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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
cristy83543962009-10-16 19:04:28 +0000467<p>The operator is not typically used for real-life images, image scans, or
cristyd934d102009-10-10 12:55:13 +0000468JPEG 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"
cristy83543962009-10-16 19:04:28 +0000478>-auto-level</a> is the perfect or ideal version these operators. </p>
cristyd934d102009-10-10 12:55:13 +0000479
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
cristy83543962009-10-16 19:04:28 +0000483href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the
484'<CODE>sync</CODE>' will ensure that the color channels will be modified
485together by the same gamma value, preserving colors, and ignoring
486transparency. </p>
cristyd934d102009-10-10 12:55:13 +0000487
488
489
cristy3ed852e2009-09-05 21:47:34 +0000490<div style="margin: auto;">
491 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
492</div>
493
494<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>
495
cristy83543962009-10-16 19:04:28 +0000496<p>This operator reads and resets the EXIF image profile setting 'Orientation'
497and then performs the appropriate 90 degree rotation on the image to orient
498the image, for correct viewing. </p>
499
500<p>This EXIF profile setting is usually set using a gravity sensor in digital
501camara, however photos taken directly downward or upward may not have an
502appropriate value. Also images that have been orientation 'corrected' without
503reseting this setting, may be 'corrected' again resulting in a incorrect
504result. If the he EXIF profile was previously stripped, the <a
505href="#auto-orient" >-auto-orient</a> operator will do nothing. </p>
506
507
cristy3ed852e2009-09-05 21:47:34 +0000508<div style="margin: auto;">
509 <h4><a name="average" id="average"></a>-average</h4>
510</div>
511
512<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>
513
514<p>An error results if the images are not identically sized.</p>
515
cristy3ed852e2009-09-05 21:47:34 +0000516
517<div style="margin: auto;">
518 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
519</div>
520
521<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>
522
523<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>
524
525<div style="margin: auto;">
526 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
527</div>
528
529<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>
530
531<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>
532
533<div style="margin: auto;">
534 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
535</div>
536
537<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>
538
539<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>
540
541<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>
542<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>
543
544<div style="margin: auto;">
545 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
546</div>
547
548<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>
549
550<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>
551
552<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>
553
554<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
555negative results without clipping to the color value range
556(0..QuantumRange).</p>
557
558<p>See the discussion on HDRI implementations of ImageMagick on the page
559<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.
560</p>
561
562<div style="margin: auto;">
563 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
564</div>
565
566<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>
567
568<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +0000569 <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 +0000570</div>
571
cristy5cadd612009-09-21 19:33:41 +0000572<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>
573
574<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.
575</p>
cristy3ed852e2009-09-05 21:47:34 +0000576
577
578<div style="margin: auto;">
579 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4>
580</div>
581
582<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>
583
584<p>Blend will average the images together ('plus') according to the
585percentages given and each pixels transparency. If only a single percentage
586value is given it sets the weight of the composite or 'source' image, while
587the background image is weighted by the exact opposite amount. That is a
588<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the
589'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p>
590
591
592<div style="margin: auto;">
593 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
594</div>
595
596<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>
597
598<div style="margin: auto;">
599 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
600</div>
601
602<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>
603
604<div style="margin: auto;">
605
606<div style="margin: auto;">
607 <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>
608</div>
609
610<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>
611
612<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
613
614<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
615</div>
616
617<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>
618
619<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>
620
621<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
622pixels which are outside the image proper are blurred into the final result.
623</p>
624
625
626<div style="margin: auto;">
627 <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>
628</div>
629
630<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>
631
632<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
633Average (EWA) of the source image, scaled according to the grayscale
634mapping. </p>
635
636<p>The ellipse is weighted with sigma set to the given <em class="arg"
637>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
638defaults to the <em class="arg" >Width</em> for a normal circular Guassian
639weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
640horizontal clock-wise. </p>
641
642<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
643pixels which are outside the image proper are blurred into the final result.
644</p>
645
646
647<div style="margin: auto;">
648 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
649</div>
650
651<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>
652
653<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>
654
655<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p>
656
657<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p>
658
659<div style="margin: auto;">
660 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
661</div>
662
663<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>
664
665<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
666
667<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
668
669<div style="margin: auto;">
670 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
671</div>
672
673<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>
674
675<div style="margin: auto;">
676 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
677</div>
678
679<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>
680
681<div style="margin: auto;">
682 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
683</div>
684
685<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>
686
687<div style="margin: auto;">
688 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
689</div>
690
691<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>
692
693<p>Here is an example color correction collection:</p>
694
695<pre class="text">
696&lt;?xml version="1.0" encoding="UTF-8"?>
697&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
698 &lt;ColorCorrection id="cc06668">
699 &lt;SOPNode>
700 &lt;Slope> 0.9 1.2 0.5 &lt;/Slope>
701 &lt;Offset> 0.4 -0.5 0.6 &lt;/Offset>
702 &lt;Power> 1.0 0.8 1.5 &lt;/Power>
703 &lt;/SOPNode>
704 &lt;SATNode>
705 &lt;Saturation> 0.85 &lt;/Saturation>
706 &lt;/SATNode>
707 &lt;/ColorCorrection>
708&lt;/ColorCorrectionCollection>
709</pre>
710
711<div style="margin: auto;">
712 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
713</div>
714
715<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>
716
717<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>
718
719<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p>
720
cristyd934d102009-10-10 12:55:13 +0000721<p>The channels above can be specified as a comma-separated list or can be
722abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>',
723'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>',
724'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'.
cristy3ed852e2009-09-05 21:47:34 +0000725
726For example, to negate only the alpha channel of an image, use</p>
727<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +0000728 -channel Alpha -negate
cristy3ed852e2009-09-05 21:47:34 +0000729</p>
730
cristyd934d102009-10-10 12:55:13 +0000731Some operators also allow the use of a special channel flag
732'<code>sync</code>'. If present operators that understand this flag will
733apply the exact same image modification to all the image channels in the image
734so as to ensure that colors are kept 'in-sync'. Without this flag such
735operators will apply there function to each channel separately. See <a
736href="#auto-level">-auto-level</a> and <a href="#auto-gamma">-auto-gamma</a>
737for examples of such an operator. </p>
cristy3ed852e2009-09-05 21:47:34 +0000738
cristyd934d102009-10-10 12:55:13 +0000739
740<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
741'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels
742except the opacity channel, and that all the color channels are to be modified
743in exactly the same way. The 'plus' form <a href="#channel" >+channel</a>
744will reset the value back to this default. </p>
745
746<p>Options that are affected by the <a href="#channel" >-channel</a> setting
747include the following.
748
749<a href="#auto-gamma">-auto-gamma</a>,
750<a href="#auto-level">-auto-level</a>,
cristy3ed852e2009-09-05 21:47:34 +0000751<a href="#black-threshold">-black-threshold</a>,
752<a href="#blur">-blur</a>,
cristyb4c03bb2009-09-27 13:55:46 +0000753<a href="#clamp">-clamp</a>,
cristy3ed852e2009-09-05 21:47:34 +0000754<a href="#clut">-clut</a>,
755<a href="#combine">-combine</a>,
756<a href="#contrast-stretch">-contrast-stretch</a>,
757<a href="#evaluate">-evaluate</a>,
758<a href="#function">-function</a>,
759<a href="#fx">-fx</a>,
cristy3ed852e2009-09-05 21:47:34 +0000760<a href="#gaussian-blur">-gaussian-blur</a>,
cristyd934d102009-10-10 12:55:13 +0000761<a href="#hald-clut">-hald-clut</a>,
cristy3ed852e2009-09-05 21:47:34 +0000762<a href="#motion-blur">-motion-blur</a>,
763<a href="#negate">-negate</a>,
764<a href="#normalize">-normalize</a>,
765<a href="#ordered-dither">-ordered-dither</a>,
766<a href="#radial-blur">-radial-blur</a>,
767<a href="#random-threshold">-random-threshold</a>,
768<a href="#separate">-separate</a>, and
cristyd934d102009-10-10 12:55:13 +0000769<a href="#threshold">-threshold</a>, and
cristy3ed852e2009-09-05 21:47:34 +0000770<a href="#white-threshold">-white-threshold</a>.
771</p>
772
cristyd934d102009-10-10 12:55:13 +0000773<p>Warning, some operators behave differentally when the <a href="#channel"
774>+channel</a> default setting is in effect, verses ANY user defined <a
775href="#channel" >-channel</a> setting (including the equivelent of the
776default). For example <a href="#threshold">-threshold</a> will by default
777gray-scale the image before thresholding, if no <a href="#channel"
778>-channel</a> setting has been defined. </p>
779
780<p>Also some operators such as <a href="#blur">-blur</a>, <a
781href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
782color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a
783href="#channel" >-channel</a>. Generally this done to ensure that
784fully-transparent colors are treated as being fully-transparent, and thus any
785underlying 'hidden' color has no effect on the final results. Typically
786resulting in 'halo' effects. </p>
787
788<p>As a alpha channel is optional within images some operators will read the
789color channels of an image as a greyscale alpha mask, when the image has no
790alpha channel present, but the <a href="#channel" >-channel</a> setting tells
791the operator to apply the alpha channel. The <a href="#clut">-clut</a>
792operator is a good example of this. </p>
793
cristy3ed852e2009-09-05 21:47:34 +0000794
795<div style="margin: auto;">
cristyb4c03bb2009-09-27 13:55:46 +0000796 <h4><a name="clamp" id="clamp"></a>-clamp</h4>
797</div>
798
799<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>
800
801<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +0000802 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
803</div>
804
805<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>
806
807<div style="margin: auto;">
808 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
809</div>
810
811<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>
812
813<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>
814
815<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>
816
817<div style="margin: auto;">
818 <h4><a name="clip" id="clip"></a>-clip</h4>
819</div>
820
821<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>
822
823<p>If a clipping path is present, it is applied to subsequent operations.</p>
824
825<p>For example, in the command</p>
826
827<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
828<p>only the pixels within the clipping path are negated.</p>
829
830<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
831
832<div style="margin: auto;">
833 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
834</div>
835
836<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>
837
838<div style="margin: auto;">
839 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
840</div>
841
842<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>
843
844<div style="margin: auto;">
845 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
846</div>
847
848<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>
849
850<p>Specify the image by its index in the sequence. The first image is index
8510. Negative indexes are relative to the end of the sequence; for example, &minus;1
852represents the last image of the sequence. Specify a range of images with a
853dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
854href="#clone">+clone</a> make a copy of the last image in the image
855sequence.</p>
856
857<div style="margin: auto;">
858 <h4><a name="clut" id="clut"></a>-clut</h4>
859</div>
860
861<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
862corresponding channel in the second image as a <b>c</b>olor
863<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
864
865<p>The second (LUT) image is ordinarily a gradient image containing the
866histogram mapping of how each channel should be modified. Typically it is a
867either a single row or column image of replacement color values. If larger
868than a single row or column, values are taken from a diagonal line from
869top-left to bottom-right corners.</p>
870
871<p>The lookup is further controlled by the <a
872href="#interpolate">-interpolate</a> setting, which is especially handy for an
873LUT which is not the full length needed by the ImageMagick installed Quality
874(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
875'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
876gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
877lookup of color values. </p>
878
879<p>This operator is especially suited to replacing a grayscale image with a
880specific color gradient from the CLUT image. </p>
881
882<p>Only the channel values defined by the <a href="#channel">-channel</a>
883setting will have their values replaced. In particular, since the default <a
884href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
885transparency (alpha/matte channel) is not affected, unless the <a
886href="#channel">-channel</a> setting is modified. When the alpha channel is
887set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
888as the other channels, implying that alpha/matte values are replaced using the
889alpha/matte values of the original image. </p>
890
891<p>If either the image being modified, or the lookup image, conatins no
892transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
893href="#channel">-channel</a> setting includes alpha replacement, then it is
894assumed that image represents a gray-scale graident which will be used for the
895replacement alpha values. That is you can use a gray-scale CLUT image to
896adjust a existing images alpha channel, or you can color a gray-scale image
897using colors form CLUT containing the desired colors, including transparency.
