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</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 +0000160
161<p>Below is list of command-line options recognized by the ImageMagick <a href="../www/command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands
162<a href="../www/convert.html">convert</a>, <a href="../www/mogrify.html">mogrify</a>, and .... </p>
163
164<div style="margin: auto;">
165 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
166</div>
167
168<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>
169
170<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>
171
172<div style="margin: auto;">
173 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4>
174</div>
175
176<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>
177
178<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>
179
180<div style="margin: auto;">
181 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
182</div>
183
184<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>
185
186<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>
187
188<div style="margin: auto;">
189 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4>
190</div>
191
192<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>
193
194<p>This option is enabled by default. An attempt is made to save all
195images of an image sequence into the given output file.
196However, some formats, such as JPEG and PNG, do not support more than one
197image per file, and in that case ImageMagick is forced to write each image as a separate file. As
198such, if more than one image needs to be written, the filename given is
199modified by adding a <a href="#scene">-scene</a> number before the
200suffix, in order to make distinct names for each image. </p>
201
202<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written
203to separate files, whether or not the file format allows multiple images
204per file (for example, GIF, MIFF, and TIFF). </p>
205
206<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>
207
208<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p>
209<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg.
210</p>
211
212<p>In summary, ImageMagick tries to write all images to one file, but will use
213multiple files if either (1) the output image's file format does not allow multi-image files,
214(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is
215present in the output filename. </p>
216
217
218<div style="margin: auto;">
219 <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/>
220 -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>
221</div>
222
223<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>
224
225<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>
226
227<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p>
228
229<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>
230
231<div class="eqn">
232<img alt="affine transformation" src="../images/affine.png"/>
233</div>
234
235<p>
236The 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>
237
238<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>
239
240<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>
241
242<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>
243
244<p class="crtsnip">
245 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em>
246</p>
247
248<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>
249
250<p class="crtsnip">
251 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>
252</p>
253
254<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting
255<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p>
256
257<p class="crtsnip">
258 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em>
259</p>
260
261<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>
262
263<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>
264
265<div style="margin: auto;">
266 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4>
267</div>
268
269<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>
270
271<p>Used to set a flag on an image indicating whether or not to use existing alpha
272channel 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>
273
274
275<table class="doc">
276 <tbody>
277 <tr valign="top">
278 <th align="left" style="width: 8%">type</th>
279 <th align="left">Description</th>
280 </tr>
281
282 <tr valign="top">
283 <td valign="top"><kbd>Off</kbd>&nbsp; or
284 <kbd>Deactivate</kbd></td>
285 <td valign="top">
286 Disables the image's transparency channel. Does not delete or change the
287 existing data, just turns off the use of that data. This is the same as
288 the older <a href="#matte" >+matte</a> operator. </td></tr>
289
290 <tr valign="top">
291 <td valign="top"><kbd>On</kbd>&nbsp; or
292 <kbd>Activate</kbd></td>
293 <td valign="top">
294 Enables the image's use of transparency. If transparency data does not
295 already exist, allocates the data and sets it to opaque. If the image has
296 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT
297 the same as the older <a href="#matte" >-matte</a> operator. </td></tr>
298
299 <tr valign="top">
300 <td valign="top"><kbd>Set</kbd></td>
301 <td valign="top">
302 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously
303 turned off resets the channel to opaque. If the image already had the
304 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr>
305
306 <tr valign="top">
307 <td valign="top"><kbd>Opaque</kbd></td>
308 <td valign="top">
309 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
310 opaque. </td></tr>
311
312 <tr valign="top">
313 <td valign="top"><kbd>Transparent</kbd></td>
314 <td valign="top">
315 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
316 transparent. This effectively creates a fully transparent image the same
317 size as the original and with all its original RGB data still intact. </td></tr>
318
319 <tr valign="top">
320 <td valign="top"><kbd>Extract</kbd></td>
321 <td valign="top">
322 Copies the alpha channel values into all the color channels and turns
323 '<kbd>Off</kbd>' the the image's transparency, so as to generate a
324 gray-scale mask of the image's shape. This is the inverse of
325 '<kbd>Copy</kbd>'. </td></tr>
326
327 <tr valign="top">
328 <td valign="top"><kbd>Copy</kbd></td>
329 <td valign="top">
330 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the
331 gray-scale intensity of the image, as an alpha mask, into the alpha
332 channel, converting a gray-scale mask into a transparent shaped image
333 ready to be colored appropriately. The color channels are not modified.
334 </td></tr>
335
336 <tr valign="top">
337 <td valign="top"><kbd>Shape</kbd></td>
338 <td valign="top">
339 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with
340 the current background color.
341 </td></tr>
342
343 <tr valign="top">
344 <td valign="top"><kbd>Background</kbd></td>
345 <td valign="top">
346 Set any fully-transparent pixel to the background color.
347 </td></tr>
348 </tbody>
349</table>
350
351<p>Note that while the <a href="#matte" >+matte</a> operation is the same as
352"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte"
353>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> set</kbd>" and
354not "<kbd><a href="#alpha" >-alpha</a> on</kbd>".
355That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the
356written image is opaque if the original image had no transparency
357channel enabled, regardless if transparency data is already present. </p>
358
359
360<div style="margin: auto;">
361 <h4><a name="annotate" id="annotate"></a>
362 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br />
363 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br />
364 -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>
365</div>
366
367<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>
368
369<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>
370
371
372<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>
373
374<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>
375
376<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>
377<div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"/></div>
378
379<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>
380
381<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>
382
383<div style="margin: auto;">
384 <h4><a name="antialias" id="antialias"></a>-antialias</h4>
385</div>
386
387<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
388drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table>
389
390<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
391drawn. Use <a href="#antialias">+antialias</a> to disable the addition of
392antialiasing edge pixels. This will then reduce the number of colors added to
393an image to just the colors being directly drawn. That is, no mixed colors
394will be added when drawing such objects. </p>
395
396<div style="margin: auto;">
397 <h4><a name="append" id="append"></a>-append</h4>
398</div>
399
400<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>
401
402<p>This option creates a single longer image image, by joining all the current
403images in sequence top-to-bottom. Use <a href="#append">+append</a> to
404stack images left-to-right. </p>
405
406<p>If they are not of the same width, narrower images are padded with the
407current <a href="#background">-background</a> color setting, and their
408position relative to each other can be controled by the current <a
409href="#gravity">-gravity</a> setting. </p>
410
411
412<div style="margin: auto;">
413 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4>
414</div>
415
416<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>
417
418
419<div style="margin: auto;">
420 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4>
421</div>
422
423<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>
424
425<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>
426
427<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p>
428
cristyd934d102009-10-10 12:55:13 +0000429
430
cristy3ed852e2009-09-05 21:47:34 +0000431<div style="margin: auto;">
432 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4>
433</div>
434
435<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>
436
cristyd934d102009-10-10 12:55:13 +0000437<p>This calculates the mean values of an image, then applies a calculated <a
438href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the
439image it will get a have a value of 50%. </p>
440
441<p>This means that any solid 'gray' image will become 50% gray. </p>
442
443<p>This works well for real-life images with little or no extreme dark and
444light areas, but tend to fail for images with large amounts of bright sky or
445dark shadows. It also does not work well for diagrmas or cartoon like images.
446</p>
447
448<p>It uses the <a href="#channel" >-channel</a> setting, (including the
449'<CODE>sync</CODE>' flag for channel syncronization), to determine which color
450values will be used and modified. As the default <a href="#channel"
451>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels will be modified
452together by the same gamma value, preserving colors. </p>
453
454
455
cristy3ed852e2009-09-05 21:47:34 +0000456<div style="margin: auto;">
457 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4>
458</div>
459
460<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>
461
cristyd934d102009-10-10 12:55:13 +0000462<p>This is a 'perfect' image normalization operator. It finds the exact
463mimimum and maximum color values in the image and then applies a <a
464href="#level" >-level</a> operator to stretch the values to the full range of
465values. </p>
466
467<p>the operator is not typically used for real-life images, image scans, or
468JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
469for the <a href="#level" >-level</a> operation. On the other hand it is the
470right operator to use for color stretching gradient images being used to
471generate Color lookup tables, distortion maps, or other 'mathematically'
472defined images. </p>
473
474<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a
475href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch"
476>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
477problems that these operators may have. That is <a href="#auto-level"
478>-auto-level</a> is the perfect or ideal for of these operators. </p>
479
480<p>It uses the <a href="#channel" >-channel</a> setting, (including the
481special '<CODE>sync</CODE>' flag for channel syncronization), to determine
482which color values will be used and modified. As the default <a
483href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', channels
484will be modified together by the same gamma value, preserving colors, and
485ignoring transparency. </p>
486
487
488
cristy3ed852e2009-09-05 21:47:34 +0000489<div style="margin: auto;">
490 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
491</div>
492
493<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>
494
495<div style="margin: auto;">
496 <h4><a name="average" id="average"></a>-average</h4>
497</div>
498
499<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>
500
501<p>An error results if the images are not identically sized.</p>
502
503<p>The sequence of images is terminated by the appearance of any option. If the <a href="#average">-average</a> option appears after all of the input images, all images are averaged.</p>
504
505<div style="margin: auto;">
506 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
507</div>
508
509<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>
510
511<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>
512
513<div style="margin: auto;">
514 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
515</div>
516
517<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>
518
519<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>
520
521<div style="margin: auto;">
522 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
523</div>
524
525<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>
526
527<p>Repeat the entire command for the given number of <em class="arg">iterations</em> and report the user-time and elapsed time. For instance, consider the following command and its output.</p>
528
529<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -resize 1000% -bench 5 biglogo.png</span><span class='crtout'>Performance: 5i 0.0539724ips 91.750u 2:33</span></p>
530<p>In this example, 5&nbsp;iterations were completed at 0.0539724&nbsp;iterations per second, using 91.750&nbsp;seconds of the user's allotted time, for a total elapsed time of 2&nbsp;minutes&nbsp;and&nbsp;33&nbsp;seconds.</p>
531
532<div style="margin: auto;">
533 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
534</div>
535
536<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>
537
538<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>
539
540<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>
541
542<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
543negative results without clipping to the color value range
544(0..QuantumRange).</p>
545
546<p>See the discussion on HDRI implementations of ImageMagick on the page
547<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.
548</p>
549
550<div style="margin: auto;">
551 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
552</div>
553
554<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>
555
556<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +0000557 <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 +0000558</div>
559
cristy5cadd612009-09-21 19:33:41 +0000560<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>
561
562<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.
563</p>
cristy3ed852e2009-09-05 21:47:34 +0000564
565
566<div style="margin: auto;">
567 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4>
568</div>
569
570<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>blend an image into another by the given percent.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
571
572<p>Blend will average the images together ('plus') according to the
573percentages given and each pixels transparency. If only a single percentage
574value is given it sets the weight of the composite or 'source' image, while
575the background image is weighted by the exact opposite amount. That is a
576<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the
577'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p>
578
579
580<div style="margin: auto;">
581 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
582</div>
583
584<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>
585
586<div style="margin: auto;">
587 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
588</div>
589
590<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>
591
592<div style="margin: auto;">
593
594<div style="margin: auto;">
595 <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>
596</div>
597
598<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>
599
600<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
601
602<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
603</div>
604
605<p>Where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. If a radius of 0 is specified, ImageMagick selects a suitable radius for you.</p>
606
607<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply by taking advantage of the separability properties of the distribution. Here we apply a single-dimensional Gaussian matrix in the horizontal direction, then repeat the process in the vertical direction.</p>
608
609<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
610pixels which are outside the image proper are blurred into the final result.
611</p>
612
613
614<div style="margin: auto;">
615 <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>
616</div>
617
618<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>
619
620<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
621Average (EWA) of the source image, scaled according to the grayscale
622mapping. </p>
623
624<p>The ellipse is weighted with sigma set to the given <em class="arg"
625>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
626defaults to the <em class="arg" >Width</em> for a normal circular Guassian
627weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
628horizontal clock-wise. </p>
629
630<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
631pixels which are outside the image proper are blurred into the final result.
632</p>
633
634
635<div style="margin: auto;">
636 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
637</div>
638
639<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>
640
641<p>Set the width and height using the <em class="arg">size</em> portion of the <em class="arg">gravity</em> argument. See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are ignored. </p>
642
643<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p>
644
645<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p>
646
647<div style="margin: auto;">
648 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
649</div>
650
651<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>
652
653<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
654
655<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
656
657<div style="margin: auto;">
658 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
659</div>
660
661<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>
662
663<div style="margin: auto;">
664 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
665</div>
666
667<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>
668
669<div style="margin: auto;">
670 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
671</div>
672
673<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>
674
675<div style="margin: auto;">
676 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
677</div>
678
679<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>
680
681<p>Here is an example color correction collection:</p>
682
683<pre class="text">
684&lt;?xml version="1.0" encoding="UTF-8"?>
685&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
686 &lt;ColorCorrection id="cc06668">
687 &lt;SOPNode>
688 &lt;Slope> 0.9 1.2 0.5 &lt;/Slope>
689 &lt;Offset> 0.4 -0.5 0.6 &lt;/Offset>
690 &lt;Power> 1.0 0.8 1.5 &lt;/Power>
691 &lt;/SOPNode>
692 &lt;SATNode>
693 &lt;Saturation> 0.85 &lt;/Saturation>
694 &lt;/SATNode>
695 &lt;/ColorCorrection>
696&lt;/ColorCorrectionCollection>
697</pre>
698
699<div style="margin: auto;">
700 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
701</div>
702
703<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>
704
705<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, <kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, <kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, <kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p>
706
707<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p>
708
cristyd934d102009-10-10 12:55:13 +0000709<p>The channels above can be specified as a comma-separated list or can be
710abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>',
711'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>',
712'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'.
cristy3ed852e2009-09-05 21:47:34 +0000713
714For example, to negate only the alpha channel of an image, use</p>
715<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +0000716 -channel Alpha -negate
cristy3ed852e2009-09-05 21:47:34 +0000717</p>
718
cristyd934d102009-10-10 12:55:13 +0000719Some operators also allow the use of a special channel flag
720'<code>sync</code>'. If present operators that understand this flag will
721apply the exact same image modification to all the image channels in the image
722so as to ensure that colors are kept 'in-sync'. Without this flag such
723operators will apply there function to each channel separately. See <a
724href="#auto-level">-auto-level</a> and <a href="#auto-gamma">-auto-gamma</a>
725for examples of such an operator. </p>
cristy3ed852e2009-09-05 21:47:34 +0000726
cristyd934d102009-10-10 12:55:13 +0000727
728<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
729'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels
730except the opacity channel, and that all the color channels are to be modified
731in exactly the same way. The 'plus' form <a href="#channel" >+channel</a>
732will reset the value back to this default. </p>
733
734<p>Options that are affected by the <a href="#channel" >-channel</a> setting
735include the following.
736
737<a href="#auto-gamma">-auto-gamma</a>,
738<a href="#auto-level">-auto-level</a>,
cristy3ed852e2009-09-05 21:47:34 +0000739<a href="#black-threshold">-black-threshold</a>,
740<a href="#blur">-blur</a>,
cristyb4c03bb2009-09-27 13:55:46 +0000741<a href="#clamp">-clamp</a>,
cristy3ed852e2009-09-05 21:47:34 +0000742<a href="#clut">-clut</a>,
743<a href="#combine">-combine</a>,
744<a href="#contrast-stretch">-contrast-stretch</a>,
745<a href="#evaluate">-evaluate</a>,
746<a href="#function">-function</a>,
747<a href="#fx">-fx</a>,
cristy3ed852e2009-09-05 21:47:34 +0000748<a href="#gaussian-blur">-gaussian-blur</a>,
cristyd934d102009-10-10 12:55:13 +0000749<a href="#hald-clut">-hald-clut</a>,
cristy3ed852e2009-09-05 21:47:34 +0000750<a href="#motion-blur">-motion-blur</a>,
751<a href="#negate">-negate</a>,
752<a href="#normalize">-normalize</a>,
753<a href="#ordered-dither">-ordered-dither</a>,
754<a href="#radial-blur">-radial-blur</a>,
755<a href="#random-threshold">-random-threshold</a>,
756<a href="#separate">-separate</a>, and
cristyd934d102009-10-10 12:55:13 +0000757<a href="#threshold">-threshold</a>, and
cristy3ed852e2009-09-05 21:47:34 +0000758<a href="#white-threshold">-white-threshold</a>.
759</p>
760
cristyd934d102009-10-10 12:55:13 +0000761<p>Warning, some operators behave differentally when the <a href="#channel"
762>+channel</a> default setting is in effect, verses ANY user defined <a
763href="#channel" >-channel</a> setting (including the equivelent of the
764default). For example <a href="#threshold">-threshold</a> will by default
765gray-scale the image before thresholding, if no <a href="#channel"
766>-channel</a> setting has been defined. </p>
767
768<p>Also some operators such as <a href="#blur">-blur</a>, <a
769href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
770color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a
771href="#channel" >-channel</a>. Generally this done to ensure that
772fully-transparent colors are treated as being fully-transparent, and thus any
773underlying 'hidden' color has no effect on the final results. Typically
774resulting in 'halo' effects. </p>
775
776<p>As a alpha channel is optional within images some operators will read the
777color channels of an image as a greyscale alpha mask, when the image has no
778alpha channel present, but the <a href="#channel" >-channel</a> setting tells
779the operator to apply the alpha channel. The <a href="#clut">-clut</a>
780operator is a good example of this. </p>
781
cristy3ed852e2009-09-05 21:47:34 +0000782
783<div style="margin: auto;">
cristyb4c03bb2009-09-27 13:55:46 +0000784 <h4><a name="clamp" id="clamp"></a>-clamp</h4>
785</div>
786
787<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>
788
789<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +0000790 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
791</div>
792
793<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>
794
795<div style="margin: auto;">
796 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
797</div>
798
799<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>
800
801<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">width</em> and <em class="arg">height</em> given in the of the <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument give the number of columns and rows to remove. The <em class="arg">offset</em> portion of the <em class="arg">geometry</em> argument is influenced by a <a href="#gravity">-gravity</a> setting, if present.</p>
802
803<p>The <a href="#chop">-chop</a> option removes entire rows and columns, and moves the remaining corner blocks leftward and upward to close the gaps.</p>
804
805<div style="margin: auto;">
806 <h4><a name="clip" id="clip"></a>-clip</h4>
807</div>
808
809<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>
810
811<p>If a clipping path is present, it is applied to subsequent operations.</p>
812
813<p>For example, in the command</p>
814
815<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
816<p>only the pixels within the clipping path are negated.</p>
817
818<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
819
820<div style="margin: auto;">
821 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
822</div>
823
824<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>
825
826<div style="margin: auto;">
827 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
828</div>
829
830<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>
831
832<div style="margin: auto;">
833 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
834</div>
835
836<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>
837
838<p>Specify the image by its index in the sequence. The first image is index
8390. Negative indexes are relative to the end of the sequence; for example, &minus;1
840represents the last image of the sequence. Specify a range of images with a
841dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
842href="#clone">+clone</a> make a copy of the last image in the image
843sequence.</p>
844
845<div style="margin: auto;">
846 <h4><a name="clut" id="clut"></a>-clut</h4>
847</div>
848
849<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
850corresponding channel in the second image as a <b>c</b>olor
851<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
852
853<p>The second (LUT) image is ordinarily a gradient image containing the
854histogram mapping of how each channel should be modified. Typically it is a
855either a single row or column image of replacement color values. If larger
856than a single row or column, values are taken from a diagonal line from
857top-left to bottom-right corners.</p>
858
859<p>The lookup is further controlled by the <a
860href="#interpolate">-interpolate</a> setting, which is especially handy for an
861LUT which is not the full length needed by the ImageMagick installed Quality
862(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
863'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
864gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
865lookup of color values. </p>
866
867<p>This operator is especially suited to replacing a grayscale image with a
868specific color gradient from the CLUT image. </p>
869
870<p>Only the channel values defined by the <a href="#channel">-channel</a>
871setting will have their values replaced. In particular, since the default <a
872href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
873transparency (alpha/matte channel) is not affected, unless the <a
874href="#channel">-channel</a> setting is modified. When the alpha channel is
875set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
876as the other channels, implying that alpha/matte values are replaced using the
877alpha/matte values of the original image. </p>
878
879<p>If either the image being modified, or the lookup image, conatins no
880transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
881href="#channel">-channel</a> setting includes alpha replacement, then it is
882assumed that image represents a gray-scale graident which will be used for the
883replacement alpha values. That is you can use a gray-scale CLUT image to
884adjust a existing images alpha channel, or you can color a gray-scale image
885using colors form CLUT containing the desired colors, including transparency.
