a name="shared-memory"
5142id="shared-memory"></a>-shared-memory</h4>
5143</div>
5144
5145<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>
5146
5147<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>
5148
5149<div style="margin: auto;">
5150 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
5151</div>
5152
5153<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>
5154
5155<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
5156
5157<div style="margin: auto;">
5158 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
5159</div>
5160
5161<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>
5162
5163<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>
5164
5165<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>
5166
5167<div style="margin: auto;">
5168 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
5169</div>
5170
5171<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>
5172
5173<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>
5174
5175<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>
5176
5177<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>
5178
5179<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>
5180
5181<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>
5182<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>
5183
5184<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
5185<div style="margin: auto;">
5186 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
5187</div>
5188
5189<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>
5190
5191<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>
5192
5193<div style="margin: auto;">
5194 <h4><a name="silent" id="silent"></a>-silent</h4>
5195</div>
5196
5197<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>
5198
5199<div style="margin: auto;">
5200 <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>
5201</div>
5202
5203<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>
5204
5205<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>
5206
5207<p>For Photo CD images, choose from these sizes:</p>
5208
5209<pre class="text">
5210 192x128
5211 384x256
5212 768x512
5213 1536x1024
5214 3072x2048
5215</pre>
5216
cristy3ed852e2009-09-05 21:47:34 +00005217<div style="margin: auto;">
5218 <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>
5219</div>
5220
5221<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>
5222
5223<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>
5224
5225<div style="margin: auto;">
5226 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
5227</div>
5228
5229<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>
5230
5231<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
5232
5233<div style="margin: auto;">
5234 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
5235</div>
5236
5237<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>
5238
5239<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
5240
5241<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
5242
5243<div style="margin: auto;">
5244 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
5245 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
5246</div>
5247
5248<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>
5249
5250
5251<table class="doc">
5252 <tbody>
5253 <tr valign="top">
5254 <th align="left" style="width: 8%">Method</th>
5255 <th align="left">Description</th>
5256 </tr>
5257
5258 <tr valign="top">
5259 <td valign="top">voronoi</td>
5260 <td valign="top">Simply map each pixel to the to nearest color point
5261 given. The result are polygonal 'cells' of solid color. </td>
5262 </tr>
5263
5264 <tr valign="top">
5265 <td valign="top">shepards</td>
cristyd0bda5e2010-09-21 16:22:45 +00005266 <td valign="top">Colors points biased on the ratio of inverse distance
cristy3ed852e2009-09-05 21:47:34 +00005267 squared. Generating spots of color in a sea of the average of
5268 colors. </td>
5269 </tr>
5270
5271 <tr valign="top">
5272 <td valign="top">barycentric</td>
5273 <td valign="top">three point triangle of color given 3 points.
5274 Giving only 2 points will form a linear gradient between those points.
5275 Gradient is however not restricted to just the triangle or line. </td>
5276 </tr>
5277
5278 <tr valign="top">
5279 <td valign="top">bilinear</td>
5280 <td valign="top">Like barycentric but for 4 points. Less than 4 points
5281 fall back to barycentric. </td>
5282 </tr>
5283
5284 </tbody>
5285</table>
5286
5287<p>The points are placed according to the images location on the virtual
5288canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
5289offset), and do not actually have to exist on the given image, but may be
5290some point beyond the edge of the image. All points are floating point values.