898</p>
899
900<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
901the lookup of the full color RGB value from a 2D representation of a 3D color
902cube. </p>
903
904
905<div style="margin: auto;">
906 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
907</div>
908
909<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>
910
911<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>
912
913<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>
914
915
916<div style="margin: auto;">
917 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
918</div>
919
920<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>
921
922<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>
923
924<div style="margin: auto;">
925 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
926</div>
927
928<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>
929
930<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
931
932<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>
933
934<div style="margin: auto;">
935 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
936</div>
937
938<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>
939
940<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>
941
942<div style="margin: auto;">
943 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
944</div>
945
946<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>
947
948<p>Choices are:</p>
949
950<pre class="text">
951 CMY
952 CMYK
953 Gray
954 HSB
955 HSL
956 HWB
957 Lab
958 Log
959 OHTA
960 Rec601Luma
961 Rec601YCbCr
962 Rec709Luma
963 Rec709YCbCr
964 RGB
965 sRGB
966 Transparent
967 XYZ
968 YCbCr
969 YCC
970 YIQ
971 YPbPr
972 YUV
973</pre>
974
975<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
976
977<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>
978
979<table class="doc">
980 <caption>Conversion Of RGB To Other Color Spaces</caption>
981 <tr><th align="left" valign="middle">CMY</th></tr>
982 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
983 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
984 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
985 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
986 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
987 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
988 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
989 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
990
991 <tr><th align="left" valign="middle">Gray</th></tr>
992 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
993
994 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
995 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
996 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
997 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
998
999 <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>
1000 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1001 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
1002 <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>
1003
1004 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
1005 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
1006 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
1007 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
1008
1009 <tr><th align="left" valign="middle">LAB</th></tr>
1010 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1011 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1012 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1013
1014 <tr><th align="left" valign="middle">LOG</th></tr>
1015 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1016 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1017 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1018
1019 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
1020 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
1021 <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>
1022 <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>
1023
1024 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
1025 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
1026
1027 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
1028 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1029 <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>
1030 <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>
1031
1032 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
1033 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
1034
1035 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
1036 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
1037 <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>
1038 <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>
1039
1040 <tr><th align="left" valign="middle">sRGB</th></tr>
1041 <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>
1042 <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>
1043 <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>
1044
1045 <tr><th align="left" valign="middle">XYZ</th></tr>
1046 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
1047 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
1048 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
1049
1050 <tr><th align="left" valign="middle">YCC</th></tr>
1051 <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>
1052 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
1053 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
1054
1055 <tr><th align="left" valign="middle">YCbCr</th></tr>
1056 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1057 <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>
1058 <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>
1059
1060 <tr><th align="left" valign="middle">YIQ</th></tr>
1061 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1062 <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>
1063 <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>
1064
1065 <tr><th align="left" valign="middle">YPbPr</th></tr>
1066 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
1067 <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>
1068 <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>
1069
1070 <tr><th align="left" valign="middle">YUV</th></tr>
1071 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
1072 <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>
1073 <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>
1074</table>
1075
1076<div style="margin: auto;">
1077 <h4><a name="combine" id="combine"></a>-combine</h4>
1078</div>
1079
1080<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>
1081
1082<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>
1083
1084<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.
1085</p>
1086
1087<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>
1088<div style="margin: auto;">
1089 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
1090</div>
1091
1092<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>
1093
1094<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>
1095
1096<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>
1097
1098<p>For example,</p>
1099
1100<p class="crtsnip">
1101 -comment "%m:%f %wx%h"
1102</p>
1103
1104<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>
1105
1106<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>
1107
1108<div style="margin: auto;">
1109 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1110</div>
1111
1112<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>
1113
1114<p>The description of composition uses abstract terminology in order to allow
1115the description to be more precise, while avoiding constant values which are
1116specific to a particular build configuration. Each image pixel is represented
1117by red, green, and blue levels (which are equal for a gray pixel). The
1118build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1119value which may be stored, per pixel, in the red, green, or blue channels of
1120the image. Each image pixel may also optionally (if the image matte channel is
1121enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1122<em>transparent</em>, which may be used to determine the influence of the pixel
1123color when compositing the pixel with another image pixel. If the image matte
1124channel is disabled, then all pixels in the image are treated as opaque. The
1125color of an opaque pixel is fully visible while the color of a transparent
1126pixel color is entirely absent (pixel color is ignored).</p>
1127
1128<p>By definition, raster images have a rectangular shape. All image rows are of
1129equal length, as are all image columns. By treating the alpha channel as a
1130visual "mask" the rectangular image may be given a "shape" by treating the
1131alpha channel as a cookie-cutter for the image. This is done by setting the
1132pixels within the shape to be opaque, with pixels outside the shape set as
1133transparent. Pixels on the boundary of the shape may be between opaque and
1134transparent in order to provide antialiasing (visually smooth edges). The
1135description of the composition operators use this concept of image "shape" in
1136order to make the description of the operators easier to understand. While it
1137is convenient to describe the operators in terms of "shapes" they are by no
1138means limited to mask-style operations since they are based on continuous
1139floating-point mathematics rather than simple boolean operations.</p>
1140
1141<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1142
1143<table class="doc">
1144 <tbody>
1145 <tr valign="top">
1146 <th align="left" style="width: 8%">Method</th>
1147 <th align="left">Description</th>
1148 </tr>
1149
1150 <tr valign="top">
1151 <td valign="top">clear</td>
1152 <td valign="top">Both the color and the alpha of the destination are
1153 cleared. Neither the source nor the destination are used (except for
1154 destinations size and other meta-data which is always preserved.</td>
1155 </tr>
1156
1157 <tr valign="top">
1158 <td valign="top">src</td>
1159 <td valign="top">The source is copied to the destination. The destination
1160 is not used as input, though it is cleared.</td>
1161 </tr>
1162
1163 <tr valign="top">
1164 <td valign="top">dst</td>
1165 <td valign="top">The destination is left untouched. The source image is
1166 completely ignored.</td>
1167 </tr>
1168
1169 <tr valign="top">
1170 <td valign="top">src-over</td>
1171 <td valign="top">The source is composited over the destination. this is
1172 the default alpha blending compose method, when neither the compose
1173 setting is set, nor is set in the image meta-data.</td>
1174 </tr>
1175
1176 <tr valign="top">
1177 <td valign="top">dst-over</td>
1178 <td valign="top">The destination is composited over the source and the
1179 result replaces the destination.</td>
1180 </tr>
1181
1182 <tr valign="top">
1183 <td valign="top">src-in</td>
1184 <td valign="top">The part of the source lying inside of the destination
1185 replaces the destination.</td>
1186 </tr>
1187
1188 <tr valign="top">
1189 <td valign="top">dst-in</td>
1190 <td valign="top">The part of the destination lying inside of the source
1191 replaces the destination. Areas not overlaid are cleared.</td>
1192 </tr>
1193
1194 <tr valign="top">
1195 <td valign="top">src-out</td>
1196 <td valign="top">The part of the source lying outside of the destination
1197 replaces the destination.</td>
1198 </tr>
1199
1200 <tr valign="top">
1201 <td valign="top">dst-out</td>
1202 <td valign="top">The part of the destination lying outside of the source
1203 replaces the destination.</td>
1204 </tr>
1205
1206 <tr valign="top">
1207 <td valign="top">src-atop</td>
1208 <td valign="top">The part of the source lying inside of the destination is
1209 composited onto the destination.</td>
1210 </tr>
1211
1212 <tr valign="top">
1213 <td valign="top">dst-atop</td>
1214 <td valign="top">The part of the destination lying inside of the source is
1215 composited over the source and replaces the destination. Areas not
1216 overlaid are cleared. </td>
1217 </tr>
1218
1219 <tr valign="top">
1220 <td valign="top">xor</td>
1221 <td valign="top">The part of the source that lies outside of the
1222 destination is combined with the part of the destination that lies
1223 outside of the source. Source or Destination, but not both. </td>
1224 </tr>
1225
1226 </tbody>
1227</table>
1228
1229<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1230For example the defaul compose method can be specified as just 'Over'.</p>
1231
1232
1233<p>The following mathemathical composition methods are also available. </p>
1234
1235<p>Typically these use the default 'Over' alpha blending when transparencies
1236are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1237also composes the alpha channel using the same process as the color channels.
1238This allows them to be used for special image masking techniques. </p>
1239
1240<table class="doc">
1241 <tbody>
1242 <tr valign="top">
1243 <th align="left" style="width: 8%">Method</th>
1244 <th align="left">Description</th>
1245 </tr>
1246
1247 <tr valign="top">
1248 <td valign="top">multiply</td>
1249 <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>
1250 </tr>
1251
1252 <tr valign="top">
1253 <td valign="top">screen</td>
1254 <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>
1255 </tr>
1256
1257 <tr valign="top">
1258 <td valign="top">plus</td>
1259 <td valign="top">The source is added to the destination and replaces the
1260 destination. This operator is useful for averaging or a controled
1261 merger of two images, rather than a direct overlay.</td>
1262 </tr>
1263
1264 <tr valign="top">
1265 <td valign="top">add</td>
1266 <td valign="top">As per 'plus' but transparency data is treated as matte
1267 values. As such any transparent areas in either image remain
1268 transparent. </td>
1269 </tr>
1270
1271 <tr valign="top">
1272 <td valign="top">minus</td>
1273 <td valign="top">Subtract the colors in the source image from the
1274 destination image. When transparency is involved, opaque areas is
1275 subtracted from any destination opaque areas. </td>
1276 </tr>
1277
1278 <tr valign="top">
1279 <td valign="top">subtract</td>
1280 <td valign="top">Subtract the colors in the source image from the
1281 destination image. When transparency is involved transparent areas are
1282 subtracted, so only the opaque areas in the source remain opaque in
1283 the destination image. </td>
1284 </tr>
1285
1286 <tr valign="top">
1287 <td valign="top">difference</td>
1288 <td valign="top">Subtracts the darker of the two constituent colors from
1289 the lighter. Painting with white inverts the destination color.