886</p>
887
888<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
889the lookup of the full color RGB value from a 2D representation of a 3D color
890cube. </p>
891
892
893<div style="margin: auto;">
894 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
895</div>
896
897<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>
898
899<p>Overlay each image in an image sequence according to its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of an animation at each point in the animation sequence. All images should be the same size, and are assigned appropriate GIF disposal settings for the animation to continue working as expected as a GIF animation. Such frames are more easilly viewed and processed than the highly optimized GIF overlay images. </p>
900
901<p>The animation can be re-optimized after processing using the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', though there is no guarantee that the restored GIF animation optimization is better than the original. </p>
902
903
904<div style="margin: auto;">
905 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
906</div>
907
908<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>
909
910<p>Specify the amount of colorization as a percentage. Separate colorization values can be applied to the red, green, and blue channels of the image with a comma-delimited list of colorization values (e.g., <kbd>-colorize 0,0,50</kbd>).</p>
911
912<div style="margin: auto;">
913 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
914</div>
915
916<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>
917
918<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
919
920<p>This option only applies when the default X server visual is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer to <a href="#visual">-visual</a> for more details. By default, a shared colormap is allocated. The image shares colors with other X clients. Some image colors could be approximated, therefore your image may look very different than intended. If <kbd>private</kbd> is chosen, the image colors appear exactly as they are defined. However, other clients may go <em>technicolor</em> when the image colormap is installed.</p>
921
922<div style="margin: auto;">
923 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
924</div>
925
926<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>
927
928<p>The actual number of colors in the image may be less than your request, but never more. Note that this a color reduction option. Images with fewer unique colors than specified by <em class="arg">value</em> will have any duplicate or unused colors removed. The ordering of an existing color palette may be altered. When converting an image from color to grayscale, it is more efficient to convert the image to the gray colorspace before reducing the number of colors. Refer to the <a href="../www/quantize.html">color reduction algorithm</a> for more details.</p>
929
930<div style="margin: auto;">
931 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
932</div>
933
934<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>
935
936<p>Choices are:</p>
937
938<pre class="text">
939 CMY
940 CMYK
941 Gray
942 HSB
943 HSL
944 HWB
945 Lab
946 Log
947 OHTA
948 Rec601Luma
949 Rec601YCbCr
950 Rec709Luma
951 Rec709YCbCr
952 RGB
953 sRGB
954 Transparent
955 XYZ
956 YCbCr
957 YCC
958 YIQ
959 YPbPr
960 YUV
961</pre>
962
963<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
964
965<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>
966
967<table class="doc">
968 <caption>Conversion Of RGB To Other Color Spaces</caption>
969 <tr><th align="left" valign="middle">CMY</th></tr>
970 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
971 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
972 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
973 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
974 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
975 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
976 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
977 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
978
979 <tr><th align="left" valign="middle">Gray</th></tr>
980 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
981
982 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
983 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
984 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
985 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
986
987 <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>
988 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
989 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
990 <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>
991
992 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
993 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
994 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
995 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
996
997 <tr><th align="left" valign="middle">LAB</th></tr>
998 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
999 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1000 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1001
1002 <tr><th align="left" valign="middle">LOG</th></tr>
1003 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1004 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1005 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1006
1007 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
1008 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
1009 <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>
1010 <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>
1011
1012 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
1013 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
1014
1015 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
1016 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1017 <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>
1018 <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>
1019
1020 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
1021 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
1022
1023 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
1024 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
1025 <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>
1026 <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>
1027
1028 <tr><th align="left" valign="middle">sRGB</th></tr>
1029 <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>
1030 <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>
1031 <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>
1032
1033 <tr><th align="left" valign="middle">XYZ</th></tr>
1034 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
1035 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
1036 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
1037
1038 <tr><th align="left" valign="middle">YCC</th></tr>
1039 <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>
1040 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
1041 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
1042
1043 <tr><th align="left" valign="middle">YCbCr</th></tr>
1044 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1045 <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>
1046 <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>
1047
1048 <tr><th align="left" valign="middle">YIQ</th></tr>
1049 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1050 <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>
1051 <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>
1052
1053 <tr><th align="left" valign="middle">YPbPr</th></tr>
1054 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1055 <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>
1056 <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>
1057
1058 <tr><th align="left" valign="middle">YUV</th></tr>
1059 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1060 <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>
1061 <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>
1062</table>
1063
1064<div style="margin: auto;">
1065 <h4><a name="combine" id="combine"></a>-combine</h4>
1066</div>
1067
1068<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>
1069
1070<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>
1071
1072<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.
1073</p>
1074
1075<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB -combine imagecopy.png</span></p>
1076<div style="margin: auto;">
1077 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
1078</div>
1079
1080<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>
1081
1082<p>This option places comments in a non-pixel portion of the image file. For a comment to be visibly written on the image itself, use the <a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options.</p>
1083
1084<p>Use this option to assign a specific comment to the image, when writing to an image format that supports comments. You can include the image filename, type, width, height, or other image attribute by embedding special format characters listed under the <a href="#format">-format</a> option. The comment is not drawn on the image, but is embedded in the image datastream via "Comment" tag or similar mechanism. </p>
1085
1086<p>For example,</p>
1087
1088<p class="crtsnip">
1089 -comment "%m:%f %wx%h"
1090</p>
1091
1092<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> for an image titled <kbd>bird.miff</kbd> and whose width is 512 and height is 480.</p>
1093
1094<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image comment is read from a file titled by the remaining characters in the string. Comments in a file are literal; no embedded formatting characters are recognized.</p>
1095
1096<div style="margin: auto;">
1097 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1098</div>
1099
1100<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>
1101
1102<p>The description of composition uses abstract terminology in order to allow
1103the description to be more precise, while avoiding constant values which are
1104specific to a particular build configuration. Each image pixel is represented
1105by red, green, and blue levels (which are equal for a gray pixel). The
1106build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1107value which may be stored, per pixel, in the red, green, or blue channels of
1108the image. Each image pixel may also optionally (if the image matte channel is
1109enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1110<em>transparent</em>, which may be used to determine the influence of the pixel
1111color when compositing the pixel with another image pixel. If the image matte
1112channel is disabled, then all pixels in the image are treated as opaque. The
1113color of an opaque pixel is fully visible while the color of a transparent
1114pixel color is entirely absent (pixel color is ignored).</p>
1115
1116<p>By definition, raster images have a rectangular shape. All image rows are of
1117equal length, as are all image columns. By treating the alpha channel as a
1118visual "mask" the rectangular image may be given a "shape" by treating the
1119alpha channel as a cookie-cutter for the image. This is done by setting the
1120pixels within the shape to be opaque, with pixels outside the shape set as
1121transparent. Pixels on the boundary of the shape may be between opaque and
1122transparent in order to provide antialiasing (visually smooth edges). The
1123description of the composition operators use this concept of image "shape" in
1124order to make the description of the operators easier to understand. While it
1125is convenient to describe the operators in terms of "shapes" they are by no
1126means limited to mask-style operations since they are based on continuous
1127floating-point mathematics rather than simple boolean operations.</p>
1128
1129<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1130
1131<table class="doc">
1132 <tbody>
1133 <tr valign="top">
1134 <th align="left" style="width: 8%">Method</th>
1135 <th align="left">Description</th>
1136 </tr>
1137
1138 <tr valign="top">
1139 <td valign="top">clear</td>
1140 <td valign="top">Both the color and the alpha of the destination are
1141 cleared. Neither the source nor the destination are used (except for
1142 destinations size and other meta-data which is always preserved.</td>
1143 </tr>
1144
1145 <tr valign="top">
1146 <td valign="top">src</td>
1147 <td valign="top">The source is copied to the destination. The destination
1148 is not used as input, though it is cleared.</td>
1149 </tr>
1150
1151 <tr valign="top">
1152 <td valign="top">dst</td>
1153 <td valign="top">The destination is left untouched. The source image is
1154 completely ignored.</td>
1155 </tr>
1156
1157 <tr valign="top">
1158 <td valign="top">src-over</td>
1159 <td valign="top">The source is composited over the destination. this is
1160 the default alpha blending compose method, when neither the compose
1161 setting is set, nor is set in the image meta-data.</td>
1162 </tr>
1163
1164 <tr valign="top">
1165 <td valign="top">dst-over</td>
1166 <td valign="top">The destination is composited over the source and the
1167 result replaces the destination.</td>
1168 </tr>
1169
1170 <tr valign="top">
1171 <td valign="top">src-in</td>
1172 <td valign="top">The part of the source lying inside of the destination
1173 replaces the destination.</td>
1174 </tr>
1175
1176 <tr valign="top">
1177 <td valign="top">dst-in</td>
1178 <td valign="top">The part of the destination lying inside of the source
1179 replaces the destination. Areas not overlaid are cleared.</td>
1180 </tr>
1181
1182 <tr valign="top">
1183 <td valign="top">src-out</td>
1184 <td valign="top">The part of the source lying outside of the destination
1185 replaces the destination.</td>
1186 </tr>
1187
1188 <tr valign="top">
1189 <td valign="top">dst-out</td>
1190 <td valign="top">The part of the destination lying outside of the source
1191 replaces the destination.</td>
1192 </tr>
1193
1194 <tr valign="top">
1195 <td valign="top">src-atop</td>
1196 <td valign="top">The part of the source lying inside of the destination is
1197 composited onto the destination.</td>
1198 </tr>
1199
1200 <tr valign="top">
1201 <td valign="top">dst-atop</td>
1202 <td valign="top">The part of the destination lying inside of the source is
1203 composited over the source and replaces the destination. Areas not
1204 overlaid are cleared. </td>
1205 </tr>
1206
1207 <tr valign="top">
1208 <td valign="top">xor</td>
1209 <td valign="top">The part of the source that lies outside of the
1210 destination is combined with the part of the destination that lies
1211 outside of the source. Source or Destination, but not both. </td>
1212 </tr>
1213
1214 </tbody>
1215</table>
1216
1217<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1218For example the defaul compose method can be specified as just 'Over'.</p>
1219
1220
1221<p>The following mathemathical composition methods are also available. </p>
1222
1223<p>Typically these use the default 'Over' alpha blending when transparencies
1224are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1225also composes the alpha channel using the same process as the color channels.
1226This allows them to be used for special image masking techniques. </p>
1227
1228<table class="doc">
1229 <tbody>
1230 <tr valign="top">
1231 <th align="left" style="width: 8%">Method</th>
1232 <th align="left">Description</th>
1233 </tr>
1234
1235 <tr valign="top">
1236 <td valign="top">multiply</td>
1237 <td valign="top">The source is multiplied by the destination and replaces the destination. The resultant color is always at least as dark as either of the two constituent colors. Multiplying any color with black produces black. Multiplying any color with white leaves the original color unchanged.</td>
1238 </tr>
1239
1240 <tr valign="top">
1241 <td valign="top">screen</td>
1242 <td valign="top">The source and destination are complemented and then multiplied and then replace the destination. The resultant color is always at least as light as either of the two constituent colors. Screening any color with white produces white. Screening any color with black leaves the original color unchanged.</td>
1243 </tr>
1244
1245 <tr valign="top">
1246 <td valign="top">plus</td>
1247 <td valign="top">The source is added to the destination and replaces the
1248 destination. This operator is useful for averaging or a controled
1249 merger of two images, rather than a direct overlay.</td>
1250 </tr>
1251
1252 <tr valign="top">
1253 <td valign="top">add</td>
1254 <td valign="top">As per 'plus' but transparency data is treated as matte
1255 values. As such any transparent areas in either image remain
1256 transparent. </td>
1257 </tr>
1258
1259 <tr valign="top">
1260 <td valign="top">minus</td>
1261 <td valign="top">Subtract the colors in the source image from the
1262 destination image. When transparency is involved, opaque areas is
1263 subtracted from any destination opaque areas. </td>
1264 </tr>
1265
1266 <tr valign="top">
1267 <td valign="top">subtract</td>
1268 <td valign="top">Subtract the colors in the source image from the
1269 destination image. When transparency is involved transparent areas are
1270 subtracted, so only the opaque areas in the source remain opaque in
1271 the destination image. </td>
1272 </tr>
1273
1274 <tr valign="top">
1275 <td valign="top">difference</td>
1276 <td valign="top">Subtracts the darker of the two constituent colors from
1277 the lighter. Painting with white inverts the destination color.
1278 Painting with black produces no change.</td>
1279 </tr>
1280
1281 <tr valign="top">
1282 <td valign="top">exclusion</td>
1283 <td valign="top">Produces an effect similar to that of 'difference', but
1284 appears as lower contrast. Painting with white inverts the
1285 destination color. Painting with black produces no change.</td>
1286 </tr>
1287
1288 <tr valign="top">
1289 <td valign="top">darken</td>
1290 <td valign="top">Selects the darker of the destination and source colors.
1291 The destination is replaced with the source when the source is darker,
1292 otherwise it is left unchanged.</td>
1293 </tr>
1294
1295 <tr valign="top">
1296 <td valign="top">lighten</td>
1297 <td valign="top">Selects the lighter of the destination and source colors.
1298 The destination is replaced with the source when the source is
1299 lighter, otherwise it is left unchanged. </td>
1300 </tr>
1301
1302 <tr valign="top">
1303 <td valign="top">linear-dodge</td>
1304 <td valign="top">This is equivelent to 'Plus' in that the color channels
1305 are simply added, however it does not 'Plus' the alpha channel, but
1306 uses the normal 'Over' alpha blending, which transparencies are
1307 involved. Produces a sort of additive multiply-like result. Added
1308 ImageMagick version 6.5.4-3. </td>
1309 </tr>
1310
1311 <tr valign="top">
1312 <td valign="top">linear-burn</td>
1313 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1314 Sort of a additive 'Screen' of the images. Added ImageMagick version
1315 6.5.4-3. </td>
1316 </tr>
1317
1318 <tr valign="top">
1319 <td valign="top">color-dodge</td>
1320 <td valign="top">Brightens the destination color to reflect the source
1321 color. Painting with black produces no change.</td>
1322 </tr>
1323
1324 <tr valign="top">
1325 <td valign="top">color-burn</td>
1326 <td valign="top">Darkens the destination color to reflect the source
1327 color. Painting with white produces no change. Fixed in ImageMagick
1328 version 6.5.4-3. </td>
1329 </tr>
1330
1331 <tr valign="top">
1332 <td valign="top">overlay</td>
1333 <td valign="top">Multiplies or screens the colors, dependent on the
1334 destination color. Source colors overlay the destination whilst
1335 preserving its highlights and shadows. The destination color is not
1336 replaced, but is mixed with the source color to reflect the lightness
1337 or darkness of the destination.</td>
1338 </tr>
1339
1340 <tr valign="top">
1341 <td valign="top">hard-light</td>
1342 <td valign="top">Multiplies or screens the colors, dependent on the source
1343 color value. If the source color is lighter than 0.5, the destination
1344 is lightened as if it were screened. If the source color is darker
1345 than 0.5, the destination is darkened, as if it were multiplied. The
1346 degree of lightening or darkening is proportional to the difference
1347 between the source color and 0.5. If it is equal to 0.5 the
1348 destination is unchanged. Painting with pure black or white produces
1349 black or white.</td>
1350 </tr>
1351
1352
1353 <tr valign="top">
1354 <td valign="top">linear-light</td>
1355 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1356 instead. Increases contrast slightly with an impact on the
1357 foreground's tonal values.</td>
1358 </tr>
1359
1360 <tr valign="top">
1361 <td valign="top">soft-light</td>
1362 <td valign="top">Darkens or lightens the colors, dependent on the source
1363 color value. If the source color is lighter than 0.5, the destination
1364 is lightened. If the source color is darker than 0.5, the destination
1365 is darkened, as if it were burned in. The degree of darkening or
1366 lightening is proportional to the difference between the source color
1367 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1368 with pure black or white produces a distinctly darker or lighter area,
1369 but does not result in pure black or white. Fixed in ImageMagick
1370 version 6.5.4-3. </td>
1371 </tr>
1372
1373 <tr valign="top">
1374 <td valign="top">pegtop-light</td>
1375 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1376 continuious mathematical formula rather than two conditionally
1377 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1378 </tr>
1379
1380 <tr valign="top">
1381 <td valign="top">vivid-light</td>
1382 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1383 primary and secondary colors in the image. Added ImageMagick version
1384 6.5.4-3. </td>
1385 </tr>
1386
1387 <tr valign="top">
1388 <td valign="top">pin-light</td>
1389 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1390 to similate the effects of a strong 'pinhole' light source. Added
1391 ImageMagick version 6.5.4-3. </td>
1392 </tr>
1393
1394 </tbody>
1395</table>
1396
1397
1398<p>Also included are these special purpose compose methods:</p>
1399
1400<table class="doc">
1401 <tbody>
1402 <tr valign="top">
1403 <th align="left" style="width: 8%">Method</th>
1404 <th align="left">Description</th>
1405 </tr>
1406
1407 <tr valign="top">
1408 <td valign="top">copy-*</td>
1409 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1410 Magenta, Yellow, Black, or Opacity) in the source image to the
1411 same channel in the destination image. If the channel specified
1412 does not exist in the source image, (which can only happen for methods,
1413 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1414 assumed that the source image is a special grayscale channel image
1415 of the values to be copied. </td>
1416 </tr>
1417
1418 <tr valign="top">
1419 <td valign="top">change-mask</td>
1420 <td valign="top">Replace any destination pixel that is the similar to the source images pixel (as defined by the current <a href="#fuzz">-fuzz</a> factor), with transparency. </td>
1421 </tr>
1422 </tbody>
1423</table>
1424
1425<p>On top of these composed methods are a few special ones that not only require
1426the two images that are being merged or overlaid, but have some extra numerical
1427arguments, which are tabled below. </p>
1428
1429<p>In the "<code>composite</code>" command these composition methods are
1430selected using special options with the arguments needed. They are usually,
1431but not always, the same name as the composte 'method' they use, and replaces
1432the normal use of the <a href="#compose" >-compose</a> setting in the
1433"<code>composite</code>" command. For example... </p>
1434
1435<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1436<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1437these extra arguments to its <a href="#composite" >-composite</a> operator,
1438using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1439these special argumented <a href="#compose" >-compose</a> methods, those the
1440argument and the method both need to be set separatally. For example... </p>
1441
1442<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1443<p>The following is a table of these special 'argumented' compose methods,
1444with a brief summary of what they do. For more details see the equivalent
1445"composite" command option name. </p>
1446
1447<table class="doc">
1448 <tbody>
1449 <tr valign="top">
1450 <th align="left" style="width: 8%">Method</th>
1451 <th align="left">Description</th>
1452 </tr>
1453
1454 <tr valign="top">
1455 <td valign="top">dissolve</td>
1456 <td valign="top">Arguments:
1457 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1458 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1459 <br>Dissolve the 'source' image by the percentage given before overlaying
1460 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1461 greater than 100, it starts dissolving the main image so it will
1462 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1463 both percentages are given, each image are dissolved to the
1464 percentages given.