5291</p>
5292
5293<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
5294modified, whcih means the matte/alpha transparency channel is not effected by
5295default. If enabled, the image also needs a the matte/alpha channel to be
5296enabled for this operator to effect an images transparency. This is typical
5297transparency handling for images. </p>
5298
5299<p>All the above methods when given a single point of color will replace all
5300the colors in the image with the color given, regardless of the point. This is
5301logical, and provides an alternative technique to recolor a image to some
5302default value. </p>
5303
5304
5305<div style="margin: auto;">
5306 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
5307</div>
5308
5309<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>
5310
5311<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>
5312
5313<div style="margin: auto;">
5314 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
5315</div>
5316
5317<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>
5318
5319<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>
5320
5321<div style="margin: auto;">
5322 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
5323</div>
5324
5325<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>
5326
5327<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>
5328
5329<div style="margin: auto;">
5330 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
5331</div>
5332
5333<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>
5334
5335<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>
5336
5337<div style="margin: auto;">
5338 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
5339</div>
5340
5341<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>
5342
5343<pre class="text">
5344 char store pixels as unsigned characters
5345 double store pixels as doubles
5346 float store pixels as floats
5347 integer store pixels as integers
5348 long store pixels as longs
5349 quantum store pixels in the native depth of your ImageMagick distribution
5350 short store pixels as unsigned shorts
5351</pre>
5352
5353<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
5354values range from 0 to the maximum value the storage type can support.</p>
5355
5356<div style="margin: auto;">
5357 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
5358</div>
5359
5360<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>
5361
5362<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>
5363
5364<pre class="text">
5365 Any
5366 Condensed
5367 Expanded
5368 ExtraCondensed
5369 ExtraExpanded
5370 Normal
5371 SemiCondensed
5372 SemiExpanded
5373 UltraCondensed
5374 UltraExpanded
5375</pre>
5376
5377<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
5378
5379<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>
5380
5381<div style="margin: auto;">
5382 <h4><a name="strip" id="strip"></a>-strip</h4>
5383</div>
5384
5385<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>
5386
5387<div style="margin: auto;">
5388 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
5389</div>
5390
5391<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>
5392
5393<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5394
5395<p>See <a href="#draw">-draw</a> for further details.</p>
5396
5397<div style="margin: auto;">
5398 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5399</div>
5400
5401<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>
5402
5403<p>See <a href="#draw">-draw</a> for further details.</p>
5404
5405<div style="margin: auto;">
5406 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5407</div>
5408
5409<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>
5410
cristy71a3f602010-09-15 12:38:16 +00005411<p>This setting suggests a font style that ImageMagick should try to apply to
5412the currently selected font family. Select <em class="arg">fontStyle</em> from
5413the following.</p>
cristy3ed852e2009-09-05 21:47:34 +00005414
5415<pre class="text">
5416 Any
5417 Italic
5418 Normal
5419 Oblique
5420</pre>
5421
5422<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>
5423
5424<div style="margin: auto;">
cristyae6203d2010-08-09 01:12:14 +00005425 <h4><a name="subimage-search" id="subimage-search"></a>-subimage-search</h4>
5426</div>
5427
cristyd4d64ed2010-08-22 22:19:33 +00005428<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>search for subimage.</td><td style='text-align:right;'>[<a href="../www/compare.html">compare</a>]</td></tr></table>
5429
cristy71a3f602010-09-15 12:38:16 +00005430<p>This option is required to have compare search for the best match location
5431of a small image within a larger image. This search will produce two images
cristyd0bd44a2010-09-24 12:38:11 +00005432(or two frames). The first is the "difference" image and the second will
cristy71a3f602010-09-15 12:38:16 +00005433be the "match score" image.</p>
5434
cristyd0bd44a2010-09-24 12:38:11 +00005435<p>The "match-score" image is smaller containing a pixel for ever possible
cristy71a3f602010-09-15 12:38:16 +00005436position of the top-left corner of the given sub-image. that is its size will
5437be the size of the larger_image - sub_image + 1. The brightest location in
5438this image is the location s the locate on the best match that is also
5439reported. Note that this may or may nor be a perfect match, and the actual
5440brightness will reflect this. Other bright 'peaks' can be used to locate other
cristyd0bda5e2010-09-21 16:22:45 +00005441possible matching loctions. </p>
cristy71a3f602010-09-15 12:38:16 +00005442
cristyd0bda5e2010-09-21 16:22:45 +00005443<p>Note that the search will try to compare teh sub-image at every possible
cristy71a3f602010-09-15 12:38:16 +00005444location in the larger image, as such it can be very slow. The smaller the
cristyd0bd44a2010-09-24 12:38:11 +00005445sub-image the faster this search is. </p>
cristy71a3f602010-09-15 12:38:16 +00005446