1290 Painting with black produces no change.</td>
1291 </tr>
1292
1293 <tr valign="top">
1294 <td valign="top">exclusion</td>
1295 <td valign="top">Produces an effect similar to that of 'difference', but
1296 appears as lower contrast. Painting with white inverts the
1297 destination color. Painting with black produces no change.</td>
1298 </tr>
1299
1300 <tr valign="top">
1301 <td valign="top">darken</td>
1302 <td valign="top">Selects the darker of the destination and source colors.
1303 The destination is replaced with the source when the source is darker,
1304 otherwise it is left unchanged.</td>
1305 </tr>
1306
1307 <tr valign="top">
1308 <td valign="top">lighten</td>
1309 <td valign="top">Selects the lighter of the destination and source colors.
1310 The destination is replaced with the source when the source is
1311 lighter, otherwise it is left unchanged. </td>
1312 </tr>
1313
1314 <tr valign="top">
1315 <td valign="top">linear-dodge</td>
1316 <td valign="top">This is equivelent to 'Plus' in that the color channels
1317 are simply added, however it does not 'Plus' the alpha channel, but
1318 uses the normal 'Over' alpha blending, which transparencies are
1319 involved. Produces a sort of additive multiply-like result. Added
1320 ImageMagick version 6.5.4-3. </td>
1321 </tr>
1322
1323 <tr valign="top">
1324 <td valign="top">linear-burn</td>
1325 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1326 Sort of a additive 'Screen' of the images. Added ImageMagick version
1327 6.5.4-3. </td>
1328 </tr>
1329
1330 <tr valign="top">
1331 <td valign="top">color-dodge</td>
1332 <td valign="top">Brightens the destination color to reflect the source
1333 color. Painting with black produces no change.</td>
1334 </tr>
1335
1336 <tr valign="top">
1337 <td valign="top">color-burn</td>
1338 <td valign="top">Darkens the destination color to reflect the source
1339 color. Painting with white produces no change. Fixed in ImageMagick
1340 version 6.5.4-3. </td>
1341 </tr>
1342
1343 <tr valign="top">
1344 <td valign="top">overlay</td>
1345 <td valign="top">Multiplies or screens the colors, dependent on the
1346 destination color. Source colors overlay the destination whilst
1347 preserving its highlights and shadows. The destination color is not
1348 replaced, but is mixed with the source color to reflect the lightness
1349 or darkness of the destination.</td>
1350 </tr>
1351
1352 <tr valign="top">
1353 <td valign="top">hard-light</td>
1354 <td valign="top">Multiplies or screens the colors, dependent on the source
1355 color value. If the source color is lighter than 0.5, the destination
1356 is lightened as if it were screened. If the source color is darker
1357 than 0.5, the destination is darkened, as if it were multiplied. The
1358 degree of lightening or darkening is proportional to the difference
1359 between the source color and 0.5. If it is equal to 0.5 the
1360 destination is unchanged. Painting with pure black or white produces
1361 black or white.</td>
1362 </tr>
1363
1364
1365 <tr valign="top">
1366 <td valign="top">linear-light</td>
1367 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1368 instead. Increases contrast slightly with an impact on the
1369 foreground's tonal values.</td>
1370 </tr>
1371
1372 <tr valign="top">
1373 <td valign="top">soft-light</td>
1374 <td valign="top">Darkens or lightens the colors, dependent on the source
1375 color value. If the source color is lighter than 0.5, the destination
1376 is lightened. If the source color is darker than 0.5, the destination
1377 is darkened, as if it were burned in. The degree of darkening or
1378 lightening is proportional to the difference between the source color
1379 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1380 with pure black or white produces a distinctly darker or lighter area,
1381 but does not result in pure black or white. Fixed in ImageMagick
1382 version 6.5.4-3. </td>
1383 </tr>
1384
1385 <tr valign="top">
1386 <td valign="top">pegtop-light</td>
1387 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1388 continuious mathematical formula rather than two conditionally
1389 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1390 </tr>
1391
1392 <tr valign="top">
1393 <td valign="top">vivid-light</td>
1394 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1395 primary and secondary colors in the image. Added ImageMagick version
1396 6.5.4-3. </td>
1397 </tr>
1398
1399 <tr valign="top">
1400 <td valign="top">pin-light</td>
1401 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1402 to similate the effects of a strong 'pinhole' light source. Added
1403 ImageMagick version 6.5.4-3. </td>
1404 </tr>
1405
1406 </tbody>
1407</table>
1408
1409
1410<p>Also included are these special purpose compose methods:</p>
1411
1412<table class="doc">
1413 <tbody>
1414 <tr valign="top">
1415 <th align="left" style="width: 8%">Method</th>
1416 <th align="left">Description</th>
1417 </tr>
1418
1419 <tr valign="top">
1420 <td valign="top">copy-*</td>
1421 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1422 Magenta, Yellow, Black, or Opacity) in the source image to the
1423 same channel in the destination image. If the channel specified
1424 does not exist in the source image, (which can only happen for methods,
1425 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1426 assumed that the source image is a special grayscale channel image
1427 of the values to be copied. </td>
1428 </tr>
1429
1430 <tr valign="top">
1431 <td valign="top">change-mask</td>
1432 <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>
1433 </tr>
1434 </tbody>
1435</table>
1436
1437<p>On top of these composed methods are a few special ones that not only require
1438the two images that are being merged or overlaid, but have some extra numerical
1439arguments, which are tabled below. </p>
1440
1441<p>In the "<code>composite</code>" command these composition methods are
1442selected using special options with the arguments needed. They are usually,
1443but not always, the same name as the composte 'method' they use, and replaces
1444the normal use of the <a href="#compose" >-compose</a> setting in the
1445"<code>composite</code>" command. For example... </p>
1446
1447<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1448<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1449these extra arguments to its <a href="#composite" >-composite</a> operator,
1450using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1451these special argumented <a href="#compose" >-compose</a> methods, those the
1452argument and the method both need to be set separatally. For example... </p>
1453
1454<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1455<p>The following is a table of these special 'argumented' compose methods,
1456with a brief summary of what they do. For more details see the equivalent
1457"composite" command option name. </p>
1458
1459<table class="doc">
1460 <tbody>
1461 <tr valign="top">
1462 <th align="left" style="width: 8%">Method</th>
1463 <th align="left">Description</th>
1464 </tr>
1465
1466 <tr valign="top">
1467 <td valign="top">dissolve</td>
1468 <td valign="top">Arguments:
1469 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1470 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1471 <br>Dissolve the 'source' image by the percentage given before overlaying
1472 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1473 greater than 100, it starts dissolving the main image so it will
1474 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1475 both percentages are given, each image are dissolved to the
1476 percentages given.
1477 </td>
1478 </tr>
1479
1480 <tr valign="top">
1481 <td valign="top">blend</td>
1482 <td valign="top">Arguments:
1483 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1484 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1485 <br>Average the images together ('plus') according to the percentages
1486 given and each pixels transparency. If only a single percentage value
1487 is given it sets the weight of the composite or 'source' image, while
1488 the background image is weighted by the exact opposite amount. That is
1489 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1490 the 'destination' image. Thus it is equivalent to <kbd>-blend
1491 30x70</kbd>.
1492 </td>
1493 </tr>
1494
1495 <tr valign="top">
1496 <td valign="top">mathematics</td>
1497 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1498 <br>Not available in "<code>composite</code>" at this time.
1499 <br>Merge the source and destination images according to the formula
1500 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1501 <br>Can be used to generate a custom composition method that would
1502 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1503 DIY image operator. Added to ImageMagick version 6.5.4-3.
1504 </td>
1505 </tr>
1506
1507 <tr valign="top">
1508 <td valign="top">modulate</td>
1509 <td valign="top">Arguments:
1510 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1511 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1512 <br>Take a grayscale image (with alpha mask) and modify the destination
1513 image's brightness according to watermark image's grayscale value and
1514 the <em class="arg">brightness</em> percentage. The destinations
1515 color saturation attribute is just direct modified by the <em
1516 class="arg">saturation</em> percentage, which defaults to 100 percent
1517 (no color change).
1518
1519 </td>
1520 </tr>
1521
1522 <tr valign="top">
1523 <td valign="top">displace</td>
1524 <td valign="top">Arguments:
1525 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1526 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1527 <br>With this option, the 'overlay' image, and optionally the 'mask'
1528 image, is used as a relative displacement map, which is used to
1529 displace the lookup of what part of the destination image is seen at
1530 each point of the overlaid area. Much like the displacement map is a
1531 'lens' that distorts the original 'background' image behind it.
1532 <br><br>
1533 The X-scale is modilated by the 'red' channel of the overlay image
1534 while the Y-scale is modulated by the green channel, (the mask image
1535 if given is rolled into green channel of the overlay image. This
1536 separation allows you to modulate the X and Y lookup displacement
1537 separatally allowing you to di 2 dimentional displacements, rather
1538 than 1 dimentional verctored displacements (using grayscale image).
1539 <br><br>
1540 If the overlay image contains transparency this is used as a mask
1541 of the resulting image to remove 'invalid' pixels.
1542 <br><br>
1543 The '%' flag makes the displacement scale relative to the size of the
1544 overlay image (100% = half width/height of image). Using '!' switches
1545 percentage arguments to refer to the destination image size instead.
1546 <br><br>
1547 Special flags were added Added to ImageMagick version 6.5.3-5.
1548 </td>
1549 </tr>
1550
1551 <tr valign="top">
1552 <td valign="top">distort</td>
1553 <td valign="top">Arguments:
1554 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1555 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1556 <br>Not available in "<code>composite</code>" at this time.
1557 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1558 relative to the center of the overlay (or that given). Basically
1559 allows you to generate absolute distortion maps where 'black' will
1560 look up the left/top edge, and 'white' looks up the bottom/right
1561 edge of the destination image, according to the scale given.
1562 <br><br>
1563 The '!' flag not only switches percentage scaling, to use the
1564 destination image, but also the image the center offset of the lookup.
1565 This means the overlay can lookup a completely different region of the
1566 destination image.
1567 <br><br>
1568 Added to ImageMagick version 6.5.3-5.
1569 </td>
1570 </tr>
1571
1572 <tr valign="top">
1573 <td valign="top">blur</td>
1574 <td valign="top">Arguments:
1575 <em class="arg">Width</em>[x<em class="arg">Height</em
1576 >[+<em class="arg">Angle</em>]]
1577 <br>Equivalent to "<code>composite</code>"
1578 <a href="#blur-composite">-blur</a>
1579 <br>A Variable Blur Mapping Composition method, where each pixel in the
1580 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1581 with an ellipse (typically a circle) of the given sigma size, scaled
1582 according to overlay (source image) grayscale mapping.