1465 </td>
1466 </tr>
1467
1468 <tr valign="top">
1469 <td valign="top">blend</td>
1470 <td valign="top">Arguments:
1471 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1472 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1473 <br>Average the images together ('plus') according to the percentages
1474 given and each pixels transparency. If only a single percentage value
1475 is given it sets the weight of the composite or 'source' image, while
1476 the background image is weighted by the exact opposite amount. That is
1477 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1478 the 'destination' image. Thus it is equivalent to <kbd>-blend
1479 30x70</kbd>.
1480 </td>
1481 </tr>
1482
1483 <tr valign="top">
1484 <td valign="top">mathematics</td>
1485 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1486 <br>Not available in "<code>composite</code>" at this time.
1487 <br>Merge the source and destination images according to the formula
1488 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1489 <br>Can be used to generate a custom composition method that would
1490 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1491 DIY image operator. Added to ImageMagick version 6.5.4-3.
1492 </td>
1493 </tr>
1494
1495 <tr valign="top">
1496 <td valign="top">modulate</td>
1497 <td valign="top">Arguments:
1498 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1499 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1500 <br>Take a grayscale image (with alpha mask) and modify the destination
1501 image's brightness according to watermark image's grayscale value and
1502 the <em class="arg">brightness</em> percentage. The destinations
1503 color saturation attribute is just direct modified by the <em
1504 class="arg">saturation</em> percentage, which defaults to 100 percent
1505 (no color change).
1506
1507 </td>
1508 </tr>
1509
1510 <tr valign="top">
1511 <td valign="top">displace</td>
1512 <td valign="top">Arguments:
1513 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1514 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1515 <br>With this option, the 'overlay' image, and optionally the 'mask'
1516 image, is used as a relative displacement map, which is used to
1517 displace the lookup of what part of the destination image is seen at
1518 each point of the overlaid area. Much like the displacement map is a
1519 'lens' that distorts the original 'background' image behind it.
1520 <br><br>
1521 The X-scale is modilated by the 'red' channel of the overlay image
1522 while the Y-scale is modulated by the green channel, (the mask image
1523 if given is rolled into green channel of the overlay image. This
1524 separation allows you to modulate the X and Y lookup displacement
1525 separatally allowing you to di 2 dimentional displacements, rather
1526 than 1 dimentional verctored displacements (using grayscale image).
1527 <br><br>
1528 If the overlay image contains transparency this is used as a mask
1529 of the resulting image to remove 'invalid' pixels.
1530 <br><br>
1531 The '%' flag makes the displacement scale relative to the size of the
1532 overlay image (100% = half width/height of image). Using '!' switches
1533 percentage arguments to refer to the destination image size instead.
1534 <br><br>
1535 Special flags were added Added to ImageMagick version 6.5.3-5.
1536 </td>
1537 </tr>
1538
1539 <tr valign="top">
1540 <td valign="top">distort</td>
1541 <td valign="top">Arguments:
1542 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1543 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1544 <br>Not available in "<code>composite</code>" at this time.
1545 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1546 relative to the center of the overlay (or that given). Basically
1547 allows you to generate absolute distortion maps where 'black' will
1548 look up the left/top edge, and 'white' looks up the bottom/right
1549 edge of the destination image, according to the scale given.
1550 <br><br>
1551 The '!' flag not only switches percentage scaling, to use the
1552 destination image, but also the image the center offset of the lookup.
1553 This means the overlay can lookup a completely different region of the
1554 destination image.
1555 <br><br>
1556 Added to ImageMagick version 6.5.3-5.
1557 </td>
1558 </tr>
1559
1560 <tr valign="top">
1561 <td valign="top">blur</td>
1562 <td valign="top">Arguments:
1563 <em class="arg">Width</em>[x<em class="arg">Height</em
1564 >[+<em class="arg">Angle</em>]]
1565 <br>Equivalent to "<code>composite</code>"
1566 <a href="#blur-composite">-blur</a>
1567 <br>A Variable Blur Mapping Composition method, where each pixel in the
1568 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1569 with an ellipse (typically a circle) of the given sigma size, scaled
1570 according to overlay (source image) grayscale mapping.
1571 <br><br>
1572 As per 'Displace' and 'Distort', the red channel will modulate the
1573 width of the ellipse, while the green channel will modulate the height
1574 of the ellipse. However at this time the ellipse angle is not
1575 modulated though this may be a future posibility (perhaps with a
1576 special flag to enable use of blur channel for this purpose).
1577 <br><br>
1578 Added to ImageMagick version 6.5.4-0.
1579 </td>
1580 </tr>
1581
1582 </tbody>
1583</table>
1584
1585<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1586
1587
1588<div style="margin: auto;">
1589 <h4><a name="composite" id="composite"></a>-composite</h4>
1590</div>
1591
1592<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on the current image sequence.</td><td style='text-align:right;'></td></tr></table>
1593
1594<p>Take the first image 'destination' and overlay the second 'source' image
1595according to the current <a href="#compose">-compose</a> setting. The location
1596of the 'source' or 'overlay' image is controlled according to <a
1597href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1598settings. </p>
1599
1600<p>If a third image is given this is treated as a gray-scale 'mask' image
1601relative to the first 'destination' image. This mask will limit what parts of
1602the destination can be modified by the image composition. However for the
1603'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1604Y-displacement image instead. </p>
1605
1606<p>If a <a href="#compose">-compose</a> method requires extra numerical
1607arguments or flags these can be provided by setting the <a
1608href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1609appropriatally for the compose method. </p>
1610
1611<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1612image outside the overlay area. You can disable this by setting the special <a
1613href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1614to '<kbd>false</kbd>'. </p>
1615
1616
1617<div style="margin: auto;">
1618 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1619</div>
1620
1621<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>
1622
1623<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>
1624
1625<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1626
1627<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>
1628
1629<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>
1630
1631<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>
1632
1633<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>
1634
1635<div style="margin: auto;">
1636 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1637</div>
1638
1639<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>
1640
1641<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>
1642
1643<p>For a more pronounced effect you can repeat the option:</p>
1644
1645<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1646<div style="margin: auto;">
1647 <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>
1648</div>
1649
1650<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>
1651
cristyd934d102009-10-10 12:55:13 +00001652<p>While performing the stretch, black-out at most <em
1653class="arg" >black-point</em> pixels and white-out at most <em
1654class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most
1655<em class="arg" >black-point %</em> pixels and white-out at most <em
1656class="arg" >white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001657
cristyd934d102009-10-10 12:55:13 +00001658<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch"
1659>-contrast-stretch</a> will black-out at most <em class="arg"
1660>black-point</em> pixels and white-out at most <em class="arg" >total pixels
1661minus white-point</em> pixels. Or, if percent is used, black-out at most <em
1662class="arg">black-point %</em> pixels and white-out at most <em class="arg"
1663>100% minus white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001664
cristyd934d102009-10-10 12:55:13 +00001665<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that
1666the image's min and max values are stretched to 0 and <em class="QR"
1667>QuantumRange</em>, respectively, without any loss of data due to burn-out or
1668clipping at either end. This is not the same as <a href="#normalize"
1669>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or
1670prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p>
cristy3ed852e2009-09-05 21:47:34 +00001671
cristyd934d102009-10-10 12:55:13 +00001672<p>Internally operator works by creating a histogram bin, and then uses that
1673bin to modify the image. As such some colors may be merged together when they
1674originally fell into the same 'bin'. </p>
1675
1676<p>All the channels are normalized in concert by the came amount so as to
1677preserve color integrity, when the default <a href="#channel" >+channel</a>
1678setting is in use. Specifing any other <a href="#channel" >-channel</a>
1679setting will normalize the RGB channels independently.</p>
1680
1681<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
1682normalization of mathematical images. </p>
1683
1684<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00001685
1686
1687<div style="margin: auto;">
1688 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1689</div>
1690
1691<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>
1692
cristyd934d102009-10-10 12:55:13 +00001693<p>The <em class="arg">kernel</em> is a square matrix specified as
1694a comma-separated list of integers (with no spaces), ordered left-to right,
1695starting with the top row. Presently, only odd-dimensioned kernels are
1696supported, and therefore the number of entries in the specified <em
1697class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
16987<sup>2</sup>=49, etc. </p>
cristy3ed852e2009-09-05 21:47:34 +00001699
cristyd934d102009-10-10 12:55:13 +00001700<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
1701positive and negative results are relative to a user-specified bias value.
1702This is important for non-HDRI compilations of ImageMagick when dealing with
1703convolutions that contain negative as well as positive values. This is
1704especially the case with convolutions involving high pass filters or edge
1705detection. Without an output bias, the negative values is clipped at zero.
cristy3ed852e2009-09-05 21:47:34 +00001706</p>
1707
cristyd934d102009-10-10 12:55:13 +00001708<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
1709negative results without clipping to the color value range (0..QuantumRange).
1710See the discussion on HDRI implementations of ImageMagick on the page <a
1711href="/www/high-dynamic-range.html">High
1712Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a
1713href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1714<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1715entry. </p>
cristy3ed852e2009-09-05 21:47:34 +00001716
cristy3ed852e2009-09-05 21:47:34 +00001717
1718<div style="margin: auto;">
1719 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1720</div>
1721
1722<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>
1723
1724<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>
1725
1726<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>
1727
1728<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>
1729
1730<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>
1731
1732<p>By adding a exclamation character flag to the geometry argument, the
1733cropped images virtual canvas page size and offset is set as if the
1734geometry argument was a viewport or window. This means the canvas page size
1735is set to exactly the same size you specified, the image offset set
1736relative top left corner of the region cropped. </p>
1737
1738<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1739special single pixel transparent 'missed' image is returned, and a 'crop
1740missed' warning given. </p>
1741
1742
1743<div style="margin: auto;">
1744 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1745</div>
1746
1747<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>
1748
1749<p><em class="arg">Amount</em> defines the number of positions each
1750colormap entry is shifted.</p>
1751
1752
1753<div style="margin: auto;">
1754 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1755</div>
1756
1757<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>
1758
1759<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>
1760
1761
1762<p>For example, to log cache and blob events, use.</p>
1763
1764<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1765<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1766
1767<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1768
1769<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1770
1771<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1772
1773<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>
1774
1775
1776<div style="margin: auto;">
1777 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1778</div>
1779
1780<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>
1781
1782<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1783
1784<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1785
1786
1787<div style="margin: auto;">
1788 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1789</div>
1790
1791<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>
1792
1793<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>
1794
1795<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>
1796
1797<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1798
1799
1800<div style="margin: auto;">
1801 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1802</div>
1803
1804<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add coder/decoder specific options.</td><td style='text-align:right;'></td></tr></table>
1805
1806<p>This option creates one or more definitions for coders and decoders to use while reading and writing image data. Definitions may be passed to coders and decoders to control options that are specific to certain image formats. If <em class="arg">value</em> is missing for a definition, an empty-valued definition of a flag is created with that name. This used to control on/off options. Use <a href="#define">+define key</a> to remove definitions previously created. Use <a href="#define">+define "*"</a> to remove all existing definitions.</p>
1807
1808<p>The following definitions may be created:</p>
1809
1810<ul>
cristy48dd1af2009-10-02 01:21:56 +00001811<dt>jpeg:size=geometry</dt>
1812 <dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. It is most useful for increasing performance and reducing the memory requirements when reducing the size of a large JPEG image.</dd><br />
cristy3ed852e2009-09-05 21:47:34 +00001813<dt>jp2:rate=value</dt>
1814 <dd>Specify the compression factor to use while writing JPEG-2000 files. The compression factor is the reciprocal of the compression ratio. The valid range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, this value overrides the -quality setting. A quality setting of 75 results in a rate value of 0.06641.</dd><br />
1815<dt>mng:need-cacheoff</dt>
1816 <dd>turn playback caching off for streaming MNG.</dd><br />
1817<dt>png:bit-depth=value</dt>
1818<dt>png:color-type=value</dt>
1819 <dd>desired bit-depth and color-type for PNG output. You can force the PNG encoder to use a different bit-depth and color-type than it would have normally selected, but only if this does not cause any loss of image quality. Any attempt to reduce image quality is treated as an error and no PNG file is written. E.g., if you have a 1-bit black-and-white image, you can use these "defines" to cause it to be written as an 8-bit grayscale, indexed, or even a 64-bit RGBA. But if you have a 16-million color image, you cannot force it to be written as a grayscale or indexed PNG. If you wish to do this, you must use the appropriate <a href="#depth">-depth</a>, <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to reduce the image quality prior to using the PNG encoder. Note that in indexed PNG files, "bit-depth" refers to the number of bits per index, which can range from 1 to 8. In such files, the color samples always have 8-bit depth.</dd><br />
1820<dt>ps:imagemask</dt>
1821 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create Postscript files that render bilevel images with the Postscript imagemask operator instead of the image operator.</dd>
1822</ul>
1823
1824<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1825
1826<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1827<p>Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>. For example, to set a temporary path to put work files, use:</p>
1828
1829<p class="crtsnip">
1830-define registry:temporary-path=/data/tmp
1831</p>
1832
1833<div style="margin: auto;">
1834 <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>
1835</div>
1836
1837<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>
1838
1839<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>
1840
1841<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>
1842
1843
1844<div style="margin: auto;">
1845 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1846</div>
1847
1848<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>
1849
1850<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>
1851
1852
1853<div style="margin: auto;">
1854 <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>
1855</div>
1856
1857<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>
1858
1859<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>
1860
1861<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>
1862
1863<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>
1864
1865<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>
1866
1867<div style="margin: auto;">
1868 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1869</div>
1870
1871<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>
1872
1873<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>
1874
1875<div style="margin: auto;">
1876 <h4><a name="descend" id="descend"></a>-descend</h4>
1877</div>
1878
1879<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>
1880
1881<div style="margin: auto;">
1882 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1883</div>
1884
1885<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>
1886
1887<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>
1888
1889<div style="margin: auto;">
1890 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1891</div>
1892
1893<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>
1894
1895<div style="margin: auto;">
1896 <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>
1897</div>
1898
1899<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>
1900
1901<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1902will be used as a displacement map, which is used to displace the lookup of
1903what part of the 'background' image is seen at each point of the overlaid
1904area. Much like the displacement map is a 'lens' that redirects light shining
1905through it so as to present a distorted view the original 'background' image
1906behind it. </p>
1907
1908<p>Any perfect grey areas of the displacement map produce a zero
1909displacement of the image. Black areas produce the given maximum negative
1910displacement of the lookup point, while white produce a maximum positive
1911displacement of the lookup. </p>
1912
1913<p>Note that it is the lookup of the 'background' that is displaced, not a
1914displacement of the image itself. As such an area of the displacement map
1915containing 'white' will have the lookup point 'shifted' by a positive amount,
1916and thus generating a copy of the destination image to the right/downward from
1917the correct position. That is the image will look like it may have been
1918'shifted' in a negative left/upward direction. Understanding this is a very
1919important in understanding how displacement maps work. </p>
1920
1921<p>The given arguments define the maximum amount of displacement in pixels
1922that a particular map can produce. If the displacement scale is large enough
1923it is also posible to lookup parts of the 'background' image that lie well
1924outside the bounds of the displacement map itself. That is you could very
1925easilly copy a section of the original image from outside the overlay area
1926into the overlay area. </p>
1927
1928<p>The '%' flag makes the displacement scale relative to the size of the
1929overlay image (100% = half width/height of image). Using '!' switches
1930percentage arguments to refer to the destination image size instead.
1931these flags were added as of IM v6.5.3-5.</p>
1932
1933<p>Normally a single grayscale displacement map is provided, which with the
1934given scaling values will determine a single direction (vector) in which
1935displacements can occur (positivally or negativally). However, if you also
1936specify a third image which is normally used as a <em class="arg">mask</em>,
1937then the <em class="arg">composite image</em> will be used for horizontal X
1938displacement, while the <em class="arg">mask image</em> is used for vertical Y
1939displacement. This allows you to define completely different displacement
1940values for the X and Y directions, and allowing you to lookup any point within
1941the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1942any other nearby pixel, producing complex 2 dimentional displacements, rather
1943than a simple 1 dimentional vector displacements. </p>
1944
1945<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1946you can use the 'red' channel of the overlay image to specify the horizontal
1947or X displacement, and the 'green' channel for the vertical or Y displacement.
1948</p>
1949
1950<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1951mask the transparency of the destination image. However areas outside the
1952overlaid areas will not be effected. </p>
1953
1954
1955<div style="margin: auto;">
1956 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1957</div>
1958
1959<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>
1960
1961<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1962
1963<div style="margin: auto;">
1964 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1965</div>
1966
1967<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>
1968
1969<p>The layer disposal method defines the way each the displayed image is to be
1970modified after the current 'frame' of an animation has finished being
1971displayed (after its 'delay' period), but before the next frame on an
1972animation is to be overlaid onto the display. </p>
1973
1974<p>Here are the valid methods:</p>
1975
1976<pre class="text">
1977Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1978None 1 Do not dispose, just overlay next frame image.