cristyae6203d2010-08-09 01:12:14 +00005447
5448<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00005449 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5450</div>
5451
5452<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>
5453
cristy71a3f602010-09-15 12:38:16 +00005454<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third
5455images in the current image sequence. Use <a href="#swap">+swap</a> to switch
5456the last two images in the sequence.</p>
cristy3ed852e2009-09-05 21:47:34 +00005457
5458<div style="margin: auto;">
5459 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5460</div>
5461
5462<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>
5463
5464<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5465
5466<div style="margin: auto;">
cristy5063d812010-10-19 16:28:10 +00005467 <h4><a name="synchronize" id="synchronize"></a>-synchronize</h4>
5468</div>
5469
5470<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>synchronize image to storage device.</td><td style='text-align:right;'></td></tr></table>
5471
5472<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00005473 <h4><a name="taint" id="taint"></a>-taint</h4>
5474</div>
5475
cristy5063d812010-10-19 16:28:10 +00005476<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00005477
5478<div style="margin: auto;">
5479 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5480</div>
5481
5482<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>
5483
5484<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>
5485
5486<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>
5487
5488<div style="margin: auto;">
5489 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5490</div>
5491
5492<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>
5493
5494<div style="margin: auto;">
5495 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5496</div>
5497
5498<!-- {<em class="arg">green,blue,opacity</em>}
5499<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>
5500-->
5501
5502<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>
5503
5504<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>
5505
5506<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.
5507</p>
5508
5509<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>
5510
5511<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5512<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>
5513
5514
5515<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>
5516<p>Note that the values of the transparency channel is treated as 'matte'
5517values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5518
5519<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>.
5520</p>
5521
5522<div style="margin: auto;">
5523 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5524</div>
5525
5526<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>
5527
5528<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>
5529
5530<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>
5531
5532<div style="margin: auto;">
5533 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5534</div>
5535
5536<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>
5537
5538<div style="margin: auto;">
5539 <h4>-tile <em class="arg">geometry</em></h4>
5540</div>
5541
5542<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>
5543
5544<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>
5545
5546<div style="margin: auto;">
5547 <h4>-tile</h4>
5548</div>
5549
5550<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>
5551
5552<div style="margin: auto;">
5553 <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>
5554</div>
5555
5556<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>
5557
5558<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>
5559
5560<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>
5561
5562<div style="margin: auto;">
5563 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5564</div>
5565
5566<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>
5567
5568<p>Tint the image with the fill color.</p>
5569
5570<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>
5571
5572<div style="margin: auto;">
5573 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5574</div>
5575
5576<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>
5577
5578<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>
5579
5580<p>For example,</p>
5581
5582<p class="crtsnip">
5583 -title "%m:%f %wx%h"
5584</p>
5585
5586<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>
5587
5588
5589<div style="margin: auto;">
5590 <h4><a name="transform" id="transform"></a>-transform</h4>
5591</div>
5592
5593<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>
5594
5595<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5596
5597<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>
cristy83a272e2010-05-07 20:40:35 +00005598
5599<p>This operator has been now been superseded by the <a
5600href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p>
5601
5602
cristy3ed852e2009-09-05 21:47:34 +00005603<div style="margin: auto;">
5604 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5605</div>
5606
5607<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>
5608
5609<p>The <em class="arg">color</em> argument is defined using the format
5610described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5611>-fuzz</a> setting can be used to match and replace colors similar to the one
5612given. </p>
5613
cristyb36feb22010-03-26 16:54:37 +00005614<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched.
5615that is make all non-matching colors transparent. </p>
5616
cristy3ed852e2009-09-05 21:47:34 +00005617<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
cristyb36feb22010-03-26 16:54:37 +00005618href="#transparent" >-transparent</a> but replaces the matching color with the
5619current <a href="#fill">-fill</a> color setting, rather than transparent.