1583 <br><br>
1584 As per 'Displace' and 'Distort', the red channel will modulate the
1585 width of the ellipse, while the green channel will modulate the height
1586 of the ellipse. However at this time the ellipse angle is not
1587 modulated though this may be a future posibility (perhaps with a
1588 special flag to enable use of blur channel for this purpose).
1589 <br><br>
1590 Added to ImageMagick version 6.5.4-0.
1591 </td>
1592 </tr>
1593
1594 </tbody>
1595</table>
1596
1597<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1598
1599
1600<div style="margin: auto;">
1601 <h4><a name="composite" id="composite"></a>-composite</h4>
1602</div>
1603
1604<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>
1605
1606<p>Take the first image 'destination' and overlay the second 'source' image
1607according to the current <a href="#compose">-compose</a> setting. The location
1608of the 'source' or 'overlay' image is controlled according to <a
1609href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1610settings. </p>
1611
1612<p>If a third image is given this is treated as a gray-scale 'mask' image
1613relative to the first 'destination' image. This mask will limit what parts of
1614the destination can be modified by the image composition. However for the
1615'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1616Y-displacement image instead. </p>
1617
1618<p>If a <a href="#compose">-compose</a> method requires extra numerical
1619arguments or flags these can be provided by setting the <a
1620href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1621appropriatally for the compose method. </p>
1622
1623<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1624image outside the overlay area. You can disable this by setting the special <a
1625href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1626to '<kbd>false</kbd>'. </p>
1627
1628
1629<div style="margin: auto;">
1630 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1631</div>
1632
1633<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>
1634
1635<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>
1636
1637<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1638
1639<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>
1640
1641<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>
1642
1643<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>
1644
1645<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>
1646
1647<div style="margin: auto;">
1648 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1649</div>
1650
1651<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>
1652
1653<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>
1654
1655<p>For a more pronounced effect you can repeat the option:</p>
1656
1657<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1658<div style="margin: auto;">
1659 <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>
1660</div>
1661
1662<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>
1663
cristyd934d102009-10-10 12:55:13 +00001664<p>While performing the stretch, black-out at most <em
1665class="arg" >black-point</em> pixels and white-out at most <em
1666class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most
1667<em class="arg" >black-point %</em> pixels and white-out at most <em
1668class="arg" >white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001669
cristyd934d102009-10-10 12:55:13 +00001670<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch"
1671>-contrast-stretch</a> will black-out at most <em class="arg"
1672>black-point</em> pixels and white-out at most <em class="arg" >total pixels
1673minus white-point</em> pixels. Or, if percent is used, black-out at most <em
1674class="arg">black-point %</em> pixels and white-out at most <em class="arg"
1675>100% minus white-point %</em> pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00001676
cristyd934d102009-10-10 12:55:13 +00001677<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that
1678the image's min and max values are stretched to 0 and <em class="QR"
1679>QuantumRange</em>, respectively, without any loss of data due to burn-out or
1680clipping at either end. This is not the same as <a href="#normalize"
1681>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or
1682prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p>
cristy3ed852e2009-09-05 21:47:34 +00001683
cristyd934d102009-10-10 12:55:13 +00001684<p>Internally operator works by creating a histogram bin, and then uses that
1685bin to modify the image. As such some colors may be merged together when they
1686originally fell into the same 'bin'. </p>
1687
1688<p>All the channels are normalized in concert by the came amount so as to
1689preserve color integrity, when the default <a href="#channel" >+channel</a>
1690setting is in use. Specifing any other <a href="#channel" >-channel</a>
1691setting will normalize the RGB channels independently.</p>
1692
1693<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
1694normalization of mathematical images. </p>
1695
1696<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00001697
1698
1699<div style="margin: auto;">
1700 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1701</div>
1702
1703<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>
1704
cristyd934d102009-10-10 12:55:13 +00001705<p>The <em class="arg">kernel</em> is a square matrix specified as
1706a comma-separated list of integers (with no spaces), ordered left-to right,
1707starting with the top row. Presently, only odd-dimensioned kernels are
1708supported, and therefore the number of entries in the specified <em
1709class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
17107<sup>2</sup>=49, etc. </p>
cristy3ed852e2009-09-05 21:47:34 +00001711
cristyd934d102009-10-10 12:55:13 +00001712<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
1713positive and negative results are relative to a user-specified bias value.
1714This is important for non-HDRI compilations of ImageMagick when dealing with
1715convolutions that contain negative as well as positive values. This is
1716especially the case with convolutions involving high pass filters or edge
1717detection. Without an output bias, the negative values is clipped at zero.
cristy3ed852e2009-09-05 21:47:34 +00001718</p>
1719
cristyd934d102009-10-10 12:55:13 +00001720<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
1721negative results without clipping to the color value range (0..QuantumRange).
1722See the discussion on HDRI implementations of ImageMagick on the page <a
1723href="/www/high-dynamic-range.html">High
1724Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a
1725href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1726<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1727entry. </p>
cristy3ed852e2009-09-05 21:47:34 +00001728
cristy3ed852e2009-09-05 21:47:34 +00001729
1730<div style="margin: auto;">
1731 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1732</div>
1733
1734<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>
1735
1736<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>
1737
1738<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>
1739
1740<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>
1741
1742<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>
1743
1744<p>By adding a exclamation character flag to the geometry argument, the
1745cropped images virtual canvas page size and offset is set as if the
1746geometry argument was a viewport or window. This means the canvas page size
1747is set to exactly the same size you specified, the image offset set
1748relative top left corner of the region cropped. </p>
1749
1750<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1751special single pixel transparent 'missed' image is returned, and a 'crop
1752missed' warning given. </p>
1753
1754
1755<div style="margin: auto;">
1756 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1757</div>
1758
1759<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>
1760
1761<p><em class="arg">Amount</em> defines the number of positions each
1762colormap entry is shifted.</p>
1763
1764
1765<div style="margin: auto;">
1766 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1767</div>
1768
1769<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>
1770
1771<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>
1772
1773
1774<p>For example, to log cache and blob events, use.</p>
1775
1776<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1777<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1778
1779<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1780
1781<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1782
1783<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1784
1785<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>
1786
1787
1788<div style="margin: auto;">
1789 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1790</div>
1791
1792<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>
1793
1794<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1795
1796<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1797
1798
1799<div style="margin: auto;">
1800 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1801</div>
1802
1803<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>
1804
1805<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>
1806
1807<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>
1808
1809<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1810
1811
1812<div style="margin: auto;">
1813 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1814</div>
1815
1816<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>
1817
1818<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>
1819
1820<p>The following definitions may be created:</p>
1821
1822<ul>
cristy48dd1af2009-10-02 01:21:56 +00001823<dt>jpeg:size=geometry</dt>
1824 <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 +00001825<dt>jp2:rate=value</dt>
1826 <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 />
1827<dt>mng:need-cacheoff</dt>
1828 <dd>turn playback caching off for streaming MNG.</dd><br />
1829<dt>png:bit-depth=value</dt>
1830<dt>png:color-type=value</dt>
1831 <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 />
1832<dt>ps:imagemask</dt>
1833 <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>
1834</ul>
1835
1836<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1837
1838<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1839<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>
1840
1841<p class="crtsnip">
1842-define registry:temporary-path=/data/tmp
1843</p>
1844
1845<div style="margin: auto;">
1846 <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>
1847</div>
1848
1849<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>
1850
1851<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>
1852
1853<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>
1854
1855
1856<div style="margin: auto;">
1857 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1858</div>
1859
1860<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>
1861
1862<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>
1863
1864
1865<div style="margin: auto;">
1866 <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>
1867</div>
1868
1869<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>
1870
1871<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>
1872
1873<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>
1874
1875<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>
1876
1877<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>
1878
1879<div style="margin: auto;">
1880 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1881</div>
1882
1883<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>
1884
1885<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>
1886
1887<div style="margin: auto;">
1888 <h4><a name="descend" id="descend"></a>-descend</h4>
1889</div>
1890
1891<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>
1892
1893<div style="margin: auto;">
1894 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1895</div>
1896
1897<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>
1898
1899<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>
1900
1901<div style="margin: auto;">
1902 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1903</div>
1904
1905<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>
1906
1907<div style="margin: auto;">
1908 <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>
1909</div>
1910
1911<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>
1912
1913<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1914will be used as a displacement map, which is used to displace the lookup of
1915what part of the 'background' image is seen at each point of the overlaid
1916area. Much like the displacement map is a 'lens' that redirects light shining
1917through it so as to present a distorted view the original 'background' image
1918behind it. </p>
1919
1920<p>Any perfect grey areas of the displacement map produce a zero
1921displacement of the image. Black areas produce the given maximum negative
1922displacement of the lookup point, while white produce a maximum positive
1923displacement of the lookup. </p>
1924
1925<p>Note that it is the lookup of the 'background' that is displaced, not a
1926displacement of the image itself. As such an area of the displacement map
1927containing 'white' will have the lookup point 'shifted' by a positive amount,
1928and thus generating a copy of the destination image to the right/downward from
1929the correct position. That is the image will look like it may have been
1930'shifted' in a negative left/upward direction. Understanding this is a very
1931important in understanding how displacement maps work. </p>
1932
1933<p>The given arguments define the maximum amount of displacement in pixels
1934that a particular map can produce. If the displacement scale is large enough
1935it is also posible to lookup parts of the 'background' image that lie well
1936outside the bounds of the displacement map itself. That is you could very
1937easilly copy a section of the original image from outside the overlay area
1938into the overlay area. </p>
1939
1940<p>The '%' flag makes the displacement scale relative to the size of the
1941overlay image (100% = half width/height of image). Using '!' switches
1942percentage arguments to refer to the destination image size instead.
1943these flags were added as of IM v6.5.3-5.</p>
1944
1945<p>Normally a single grayscale displacement map is provided, which with the
1946given scaling values will determine a single direction (vector) in which
1947displacements can occur (positivally or negativally). However, if you also
1948specify a third image which is normally used as a <em class="arg">mask</em>,
1949then the <em class="arg">composite image</em> will be used for horizontal X
1950displacement, while the <em class="arg">mask image</em> is used for vertical Y
1951displacement. This allows you to define completely different displacement
1952values for the X and Y directions, and allowing you to lookup any point within
1953the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1954any other nearby pixel, producing complex 2 dimentional displacements, rather
1955than a simple 1 dimentional vector displacements. </p>
1956
1957<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1958you can use the 'red' channel of the overlay image to specify the horizontal
1959or X displacement, and the 'green' channel for the vertical or Y displacement.
1960</p>
1961
1962<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1963mask the transparency of the destination image. However areas outside the
1964overlaid areas will not be effected. </p>
1965
1966
1967<div style="margin: auto;">
1968 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1969</div>
1970
1971<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>
1972
1973<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1974
1975<div style="margin: auto;">
1976 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1977</div>
1978
1979<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>
1980
1981<p>The layer disposal method defines the way each the displayed image is to be
1982modified after the current 'frame' of an animation has finished being
1983displayed (after its 'delay' period), but before the next frame on an
1984animation is to be overlaid onto the display. </p>
1985
1986<p>Here are the valid methods:</p>
1987
1988<pre class="text">
1989Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1990None 1 Do not dispose, just overlay next frame image.