1979Background 2 Clear the frame area with the background color.
1980Previous 3 Clear to the image prior to this frames overlay.
1981</pre>
1982
1983<p>You can also use the numbers given above, which is what the GIF format
1984uses internally to represent the above settings. </p>
1985
1986<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1987
1988<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1989resetting the layer disposal methods of images being read in. </p>
1990
1991<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1992disposal method for images already in memory.</p>
1993
1994<div style="margin: auto;">
1995 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1996</div>
1997
1998<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>
1999
2000
2001<div style="margin: auto;">
2002 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
2003</div>
2004
2005<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>
2006
2007<p>The opacity of the composite image is multiplied by the given percent, then
2008it is composited 'over' the main image. If <em class="arg">src_percent</em>
2009is greater than 100, start dissolving the main image so it will become
2010transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
2011are given, each image are dissolved to the percentages given. </p>
2012
2013<p>Note that dissolve percentages do not add, two opaque images dissolved
2014'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2015images, you would need to use dissolve values of '50,100'. </p>
2016
2017<div style="margin: auto;">
2018 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
2019</div>
2020
2021<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>
2022
2023<p>The <em class="arg">arguments</em> is a single string containing a list
2024of floating point numbers separated by commas or spaces. The number of
2025and meaning of the floating point values depends on the distortion <em
2026class="arg">method</em> being used. </p>
2027
2028<p>Choose from these distortion types:</p>
2029
2030<table class="doc">
2031 <tr valign="top">
2032 <th align="left" style="width: 8%">Method</th>
2033 <th align="left">Description</th>
2034 </tr>
2035
2036 <tr valign="top">
2037 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
2038 <br/>or &nbsp; <kbd>SRT</kbd></td>
2039 <td valign="top">
2040 Distort image by first scaling and rotating about a given 'center',
2041 before translating that 'center' to the new location, in that order. It
2042 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
2043 distortion, but without shearing effects. It also provides a good way
2044 of rotating and displacing a smaller image for tiling onto a larger
2045 background (IE 2-dimensional animations). <br/>
2046
2047 The number of arguments determine the specific meaning of each
2048 argument for the scales, rotation, and translation operations. <br/>
2049
2050 <table style="margin-left:auto; margin-right:auto;">
2051 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
2052 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
2053 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
2054 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2055 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
2056 <tr><td>5:</td>
2057 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2058 <tr><td>6:</td>
2059 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
2060 <tr><td>7:</td>
2061 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
2062 &nbsp; NewX,NewY</em></td></tr>
2063 </table>
2064
2065 This is actually an alternative way of specifing a 2 dimensional linear
2066 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
2067
2068 <tr valign="top">
2069 <td valign="top"><kbd>Affine</kbd></td>
2070 <td valign="top">
2071 Distort the image linearly by moving a list of at least 3 or more sets
2072 of control points (as defined below). Idealy 3 sets or 12 floating
2073 point values are given allowing the image to be linearly scaled,
2074 rotated, sheared, and translated, according to those three points. See
2075 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
2076 distortions. <br/>
2077
2078 More than 3 sets given control point pairs (12 numbers) is least
2079 squares fitted to best match a lineary affine distortion. If only 2
2080 control point pairs (8 numbers) are given a two point image translation
2081 rotation and scaling is performed, without any posible shearing,
2082 flipping or changes in aspect ratio to the resulting image. If only one
2083 control point pair is provides the image is only translated, (which may
2084 be a floating point non-integer translation). <br/>
2085
2086 This distortion does not include any form of perspective distortion.
2087 </td>
2088
2089 </tr>
2090
2091 <tr valign="top">
2092 <td valign="top"><kbd>AffineProjection</kbd></td>
2093 <td valign="top">
2094 Linearly distort an image using the given Affine Matrix of 6
2095 pre-calculated coefficients forming a set of Affine Equations to map
2096 the source image to the destination image.
2097
2098 <div style="text-align: center"><em>
2099 s<sub>x</sub>, r<sub>x</sub>,
2100 r<sub>y</sub>, s<sub>y</sub>,
2101 t<sub>x</sub>, t<sub>y</sub>
2102 </em></div>
2103
2104 See <a href="#affine" >-affine</a> setting for more detail, and
2105 meanings of these coefficients. <br/>
2106
2107 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
2108 alternative methods of defining this distortion, with ImageMagick doing the
2109 calculations needed to generate the required coefficients. You can see
2110 the internally generated coefficients, by using a <a href="#verbose"
2111 >-verbose</a> setting. </td>
2112
2113 </tr>
2114
2115<!-- still under development, do not display - Anthony
2116 <tr valign="top">
2117 <td valign="top"><kbd>Bilinear</kbd></td>
2118 <td valign="top">
2119 Bilinear (reversed) Distortion, given a minimum of 4 sets of
2120 coordinate pairs, or 16 values (see below). Not that lines may not
2121 appear straight after distortion, though the distance between
2122 coordinates will remain consistant. </td>
2123 </tr>
2124-->
2125
2126 <tr valign="top">
2127 <td valign="top"><kbd>Perspective</kbd></td>
2128 <td valign="top">
2129 Perspective distort the images, using a list of 4 or more sets of
2130 control points (as defined below). More that 4 sets (16 numbers) of
2131 control points provide least squares fitting for more accurate
2132 distortions (for the purposes of image registration and panarama
2133 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2134 linear distortion. <br/>
2135
2136 Perspective Distorted images ensures that straight lines remain
2137 straight, but the scale of the distorted image will vary. The horizon
2138 is anti-aliased, and the 'sky' color may be set using the
2139 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2140 </tr>
2141
2142 <tr valign="top">
2143 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2144 <td valign="top">
2145 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2146 pre-calculated coefficients. You can get these coefficients by looking
2147 at the <a href="#verbose" >-verbose</a> output of a
2148 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2149 If the last two perspective scaling coefficients are zero, the
2150 remaining 6 represents a transposed 'Affine Matrix'. </td>
2151
2152 </tr>
2153
2154 <tr valign="top">
2155 <td valign="top"><kbd>Arc</kbd></td>
2156 <td valign="top">
2157 Arc the image (variation of polar mapping) over the angle given around
2158 a circle. <br/>
2159 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2160 <tr valign="top"><td>Argument</td>
2161 <td>Meaning</td></tr>
2162 <tr valign="top"><td><em>arc_angle</em></td>
2163 <td>The angle over which to arc the image side-to-side</td></tr>
2164 <tr valign="top"><td><em>rotate_angle</em></td>
2165 <td>Angle to rotate resulting image from vertical center</td></tr>
2166 <tr valign="top"><td><em>top_radius</em></td>
2167 <td>Set top edge of source image at this radius</td></tr>
2168 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2169 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2170 </table>
2171
2172 The resulting image is always resized to best fit the resulting image,
2173 (as if using <a href="#distort" >+distort</a>) while attempting to
2174 preserve scale and aspect ratio of the original image as much as
2175 possible with the arguments given by the user. All four arguments will
2176 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2177
2178 This a variation of a polar distortion designed to try to preserve the
2179 aspect ratio of the image rather than direct Cartesian to Polar
2180 conversion. </td>
2181 </tr>
2182
2183 <tr valign="top">
2184 <td valign="top"><kbd>Polar</kbd></td>
2185 <td valign="top">
2186 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2187 the image. that is the height of the input image is mapped to the
2188 radius limits, while the width is wrapped around between the
2189 angle limits. <br/>
2190
2191 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2192
2193 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2194 center to the center of the image, and the angles going from -180 (top)
2195 to +180 (top). If <em>Rmax</em> is given the special value of
2196 '<code>0</code>', the the distance from the center to the nearest edge
2197 is used for the radius of the output image, which will ensure the whole
2198 image is visible (though scaled smaller). However a special value of
2199 '<code>-1</code>' will use the distance from the center to the furthest
2200 corner, This may 'clip' the corners from the input rectangular image,
2201 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2202 the same arguments. <br/>
2203
2204 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2205 output image center will default to <code>0,0</code> of the virtual
2206 canvas, and the image size adjusted to ensure the whole input image is
2207 made visible in the output image on the virtual canvas. </td>
2208
2209 </tr>
2210
2211 <tr valign="top">
2212 <td valign="top"><kbd>DePolar</kbd></td>
2213 <td valign="top">
2214 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2215 but generates the reverse Polar to Cartesian distortion. <br/>
2216
2217 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2218 the corners of the input image. However using the special
2219 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2220 distance) will ensure the whole distorted image is preserved in the
2221 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2222 reverse the distortion re-producing the original.
2223
2224 Note that as this distortion requires the area resampling of a circular
2225 arc, which can not be handled by the builtin EWA resampling function.
2226 As such the normal EWA filters are turned off. It is recomended some
2227 form of 'super-sampling' image processing technique be used to produce
2228 a high quality result. </td>
2229
2230 </tr>
2231
2232 <tr valign="top">
2233 <td valign="top"><kbd>Barrel</kbd></td>
2234 <td valign="top">
2235 Given the four coefficients (A,B,C,D) as defined by <a
2236 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2237 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2238 correct radial lens distortions. That is in photographs, make straight
2239 lines straight again. <br/>
2240
2241 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2242 <em>X</em> , <em>Y</em> ] ] <br/>
2243 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2244 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2245 [ <em>X</em> , <em>Y</em> ] <br/>
2246 So that it forms the function <br/>
2247 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2248 <em>C</em>*r + <em>D</em> )<br/>
2249
2250 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2251 (defaulting to the center of the image). <br/>
2252 The second form is typically used to distort images, rather than
2253 correct lens distortions. <br/>
2254 </td>
2255
2256 </tr>
2257
2258 <tr valign="top">
2259 <td valign="top"><kbd>BarrelInverse</kbd></td>
2260 <td valign="top">
2261 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2262 arguments, and argument handling. However it uses the inverse
2263 of the radial polynomial,
2264 so that it forms the function <br/>
2265 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2266 <em>C</em>*r + <em>D</em> )
2267 </td>
2268 </tr>
2269
2270 <tr valign="top">
2271 <td valign="top"><kbd>Shepards</kbd></td>
2272 <td valign="top">
2273 Distort the given list control points (any number) using an Inverse
2274 Squared Distance Interpolation Method (<a
2275 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2276 >Shepards Method</a>). The control points in effect do 'localized'
2277 distortions of the image around the given control point. For best
2278 results extra control points should be added to 'lock' the positions of
2279 the corners and other unchanging parts of the image. <br/>
2280
2281 The distortion has been likened to 'taffy pulling' using nails, pins or
2282 sticks. It basically uses the <a href="#sparse-color"
2283 >-sparse-color</a> method of the same name to generate separate X and Y
2284 displacement maps (see <a href="#displace" >-displace</a>) for source
2285 image color look-up. </td>
2286
2287 </tr>
2288
2289</table>
2290
2291<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2292
2293<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2294'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2295defining how these points in the given image should be distorted in the
2296destination image. Each set of four floating point values represent a source
2297image coordinate, followed immediately by the destination image coordinate.
2298This produces a list of values such as...</p>
2299<div style="text-align: center"><em>
2300 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2301 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2302 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2303 ... &nbsp;
2304 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2305</em></div>
2306<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2307destination image. </p>
2308
2309<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2310needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2311perspective distortion of the built-in "rose:" image. Note how spaces were
2312used to group the 4 sets of coordinate pairs, to make it easier to read and
2313understand.</p>
2314
2315<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2316 convert rose: -virtual-pixel black \ <br/>
2317 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2318 rose_3d_rotated.gif</span></p>
2319<p>If more that the required number of coordinate pairs are given for a
2320distortion, the distortion method is 'least squares' fitted to
2321produce the best result for all the coordinate pairs given. If less than the
2322ideal number of points are given, the distort will generally fall back to a
2323simpler form of distortion that can handles the smaller number of coordinates
2324(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2325
2326<p>By using more coodinates you can make use of image registration tool to
2327find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2328of the distortion. Of course a bad coordinate pair can also make the 'fit'
2329worse. Caution is always advised. </p>
2330
2331<p>Colors are acquired from the source image according to the <a
2332href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2333magnified. However if the viewed image is minified (image becomes smaller), a
2334special area resampling function (added ImageMagick v6.3.5-9), is used to
2335produce a higher quality image. For example you can use a
2336'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2337way to the horizon. </p>
2338
2339<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2340 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2341 checks_tiled.jpg</span></p>
2342<p>Note that a infinitely tiled perspective images involving the horizon can
2343be very slow to generate due to the use of the high quality 'area resampling'
2344function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2345using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2346(recommended if you plan to use super-sampling instead). </p>
2347
2348<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2349'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2350will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2351pixels. If you do not what these pixels to be visible, set the color to match
2352the rest of the ground. </p>
2353
2354<p>The output image size will by default be the same as the input image. This
2355means that if the part of the distorted image falls outside the viewed area of
2356the 'distorted space', those parts is clipped and lost. However if you
2357use the plus form of the operator (<a href="#distort" >+distort</a>) the
2358operator will attempt (if posible) to show the whole of the distorted image,
2359while retaining a correct 'virtual canvas' offset, for image layering. This
2360offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2361if it is unwanted. </p>
2362
2363<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2364option:distort:viewport {geometry_string}</kbd>" setting which will specify
2365the size and the offset of the generated 'viewport' image of the distorted
2366image space.</p>
2367
2368<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2369{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2370that factor without changing the viewed contents of the distorted image. This
2371can be used either for 'super-sampling' the image for a higher quality result,
2372or for panning and zooming around the image (with appropriate viewport
2373changes, or post-distort cropping and resizing). </p>
2374
2375<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2376href="#distort" >-distort</a> to attempt to output the internal coefficients,
2377and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2378and debugging purposes. This many not be available for all distorts. </p>
2379
2380<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2381produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2382and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2383above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2384</p>
2385
2386
2387<div style="margin: auto;">
2388 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2389</div>
2390
2391<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>
2392
2393<p>Dithering places two or more colors in neighbouring pixels so that to the eye a closer approximation of the images original color is reproduced. This reduces the number of colors needed to reproduce the image but at the cost of a lower level pattern of colors. Error diffusion dithers can use any set of colors (generated or user defined) to an image. </p>
2394
2395<p>Dithering is turned on by default, to turn it off use the plus form of the
2396setting, <a href="#dither">+dither</a>. This will also also render PostScript
2397without text or graphic aliasing. Disabling dithering often (but not always)
2398leads to faster process, a smaller number of colors, but more cartoon like
2399image coloring. Generally resulting in 'color banding' effects in areas with
2400color gradients. </p>
2401
2402<p>The color reduction operators <a href="#colors">-colors</a>, <a
2403href="#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>
2404
2405<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>
2406
2407
2408<div style="margin: auto;">
2409 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2410</div>
2411
2412<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>
2413
2414<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>
2415
2416<p>The shape primitives:</p>
2417
2418<pre class="text">
2419 point x,y
2420 line x0,y0 x1,y1
2421 rectangle x0,y0 x1,y1
2422 roundRectangle x0,y0 x1,y1 wc,hc
2423 arc x0,y0 x1,y1 a0,a1
2424 ellipse x0,y0 rx,ry a0,a1
2425 circle x0,y0 x1,y1
2426 polyline x0,y0 ... xn,yn
2427 polygon x0,y0 ... xn,yn
2428 bezier x0,y0 ... xn,yn
2429 path path specification
2430 image operator x0,y0 w,h filename
2431</pre>
2432
2433<p>The text primitive:</p>
2434
2435<pre class="text">
2436 text x0,y0 string
2437</pre>
2438<p>The text gravity primitive:</p>
2439
2440<pre class="text">
2441 gravity NorthWest, North, NorthEast, West, Center,
2442 East, SouthWest, South, or SouthEast
2443</pre>
2444
2445<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>
2446
2447<p>The transformation primitives:</p>
2448
2449<pre class="text">
2450 rotate degrees
2451 translate dx,dy
2452 scale sx,sy
2453 skewX degrees
2454 skewY degrees
2455</pre>
2456
2457<p>The pixel operation primitives:</p>
2458
2459<pre class="text">
2460 color x0,y0 method
2461 matte x0,y0 method
2462</pre>
2463
2464<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>
2465
2466<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>
2467
2468<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2469
2470<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2471
2472<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>
2473
2474<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2475
2476<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>
2477
2478<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>
2479
2480<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>.
2481</p>
2482
2483<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2484
2485<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2486
2487<p class="crtsnip">
2488 -draw 'circle 100,100 150,150'
2489</p>
2490
2491<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
2492draw 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>
2493
2494<p class="crtsnip">
2495 -draw 'bezier 20,50 45,100 45,0 70,50'
2496</p>
2497<p class="crtsnip">
2498 -draw 'bezier 70,50 95,100 95,0 120,50'
2499</p>
2500
2501
2502<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>
2503
2504<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>
2505
2506<p class="crtsnip">
2507 -draw 'image SrcOver 100,100 225,225 image.jpg'
2508</p>
2509
2510<p>You can use 0,0 for the image size, which means to use the actual dimensions found in the image header. Otherwise, it is scaled to the given dimensions. See <a href="#compose">-compose</a> for a description of the composite operators.</p>
2511
2512<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>
2513
2514<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2515
2516<p class="crtsnip">
2517 -draw 'text 100,100 "Works like magick!"'