5620However the <a href="#transparent" >-transparent</a> operator also ensures
5621that the image has an alpha channel enabled, as per "<kbd><a href="#alpha"
5622>-alpha</a> set</kbd>", and does not require you to modify the <a
5623href="#channel">-channel</a> to enable alpha channel handling. </p>
cristy3ed852e2009-09-05 21:47:34 +00005624
cristyb36feb22010-03-26 16:54:37 +00005625<p>Note that this does not define the color as being the 'transparency color'
5626used for color-mapped image formats, such as GIF. For that use <a
5627href="#transparent-color" >-transparent-color</a> </p>
cristy3ed852e2009-09-05 21:47:34 +00005628
5629
5630<div style="margin: auto;">
5631 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5632</div>
5633
5634<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>
5635
5636<p>Sometimes this is used for saving to image formats such as
5637GIF and PNG8 which uses this color to represent boolean transparency. This
5638does not make a color transparent, it only defines what color the transparent
5639color is in the color palette of the saved image. Use <a
5640href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5641
5642<p>This option allows you to have both an opaque visible color, as well as a
5643transparent color of the same color value without conflict. That is, you can
5644use the same color for both the transparent and opaque color areas within an
5645image. This, in turn, frees to you to select a transparent color that is
5646appropriate when an image is displayed by an application that does not handle a
5647transparent color index, while allowing ImageMagick to correctly handle images of this
5648type. </p>
5649
5650<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5651
5652<div style="margin: auto;">
5653 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5654</div>
5655
5656<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>
5657
5658<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5659</p>
5660
5661<div style="margin: auto;">
5662 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5663</div>
5664
5665<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>
5666
5667
5668<div style="margin: auto;">
5669 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5670</div>
5671
5672<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>
5673
5674<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>
5675
5676<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>
5677
5678<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>
5679
5680<div style="margin: auto;">
5681 <h4><a name="trim" id="trim"></a>-trim</h4>
5682</div>
5683
5684<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>
5685
5686<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>
5687
5688<p>The page or virtual canvas information of the image is preserved allowing
5689you to extract the result of the <a href="#trim">-trim</a> operation from the
5690image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5691information if it is unwanted.</p>
5692
5693<p>If the trimmed image 'disappears' an warning is produced, and a special
5694single pixel transparent 'missed' image is returned, in the same way as when a
5695<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5696
5697
5698<div style="margin: auto;">
5699 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5700</div>
5701
5702<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>
cristyefb2bdb2010-11-20 19:35:22 +00005703 <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>, or <kbd>ColorSeparationMatte</kbd>.</p>
cristy3ed852e2009-09-05 21:47:34 +00005704
5705<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>
5706
5707<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5708<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>
5709
5710<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5711
5712<div style="margin: auto;">
5713 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5714</div>
5715
5716<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>
5717
5718<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5719
5720<p>See <a href="#draw">-draw</a> for further details.</p>
5721
5722
5723<div style="margin: auto;">
5724 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5725</div>
5726
5727<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>
5728
5729<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>
5730
5731
5732<div style="margin: auto;">
5733 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5734</div>
5735
5736<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>
5737
5738
5739<div style="margin: auto;">
5740 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5741</div>
5742
5743<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>
5744
5745<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>
5746
5747
5748<div style="margin: auto;">
5749 <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>
5750</div>
5751
5752<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>
5753
5754<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>
5755
5756<p>The parameters are:</p>
5757
5758<pre class="text">
5759 radius: The radius of the Gaussian, in pixels, not counting the center
5760 pixel (default 0).
5761 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5762 amount: The fraction of the difference between the original and the blur
5763 image that is added back into the original (default 1.0).
5764 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5765 difference amount (default 0.05).