1991Background 2 Clear the frame area with the background color.
1992Previous 3 Clear to the image prior to this frames overlay.
1993</pre>
1994
1995<p>You can also use the numbers given above, which is what the GIF format
1996uses internally to represent the above settings. </p>
1997
1998<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1999
2000<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
2001resetting the layer disposal methods of images being read in. </p>
2002
2003<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
2004disposal method for images already in memory.</p>
2005
2006<div style="margin: auto;">
2007 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
2008</div>
2009
2010<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>
2011
2012
2013<div style="margin: auto;">
2014 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
2015</div>
2016
2017<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>
2018
2019<p>The opacity of the composite image is multiplied by the given percent, then
2020it is composited 'over' the main image. If <em class="arg">src_percent</em>
2021is greater than 100, start dissolving the main image so it will become
2022transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
2023are given, each image are dissolved to the percentages given. </p>
2024
2025<p>Note that dissolve percentages do not add, two opaque images dissolved
2026'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2027images, you would need to use dissolve values of '50,100'. </p>
2028
2029<div style="margin: auto;">
2030 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
2031</div>
2032
2033<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>
2034
2035<p>The <em class="arg">arguments</em> is a single string containing a list
2036of floating point numbers separated by commas or spaces. The number of
2037and meaning of the floating point values depends on the distortion <em
2038class="arg">method</em> being used. </p>
2039
2040<p>Choose from these distortion types:</p>
2041
2042<table class="doc">
2043 <tr valign="top">
2044 <th align="left" style="width: 8%">Method</th>
2045 <th align="left">Description</th>
2046 </tr>
2047
2048 <tr valign="top">
2049 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
2050 <br/>or &nbsp; <kbd>SRT</kbd></td>
2051 <td valign="top">
2052 Distort image by first scaling and rotating about a given 'center',
2053 before translating that 'center' to the new location, in that order. It
2054 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
2055 distortion, but without shearing effects. It also provides a good way
2056 of rotating and displacing a smaller image for tiling onto a larger
2057 background (IE 2-dimensional animations). <br/>
2058
2059 The number of arguments determine the specific meaning of each
2060 argument for the scales, rotation, and translation operations. <br/>
2061
2062 <table style="margin-left:auto; margin-right:auto;">
2063 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
2064 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
2065 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
2066 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2067 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
2068 <tr><td>5:</td>
2069 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2070 <tr><td>6:</td>
2071 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
2072 <tr><td>7:</td>
2073 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
2074 &nbsp; NewX,NewY</em></td></tr>
2075 </table>
2076
2077 This is actually an alternative way of specifing a 2 dimensional linear
2078 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
2079
2080 <tr valign="top">
2081 <td valign="top"><kbd>Affine</kbd></td>
2082 <td valign="top">
2083 Distort the image linearly by moving a list of at least 3 or more sets
2084 of control points (as defined below). Idealy 3 sets or 12 floating
2085 point values are given allowing the image to be linearly scaled,
2086 rotated, sheared, and translated, according to those three points. See
2087 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
2088 distortions. <br/>
2089
2090 More than 3 sets given control point pairs (12 numbers) is least
2091 squares fitted to best match a lineary affine distortion. If only 2
2092 control point pairs (8 numbers) are given a two point image translation
2093 rotation and scaling is performed, without any posible shearing,
2094 flipping or changes in aspect ratio to the resulting image. If only one
2095 control point pair is provides the image is only translated, (which may
2096 be a floating point non-integer translation). <br/>
2097
2098 This distortion does not include any form of perspective distortion.
2099 </td>
2100
2101 </tr>
2102
2103 <tr valign="top">
2104 <td valign="top"><kbd>AffineProjection</kbd></td>
2105 <td valign="top">
2106 Linearly distort an image using the given Affine Matrix of 6
2107 pre-calculated coefficients forming a set of Affine Equations to map
2108 the source image to the destination image.
2109
2110 <div style="text-align: center"><em>
2111 s<sub>x</sub>, r<sub>x</sub>,
2112 r<sub>y</sub>, s<sub>y</sub>,
2113 t<sub>x</sub>, t<sub>y</sub>
2114 </em></div>
2115
2116 See <a href="#affine" >-affine</a> setting for more detail, and
2117 meanings of these coefficients. <br/>
2118
2119 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
2120 alternative methods of defining this distortion, with ImageMagick doing the
2121 calculations needed to generate the required coefficients. You can see
2122 the internally generated coefficients, by using a <a href="#verbose"
2123 >-verbose</a> setting. </td>
2124
2125 </tr>
2126
2127<!-- still under development, do not display - Anthony
2128 <tr valign="top">
2129 <td valign="top"><kbd>Bilinear</kbd></td>
2130 <td valign="top">
2131 Bilinear (reversed) Distortion, given a minimum of 4 sets of
2132 coordinate pairs, or 16 values (see below). Not that lines may not
2133 appear straight after distortion, though the distance between
2134 coordinates will remain consistant. </td>
2135 </tr>
2136-->
2137
2138 <tr valign="top">
2139 <td valign="top"><kbd>Perspective</kbd></td>
2140 <td valign="top">
2141 Perspective distort the images, using a list of 4 or more sets of
2142 control points (as defined below). More that 4 sets (16 numbers) of
2143 control points provide least squares fitting for more accurate
2144 distortions (for the purposes of image registration and panarama
2145 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2146 linear distortion. <br/>
2147
2148 Perspective Distorted images ensures that straight lines remain
2149 straight, but the scale of the distorted image will vary. The horizon
2150 is anti-aliased, and the 'sky' color may be set using the
2151 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2152 </tr>
2153
2154 <tr valign="top">
2155 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2156 <td valign="top">
2157 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2158 pre-calculated coefficients. You can get these coefficients by looking
2159 at the <a href="#verbose" >-verbose</a> output of a
2160 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2161 If the last two perspective scaling coefficients are zero, the
2162 remaining 6 represents a transposed 'Affine Matrix'. </td>
2163
2164 </tr>
2165
2166 <tr valign="top">
2167 <td valign="top"><kbd>Arc</kbd></td>
2168 <td valign="top">
2169 Arc the image (variation of polar mapping) over the angle given around
2170 a circle. <br/>
2171 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2172 <tr valign="top"><td>Argument</td>
2173 <td>Meaning</td></tr>
2174 <tr valign="top"><td><em>arc_angle</em></td>
2175 <td>The angle over which to arc the image side-to-side</td></tr>
2176 <tr valign="top"><td><em>rotate_angle</em></td>
2177 <td>Angle to rotate resulting image from vertical center</td></tr>
2178 <tr valign="top"><td><em>top_radius</em></td>
2179 <td>Set top edge of source image at this radius</td></tr>
2180 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2181 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2182 </table>
2183
2184 The resulting image is always resized to best fit the resulting image,
2185 (as if using <a href="#distort" >+distort</a>) while attempting to
2186 preserve scale and aspect ratio of the original image as much as
2187 possible with the arguments given by the user. All four arguments will
2188 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2189
2190 This a variation of a polar distortion designed to try to preserve the
2191 aspect ratio of the image rather than direct Cartesian to Polar
2192 conversion. </td>
2193 </tr>
2194
2195 <tr valign="top">
2196 <td valign="top"><kbd>Polar</kbd></td>
2197 <td valign="top">
2198 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2199 the image. that is the height of the input image is mapped to the
2200 radius limits, while the width is wrapped around between the
2201 angle limits. <br/>
2202
2203 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2204
2205 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2206 center to the center of the image, and the angles going from -180 (top)
2207 to +180 (top). If <em>Rmax</em> is given the special value of
2208 '<code>0</code>', the the distance from the center to the nearest edge
2209 is used for the radius of the output image, which will ensure the whole
2210 image is visible (though scaled smaller). However a special value of
2211 '<code>-1</code>' will use the distance from the center to the furthest
2212 corner, This may 'clip' the corners from the input rectangular image,
2213 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2214 the same arguments. <br/>
2215
2216 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2217 output image center will default to <code>0,0</code> of the virtual
2218 canvas, and the image size adjusted to ensure the whole input image is
2219 made visible in the output image on the virtual canvas. </td>
2220
2221 </tr>
2222
2223 <tr valign="top">
2224 <td valign="top"><kbd>DePolar</kbd></td>
2225 <td valign="top">
2226 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2227 but generates the reverse Polar to Cartesian distortion. <br/>
2228
2229 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2230 the corners of the input image. However using the special
2231 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2232 distance) will ensure the whole distorted image is preserved in the
2233 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2234 reverse the distortion re-producing the original.
2235
2236 Note that as this distortion requires the area resampling of a circular
2237 arc, which can not be handled by the builtin EWA resampling function.
2238 As such the normal EWA filters are turned off. It is recomended some
2239 form of 'super-sampling' image processing technique be used to produce
2240 a high quality result. </td>
2241
2242 </tr>
2243
2244 <tr valign="top">
2245 <td valign="top"><kbd>Barrel</kbd></td>
2246 <td valign="top">
2247 Given the four coefficients (A,B,C,D) as defined by <a
2248 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2249 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2250 correct radial lens distortions. That is in photographs, make straight
2251 lines straight again. <br/>
2252
2253 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2254 <em>X</em> , <em>Y</em> ] ] <br/>
2255 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2256 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2257 [ <em>X</em> , <em>Y</em> ] <br/>
2258 So that it forms the function <br/>
2259 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2260 <em>C</em>*r + <em>D</em> )<br/>
2261
2262 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2263 (defaulting to the center of the image). <br/>
2264 The second form is typically used to distort images, rather than
2265 correct lens distortions. <br/>
2266 </td>
2267
2268 </tr>
2269
2270 <tr valign="top">
2271 <td valign="top"><kbd>BarrelInverse</kbd></td>
2272 <td valign="top">
2273 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2274 arguments, and argument handling. However it uses the inverse
2275 of the radial polynomial,
2276 so that it forms the function <br/>
2277 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2278 <em>C</em>*r + <em>D</em> )
2279 </td>
2280 </tr>
2281
2282 <tr valign="top">
2283 <td valign="top"><kbd>Shepards</kbd></td>
2284 <td valign="top">
2285 Distort the given list control points (any number) using an Inverse
2286 Squared Distance Interpolation Method (<a
2287 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2288 >Shepards Method</a>). The control points in effect do 'localized'
2289 distortions of the image around the given control point. For best
2290 results extra control points should be added to 'lock' the positions of
2291 the corners and other unchanging parts of the image. <br/>
2292
2293 The distortion has been likened to 'taffy pulling' using nails, pins or
2294 sticks. It basically uses the <a href="#sparse-color"
2295 >-sparse-color</a> method of the same name to generate separate X and Y
2296 displacement maps (see <a href="#displace" >-displace</a>) for source
2297 image color look-up. </td>
2298
2299 </tr>
2300
2301</table>
2302
2303<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2304
2305<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2306'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2307defining how these points in the given image should be distorted in the
2308destination image. Each set of four floating point values represent a source
2309image coordinate, followed immediately by the destination image coordinate.