2518</p>
2519
2520<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2521
2522<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>
2523
2524<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2525
2526<p>The <kbd>scale</kbd> primitive scales them.</p>
2527
2528<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>
2529
2530<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
2531matrix.</p>
2532
2533<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>
2534
2535<pre class="text">
2536 point
2537 replace
2538 floodfill
2539 filltoborder
2540 reset
2541</pre>
2542
2543<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>
2544
2545<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>
2546
2547<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>
2548
2549<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2550
2551<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2552
2553
2554<div style="margin: auto;">
2555 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2556</div>
2557
2558<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>
2559
2560<div style="margin: auto;">
2561 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2562</div>
2563
2564<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>
2565
2566<div style="margin: auto;">
2567 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2568</div>
2569
2570<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>
2571
2572<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2573
2574<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2575
2576<div style="margin: auto;">
2577 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2578</div>
2579
2580<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>
2581
2582<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>
2583
2584<div style="margin: auto;">
2585 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2586</div>
2587
2588<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>
2589
2590<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2591
2592<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2593
2594
2595<div style="margin: auto;">
2596 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2597</div>
2598
2599<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>
2600
2601
2602<div style="margin: auto;">
2603 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2604</div>
2605
2606<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>
2607
2608<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>
2609
2610<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2611
2612<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>
2613
2614<div style="margin: auto;">
2615 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2616</div>
2617
2618<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>
2619
2620<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>
2621
2622<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>
2623
2624<table class="doc">
2625 <col width="25%" />
2626 <col width="75%" />
2627 <thead>
2628 <tr>
2629 <th><em class="arg">operator</em></th>
2630 <th>Summary (see further below for details)</th>
2631 </tr>
2632 </thead>
2633 <tbody>
2634
2635 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2636 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2637 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2638 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2639 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2640 <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>
2641 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2642 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2643 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2644 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2645 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2646 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2647 <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>
2648 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2649 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2650 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2651 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2652
2653 <tr><td>&nbsp;</td></tr>
2654
2655 <tr><td>Gaussian-noise</td></tr>
2656 <tr><td>Impulse-noise</td></tr>
2657 <tr><td>Laplacian-noise</td></tr>
2658 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2659 <tr><td>PoissonNoise</td></tr>
2660 <tr><td>Uniform-noise</td></tr>
2661
2662 <tr><td>&nbsp;</td></tr>
2663
2664 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2665 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2666 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2667 </tbody>
2668 </table>
2669
2670<p>The specified functions are applied only to each previously set <a
2671href="#channel" >-channel</a> in the image. If necessary, the results of the
2672calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2673class="QR">QuantumRange</em>]. The transparency channel of the image is
2674represented as a 'alpha' values (0 = fully transparent), so, for example, a
2675<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2676semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2677as a percentage of the <em class="QR">QuantumRange</em>.</p>
2678
2679<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2680<a href="#list">-list evaluate</a>.</p>
2681
2682<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2683<kbd>Multiply</kbd> methods can also be achieved using either the <a
2684href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2685appropriate argument, to linearly modify the overall range of color values.
2686Please note, however, that <a href="#level" >-level</a> treats transparency as
2687'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2688'alpha' values.</p>
2689
2690<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>
2691
2692<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>
2693
2694 <div style="text-align:center;">
2695 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2696 </div>
2697
2698<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2699normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2700href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2701to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2702with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2703with <kbd>Pow</kbd>.</p>
2704
2705<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2706converts the image values into a value according to a (co)sine wave function.
2707The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2708is biased 50% and normalized by 50% so as to fit in the respective color value
2709range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2710function (its frequency), and thus determines the number of 'waves' that will
2711be generated over the input color range. For example, if the <em
2712class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2713class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2714then the effective period is the <em>half</em> the <em
2715class="QR">QuantumRange</em>.
2716
2717 <div style="text-align:center;">
2718 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2719 </div>
2720
2721See also the <a href="#function" >-function</a> operator, which is a
2722multi-value version of evaluate. </P>
2723
2724
2725<div style="margin: auto;">
2726 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2727</div>
2728
2729<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>
2730
2731<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting.</p>
2732
2733<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>
2734
2735<div style="margin: auto;">
2736 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2737</div>
2738
2739<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>
2740
2741<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2742
2743<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' image.rgb image.png</span></p><p>If you omit the offsets, as in</p>
2744
2745<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p>
2746<p>then the image will be <em>resized</em> to the specified dimensions instead,
2747equivalent to:</p>
2748
2749<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>
2750<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>
2751
2752<div style="margin: auto;">
2753 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2754</div>
2755
2756<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>
2757
2758<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).
2759</p>
2760
2761<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>.
2762</p>
2763
2764<div style="margin: auto;">
2765 <h4><a name="fft" id="fft"></a>-fft</h4>
2766</div>
2767
2768<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>
2769
2770<p>This option is new as of ImageMagick 6.5.4-3 and transforms an image from the normal (spatial) domain to the frequency domain. In the frequency domain, an image is represented as a superposition of complex sinusoidal waves of varying amplitudes. The image x and y coordinates are the possible frequencies along the x and y directions, respectively, and the pixel intensity values are complex numbers that correspond to the sinusoidal wave amplitudes. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p>
2771
2772<p>A single image name is provided as output for this option. However, the output result will have two components. It will be either a two-frame image or two separate images, depending upon whether the image format specified supports multi-frame images. The reason that we get a dual output result is because the frequency domain represents an image using complex numbers, which cannot be visualized directly. Therefore, the complex values are automagically separated into a two-component image representation. The first component is the magnitude of the complex number and the second is the phase of the complex number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers" target="_blank">Complex Numbers</a>.<p>
2773
2774<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>
2775
2776<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2777<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>
2778
2779<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2780<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>
2781
2782<p>The input image can be any size, but if not square and even-dimensioned, it will be padded automagically to the larger of the width or height of the input image and to an even number of pixels. The padding will occur at the bottom and/or right sides of the input image. The resulting output magnitude and phase images will be square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p>
2783
2784<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>
2785
2786<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2787 -evaluate log 1000 fft_image_spectrum.png</span></p>
2788<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>
2789
2790<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2791
2792<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>
2793
2794<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>
2795
2796<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> also will be square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a>
2797
2798<p>See the discussion on HDRI implementations of ImageMagick on the page
2799<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.
2800</p>
2801
2802
2803<div style="margin: auto;">
2804 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2805</div>
2806
2807<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>
2808
2809<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>
2810
2811<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2812
2813<p>For example,</p>
2814
2815<p class="crtsnip">
2816 -fill blue
2817</p>
2818<p class="crtsnip">
2819 -fill "#ddddff"
2820</p>
2821<p class="crtsnip">
2822 -fill "rgb(255,255,255)"
2823</p>
2824
2825<p>See <a href="#draw">-draw</a> for further details.</p>
2826
2827<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2828
2829<div style="margin: auto;">
2830 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2831</div>
2832
2833<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use this <em class="arg">type</em> of filter when resizing an image.</td><td style='text-align:right;'></td></tr></table>
2834
2835<p>Use this option to affect the resizing operation of an image (see <a
2836href="#resize">-resize</a>). For example you can use a simple resize filter
2837such as:</p>
2838
2839<pre class="text">
2840 Point Hermite Cubic
2841 Box Gaussian Catrom
2842 Triangle Quadratic Mitchell
2843</pre>
2844
2845<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2846by default <kbd>blackman</kbd>-windowed. However these filters define a
2847windowing filter for the Sinc or Bessel filter function, as appropriate for
2848the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2849>-resize</a>). Windowed filters include: </p>
2850
2851<pre class="text">
2852 Lanczos Hamming Parzen
2853 Blackman Kaiser Welsh
2854 Hanning Bartlett Bohman
2855</pre>
2856
2857<p>Also one special self-windowing filter is also provided
2858<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2859on the current 'support' or 'lobes' expert settings (see below).</p>
2860
2861<p>If you do not select a filter with this option, the filter defaults to <kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or if the image is enlarged. Otherwise the filter default to <kbd>Lanczos</kbd>.</p>
2862
2863<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2864
2865<p>You can modify how the filter behaves as it scales your image through the
2866use of these expert settings:</p>
2867
2868<dl class="doc">
2869<dt>-set filter:blur <em>factor</em></dt>
2870<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2871 blurry or &lt; 1.0 for sharp.</dd>
2872
2873<dt>-set filter:support <em>radius</em></dt>
2874<dd>Set the filter support radius.</dd>
2875
2876<dt>-set filter:lobes <em>count</em></dt>
2877<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2878 alternative way of specifying the 'support' range of the filter.</dd>
2879
2880<dt>-set filter:b <em>b-spline_factor</em></dt>
2881<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2882<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2883 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2884 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2885 are defined, the other is set so as to generate a 'Keys' type cubic
2886 filter.
2887
2888<dt>-set filter:filter <em>filter</em></dt>
2889<dd>Use this function directly as the scaling filter. This will allow
2890 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2891 rather than as its normal usage as a windowing function for 'Sinc' or
2892 'Bessel'. If defined, no windowing function is used, unless the following
2893 expert setting is also defined.</dd>
2894
2895<dt>-set filter:window <em>filter</em></dt>
2896<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2897 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2898 support range) with the given filter. This allows you to use a filter that
2899 is not normally used as a windowing function, such as <kbd>box</kbd>,
2900 (which effectivally turns off the windowing function). </dd>
2901
2902</dl>
2903
2904<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2905
2906<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2907 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2908 -resize 150% image.jpg</span></p>
2909<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2910
2911<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2912 -resize 150% image.jpg</span></p>
2913<p>Note that the use of expert options (except for 'blur' with simple resize
2914filters), are provided for image processing experts who have studied and
2915understood how resize filters work. Without this knowledge, and an
2916understanding of the defination of the actual filters involved, using expert
2917settings are more likely to be detremental to your image resizing.</p>
2918
2919
2920<div style="margin: auto;">
2921 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2922</div>
2923
2924<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>
2925
2926
2927<div style="margin: auto;">
2928 <h4><a name="flip" id="flip"></a>-flip</h4>
2929</div>
2930
2931<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>
2932
2933<p>reflect the scanlines in the vertical direction.</p>
2934
2935<div style="margin: auto;">
2936 <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>
2937</div>
2938
2939<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>
2940
2941<div style="margin: auto;">
2942 <h4><a name="flop" id="flop"></a>-flop</h4>
2943</div>
2944
2945<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>
2946
2947<p>reflect the scanlines in the horizontal direction.</p>
2948
2949
2950<div style="margin: auto;">
2951 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2952</div>
2953
2954<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>
2955
2956<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>
2957
2958<p>In addition to the fonts specified by the above pre-defined list, you can
2959also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2960is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2961<kbd>x:fixed</kbd> is X11 font.</p>
2962
2963<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>
2964
2965
2966<div style="margin: auto;">
2967 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2968</div>
2969
2970<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>
2971
2972<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2973
2974<p>The default foreground color is black.</p>
2975
2976<div style="margin: auto;">
2977 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2978</div>
2979
2980<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>
2981
2982<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>
2983
2984<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>
2985
2986<div style="margin: auto;">
2987 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2988</div>
2989
2990<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>
2991
2992<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>
2993
2994<div style="margin: auto;">
2995 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2996</div>
2997
2998<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>
2999
3000<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
3001
3002<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument indicates the amount of extra width and height that is added to the dimensions of the image. If no offsets are given in the <em class="arg">geometry</em> argument, then the border added is a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that the width and height of the border is partitioned to form an outer bevel of thickness <em>x</em>&nbsp;pixels and an inner bevel of thickness <em>y</em>&nbsp;pixels. (Negative offsets make no sense here.) The <a href="#frame">-frame</a> option is not affected by the <a href="#gravity">-gravity</a> option.</p>
3003
3004
3005<div style="margin: auto;">
3006 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
3007</div>
3008
3009<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>
3010
3011<div style="margin: auto;">
3012 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
3013</div>
3014
3015<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>
3016
3017<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>
3018
3019<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>
3020
3021<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>
3022
3023<pre class="text">
3024 Polynomial
3025 Sinusoid
3026 Arcsin
3027 Arctan
3028</pre>
3029
3030<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
3031
3032<dl class="doc">
3033<dt><kbd>Polynomial</kbd></dt>
3034<dd>
3035<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>
3036
3037<div style="text-align: center">
3038 -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>
3039</div>
3040
3041<p>will invoke a polynomial function given by</p>
3042
3043<div style="text-align: center">
3044 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
3045 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
3046 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
3047</div>
3048
3049<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
3050
3051<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>
3052
3053<table class="doc">
3054 <col width="35%" />
3055 <col width="35%" />
3056 <col width="30%" />
3057 <tr>
3058 <td>-evaluate Set <em class="arg">value</em> </td>
3059 <td>-function Polynomial <em class="arg">value</em></td>
3060 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
3061 </tr>
3062 <tr>
3063 <td>-evaluate Add <em class="arg">value</em> </td>
3064 <td>-function Polynomial 1,<em class="arg">value</em></td>
3065 </tr>
3066 <tr>
3067 <td>-evaluate Subtract <em class="arg">value</em> </td>
3068 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
3069 </tr>
3070 <tr>
3071 <td>-evaluate Multiply <em class="arg">value</em> </td>
3072 <td>-function Polynomial <em class="arg">value</em>,0</td>
3073 </tr>
3074 <tr>
3075 <td>+level black% x white%</td>
3076 <td>-function Polynomial A,B</td>
3077 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3078 </tr>
3079</table>
3080
3081<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>
3082</dd>
3083
3084<dt><kbd>Sinusoid</kbd></dt>
3085<dd>
3086<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>
3087
3088<div style="text-align: center">
3089 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
3090</div>
3091
3092<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>
3093
3094<div style="text-align: center">
3095<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>
3096</div>
3097
3098<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>
3099
3100<p class="crtsnip">
3101 -function Sinusoid 3,-90,.2,.7
3102</p>
3103
3104<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>
3105
3106<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>
3107
3108<table class="doc">
3109 <tr>
3110 <td>-evaluate Sin <em class="arg">freq</em> </td>
3111 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
3112 </tr>
3113 <tr>
3114 <td>-evaluate Cos <em class="arg">freq</em> </td>
3115 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
3116 </tr>
3117</table>
3118</dd>
3119
3120<dt><kbd>ArcSin</kbd></dt>
3121<dd>
3122<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
3123and can be used to generate cylindrical distortion and displacement maps.
3124The curve can be adjusted relative to both the input values and output range
3125of values.
3126
3127<div style="text-align: center">
3128 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3129</div>
3130
3131<p>with all values given in terms of noramlize color values (0.0 for black,
31321.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3133for bout input (<em class="arg">width</em>), and output (<em
3134class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3135
3136<div style="text-align: center">
3137<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>
3138</div>
3139
3140</dd>
3141
3142<dt><kbd>ArcTan</kbd></dt>
3143<dd>
3144<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3145limit values at infinities, though a center using the given slope value.
3146All these values can be adjusted via the arguments.
3147
3148<div style="text-align: center">
3149 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3150</div>
3151
3152<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3153</p>
3154
3155<div style="text-align: center">
3156<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>
3157</div>
3158
3159</dd>
3160
3161</dl>
3162
3163
3164<div style="margin: auto;">
3165 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3166</div>
3167
3168<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>
3169
3170<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>
3171
3172<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>
3173
3174
3175<div style="margin: auto;">
3176 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3177</div>
3178
3179<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>
3180
3181<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>
3182
3183<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3184
3185
3186<div style="margin: auto;">
3187 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3188</div>
3189
3190<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>
3191
3192<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>
3193
3194<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>
3195
3196<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>
3197
3198<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>
3199
3200<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3201
3202<div style="margin: auto;">
3203 <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>
3204</div>
3205
3206<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>
3207
3208<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3209
3210<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3211</div>
3212
3213<p>where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. Specify a radius of 0 and ImageMagick selects a suitable radius for you.</p>
3214
3215<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3216full 2-dimentional convolution is used to generate the weighted average of the
3217neighbouring pixels. </p>
3218
3219<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3220pixels which are outside the image proper are blurred into the final result.
3221</p>
3222
3223
3224<div style="margin: auto;">
3225 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3226</div>
3227
3228<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>
3229
3230<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>
3231
3232<div style="margin: auto;">
3233 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3234</div>
3235
3236<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>
3237
3238<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3239<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3240<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3241list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3242installation.</p>
3243
3244<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>
3245
3246<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>
3247
3248<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>
3249
3250<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p>
3251<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>
3252
3253<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>
3254
3255
3256<div style="margin: auto;">
3257 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3258</div>
3259
3260<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>
3261
3262
3263<div style="margin: auto;">
3264 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3265</div>
3266
3267<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>
3268
3269<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3270dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3271can apply any color transformation to the Hald image and then use this option
3272to apply the transform to the image. </p>
3273
3274<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3275<p>This option provides a convenient method for you to use Gimp or Photoshop
3276to make color corrections to the Hald CLUT image and subsequently apply them
3277to multiple images using an ImageMagick script. </p>
3278
3279<p>Note that the representation is only of the normal RGB color space and that
3280the whole color value triplet is used for the interpolated lookup of the
3281represented Hald color cube image. Because of this the operation is not <a
3282href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3283images transparency or alpha/matte channel.</p>
3284
3285<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3286of the individual color channels, usally involving a simplier gray-scale
3287image. E.g: gray-scale to color replacement, or modification by a histogram
3288mapping. </p>
3289
3290
3291<div style="margin: auto;">
3292 <h4><a name="help" id="help"></a>-help</h4>
3293</div>
3294
3295<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>
3296
3297<div style="margin: auto;">
3298 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3299</div>
3300
3301<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>
3302
3303<div style="margin: auto;">
3304 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3305</div>
3306
3307<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>
3308
3309<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>
3310
3311<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>
3312
3313<div style="margin: auto;">
3314 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3315</div>
3316
3317<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>
3318
3319<div style="margin: auto;">
3320 <h4><a name="identify" id="identify"></a>-identify</h4>
3321</div>
3322
3323<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>
3324
3325<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>
3326
3327<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>
3328
3329<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3330amounts of image properties are displayed including image statistics, profiles,
3331image histogram, and others.</p>
3332
3333<div style="margin: auto;">
3334 <h4><a name="ift" id="ift"></a>-ift</h4>
3335</div>
3336
3337<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>
3338
3339<p>This option is new as of ImageMagick 6.5.4-3 and transforms a pair of magnitude and phase images from the frequency domain to a single image in the normal or spatial domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p>
3340
3341<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>
3342
3343<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3344<p>or</p>
3345
3346<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>
3347
3348<p>The resulting image may need to be cropped due to padding introduced when the original image, prior to the <a href="#fft">-fft</a> or <a href="#fft">+fft</a>, was not square or even dimensioned. Any padding will be at the right and/or bottom sides of the image.
3349
3350<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3351
3352<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.