5766</pre>
5767
5768
5769<div style="margin: auto;">
5770 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5771</div>
5772
cristyd0bda5e2010-09-21 16:22:45 +00005773<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 precedes the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table>
cristy3ed852e2009-09-05 21:47:34 +00005774
5775
5776<div style="margin: auto;">
5777 <h4><a name="version" id="version"></a>-version</h4>
5778</div>
5779
5780<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>
5781
5782
5783<div style="margin: auto;">
5784 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5785</div>
5786
5787<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>
5788
5789
5790<div style="margin: auto;">
5791 <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>
5792</div>
5793
5794<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>
5795
5796
5797<div style="margin: auto;">
5798 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5799</div>
5800
5801<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>
5802
5803<p>This option defines what color source should be used if and when a color
5804lookup completely 'misses' the source image. The color(s) that appear to
5805surround the source image. Generally this color is derived from the source
5806image, but could also be set to a specify background color. </p>
5807
5808<p>Choose from these methods:</p>
5809
5810<pre class="text">
5811 background: the area surrounding the image is the background color
5812 black: the area surrounding the image is black
5813 checker-tile: alternate squares with image and background color
5814 dither: non-random 32x32 dithered pattern
5815 edge: extend the edge pixel toward infinity
5816 gray: the area surrounding the image is gray
5817 horizontal-tile: horizontally tile the image, background color above/below
5818 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5819 mirror: mirror tile the image
5820 random: choose a random pixel from the image
5821 tile: tile the image (default)
5822 transparent: the area surrounding the image is transparent blackness
5823 vertical-tile: vertically tile the image, sides are background color
5824 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5825 white: the area surrounding the image is white
5826</pre>
5827
5828<p>The default value is "edge".</p>
5829
5830<p>This most important for distortion operators such as <a href="#distort"
5831>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5832However it also effects operations that may access pixels just outside the
5833image proper, such as <a href="#convolve">-convolve</a>, <a
5834href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5835
5836<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5837
5838
5839<div style="margin: auto;">
5840 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5841</div>
5842
5843<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>
5844
5845<p>Choose from these visual classes:</p>
5846
5847<pre class="text">
5848 StaticGray
5849 GrayScale
5850 StaticColor
5851 PseudoColor
5852 TrueColor
5853 DirectColor
5854 default
5855 visual id
5856</pre>
5857
5858<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>
5859
5860
5861<div style="margin: auto;">
5862 <h4><a name="watermark" id="watermark"></a>-watermark <em
5863 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5864</div>
5865
5866<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
5867saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5868
5869<p>Take a grayscale image (with alpha mask) and modify the destination image's
5870brightness according to watermark image's grayscale value and the <em
5871class="arg">brightness</em> percentage. The destinations color saturation
5872attribute is just direct modified by the <em class="arg">saturation</em>
5873percentage, which defaults to 100 percent (no color change). </p>
5874
5875
5876<div style="margin: auto;">
5877 <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>
5878</div>
5879
5880<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>
5881
5882<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5883
5884<div style="margin: auto;">
5885 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5886</div>
5887
5888<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>
5889
5890<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>
5891
5892<table class="doc">
5893 <col width="25%" />
5894 <col width="75%" />
5895 <thead>
5896 <tr>
5897 <th><em class="arg">fontWeight</em></th>
5898 <th>Description</th>
5899 </tr>
5900 </thead>
5901 <tbody>
5902 <tr><td>All </td> <td>No effect. </td></tr>
5903 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5904 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5905 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5906 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5907 </tbody>
5908 </table>
5909
5910<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5911
5912<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>
5913
5914<div style="margin: auto;">
5915 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5916</div>
5917
5918<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>
5919
5920<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005921 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
cristy3ed852e2009-09-05 21:47:34 +00005922</div>
5923
cristy5cadd612009-09-21 19:33:41 +00005924<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</td><td style='text-align:right;'></td></tr></table>
5925
5926<p> The threshold value can be given as a percentage or as an absolute integer value within [0,&nbsp;<em class="QR">QuantumRange</em>] corresponding to the desired <a href="../www/command-line-options.html#channel">&#x2011;channel</a> value. See <a href="../www/command-line-options.html#threshold">&#x2011;threshold</a> for more details on thresholds and resulting values.
5927</p>
cristy3ed852e2009-09-05 21:47:34 +00005928
5929<div style="margin: auto;">
5930 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5931</div>
5932
5933<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>
5934
5935<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>
5936
5937<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>
5938
5939<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>
5940
5941<div style="margin: auto;">
5942 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5943</div>
5944
5945<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>
5946
5947<div style="margin: auto;">
5948 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5949</div>
5950
5951<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>
5952 <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>
5953
5954<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5955
cristy3eaa0ef2010-03-06 20:35:26 +00005956
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5958
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5968 <span id="footer-west">&copy; 1999-2010 ImageMagick Studio LLC</span>
5969 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
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