2310This produces a list of values such as...</p>
2311<div style="text-align: center"><em>
2312 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2313 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2314 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2315 ... &nbsp;
2316 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2317</em></div>
2318<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2319destination image. </p>
2320
2321<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2322needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2323perspective distortion of the built-in "rose:" image. Note how spaces were
2324used to group the 4 sets of coordinate pairs, to make it easier to read and
2325understand.</p>
2326
2327<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2328 convert rose: -virtual-pixel black \ <br/>
2329 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2330 rose_3d_rotated.gif</span></p>
2331<p>If more that the required number of coordinate pairs are given for a
2332distortion, the distortion method is 'least squares' fitted to
2333produce the best result for all the coordinate pairs given. If less than the
2334ideal number of points are given, the distort will generally fall back to a
2335simpler form of distortion that can handles the smaller number of coordinates
2336(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2337
2338<p>By using more coodinates you can make use of image registration tool to
2339find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2340of the distortion. Of course a bad coordinate pair can also make the 'fit'
2341worse. Caution is always advised. </p>
2342
2343<p>Colors are acquired from the source image according to the <a
2344href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2345magnified. However if the viewed image is minified (image becomes smaller), a
2346special area resampling function (added ImageMagick v6.3.5-9), is used to
2347produce a higher quality image. For example you can use a
2348'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2349way to the horizon. </p>
2350
2351<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2352 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2353 checks_tiled.jpg</span></p>
2354<p>Note that a infinitely tiled perspective images involving the horizon can
2355be very slow to generate due to the use of the high quality 'area resampling'
2356function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2357using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2358(recommended if you plan to use super-sampling instead). </p>
2359
2360<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2361'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2362will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2363pixels. If you do not what these pixels to be visible, set the color to match
2364the rest of the ground. </p>
2365
2366<p>The output image size will by default be the same as the input image. This
2367means that if the part of the distorted image falls outside the viewed area of
2368the 'distorted space', those parts is clipped and lost. However if you
2369use the plus form of the operator (<a href="#distort" >+distort</a>) the
2370operator will attempt (if posible) to show the whole of the distorted image,
2371while retaining a correct 'virtual canvas' offset, for image layering. This
2372offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2373if it is unwanted. </p>
2374
2375<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2376option:distort:viewport {geometry_string}</kbd>" setting which will specify
2377the size and the offset of the generated 'viewport' image of the distorted
2378image space.</p>
2379
2380<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2381{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2382that factor without changing the viewed contents of the distorted image. This
2383can be used either for 'super-sampling' the image for a higher quality result,
2384or for panning and zooming around the image (with appropriate viewport
2385changes, or post-distort cropping and resizing). </p>
2386
2387<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2388href="#distort" >-distort</a> to attempt to output the internal coefficients,
2389and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2390and debugging purposes. This many not be available for all distorts. </p>
2391
2392<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2393produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2394and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2395above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2396</p>
2397
2398
2399<div style="margin: auto;">
2400 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2401</div>
2402
2403<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>
2404
2405<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>
2406
2407<p>Dithering is turned on by default, to turn it off use the plus form of the
2408setting, <a href="#dither">+dither</a>. This will also also render PostScript
2409without text or graphic aliasing. Disabling dithering often (but not always)
2410leads to faster process, a smaller number of colors, but more cartoon like
2411image coloring. Generally resulting in 'color banding' effects in areas with
2412color gradients. </p>
2413
2414<p>The color reduction operators <a href="#colors">-colors</a>, <a
2415href="#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>
2416
2417<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>
2418
2419
2420<div style="margin: auto;">
2421 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2422</div>
2423
2424<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>
2425
2426<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>
2427
2428<p>The shape primitives:</p>
2429
2430<pre class="text">
2431 point x,y
2432 line x0,y0 x1,y1
2433 rectangle x0,y0 x1,y1
2434 roundRectangle x0,y0 x1,y1 wc,hc
2435 arc x0,y0 x1,y1 a0,a1
2436 ellipse x0,y0 rx,ry a0,a1
2437 circle x0,y0 x1,y1
2438 polyline x0,y0 ... xn,yn
2439 polygon x0,y0 ... xn,yn
2440 bezier x0,y0 ... xn,yn
2441 path path specification
2442 image operator x0,y0 w,h filename
2443</pre>
2444
2445<p>The text primitive:</p>
2446
2447<pre class="text">
2448 text x0,y0 string
2449</pre>
2450<p>The text gravity primitive:</p>
2451
2452<pre class="text">
2453 gravity NorthWest, North, NorthEast, West, Center,
2454 East, SouthWest, South, or SouthEast
2455</pre>
2456
2457<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>
2458
2459<p>The transformation primitives:</p>
2460
2461<pre class="text">
2462 rotate degrees
2463 translate dx,dy
2464 scale sx,sy
2465 skewX degrees
2466 skewY degrees
2467</pre>
2468
2469<p>The pixel operation primitives:</p>
2470
2471<pre class="text">
2472 color x0,y0 method
2473 matte x0,y0 method
2474</pre>
2475
2476<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>
2477
2478<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>
2479
2480<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2481
2482<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2483
2484<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>
2485
2486<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2487
2488<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>
2489
2490<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>
2491
2492<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>.
2493</p>
2494
2495<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2496
2497<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2498
2499<p class="crtsnip">
2500 -draw 'circle 100,100 150,150'
2501</p>
2502
2503<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
2504draw 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>
2505
2506<p class="crtsnip">
2507 -draw 'bezier 20,50 45,100 45,0 70,50'
2508</p>
2509<p class="crtsnip">
2510 -draw 'bezier 70,50 95,100 95,0 120,50'
2511</p>
2512
2513
2514<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>
2515
2516<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>
2517
2518<p class="crtsnip">
2519 -draw 'image SrcOver 100,100 225,225 image.jpg'
2520</p>
2521
2522<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>
2523
2524<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>
2525
2526<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2527
2528<p class="crtsnip">
2529 -draw 'text 100,100 "Works like magick!"'
2530</p>
2531
2532<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2533
2534<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>
2535
2536<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2537
2538<p>The <kbd>scale</kbd> primitive scales them.</p>
2539
2540<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>
2541
2542<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
2543matrix.</p>
2544
2545<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>
2546
2547<pre class="text">
2548 point
2549 replace
2550 floodfill
2551 filltoborder
2552 reset
2553</pre>
2554
2555<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>
2556
2557<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>
2558
2559<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>
2560
2561<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2562
2563<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2564
2565
2566<div style="margin: auto;">
2567 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2568</div>
2569
2570<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>
2571
2572<div style="margin: auto;">
2573 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2574</div>
2575
2576<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>
2577
2578<div style="margin: auto;">
2579 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2580</div>
2581
2582<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>
2583
2584<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2585
2586<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2587
2588<div style="margin: auto;">
2589 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2590</div>
2591
2592<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>
2593
2594<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>
2595
2596<div style="margin: auto;">
2597 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2598</div>
2599
2600<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>
2601
2602<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2603
2604<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2605
2606
2607<div style="margin: auto;">
2608 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2609</div>
2610
2611<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>
2612
2613
2614<div style="margin: auto;">
2615 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2616</div>
2617
2618<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>
2619
2620<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>
2621
2622<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2623
2624<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>
2625
2626<div style="margin: auto;">
2627 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2628</div>
2629
2630<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</td><td style='text-align:right;'></td></tr></table>
2631
2632<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>
2633
2634<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>
2635
2636<table class="doc">
2637 <col width="25%" />
2638 <col width="75%" />
2639 <thead>
2640 <tr>
2641 <th><em class="arg">operator</em></th>
2642 <th>Summary (see further below for details)</th>
2643 </tr>
2644 </thead>
2645 <tbody>
2646
2647 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2648 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2649 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2650 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2651 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2652 <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>
2653 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2654 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2655 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2656 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2657 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2658 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2659 <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>
2660 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2661 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2662 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2663 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2664
2665 <tr><td>&nbsp;</td></tr>
2666
2667 <tr><td>Gaussian-noise</td></tr>
2668 <tr><td>Impulse-noise</td></tr>
2669 <tr><td>Laplacian-noise</td></tr>
2670 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2671 <tr><td>PoissonNoise</td></tr>
2672 <tr><td>Uniform-noise</td></tr>
2673
2674 <tr><td>&nbsp;</td></tr>
2675
2676 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2677 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2678 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2679 </tbody>
2680 </table>
2681
2682<p>The specified functions are applied only to each previously set <a
2683href="#channel" >-channel</a> in the image. If necessary, the results of the
2684calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2685class="QR">QuantumRange</em>]. The transparency channel of the image is
2686represented as a 'alpha' values (0 = fully transparent), so, for example, a
2687<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2688semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2689as a percentage of the <em class="QR">QuantumRange</em>.</p>
2690
2691<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2692<a href="#list">-list evaluate</a>.</p>
2693
2694<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2695<kbd>Multiply</kbd> methods can also be achieved using either the <a
2696href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2697appropriate argument, to linearly modify the overall range of color values.
2698Please note, however, that <a href="#level" >-level</a> treats transparency as
2699'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2700'alpha' values.</p>
2701
2702<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>
2703
2704<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>
2705
2706 <div style="text-align:center;">
2707 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2708 </div>
2709
2710<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2711normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2712href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2713to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2714with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2715with <kbd>Pow</kbd>.</p>
2716
2717<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2718converts the image values into a value according to a (co)sine wave function.
2719The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2720is biased 50% and normalized by 50% so as to fit in the respective color value
2721range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2722function (its frequency), and thus determines the number of 'waves' that will
2723be generated over the input color range. For example, if the <em
2724class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2725class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2726then the effective period is the <em>half</em> the <em
2727class="QR">QuantumRange</em>.
2728
2729 <div style="text-align:center;">
2730 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2731 </div>
2732
2733See also the <a href="#function" >-function</a> operator, which is a
2734multi-value version of evaluate. </P>
2735
2736
2737<div style="margin: auto;">
2738 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2739</div>
2740
2741<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>
2742
2743<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>
2744
2745<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>
2746
2747<div style="margin: auto;">
2748 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2749</div>
2750
2751<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>
2752
2753<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2754
2755<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>
2756
2757<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>
2758<p>then the image will be <em>resized</em> to the specified dimensions instead,
2759equivalent to:</p>
2760
2761<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>
2762<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>
2763
2764<div style="margin: auto;">
2765 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2766</div>
2767
2768<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>
2769
2770<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).
2771</p>
2772
2773<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>.