3353
3354<div style="margin: auto;">
3355 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3356</div>
3357
3358<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>
3359
3360<div style="margin: auto;">
3361 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3362</div>
3363
3364<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>
3365
3366<div style="margin: auto;">
3367 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3368</div>
3369
3370<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>
3371
3372<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>
3373
3374<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>
3375
3376<div style="margin: auto;">
3377 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3378</div>
3379
3380<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>
3381
3382<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>
3383
3384<p>The default intent is undefined.</p>
3385
3386<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3387
3388<div style="margin: auto;">
3389 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3390</div>
3391
3392<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>
3393
3394<p>Choose from:</p>
3395
3396<pre class="text">
3397 none
3398 line
3399 plane
3400 partition
3401 JPEG
3402 GIF
3403 PNG
3404</pre>
3405
3406<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>
3407
3408<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3409
3410<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3411
3412<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3413
3414<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3415image.G, and image.B).</p>
3416
3417<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>
3418image.</p>
3419
3420<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3421
3422<div style="margin: auto;">
3423 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3424</div>
3425
3426<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>
3427
3428<p>When looking up the color of a pixel using a non-interger floating point
3429value, you typically fall in between the pixel colors defined by the source
3430image. This setting determines how the color is determined from the colors of
3431the pixels surrounding that point. That is how to determine the color of a
3432point that falls between two, or even four different colored pixels. </p>
3433
3434<pre class="text">
3435 integer: The color of the top-left pixel (floor function)
3436 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3437 average: The average color of the surrounding four pixels
3438 bilinear A double linear interpolation of pixels (the default)
3439 mesh Divide area into two flat triangular interpolations
3440 bicubic Fitted bicubic-spines of surrounding 16 pixels
3441 spline Direct spline curves (colors are blurred)
3442 filter Use resize <a href="#filter">-filter</a> settings
3443</pre>
3444
3445<p>This most important for distortion operators such as <a href="#distort"
3446>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3447>-transform</a> and <a href="#fx" >-fx</a>. </p>
3448
3449<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3450
3451<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3452lookup for positions outside the boundaries of the image. </p>
3453
3454
3455<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003456 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3457</div>
3458
3459<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>
3460
3461<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003462 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3463</div>
3464
3465<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>
3466
3467<div style="margin: auto;">
3468 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3469</div>
3470
3471<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>
3472
3473<div style="margin: auto;">
3474 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3475</div>
3476
3477<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>
3478
3479<p>Use this option to assign a specific label to the image, as it is read in or created. You can use the <a href="#set" >-set</a> operation to re-assign a the labels of images already read in. Image formats such as TIFF, PNG, MIFF, supports saving the label information with the image.</p>
3480
3481<p>When saving an image to a <em class="arg">PostScript</em> file, any label assigned to an image is used as a header string to print above the postscript image. </p>
3482
3483<p>You can include the image filename, type, width, height, or other image attribute by embedding special format character. See <a href="#format">-format</a> for details of the percent escape codes.</p>
3484
3485<p>For example,</p>
3486
3487<p class="crtsnip">
3488 -label "%m:%f %wx%h" bird.miff
3489</p>
3490
3491<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the "<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it is read in. If a <a href="#label">+label</a> option was used instead, any existing label present in the image would be used. You can remove all labels from an image by assigning the empty string. </p>
3492
3493<p>A label is not drawn on the image, but is embedded in the image datastream via <em>Label</em> tag or similar mechanism. If you want the label to be visible on the image itself, use the <a href="#draw">-draw</a> option, or during the final processing in the creation of a image montage.</p>
3494
3495<p>The label font can be specified with <a href="#font">-font</a>, and the
3496other font attribute settings.</p>
3497
3498<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image label is read from a file titled by the remaining characters in the string. Labels in a file are literal, no embedded formatting characters are recognized.</p>
3499
3500
3501<div style="margin: auto;">
3502 <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>
3503</div>
3504
3505<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>
3506
3507<p>Adaptively threshold each pixel based on the value of pixels in a
3508surrounding window. If the current pixel is lighter than this average plus
3509the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3510black. Small variations in pixel values such as found in scanned documents
3511can be ignored if offset is positive. A negative offset will make it more
3512sensitive to those small variations. </p>
3513
3514<p>This is commonly used to threshold images with an uneven background. It is
3515based on the assumption that average color of the small window is the
3516the local background color, from which to separate the forground color. </p>
3517
3518
3519<div style="margin: auto;">
3520 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3521</div>
3522
3523<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>
3524
3525<p>Perform various image operation methods to a ordered sequence of images
3526which may represent either a set of overlaid 'image layers', a GIF disposal
3527animation, or a fully-'coalesced' animation sequence. </p>
3528
3529<table class="doc">
3530 <tbody>
3531 <tr valign="top">
3532 <th align="left" style="width: 8%">Method</th>
3533 <th align="left">Description</th>
3534 </tr>
3535
3536 <tr valign="top">
3537 <td valign="top">compare-any</td>
3538 <td valign="top">Crop the second and later frames to the smallest rectangle
3539 that contains all the differences between the two images. No GIF <a
3540 href="#dispose" >-dispose</a> methods are taken into account. </td>
3541 </tr>
3542
3543 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3544 >-deconstruct</a> operator, and does not preserve animations normal
3545 working, especially when animation used layer disposal methods such as
3546 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3547 </tr>
3548
3549 <tr valign="top">
3550 <td valign="top">compare-clear</td>
3551 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3552 opaque pixels which become transparent in the second frame. That is the
3553 smallest image needed to mask or erase pixels for the next frame. </td>
3554 </tr>
3555
3556 <tr valign="top">
3557 <td valign="top">compare-overlay</td>
3558 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3559 extra color to the next image, as a result of overlaying color pixels.
3560 That is the smallest single overlaid image to add or change colors. </td>
3561 </tr>
3562
3563 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3564 composition method '<kbd>change-mask</kbd>', to reduce the image to
3565 just the pixels that need to be overlaid. </td>
3566 </tr>
3567
3568 <tr valign="top">
3569 <td valign="top">coalesce</td>
3570 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3571 >-coalesce</a> operator. Apply the layer disposal methods set in the
3572 current image sequence to form a fully defined animation sequence, as
3573 it should be displayed. Effectively converting a GIF animation into a
3574 'film strip'-like animation. </td>
3575 </tr>
3576
3577 <tr valign="top">
3578 <td valign="top">composite</td>
3579 <td valign="top">Alpha Composition of two image lists, separated by a
3580 "<kbd>null:</kbd>" image, with the destination image list first, and
3581 the source images last. An image from each list are composited
3582 together until one list is finished. The separator image and source
3583 image lists are removed. </td>
3584 </tr>
3585
3586
3587 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3588 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3589 size of the first image in each list. Unlike a normal <a
3590 href="#composite" >-composite</a> operation, the canvas offset is also
3591 added to the final composite positioning of each image. </td>
3592 </tr>
3593
3594 <tr><td></td><td>If one of the image lists only contains one image, that image is
3595 applied to all the images in the other image list, regardless of which
3596 list it is. In this case it is the image meta-data of the list which
3597 preserved. </td>
3598 </tr>
3599
3600
3601 <tr valign="top">
3602 <td valign="top">dispose</td>
3603 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3604 the animation after the layer disposal method has been applied, before
3605 the next sub-frame image is overlaid. That is the 'dispose' image that
3606 results from the application of the GIF <a href="#dispose"
3607 >-dispose</a> method. This allows you to check what
3608 is going wrong with a particular animation you may be developing.
3609 </td>
3610 </tr>
3611
3612 <tr valign="top">
3613 <td valign="top">flatten</td>
3614 <td valign="top">Create a canvas the size of the first images virtual
3615 canvas using the current <a href="#background" >-background</a> color,
3616 and <a href="#compose" >-compose</a> each image in turn onto that
3617 canvas. Images falling outside that canvas is clipped. Final
3618 image will have a zero virtual canvas offset. </td>
3619 </tr>
3620
3621 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3622 overlaying all the prepared image layers into a final image. </td>
3623 </tr>
3624
3625 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3626 canvas with real pixels, or to underlay a opaque color to remove
3627 transparency from an image.</td>
3628 </tr>
3629
3630
3631 <tr valign="top">
3632 <td valign="top">merge</td>
3633 <td valign="top">As 'flatten' method but merging all the given image
3634 layers into a new layer image just large enough to hold all the image
3635 without clipping or extra space. The new images virtual offset will
3636 prevere the position of the new layer, even if this offset is
3637 negative. the virtual canvas size of the first image is preserved.
3638 </td>
3639 </tr>
3640
3641 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3642 as few image file formats handle them correctly. </td>
3643 </tr>
3644
3645 <tr valign="top">
3646 <td valign="top">mosaic</td>
3647 <td valign="top">As 'flatten' method but expanding the initial canvas size
3648 of the first image so as to hold all the image layers. However as a
3649 virtual canvas is 'locked' to the origin, by defination, image layers
3650 with a negative offsets will still be clipped by the top and left
3651 edges.</td>
3652 </tr>
3653
3654 <tr><td></td><td>This method is commonly used to layout individual image using various
3655 offset but without knowning the final canvas size. The resulting image
3656 will, like 'flatten' not have any virtual offset, so can be saved to
3657 any image file format. </td>
3658 </tr>
3659
3660
3661 <tr valign="top">
3662 <td valign="top">optimize</td>
3663 <td valign="top">Optimize a coalesced animation, into GIF animation using
3664 a number of general techniques. This currently a short cut to
3665 apply both the '<kbd>optimize-frame</kbd>', and
3666 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3667 include other optimization methods as they are developed. </td>
3668 </tr>
3669
3670 <tr valign="top">
3671 <td valign="top">optimize-frame</td>
3672 <td valign="top">Optimize a coalesced animation, into GIF animation by
3673 reducing the number of pixels per frame as much as possible by
3674 attempting to pick the best layer disposal method to use, while ensuring
3675 the result will continue to animate properly. </td>
3676 </tr>
3677
3678 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3679 then no reasonably fast GIF optimization algorithm can do this.
3680 However this does seem to do better than most other GIF frame
3681 optimizers seen. </td>
3682 </tr>
3683
3684 <tr valign="top">
3685 <td valign="top">optimize-plus</td>
3686 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3687 overall optimization by adding extra frames to the animation, without
3688 changing the final look or timing of the animation. The frames are
3689 added to attempt to separate the clearing of pixels from the
3690 overlaying of new additional pixels from one animation frame to the
3691 next. If this does not improve the optimization (for the next frame
3692 only), it will fall back to the results of the previous normal
3693 '<kbd>optimize-frame</kbd>' technique. </td>
3694 </tr>
3695
3696 <tr><td></td><td>There is the possibility that the change in the disposal style will
3697 result in a worsening in the optimization of later frames, though this
3698 is unlikely. In other words there no guarantee that it is better than
3699 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3700 however you can get a vast improvment in the final animation size. </td>
3701 </tr>
3702
3703 <tr valign="top">
3704 <td valign="top">optimize-transparency</td>
3705 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3706 overlay images with transparency, if it does not change the resulting
3707 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3708 </td>
3709 </tr>
3710
3711 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3712 into a smaller file size due to larger areas of one (transparent)
3713 color rather than a pattern of multiple colors repeating the current
3714 disposed image of the last frame. </td>
3715 </tr>
3716
3717 <tr valign="top">
3718 <td valign="top">remove-dups</td>
3719 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3720 images, so as to simplify layer overlays of coalesced animations.
3721 </td>
3722 </tr>
3723
3724 <tr><td></td><td>Usually this a result of using a constant time delay across the
3725 whole animation, or after a larger animation was split into smaller
3726 sub-animations. The duplicate frames could also have been used as
3727 part of some frame optimization methods. </td>
3728 </tr>
3729
3730 <tr valign="top">
3731 <td valign="top">remove-zero</td>
3732 <td valign="top">Remove any image with a zero time delay, unless ALL the
3733 images have a zero time delay (and is not a proper timed animation, a
3734 warning is then issued). </td>
3735 </tr>
3736
3737 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3738 partial intermediary updates between the frames that are actually
3739 displayed to users. These frames are usally added for improved frame
3740 optimization in GIF animations. </td>
3741 </tr>
3742
3743 <tr valign="top">
3744 <td valign="top">trim-bounds</td>
3745 <td valign="top">Find the bounds of all the images in the current
3746 image sequence, then adjust the offsets so all images are contained on
3747 a minimal positive canvas. None of the image data is modified, only
3748 there virtual canvas size and offset. The all the image is given
3749 the same canvas size, and and will have a positive offset, but will
3750 remain in the same position relative to each other. As a result of the
3751 minimal canvas size at least one image will touch every edge of that
3752 canvas. The image data however may be transparent.
3753 </td>
3754 </tr>
3755
3756 </tbody>
3757</table>
3758
3759<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3760
3761<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3762>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3763>-mosaic</a> are only aliases for the above methods. Also see <a
3764href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3765href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3766>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3767
3768
3769<div style="margin: auto;">
3770 <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>
3771</div>
3772
3773<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>
3774
3775<p>Given one, two or three values delimited with commas: black-point,
3776white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3777white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3778point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3779contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3780both black and white points are percentages of the full color range. Gamma
3781will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3782omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3783
3784<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3785the given '<kbd>black_point</kbd>' value in the original image is set to
3786zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3787<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3788to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3789adjusted. </p>
3790
3791<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3792adding the special '!' flag anywhere in the argument list, will cause the
3793operator to do the reverse of the level adjustment. That is a zero, or
3794<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3795adjusted to the given level values, allowing you to de-contrast, or compress
3796the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3797
3798<p>Only the channels defined by the current <a href="#channel">-channel</a>
3799setting are adjusted (defaults to RGB color channels only), allowing you to
3800limit the effect of this operator. </p>
3801
3802<p>Please note that the transparency channel is treated as 'matte'
3803values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3804
3805
3806<div style="margin: auto;">
3807 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3808 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3809</div>
3810
3811<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash seperated colors.</td><td style='text-align:right;'></td></tr></table>
3812
3813<p>This function is exactly like <a href="#level">-level</a>, except that the
3814value value for each color channel is determined by the
3815'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3816described under the <a href="#fill">-fill</a> option). </p>
3817
3818<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3819is mapped to become 'black' and 'white' respectivally, with all the other
3820colors linearly adjusted (or clipped) to match that change. Each channel is
3821adjusted separatally using the channel values of the colors specified. </p>
3822
3823<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3824will map the image color 'black' and 'white' to the given colors
3825respectivally, resulting in a gradient (de-contrasting) tint of the image to
3826those colors. This can also be used to convert a plain gray-scale image into a
3827one using the gradient of colors specified. </p>
3828
3829<p>By supplying a single color with a comma separator either before or after
3830that color, will just replace the respective 'black' or 'white' point
3831respectivally. But if no comma separator is provided, the given color is
3832used for both the black and white color points, making the operator either
3833threshold the images around that color (- form) or set all colors to that
3834color (+ form). </p>
3835
3836
3837<div style="margin: auto;">
3838 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3839</div>
3840
3841<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>
3842
3843<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>
3844
3845<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2gb of image area, 1.5gb memory, 8gb memory map, and 16tb of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p>
3846
3847<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +00003848 -limit memory 32MiB -limit map 64MiB
cristy3ed852e2009-09-05 21:47:34 +00003849</p>
3850
3851<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3852
cristyd934d102009-10-10 12:55:13 +00003853<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
3854-----------------------------------------------------------------------
3855 768 3.8187GiB 2.864GiB 7.6375GiB 16EiB 2 unlimited</pre>
cristy3ed852e2009-09-05 21:47:34 +00003856</span></p>
3857<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>
3858
3859<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>
3860
3861<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>
3862
3863<p class="crtsnip">
3864-limit area 10mb
3865</p>
3866
3867<p>Now whenever a large image is processed, the pixels are automagically cached to disk instead of memory. This of course implies that large images typically process very slowly, simply because pixel processing in memory can be an order of magnitude faster than on disk. Because your web site users might inadvertedly upload a huge image to process, you should set a disk limit as well:</p>
3868
3869<p class="crtsnip">
3870-limit area 10mb -limit disk 500mb
3871</p>
3872
3873<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3874
3875<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>
3876
3877<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.
3878</p>
3879
3880<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.
3881</p>
3882
3883<div style="margin: auto;">
3884 <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>
3885</div>
3886
3887<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>
3888
cristyd934d102009-10-10 12:55:13 +00003889<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>,
3890and uses a 'histogram bin' to determine the range of color values that needs to
3891be stretched. However it then stretchs those colors using the <a
3892href="#level" >-level</a> operator.</p>
3893
3894<p>As such while the initial determination may have 'binning' round off
3895effects, the image colors are stretched mathematically, rather than using the
3896histogram bins. This makes the operator more accurate. </p>
3897
3898<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of
3899'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near
3900perfect stretch of the color range. </p>
3901
3902<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
3903normalization of mathematical images. </p>
3904
3905<p>This operator is under review for re-development. </p>
3906
3907
cristy3ed852e2009-09-05 21:47:34 +00003908<div style="margin: auto;">
3909 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3910</div>
3911
3912<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>
3913
3914<div style="margin: auto;">
3915 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3916</div>
3917
3918<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>
3919
3920<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>
3921
3922<div style="margin: auto;">
3923 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3924</div>
3925
3926<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>
3927
3928<pre class="text">
3929 coder
3930 color
3931 configure
3932 delegate
3933 font
3934 format
3935 list
3936 log
3937 magic
3938 module
3939 resource
3940 threshold
3941</pre>
3942
3943<p>The above lists are only some of the many lists available. These lists vary depending on your version of ImageMagick. For example use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p>
3944
3945<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3946<div style="margin: auto;">
3947 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3948</div>
3949
3950<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>
3951
3952<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3953
3954<p>You can display the following components by embedding special format characters:</p>
3955
3956<pre class="text">
3957 %d domain
3958 %e event
3959 %f function
3960 %l line
3961 %m module
3962 %p process ID
3963 %r real CPU time
3964 %t wall clock time
3965 %u user CPU time
3966 %% percent sign
3967 \n newline
3968 \r carriage return
3969</pre>
3970
3971<p>For example:</p>
3972
3973<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>
3974<p>The default behavior is to print all of the components.</p>
3975
3976<div style="margin: auto;">
3977 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3978</div>
3979
3980<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>
3981
3982<p>Set iterations to zero to repeat the animation an infinite number of times, otherwise the animation repeats itself up to <em class="arg">iterations</em> times.</p>
3983
3984<div style="margin: auto;">
3985 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3986</div>
3987
3988<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>
3989
3990<div style="margin: auto;">
3991 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
3992</div>
3993
3994<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>
3995
3996
3997<div style="margin: auto;">
3998 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
3999</div>
4000
4001<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>
4002
4003<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
4004
4005<pre class="text">
4006 best
4007 default
4008 gray
4009 red
4010 green
4011 blue
4012</pre>
4013
4014<p>The <em class="arg">X server</em> must support the <em class="arg">Standard Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as the type and <kbd>display</kbd> searches the list of colormap types in <kbd>top-to-bottom</kbd> order until one is located. See <em class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p>
4015
4016
4017<div style="margin: auto;">
4018 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
4019</div>
4020
4021<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>
4022
4023<p>Here are the valid components of a map:</p>
4024
4025<pre class="text">
4026 r red pixel component
4027 g green pixel component
4028 b blue pixel component
4029 a alpha pixel component (0 is transparent)
4030 o opacity pixel component (0 is opaque)
4031 i grayscale intensity pixel component
4032 c cyan pixel component
4033 m magenta pixel component
4034 y yellow pixel component
4035 k black pixel component
4036 p pad component (always 0)
4037</pre>
4038
4039<p>You can specify as many of these components as needed in any order (e.g. bgr). The components can repeat as well (e.g. rgbr).</p>
4040
4041<div style="margin: auto;">
4042 <h4><a name="mask" id="mask"></a>-mask
4043<em class="arg">filename</em></h4>
4044</div>
4045
4046<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>
4047
4048<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
4049
4050<div style="margin: auto;">
4051 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
4052</div>
4053
4054<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>
4055
4056<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4057
4058<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
4059
4060<div style="margin: auto;">
4061 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
4062</div>
4063
4064<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>
4065
4066<div style="margin: auto;">
4067 <h4><a name="metric" id="metric"></a>-metric <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%'>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>
4071
4072<p>Choose from:</p>
4073
4074<pre class="text">
4075 AE absolute number of differnet pixels
4076 MAE mean absolute error (normalized), average channel error distance
4077 MEPP mean error per pixel (normalized mean error, normalized peak error)
4078 MSE mean error squared, average of the channel error squared
4079 PAE peak absolute (normalize peak absolute)
4080 PSNR peak signal to noise ratio
4081 RMSE root mean squared (normalized root mean squared)
4082</pre>
4083
4084<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
4085controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
4086only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
4087size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
4088'similar'. </p>
4089
4090<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
4091('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
4092normalized) from the single comparision run. </p>
4093
4094<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
4095
4096
4097<div style="margin: auto;">
4098 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
4099</div>
4100
4101<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>
4102
4103<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
4104
4105<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
4106argument for a list of <a href="#mode" >-mode</a> arguments available
4107in your ImageMagick installation.</p>
4108
4109
4110<div style="margin: auto;">
4111 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
4112</div>
4113
4114<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Vary the <em class="arg">brightness</em>, <em class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table>
4115
4116<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
4117missing values are taken to mean 100.</p>
4118
4119<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
4120means pure black, 50 is half as bright, 200 is twice as bright. To invert its
4121meaning <a href="#negate">-negate</a> the image before and after. </p>
4122
4123<p>The <em class="arg">saturation</em> controls the amount of color in an image. For example, 0 produce a grayscale image, while a large value such as 200 produce a very colorful, 'cartoonish' color.</p>
4124
4125<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors within the image by the amount specified. For example, 50 results in a counter-clockwise rotation of 90, mapping red
4126shades to purple, and so on. A value of either 0 or 200 results in a complete
4127180 degree rotation of the image. Using a value of 300 is a 360 degree
4128rotation resulting in no change to the original image. </p>
4129
4130<p>For example, to increase the color brightness by 20% and decrease the color saturation by 10% and leave the hue unchanged, use <a href="#modulate">-modulate 120,90</a>.</p>
4131
4132<p>Use <a href="#set">-set</a> attribute of '<kbd class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or <kbd>HWB</kbd>. For example,</p>
4133
4134<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>
4135<div style="margin: auto;">
4136 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
4137</div>
4138
4139<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>
4140
4141
4142<div style="margin: auto;">
4143 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
4144</div>
4145
4146<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>
4147
4148
4149<div style="margin: auto;">
4150 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4151</div>
4152
4153<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>
4154
4155<p>Both the image pixels and size are linearly interpolated to give the
4156appearance of a meta-morphosis from one image to the next, over all the images
4157in the current image list. The added images are the equivalent of a <a
4158href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4159argument determine how many images to interpolate between each image. </p>
4160
4161
4162<div style="margin: auto;">
4163 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4164</div>
4165
4166<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>
4167
4168
4169<div style="margin: auto;">
4170 <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>
4171</div>
4172
4173<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>
4174
4175<p>Blur with the given radius, standard deviation (sigma), and angle. The
4176angle given is the angle toward which the image is blurred. That is the
4177direction people would consider the object is coming from. </p>
4178
4179<p>Note that the blur is not uniform distribution, giving the motion a
4180definate sense of direction of movement. </p>
4181
4182<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4183pixels which are outside the image proper are blurred into the final result.
4184</p>
4185
4186<div style="margin: auto;">
4187 <h4><a name="name" id="name"></a>-name</h4>
4188</div>
4189
4190<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>
4191<div style="margin: auto;">
4192 <h4><a name="negate" id="negate"></a>-negate</h4>
4193</div>
4194
4195<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace every pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table>
4196
4197<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>
4198
4199<div style="margin: auto;">
4200 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4201 +noise <em class="arg">type</em></h4>
4202</div>
4203
4204<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>
4205
4206<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>
4207
4208<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>
4209
4210<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>
4211
4212<pre class="text">
4213Gaussian
4214Impulse
4215Laplacian
4216Multiplicative
4217Poisson
4218Random
4219Uniform
4220</pre>
4221
4222<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4223
4224
4225<div style="margin: auto;">
4226 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4227</div>
4228
4229<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>
4230
cristyd934d102009-10-10 12:55:13 +00004231<p>The intensity values are stretched to cover the entire range of possible
4232values. While doing so, black-out at most <em>2%</em> of the pixels and
4233white-out at most <em>1%</em> of the pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00004234
cristyd934d102009-10-10 12:55:13 +00004235<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a>
4236is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>.
4237(Before this version, it was equivalent to <a href="#contrast-stretch"
4238>-contrast-stretch 2%x99%</a>).</p>
cristy3ed852e2009-09-05 21:47:34 +00004239
cristyd934d102009-10-10 12:55:13 +00004240<p>All the channels are normalized in concert by the came amount so as to
4241preserve color integrity, when the default <a href="#channel" >+channel</a>
4242setting is in use. Specifing any other <a href="#channel" >-channel</a>
4243setting will normalize the RGB channels independently.</p>
4244
4245<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details.
4246Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization
4247of mathematical images. </p>
4248
4249<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00004250
4251
4252<div style="margin: auto;">
4253 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4254</div>
4255
cristyd934d102009-10-10 12:55:13 +00004256<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
4257class="arg">threshold map</em> specified, and a uniform color map with the
4258given 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 +00004259
4260<p>You can choose from these standard threshold maps:</p>
4261
4262<pre class="text">
cristyd934d102009-10-10 12:55:13 +00004263 threshold
cristy3ed852e2009-09-05 21:47:34 +00004264 checks
4265 o2x2
4266 o3x3
4267 o4x4
4268 o8x8
4269 h4x4a
4270 h6x6a
4271 h8x8a
4272 h4x4o
4273 h6x6o
4274 h8x8o
4275 h16x16o
4276</pre>
4277
cristyd934d102009-10-10 12:55:13 +00004278<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the
4279'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or
4280'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither
4281pattern. Or you can define your own <em class="arg" >threshold map</em> in a
4282personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
cristy3ed852e2009-09-05 21:47:34 +00004283
cristyd934d102009-10-10 12:55:13 +00004284<p>To print a complete list of threshold, use the <a href="#list" >-list
4285threshold</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004286
cristyd934d102009-10-10 12:55:13 +00004287<p>It is recommended that the <a href="#map" >+map</a> operator be used after
4288applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of
cristy3ed852e2009-09-05 21:47:34 +00004289colors an animated image sequence, to less that 256 colors. This ensures that
4290a common or global color table is used when saving the result to a color
4291limited file format such as GIF. </p>
4292
cristyd934d102009-10-10 12:55:13 +00004293<p>Note that at this time the exact same threshold dithering map is used for
4294all color channels, no attempt is made to offset or rotate the map for
4295different channels is made, to create an offset printing effect. (possible
4296future expansion) </p>
cristy3ed852e2009-09-05 21:47:34 +00004297
4298
4299<div style="margin: auto;">
4300 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4301</div>
4302
4303<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>
4304
cristyd934d102009-10-10 12:55:13 +00004305<p>The <em class="arg" >color</em> argument is defined using the format
4306described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz"
4307>-fuzz</a> setting can be used to match and replace colors similar to the one
4308given.</p>
cristy3ed852e2009-09-05 21:47:34 +00004309
cristyd934d102009-10-10 12:55:13 +00004310<p>The <a href="#transparent" >-transparent</a> operator is exactly the same
4311as <a href="#opaque" >-opaque</a> but makes the matching color transparent,
cristy3ed852e2009-09-05 21:47:34 +00004312rather than the same as the current <a href="#fill">-fill</a> color. </p>
4313
cristyd934d102009-10-10 12:55:13 +00004314<p>Use <em class="arg" >+opaque</em> to paint any pixel that does not match
4315the target color.</p>
4316
4317
cristy3ed852e2009-09-05 21:47:34 +00004318
4319<div style="margin: auto;">
4320 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4321</div>
4322
4323<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>
4324
4325<p>Choose from these orientations:</p>
4326
4327<pre class="text">
4328 bottom-left
4329 bottom-right
4330 left-bottom
4331 left-top
4332 right-bottom
4333 right-top
4334 top-left
4335 top-right
4336 undefined
4337</pre>
4338
cristyd934d102009-10-10 12:55:13 +00004339<p>To print a complete list of orientations, use the <a href="#list" >-list
4340orientation</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004341
4342
4343<div style="margin: auto;">
4344 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4345 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4346 +page
4347 </h4>
4348</div>
4349
4350<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>
4351
4352<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>
4353
4354<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>
4355
4356<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>
4357<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4358<thead>
4359 <tr valign="top">
4360 <th align="center"><em class="arg">media</em></th>
4361 <th align="center"><em class="arg">width</em></th>
4362 <th align="center"><em class="arg">height</em></th>
4363 </tr>
4364</thead>
4365<tbody>
4366<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4367<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4368<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4369<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4370<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4371<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4372<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4373<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4374<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4375<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4376<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4377<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4378<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4379<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4380<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4381<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4382<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4383<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4384<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4385<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4386<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4387<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4388<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4389<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4390<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4391<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4392<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4393<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4394<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4395<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4396<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4397<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4398<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4399<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4400<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4401<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4402<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4403<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4404</tbody>
4405</table>
4406
4407
4408
4409
4410<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>
4411
4412<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>
4413
4414<p>The default page dimensions for a TEXT image is 612x792.</p>
4415
4416<p>This option is used in concert with <a href="#density">-density</a>.</p>
4417
4418<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4419
4420<div style="margin: auto;">
4421 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4422</div>
4423
4424<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>
4425
4426<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>
4427
4428<div style="margin: auto;">
4429 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4430
4431<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>
4432
4433<div style="margin: auto;">
4434 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4435</div>
4436
4437<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>
4438
4439<p>Pause for the specified number of seconds before repeating the animation.</p>
4440
4441<div style="margin: auto;">
4442 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4443</div>
4444
4445<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>
4446
4447<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4448
4449<div style="margin: auto;">
4450 <h4><a name="ping" id="ping"></a>-ping</h4>
4451</div>
4452
4453<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>
4454
4455<div style="margin: auto;">
4456 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4457</div>
4458
4459<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>
4460
4461<div style="margin: auto;">
4462 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4463</div>
4464
4465<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>
4466
4467<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4468
4469<div style="margin: auto;">
4470 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4471</div>
4472
4473<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>
4474
4475<div style="margin: auto;">
4476 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4477</div>
4478
4479<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>
4480
4481<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>
4482
4483<pre class="text">
4484 Rotate
4485 Shear
4486 Roll
4487 Hue
4488 Saturation
4489 Brightness
4490 Gamma
4491 Spiff
4492 Dull
4493 Grayscale
4494 Quantize
4495 Despeckle
4496 ReduceNoise
4497 Add Noise
4498 Sharpen
4499 Blur
4500 Threshold
4501 EdgeDetect
4502 Spread
4503 Shade
4504 Raise
4505 Segment
4506 Solarize
4507 Swirl
4508 Implode
4509 Wave
4510 OilPaint
4511 CharcoalDrawing
4512 JPEG
4513</pre>
4514
4515<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4516
4517<p>The default preview is <kbd>JPEG</kbd>.</p>
4518
4519<div style="margin: auto;">
4520 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4521</div>
4522
4523<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>
4524
4525<div style="margin: auto;">
4526 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4527</div>
4528
4529<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>
4530
4531<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>
4532
4533<div style="margin: auto;">
4534 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4535 +profile <em class="arg">profile_name</em></h4>
4536</div>
4537
4538<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>
4539
4540<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>
4541
4542<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>
4543
4544<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>
4545
4546<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>
4547
4548<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4549
4550<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4551<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>
4552
4553<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>
4554<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4555CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4556</p>
4557
4558<div style="margin: auto;">
4559 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4560</div>
4561
4562<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>
4563
4564<p>For the JPEG and MPEG image formats, quality is 0 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default is to use the estimate quality of your input image otherwise 85. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p>
4565
4566<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>
4567
4568<p>For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 85 results in a request for 16:1 compression. The quality value 100 results in a request for non-lossy compression.</p>
4569
4570<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). Compression levels range from 0 (fastest compression) to 100 (best but slowest). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.</p>
4571
4572<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4573
4574<pre class="text">
4575 0: none
4576 1: sub
4577 2: up
4578 3: average
4579 4: Paeth
4580</pre>
4581
4582<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>
4583
4584<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4585
4586<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>
4587
4588<p>The default is quality is 85, which means nearly the best compression with adaptive filtering. The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p>
4589
4590<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4591
4592<p>When writing a JNG image with transparency, two quality values are required, one for the main image and one for the grayscale image that conveys the alpha channel. These are written as a single integer equal to the main image quality plus 1000 times the opacity quality. For example, if you want to use quality 85 for the main image and quality 90 to compress the opacity data, use <a href="#quality">-quality 90085</a>.</p>
4593
4594<div style="margin: auto;">
4595 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4596</div>
4597
4598<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors in this colorspace.</td><td style='text-align:right;'></td></tr></table>
4599
4600<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4601
4602
4603<div style="margin: auto;">
4604 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4605</div>
4606
4607<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>
4608
4609<div style="margin: auto;">
4610 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4611</div>
4612
4613<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>
4614
4615<p>Note that this is actually a rotational blur rather than a radial and as
4616such actually mis-named. </p>
4617
4618<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4619pixels which are outside the image proper are blurred into the final result.
4620</p>
4621
4622
4623<div style="margin: auto;">
4624 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4625</div>
4626
4627<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>
4628
4629<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>.
4630</p>
4631
4632<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4633
4634<div style="margin: auto;">
4635 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4636</div>
4637
4638<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>
4639
4640<div style="margin: auto;">
4641 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4642</div>
4643
4644<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Translate, scale, shear, or rotate image colors.</td><td style='text-align:right;'></td></tr></table>
4645
4646<p>Although variable-sized matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA. Populate the last row with normalized values to translate.
4647</p>
4648
4649<div style="margin: auto;">
4650 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4651</div>
4652
4653<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>
4654
4655<div style="margin: auto;">
4656 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4657</div>
4658
4659<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>
4660
4661<div style="margin: auto;">
4662 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4663</div>
4664
4665<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>
4666
4667<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4668the given colors are dithered over the image as necessary, otherwise the closest
4669color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4670
4671<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4672images in the current image sequence, all the images will have the same color
4673table. That means that when saved to a file format such as GIF, it will use
4674that color table as a single common or global color table, for all the images,
4675without requiring extra local color tables. </p>
4676
4677<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4678sequence to use a common color map over all the images. This equivalent to
4679appending all the images together (without extra background colors) and color
4680reducing those images using <a href="#colors">-colors</a> with a 256 color
4681limit, then <a href="#remap">-remap</a> those colors over the original list of
4682images. This ensures all the images follow a single color map. </p>
4683
4684<p>If the number of colors over all the images is less than 256, then <a
4685href="#remap">+remap</a> should not perform any color reduction or dithering, as
4686no color changes are needed. In that case, its only effect is to force the use
4687of a global color table. This recommended after using either <a
4688href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4689reduce the number of colors in an animated image sequence. </p>
4690
4691<div style="margin: auto;">
4692 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4693</div>
4694
4695<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>
4696
4697<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>
4698
4699<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>
4700
4701<div style="margin: auto;">
4702 <h4><a name="remote" id="remote"></a>-remote</h4>
4703</div>
4704
4705<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>
4706
4707<p>The only command recognized is the name of an image file to load.</p>
4708
4709<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>
4710
4711<div style="margin: auto;">
4712 <h4><a name="render" id="render"></a>-render</h4>
4713</div>
4714
4715<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>
4716
4717<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>
4718
4719<div style="margin: auto;">
4720<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4721</div>
4722
4723<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>
4724
4725<p>This option is like <a href="#page">-page</a> but acts as an image operator
4726rather than a setting. You can separately set the canvas size or the offset
4727of the image on that canvas by only providing those components. </p>
4728
4729<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>
4730
4731<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4732offset to move the image relative to its previous position. This useful for
4733animation sequences. </p>
4734
4735<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4736recalculate the canvas size so the image (at its current offset) will appear
4737completely on that canvas (unless it has a negative offset).</p>
4738
4739<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4740canvas meta-data from the images. </p>
4741
4742<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4743directly assign virtual canvas meta-data. </p>
4744
4745
4746<div style="margin: auto;">
4747 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4748</div>
4749
4750<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>
4751
4752<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>
4753
4754<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>
4755
4756<div style="margin: auto;">
4757 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4758</div>
4759
4760<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>
4761
4762<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>
4763
4764<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>
4765
4766<div style="margin: auto;">
4767 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4768</div>
4769
4770<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>
4771
4772<div style="margin: auto;">
4773 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4774</div>
4775
4776<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>
4777
4778
4779<div style="margin: auto;">
4780 <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>
4781</div>
4782
4783<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>
4784
4785<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>
4786
4787
4788<div style="margin: auto;">
4789 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4790</div>
4791
4792<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>
4793
4794<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>
4795
4796<p>Empty triangles in the corners, left over from rotating the image, are
4797filled with the <kbd>background</kbd> color. </p>
4798
4799<p>See also the <a href="#distort">-distort</a> operator and specifically the
4800'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4801
4802
4803<div style="margin: auto;">
4804 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4805</div>
4806
4807<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale image using pixel sampling.</td><td style='text-align:right;'></td></tr></table>
4808
4809<p><a href="#sample">-sample</a> ignores the current <a href="#resize">-resize</a> <a href="#filter">-filter</a> setting. The results are equivalent to using <a href="#resize">-resize</a> with a <a href="#filter">-filter</a> setting of <kbd>point</kbd>, though <a href="#sample">-sample</a> is a lot faster. </p>
4810
4811<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>
4812
4813
4814<div style="margin: auto;">
4815 <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>
4816</div>
4817
4818<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>
4819
4820<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>
4821
4822<div style="margin: auto;">
4823 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4824</div>
4825
4826<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale the image.</td><td style='text-align:right;'></td></tr></table>
4827
4828<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="#scale">-scale</a> option uses a simpler, faster algorithm than <a href="#resize">-resize</a>, and it ignores the <a href="#filter">-filter</a> setting if one is present. Offsets, if present in the <em class="arg">geometry</em> string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
4829
4830<div style="margin: auto;">
4831 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4832</div>
4833
4834<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>
4835
4836<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4837
4838<div style="margin: auto;">
4839 <h4><a name="screen" id="screen"></a>-screen</h4>
4840</div>
4841
4842<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>
4843
4844<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>
4845
4846<div style="margin: auto;">
4847 <h4><a name="seed" id="seed"></a>-seed</h4>
4848</div>
4849
4850<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>
4851
4852<div style="margin: auto;">
4853 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4854</div>
4855
4856<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>
4857
4858<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>
4859
4860<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>
4861
4862<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4863of the color clusters is returned.</p>
4864
4865
4866<div style="margin: auto;">
4867 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4868</div>
4869
4870<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>
4871
4872<div style="margin: auto;">
4873 <h4><a name="separate" id="separate"></a>-separate</h4>
4874</div>
4875
4876<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>
4877
4878<div style="margin: auto;">
4879 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4880</div>
4881
4882<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>
4883
4884<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4885
4886<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>
4887
4888<div style="margin: auto;">
4889 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4890</div>
4891
4892<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set an image attribute for all images in the current image sequence, after they have been created or read in. </td><td style='text-align:right;'></td></tr></table>
4893
4894<p>Attributes of interest include <a href="#comment">-comment</a>, <a href="#delay">-delay</a>, <a href="#dispose">-dispose</a>, and <a href="#page">-page</a>. For example:</p>
4895
4896<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p>
4897<p>The <a href="#repage">-repage</a> operator will also set the
4898'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4899separately set the virtual canvas's size and offset components, and also allows
4900relative offset changes, and automatic canvas size re-calculating. The above
4901<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4902virtual canvas (page) meta-data. </p>
4903
4904<p>Set image options by prefixing the value with <kbd>option:</kbd>. Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>.</p>
4905
4906<div style="margin: auto;">
4907 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4908</div>
4909
4910<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>
4911
4912<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>
4913
4914<div style="margin: auto;">
4915 <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>
4916</div>
4917
4918<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>
4919
4920<div style="margin: auto;">
4921 <h4><a name="shared-memory"
4922id="shared-memory"></a>-shared-memory</h4>
4923</div>
4924
4925<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>
4926
4927<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>
4928
4929<div style="margin: auto;">
4930 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4931</div>
4932
4933<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>
4934
4935<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4936
4937<div style="margin: auto;">
4938 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4939</div>
4940
4941<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>
4942
4943<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>
4944
4945<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>
4946
4947<div style="margin: auto;">
4948 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4949</div>
4950
4951<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>
4952
4953<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>
4954
4955<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>
4956
4957<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>
4958
4959<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>
4960
4961<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>
4962<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>
4963
4964<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4965<div style="margin: auto;">
4966 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4967</div>
4968
4969<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>
4970
4971<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>
4972
4973<div style="margin: auto;">
4974 <h4><a name="silent" id="silent"></a>-silent</h4>
4975</div>
4976
4977<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>
4978
4979<div style="margin: auto;">
4980 <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>
4981</div>
4982
4983<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>
4984
4985<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>
4986
4987<p>For Photo CD images, choose from these sizes:</p>
4988
4989<pre class="text">
4990 192x128
4991 384x256
4992 768x512
4993 1536x1024
4994 3072x2048
4995</pre>
4996
cristy3ed852e2009-09-05 21:47:34 +00004997<div style="margin: auto;">
4998 <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>
4999</div>
5000
5001<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>
5002
5003<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>
5004
5005<div style="margin: auto;">
5006 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
5007</div>
5008
5009<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>
5010
5011<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
5012
5013<div style="margin: auto;">
5014 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
5015</div>
5016
5017<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>
5018
5019<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
5020
5021<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
5022
5023<div style="margin: auto;">
5024 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
5025 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
5026</div>
5027
5028<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>
5029
5030
5031<table class="doc">
5032 <tbody>
5033 <tr valign="top">
5034 <th align="left" style="width: 8%">Method</th>
5035 <th align="left">Description</th>
5036 </tr>
5037
5038 <tr valign="top">
5039 <td valign="top">voronoi</td>
5040 <td valign="top">Simply map each pixel to the to nearest color point
5041 given. The result are polygonal 'cells' of solid color. </td>
5042 </tr>
5043
5044 <tr valign="top">
5045 <td valign="top">shepards</td>
5046 <td valign="top">Colors points basied on the ratio of inverse distance
5047 squared. Generating spots of color in a sea of the average of
5048 colors. </td>
5049 </tr>
5050
5051 <tr valign="top">
5052 <td valign="top">barycentric</td>
5053 <td valign="top">three point triangle of color given 3 points.