2774</p>
2775
2776<div style="margin: auto;">
2777 <h4><a name="fft" id="fft"></a>-fft</h4>
2778</div>
2779
2780<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>
2781
2782<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>
2783
2784<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>
2785
2786<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>
2787
2788<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2789<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>
2790
2791<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2792<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>
2793
2794<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>
2795
2796<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>
2797
2798<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2799 -evaluate log 1000 fft_image_spectrum.png</span></p>
2800<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>
2801
2802<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2803
2804<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>
2805
2806<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>
2807
2808<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>
2809
2810<p>See the discussion on HDRI implementations of ImageMagick on the page
2811<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.
2812</p>
2813
2814
2815<div style="margin: auto;">
2816 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2817</div>
2818
2819<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>
2820
2821<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>
2822
2823<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2824
2825<p>For example,</p>
2826
2827<p class="crtsnip">
2828 -fill blue
2829</p>
2830<p class="crtsnip">
2831 -fill "#ddddff"
2832</p>
2833<p class="crtsnip">
2834 -fill "rgb(255,255,255)"
2835</p>
2836
2837<p>See <a href="#draw">-draw</a> for further details.</p>
2838
2839<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2840
2841<div style="margin: auto;">
2842 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2843</div>
2844
2845<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>
2846
2847<p>Use this option to affect the resizing operation of an image (see <a
2848href="#resize">-resize</a>). For example you can use a simple resize filter
2849such as:</p>
2850
2851<pre class="text">
2852 Point Hermite Cubic
2853 Box Gaussian Catrom
2854 Triangle Quadratic Mitchell
2855</pre>
2856
2857<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2858by default <kbd>blackman</kbd>-windowed. However these filters define a
2859windowing filter for the Sinc or Bessel filter function, as appropriate for
2860the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2861>-resize</a>). Windowed filters include: </p>
2862
2863<pre class="text">
2864 Lanczos Hamming Parzen
2865 Blackman Kaiser Welsh
2866 Hanning Bartlett Bohman
2867</pre>
2868
2869<p>Also one special self-windowing filter is also provided
2870<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2871on the current 'support' or 'lobes' expert settings (see below).</p>
2872
2873<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>
2874
2875<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2876
2877<p>You can modify how the filter behaves as it scales your image through the
2878use of these expert settings:</p>
2879
2880<dl class="doc">
2881<dt>-set filter:blur <em>factor</em></dt>
2882<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2883 blurry or &lt; 1.0 for sharp.</dd>
2884
2885<dt>-set filter:support <em>radius</em></dt>
2886<dd>Set the filter support radius.</dd>
2887
2888<dt>-set filter:lobes <em>count</em></dt>
2889<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2890 alternative way of specifying the 'support' range of the filter.</dd>
2891
2892<dt>-set filter:b <em>b-spline_factor</em></dt>
2893<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2894<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2895 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2896 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2897 are defined, the other is set so as to generate a 'Keys' type cubic
2898 filter.
2899
2900<dt>-set filter:filter <em>filter</em></dt>
2901<dd>Use this function directly as the scaling filter. This will allow
2902 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2903 rather than as its normal usage as a windowing function for 'Sinc' or
2904 'Bessel'. If defined, no windowing function is used, unless the following
2905 expert setting is also defined.</dd>
2906
2907<dt>-set filter:window <em>filter</em></dt>
2908<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2909 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2910 support range) with the given filter. This allows you to use a filter that
2911 is not normally used as a windowing function, such as <kbd>box</kbd>,
2912 (which effectivally turns off the windowing function). </dd>
2913
2914</dl>
2915
2916<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2917
2918<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2919 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2920 -resize 150% image.jpg</span></p>
2921<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2922
2923<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2924 -resize 150% image.jpg</span></p>
2925<p>Note that the use of expert options (except for 'blur' with simple resize
2926filters), are provided for image processing experts who have studied and
2927understood how resize filters work. Without this knowledge, and an
2928understanding of the defination of the actual filters involved, using expert
2929settings are more likely to be detremental to your image resizing.</p>
2930
2931
2932<div style="margin: auto;">
2933 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2934</div>
2935
2936<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>
2937
2938
2939<div style="margin: auto;">
2940 <h4><a name="flip" id="flip"></a>-flip</h4>
2941</div>
2942
2943<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>
2944
2945<p>reflect the scanlines in the vertical direction.</p>
2946
2947<div style="margin: auto;">
2948 <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>
2949</div>
2950
2951<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>
2952
2953<div style="margin: auto;">
2954 <h4><a name="flop" id="flop"></a>-flop</h4>
2955</div>
2956
2957<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>
2958
2959<p>reflect the scanlines in the horizontal direction.</p>
2960
2961
2962<div style="margin: auto;">
2963 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2964</div>
2965
2966<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>
2967
2968<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>
2969
2970<p>In addition to the fonts specified by the above pre-defined list, you can
2971also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2972is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2973<kbd>x:fixed</kbd> is X11 font.</p>
2974
2975<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>
2976
2977
2978<div style="margin: auto;">
2979 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2980</div>
2981
2982<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>
2983
2984<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2985
2986<p>The default foreground color is black.</p>
2987
2988<div style="margin: auto;">
2989 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2990</div>
2991
2992<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>
2993
2994<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>
2995
2996<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>
2997
2998<div style="margin: auto;">
2999 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
3000</div>
3001
3002<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>
3003
3004<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>
3005
3006<div style="margin: auto;">
3007 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
3008</div>
3009
3010<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>
3011
3012<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
3013
3014<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>
3015
3016
3017<div style="margin: auto;">
3018 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
3019</div>
3020
3021<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>
3022
3023<div style="margin: auto;">
3024 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
3025</div>
3026
3027<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>
3028
3029<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>
3030
3031<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>
3032
3033<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>
3034
3035<pre class="text">
3036 Polynomial
3037 Sinusoid
3038 Arcsin
3039 Arctan
3040</pre>
3041
3042<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
3043
3044<dl class="doc">
3045<dt><kbd>Polynomial</kbd></dt>
3046<dd>
3047<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>
3048
3049<div style="text-align: center">
3050 -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>
3051</div>
3052
3053<p>will invoke a polynomial function given by</p>
3054
3055<div style="text-align: center">
3056 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
3057 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
3058 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
3059</div>
3060
3061<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
3062
3063<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>
3064
3065<table class="doc">
3066 <col width="35%" />
3067 <col width="35%" />
3068 <col width="30%" />
3069 <tr>
3070 <td>-evaluate Set <em class="arg">value</em> </td>
3071 <td>-function Polynomial <em class="arg">value</em></td>
3072 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
3073 </tr>
3074 <tr>
3075 <td>-evaluate Add <em class="arg">value</em> </td>
3076 <td>-function Polynomial 1,<em class="arg">value</em></td>
3077 </tr>
3078 <tr>
3079 <td>-evaluate Subtract <em class="arg">value</em> </td>
3080 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
3081 </tr>
3082 <tr>
3083 <td>-evaluate Multiply <em class="arg">value</em> </td>
3084 <td>-function Polynomial <em class="arg">value</em>,0</td>
3085 </tr>
3086 <tr>
3087 <td>+level black% x white%</td>
3088 <td>-function Polynomial A,B</td>
3089 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3090 </tr>
3091</table>
3092
3093<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>
3094</dd>
3095
3096<dt><kbd>Sinusoid</kbd></dt>
3097<dd>
3098<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>
3099
3100<div style="text-align: center">
3101 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
3102</div>
3103
3104<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>
3105
3106<div style="text-align: center">
3107<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>
3108</div>
3109
3110<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>
3111
3112<p class="crtsnip">
3113 -function Sinusoid 3,-90,.2,.7
3114</p>
3115
3116<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>
3117
3118<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>
3119
3120<table class="doc">
3121 <tr>
3122 <td>-evaluate Sin <em class="arg">freq</em> </td>
3123 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
3124 </tr>
3125 <tr>
3126 <td>-evaluate Cos <em class="arg">freq</em> </td>
3127 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
3128 </tr>
3129</table>
3130</dd>
3131
3132<dt><kbd>ArcSin</kbd></dt>
3133<dd>
3134<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
3135and can be used to generate cylindrical distortion and displacement maps.
3136The curve can be adjusted relative to both the input values and output range
3137of values.
3138
3139<div style="text-align: center">
3140 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3141</div>
3142
3143<p>with all values given in terms of noramlize color values (0.0 for black,
31441.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3145for bout input (<em class="arg">width</em>), and output (<em
3146class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3147
3148<div style="text-align: center">
3149<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>
3150</div>
3151
3152</dd>
3153
3154<dt><kbd>ArcTan</kbd></dt>
3155<dd>
3156<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3157limit values at infinities, though a center using the given slope value.
3158All these values can be adjusted via the arguments.
3159
3160<div style="text-align: center">
3161 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3162</div>
3163
3164<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3165</p>
3166
3167<div style="text-align: center">
3168<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>
3169</div>
3170
3171</dd>
3172
3173</dl>
3174
3175
3176<div style="margin: auto;">
3177 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3178</div>
3179
3180<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>
3181
3182<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>
3183
3184<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>
3185
3186
3187<div style="margin: auto;">
3188 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3189</div>
3190
3191<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>
3192
3193<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>
3194
3195<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3196
3197
3198<div style="margin: auto;">
3199 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3200</div>
3201
3202<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>
3203
3204<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>
3205
3206<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>
3207
3208<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>
3209
3210<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>
3211
3212<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3213
3214<div style="margin: auto;">
3215 <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>
3216</div>
3217
3218<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>
3219
3220<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3221
3222<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3223</div>
3224
3225<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>
3226
3227<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3228full 2-dimentional convolution is used to generate the weighted average of the
3229neighbouring pixels. </p>
3230
3231<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3232pixels which are outside the image proper are blurred into the final result.