5054 Giving only 2 points will form a linear gradient between those points.
5055 Gradient is however not restricted to just the triangle or line. </td>
5056 </tr>
5057
5058 <tr valign="top">
5059 <td valign="top">bilinear</td>
5060 <td valign="top">Like barycentric but for 4 points. Less than 4 points
5061 fall back to barycentric. </td>
5062 </tr>
5063
5064 </tbody>
5065</table>
5066
5067<p>The points are placed according to the images location on the virtual
5068canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
5069offset), and do not actually have to exist on the given image, but may be
5070some point beyond the edge of the image. All points are floating point values.
5071</p>
5072
5073<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
5074modified, whcih means the matte/alpha transparency channel is not effected by
5075default. If enabled, the image also needs a the matte/alpha channel to be
5076enabled for this operator to effect an images transparency. This is typical
5077transparency handling for images. </p>
5078
5079<p>All the above methods when given a single point of color will replace all
5080the colors in the image with the color given, regardless of the point. This is
5081logical, and provides an alternative technique to recolor a image to some
5082default value. </p>
5083
5084
5085<div style="margin: auto;">
5086 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
5087</div>
5088
5089<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>
5090
5091<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>
5092
5093<div style="margin: auto;">
5094 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
5095</div>
5096
5097<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>
5098
5099<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>
5100
5101<div style="margin: auto;">
5102 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
5103</div>
5104
5105<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>
5106
5107<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>
5108
5109<div style="margin: auto;">
5110 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
5111</div>
5112
5113<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>
5114
5115<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>
5116
5117<div style="margin: auto;">
5118 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
5119</div>
5120
5121<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>
5122
5123<pre class="text">
5124 char store pixels as unsigned characters
5125 double store pixels as doubles
5126 float store pixels as floats
5127 integer store pixels as integers
5128 long store pixels as longs
5129 quantum store pixels in the native depth of your ImageMagick distribution
5130 short store pixels as unsigned shorts
5131</pre>
5132
5133<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
5134values range from 0 to the maximum value the storage type can support.</p>
5135
5136<div style="margin: auto;">
5137 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
5138</div>
5139
5140<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>
5141
5142<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>
5143
5144<pre class="text">
5145 Any
5146 Condensed
5147 Expanded
5148 ExtraCondensed
5149 ExtraExpanded
5150 Normal
5151 SemiCondensed
5152 SemiExpanded
5153 UltraCondensed
5154 UltraExpanded
5155</pre>
5156
5157<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
5158
5159<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>
5160
5161<div style="margin: auto;">
5162 <h4><a name="strip" id="strip"></a>-strip</h4>
5163</div>
5164
5165<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>
5166
5167<div style="margin: auto;">
5168 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
5169</div>
5170
5171<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>
5172
5173<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5174
5175<p>See <a href="#draw">-draw</a> for further details.</p>
5176
5177<div style="margin: auto;">
5178 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5179</div>
5180
5181<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>
5182
5183<p>See <a href="#draw">-draw</a> for further details.</p>
5184
5185<div style="margin: auto;">
5186 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5187</div>
5188
5189<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>
5190
5191<p>This setting suggests a font style that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStyle</em> from the following.</p>
5192
5193<pre class="text">
5194 Any
5195 Italic
5196 Normal
5197 Oblique
5198</pre>
5199
5200<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>
5201
5202<div style="margin: auto;">
5203 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5204</div>
5205
5206<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>
5207
5208<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third images in the current image sequence. Use <a href="#swap">+swap</a> to switch the last two images in the sequence.</p>
5209
5210<div style="margin: auto;">
5211 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5212</div>
5213
5214<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>
5215
5216<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5217
5218<div style="margin: auto;">
5219 <h4><a name="taint" id="taint"></a>-taint</h4>
5220</div>
5221
5222<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified even if it isn't.</td><td style='text-align:right;'></td></tr></table>
5223
5224<div style="margin: auto;">
5225 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5226</div>
5227
5228<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>
5229
5230<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>
5231
5232<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>
5233
5234<div style="margin: auto;">
5235 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5236</div>
5237
5238<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>
5239
5240<div style="margin: auto;">
5241 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5242</div>
5243
5244<!-- {<em class="arg">green,blue,opacity</em>}
5245<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>
5246-->
5247
5248<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>
5249
5250<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>
5251
5252<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.
5253</p>
5254
5255<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>
5256
5257<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5258<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>
5259
5260
5261<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>
5262<p>Note that the values of the transparency channel is treated as 'matte'
5263values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5264
5265<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>.
5266</p>
5267
5268<div style="margin: auto;">
5269 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5270</div>
5271
5272<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>
5273
5274<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>
5275
5276<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>
5277
5278<div style="margin: auto;">
5279 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5280</div>
5281
5282<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>
5283
5284<div style="margin: auto;">
5285 <h4>-tile <em class="arg">geometry</em></h4>
5286</div>
5287
5288<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>
5289
5290<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>
5291
5292<div style="margin: auto;">
5293 <h4>-tile</h4>
5294</div>
5295
5296<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>
5297
5298<div style="margin: auto;">
5299 <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>
5300</div>
5301
5302<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>
5303
5304<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>
5305
5306<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>
5307
5308<div style="margin: auto;">
5309 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5310</div>
5311
5312<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>
5313
5314<p>Tint the image with the fill color.</p>
5315
5316<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>
5317
5318<div style="margin: auto;">
5319 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5320</div>
5321
5322<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>
5323
5324<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>
5325
5326<p>For example,</p>
5327
5328<p class="crtsnip">
5329 -title "%m:%f %wx%h"
5330</p>
5331
5332<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>
5333
5334
5335<div style="margin: auto;">
5336 <h4><a name="transform" id="transform"></a>-transform</h4>
5337</div>
5338
5339<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>
5340
5341<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5342
5343<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>
5344<div style="margin: auto;">
5345 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5346</div>
5347
5348<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>
5349
5350<p>The <em class="arg">color</em> argument is defined using the format
5351described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5352>-fuzz</a> setting can be used to match and replace colors similar to the one
5353given. </p>
5354
5355<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5356href="#transparent" >-transparent</a> but replaces the matching color same as
5357the current <a href="#fill">-fill</a> color setting. </p>
5358
5359<p>This does not define the 'transparency color' used for color-mapped image
5360formats, such as GIF. For that use <a href="#transparent-color"
5361>-transparent-color</a> </p>
5362
5363<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5364paint any pixel that does not match the target color, with the fill color.</p>
5365
5366
5367<div style="margin: auto;">
5368 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5369</div>
5370
5371<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>
5372
5373<p>Sometimes this is used for saving to image formats such as
5374GIF and PNG8 which uses this color to represent boolean transparency. This
5375does not make a color transparent, it only defines what color the transparent
5376color is in the color palette of the saved image. Use <a
5377href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5378
5379<p>This option allows you to have both an opaque visible color, as well as a
5380transparent color of the same color value without conflict. That is, you can
5381use the same color for both the transparent and opaque color areas within an
5382image. This, in turn, frees to you to select a transparent color that is
5383appropriate when an image is displayed by an application that does not handle a
5384transparent color index, while allowing ImageMagick to correctly handle images of this
5385type. </p>
5386
5387<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5388
5389<div style="margin: auto;">
5390 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5391</div>
5392
5393<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>
5394
5395<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5396</p>
5397
5398<div style="margin: auto;">
5399 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5400</div>
5401
5402<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>
5403
5404
5405<div style="margin: auto;">
5406 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5407</div>
5408
5409<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>
5410
5411<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>
5412
5413<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>
5414
5415<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>
5416
5417<div style="margin: auto;">
5418 <h4><a name="trim" id="trim"></a>-trim</h4>
5419</div>
5420
5421<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>
5422
5423<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>
5424
5425<p>The page or virtual canvas information of the image is preserved allowing
5426you to extract the result of the <a href="#trim">-trim</a> operation from the
5427image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5428information if it is unwanted.</p>
5429
5430<p>If the trimmed image 'disappears' an warning is produced, and a special
5431single pixel transparent 'missed' image is returned, in the same way as when a
5432<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5433
5434
5435<div style="margin: auto;">
5436 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5437</div>
5438
5439<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>
5440 <p>Choose from: <kbd>Bilevel</kbd>, <kbd>Grayscale</kbd>, <kbd>GrayscaleMatte</kbd>, <kbd>Palette</kbd>, <kbd>PaletteMatte</kbd>, <kbd>TrueColor</kbd>, <kbd>TrueColorMatte</kbd>, <kbd>ColorSeparation</kbd>, <kbd>ColorSeparationMatte</kbd>, or <kbd>Optimize</kbd>.</p>
5441
5442<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>
5443
5444<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5445<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>
5446
5447<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5448
5449<div style="margin: auto;">
5450 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5451</div>
5452
5453<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>
5454
5455<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5456
5457<p>See <a href="#draw">-draw</a> for further details.</p>
5458
5459
5460<div style="margin: auto;">
5461 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5462</div>
5463
5464<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>
5465
5466<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>
5467
5468
5469<div style="margin: auto;">
5470 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5471</div>
5472
5473<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>
5474
5475
5476<div style="margin: auto;">
5477 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5478</div>
5479
5480<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>
5481
5482<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>
5483
5484
5485<div style="margin: auto;">
5486 <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>
5487</div>
5488
5489<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>
5490
5491<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>
5492
5493<p>The parameters are:</p>
5494
5495<pre class="text">
5496 radius: The radius of the Gaussian, in pixels, not counting the center
5497 pixel (default 0).
5498 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5499 amount: The fraction of the difference between the original and the blur
5500 image that is added back into the original (default 1.0).
5501 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5502 difference amount (default 0.05).
5503</pre>
5504
5505
5506<div style="margin: auto;">
5507 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5508</div>
5509
5510<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print detailed information about the image when this option preceds the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table>
5511
5512
5513<div style="margin: auto;">
5514 <h4><a name="version" id="version"></a>-version</h4>
5515</div>
5516
5517<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>
5518
5519
5520<div style="margin: auto;">
5521 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5522</div>
5523
5524<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>
5525
5526
5527<div style="margin: auto;">
5528 <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>
5529</div>
5530
5531<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>
5532
5533
5534<div style="margin: auto;">
5535 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5536</div>
5537
5538<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>
5539
5540<p>This option defines what color source should be used if and when a color
5541lookup completely 'misses' the source image. The color(s) that appear to
5542surround the source image. Generally this color is derived from the source
5543image, but could also be set to a specify background color. </p>
5544
5545<p>Choose from these methods:</p>
5546
5547<pre class="text">
5548 background: the area surrounding the image is the background color
5549 black: the area surrounding the image is black
5550 checker-tile: alternate squares with image and background color
5551 dither: non-random 32x32 dithered pattern
5552 edge: extend the edge pixel toward infinity
5553 gray: the area surrounding the image is gray
5554 horizontal-tile: horizontally tile the image, background color above/below
5555 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5556 mirror: mirror tile the image
5557 random: choose a random pixel from the image
5558 tile: tile the image (default)
5559 transparent: the area surrounding the image is transparent blackness
5560 vertical-tile: vertically tile the image, sides are background color
5561 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5562 white: the area surrounding the image is white
5563</pre>
5564
5565<p>The default value is "edge".</p>
5566
5567<p>This most important for distortion operators such as <a href="#distort"
5568>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5569However it also effects operations that may access pixels just outside the
5570image proper, such as <a href="#convolve">-convolve</a>, <a
5571href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5572
5573<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5574
5575
5576<div style="margin: auto;">
5577 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5578</div>
5579
5580<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>
5581
5582<p>Choose from these visual classes:</p>
5583
5584<pre class="text">
5585 StaticGray
5586 GrayScale
5587 StaticColor
5588 PseudoColor
5589 TrueColor
5590 DirectColor
5591 default
5592 visual id
5593</pre>
5594
5595<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>
5596
5597
5598<div style="margin: auto;">
5599 <h4><a name="watermark" id="watermark"></a>-watermark <em
5600 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5601</div>
5602
5603<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
5604saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5605
5606<p>Take a grayscale image (with alpha mask) and modify the destination image's
5607brightness according to watermark image's grayscale value and the <em
5608class="arg">brightness</em> percentage. The destinations color saturation
5609attribute is just direct modified by the <em class="arg">saturation</em>
5610percentage, which defaults to 100 percent (no color change). </p>
5611
5612
5613<div style="margin: auto;">
5614 <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>
5615</div>
5616
5617<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>
5618
5619<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5620
5621<div style="margin: auto;">
5622 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5623</div>
5624
5625<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>
5626
5627<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>
5628
5629<table class="doc">
5630 <col width="25%" />
5631 <col width="75%" />
5632 <thead>
5633 <tr>
5634 <th><em class="arg">fontWeight</em></th>
5635 <th>Description</th>
5636 </tr>
5637 </thead>
5638 <tbody>
5639 <tr><td>All </td> <td>No effect. </td></tr>
5640 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5641 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5642 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5643 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5644 </tbody>
5645 </table>
5646
5647<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5648
5649<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>
5650
5651<div style="margin: auto;">
5652 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5653</div>
5654
5655<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>
5656
5657<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005658 <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 +00005659</div>
5660
cristy5cadd612009-09-21 19:33:41 +00005661<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>
5662
5663<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.
5664</p>
cristy3ed852e2009-09-05 21:47:34 +00005665
5666<div style="margin: auto;">
5667 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5668</div>
5669
5670<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>
5671
5672<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>
5673
5674<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>
5675
5676<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>
5677
5678<div style="margin: auto;">
5679 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5680</div>
5681
5682<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>
5683
5684<div style="margin: auto;">
5685 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5686</div>
5687
5688<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>
5689 <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>
5690
5691<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5692
cristyf3bb4782009-09-08 13:10:04 +00005693
5694</div>
5695
5696<div id="linkbar">
5697 <!-- <span id="linkbar-west">&nbsp;</span> -->
5698 <span id="linkbar-center">
5699 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> &bull;
5700 <a href="../www/mailing-list.html">Mailing Lists</a> &bull;
cristyd934d102009-10-10 12:55:13 +00005701 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
cristyf3bb4782009-09-08 13:10:04 +00005702 </span>
5703 <span id="linkbar-east">&nbsp;</span>
5704 </div>
5705 <div class="footer">
5706 <span id="footer-west">&copy; 1999-2009 ImageMagick Studio LLC</span>
5707 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
5708 </div>
5709 <div style="clear: both; margin: 0; width: 100%; "></div>
5710</body>
5711</html>