3233</p>
3234
3235
3236<div style="margin: auto;">
3237 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3238</div>
3239
3240<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>
3241
3242<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>
3243
3244<div style="margin: auto;">
3245 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3246</div>
3247
3248<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>
3249
3250<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3251<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3252<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3253list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3254installation.</p>
3255
3256<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>
3257
3258<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>
3259
3260<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>
3261
3262<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>
3263<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>
3264
3265<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>
3266
3267
3268<div style="margin: auto;">
3269 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3270</div>
3271
3272<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>
3273
3274
3275<div style="margin: auto;">
3276 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3277</div>
3278
3279<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>
3280
3281<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3282dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3283can apply any color transformation to the Hald image and then use this option
3284to apply the transform to the image. </p>
3285
3286<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3287<p>This option provides a convenient method for you to use Gimp or Photoshop
3288to make color corrections to the Hald CLUT image and subsequently apply them
3289to multiple images using an ImageMagick script. </p>
3290
3291<p>Note that the representation is only of the normal RGB color space and that
3292the whole color value triplet is used for the interpolated lookup of the
3293represented Hald color cube image. Because of this the operation is not <a
3294href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3295images transparency or alpha/matte channel.</p>
3296
3297<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3298of the individual color channels, usally involving a simplier gray-scale
3299image. E.g: gray-scale to color replacement, or modification by a histogram
3300mapping. </p>
3301
3302
3303<div style="margin: auto;">
3304 <h4><a name="help" id="help"></a>-help</h4>
3305</div>
3306
3307<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>
3308
3309<div style="margin: auto;">
3310 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3311</div>
3312
3313<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>
3314
3315<div style="margin: auto;">
3316 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3317</div>
3318
3319<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>
3320
3321<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>
3322
3323<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>
3324
3325<div style="margin: auto;">
3326 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3327</div>
3328
3329<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>
3330
3331<div style="margin: auto;">
3332 <h4><a name="identify" id="identify"></a>-identify</h4>
3333</div>
3334
3335<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>
3336
3337<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>
3338
3339<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>
3340
3341<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3342amounts of image properties are displayed including image statistics, profiles,
3343image histogram, and others.</p>
3344
3345<div style="margin: auto;">
3346 <h4><a name="ift" id="ift"></a>-ift</h4>
3347</div>
3348
3349<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>
3350
3351<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>
3352
3353<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>
3354
3355<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3356<p>or</p>
3357
3358<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>
3359
3360<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.
3361
3362<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3363
3364<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.
3365
3366<div style="margin: auto;">
3367 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3368</div>
3369
3370<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>
3371
3372<div style="margin: auto;">
3373 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3374</div>
3375
3376<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>
3377
3378<div style="margin: auto;">
3379 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3380</div>
3381
3382<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>
3383
3384<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>
3385
3386<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>
3387
3388<div style="margin: auto;">
3389 <h4><a name="intent" id="intent"></a>-intent <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%'>use this type of rendering intent when managing the image color.</td><td style='text-align:right;'></td></tr></table>
3393
3394<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>
3395
3396<p>The default intent is undefined.</p>
3397
3398<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3399
3400<div style="margin: auto;">
3401 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3402</div>
3403
3404<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>
3405
3406<p>Choose from:</p>
3407
3408<pre class="text">
3409 none
3410 line
3411 plane
3412 partition
3413 JPEG
3414 GIF
3415 PNG
3416</pre>
3417
3418<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>
3419
3420<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3421
3422<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3423
3424<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3425
3426<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3427image.G, and image.B).</p>
3428
3429<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>
3430image.</p>
3431
3432<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3433
3434<div style="margin: auto;">
3435 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3436</div>
3437
3438<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>
3439
3440<p>When looking up the color of a pixel using a non-interger floating point
3441value, you typically fall in between the pixel colors defined by the source
3442image. This setting determines how the color is determined from the colors of
3443the pixels surrounding that point. That is how to determine the color of a
3444point that falls between two, or even four different colored pixels. </p>
3445
3446<pre class="text">
3447 integer: The color of the top-left pixel (floor function)
3448 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3449 average: The average color of the surrounding four pixels
3450 bilinear A double linear interpolation of pixels (the default)
3451 mesh Divide area into two flat triangular interpolations
3452 bicubic Fitted bicubic-spines of surrounding 16 pixels
3453 spline Direct spline curves (colors are blurred)
3454 filter Use resize <a href="#filter">-filter</a> settings
3455</pre>
3456
3457<p>This most important for distortion operators such as <a href="#distort"
3458>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3459>-transform</a> and <a href="#fx" >-fx</a>. </p>
3460
3461<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3462
3463<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3464lookup for positions outside the boundaries of the image. </p>
3465
3466
3467<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003468 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <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 text lines.</td><td style='text-align:right;'></td></tr></table>
3472
3473<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003474 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3475</div>
3476
3477<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>
3478
3479<div style="margin: auto;">
3480 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3481</div>
3482
3483<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>
3484
3485<div style="margin: auto;">
3486 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3487</div>
3488
3489<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>
3490
3491<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>
3492
3493<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>
3494
3495<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>
3496
3497<p>For example,</p>
3498
3499<p class="crtsnip">
3500 -label "%m:%f %wx%h" bird.miff
3501</p>
3502
3503<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>
3504
3505<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>
3506
3507<p>The label font can be specified with <a href="#font">-font</a>, and the
3508other font attribute settings.</p>
3509
3510<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>
3511
3512
3513<div style="margin: auto;">
3514 <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>
3515</div>
3516
3517<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>
3518
3519<p>Adaptively threshold each pixel based on the value of pixels in a
3520surrounding window. If the current pixel is lighter than this average plus
3521the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3522black. Small variations in pixel values such as found in scanned documents
3523can be ignored if offset is positive. A negative offset will make it more
3524sensitive to those small variations. </p>
3525
3526<p>This is commonly used to threshold images with an uneven background. It is
3527based on the assumption that average color of the small window is the
3528the local background color, from which to separate the forground color. </p>
3529
3530
3531<div style="margin: auto;">
3532 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3533</div>
3534
3535<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>
3536
3537<p>Perform various image operation methods to a ordered sequence of images
3538which may represent either a set of overlaid 'image layers', a GIF disposal
3539animation, or a fully-'coalesced' animation sequence. </p>
3540
3541<table class="doc">
3542 <tbody>
3543 <tr valign="top">
3544 <th align="left" style="width: 8%">Method</th>
3545 <th align="left">Description</th>
3546 </tr>
3547
3548 <tr valign="top">
3549 <td valign="top">compare-any</td>
3550 <td valign="top">Crop the second and later frames to the smallest rectangle
3551 that contains all the differences between the two images. No GIF <a
3552 href="#dispose" >-dispose</a> methods are taken into account. </td>
3553 </tr>
3554
3555 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3556 >-deconstruct</a> operator, and does not preserve animations normal
3557 working, especially when animation used layer disposal methods such as
3558 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3559 </tr>
3560
3561 <tr valign="top">
3562 <td valign="top">compare-clear</td>
3563 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3564 opaque pixels which become transparent in the second frame. That is the
3565 smallest image needed to mask or erase pixels for the next frame. </td>
3566 </tr>
3567
3568 <tr valign="top">
3569 <td valign="top">compare-overlay</td>
3570 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3571 extra color to the next image, as a result of overlaying color pixels.
3572 That is the smallest single overlaid image to add or change colors. </td>
3573 </tr>
3574
3575 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3576 composition method '<kbd>change-mask</kbd>', to reduce the image to
3577 just the pixels that need to be overlaid. </td>
3578 </tr>
3579
3580 <tr valign="top">
3581 <td valign="top">coalesce</td>
3582 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3583 >-coalesce</a> operator. Apply the layer disposal methods set in the
3584 current image sequence to form a fully defined animation sequence, as
3585 it should be displayed. Effectively converting a GIF animation into a
3586 'film strip'-like animation. </td>
3587 </tr>
3588
3589 <tr valign="top">
3590 <td valign="top">composite</td>
3591 <td valign="top">Alpha Composition of two image lists, separated by a
3592 "<kbd>null:</kbd>" image, with the destination image list first, and
3593 the source images last. An image from each list are composited
3594 together until one list is finished. The separator image and source
3595 image lists are removed. </td>
3596 </tr>
3597
3598
3599 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3600 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3601 size of the first image in each list. Unlike a normal <a
3602 href="#composite" >-composite</a> operation, the canvas offset is also
3603 added to the final composite positioning of each image. </td>
3604 </tr>
3605
3606 <tr><td></td><td>If one of the image lists only contains one image, that image is
3607 applied to all the images in the other image list, regardless of which
3608 list it is. In this case it is the image meta-data of the list which
3609 preserved. </td>
3610 </tr>
3611
3612
3613 <tr valign="top">
3614 <td valign="top">dispose</td>
3615 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3616 the animation after the layer disposal method has been applied, before
3617 the next sub-frame image is overlaid. That is the 'dispose' image that
3618 results from the application of the GIF <a href="#dispose"
3619 >-dispose</a> method. This allows you to check what
3620 is going wrong with a particular animation you may be developing.
3621 </td>
3622 </tr>
3623
3624 <tr valign="top">
3625 <td valign="top">flatten</td>
3626 <td valign="top">Create a canvas the size of the first images virtual
3627 canvas using the current <a href="#background" >-background</a> color,
3628 and <a href="#compose" >-compose</a> each image in turn onto that
3629 canvas. Images falling outside that canvas is clipped. Final
3630 image will have a zero virtual canvas offset. </td>
3631 </tr>
3632
3633 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3634 overlaying all the prepared image layers into a final image. </td>
3635 </tr>
3636
3637 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3638 canvas with real pixels, or to underlay a opaque color to remove
3639 transparency from an image.</td>
3640 </tr>
3641
3642
3643 <tr valign="top">
3644 <td valign="top">merge</td>
3645 <td valign="top">As 'flatten' method but merging all the given image
3646 layers into a new layer image just large enough to hold all the image
3647 without clipping or extra space. The new images virtual offset will
3648 prevere the position of the new layer, even if this offset is
3649 negative. the virtual canvas size of the first image is preserved.
3650 </td>
3651 </tr>
3652
3653 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3654 as few image file formats handle them correctly. </td>
3655 </tr>
3656
3657 <tr valign="top">
3658 <td valign="top">mosaic</td>
3659 <td valign="top">As 'flatten' method but expanding the initial canvas size
3660 of the first image so as to hold all the image layers. However as a
3661 virtual canvas is 'locked' to the origin, by defination, image layers
3662 with a negative offsets will still be clipped by the top and left
3663 edges.</td>
3664 </tr>
3665
3666 <tr><td></td><td>This method is commonly used to layout individual image using various
3667 offset but without knowning the final canvas size. The resulting image
3668 will, like 'flatten' not have any virtual offset, so can be saved to
3669 any image file format. </td>
3670 </tr>
3671
3672
3673 <tr valign="top">
3674 <td valign="top">optimize</td>
3675 <td valign="top">Optimize a coalesced animation, into GIF animation using
3676 a number of general techniques. This currently a short cut to
3677 apply both the '<kbd>optimize-frame</kbd>', and
3678 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3679 include other optimization methods as they are developed. </td>
3680 </tr>
3681
3682 <tr valign="top">
3683 <td valign="top">optimize-frame</td>
3684 <td valign="top">Optimize a coalesced animation, into GIF animation by
3685 reducing the number of pixels per frame as much as possible by
3686 attempting to pick the best layer disposal method to use, while ensuring
3687 the result will continue to animate properly. </td>
3688 </tr>
3689
3690 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3691 then no reasonably fast GIF optimization algorithm can do this.
3692 However this does seem to do better than most other GIF frame
3693 optimizers seen. </td>
3694 </tr>
3695
3696 <tr valign="top">
3697 <td valign="top">optimize-plus</td>
3698 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3699 overall optimization by adding extra frames to the animation, without
3700 changing the final look or timing of the animation. The frames are
3701 added to attempt to separate the clearing of pixels from the
3702 overlaying of new additional pixels from one animation frame to the
3703 next. If this does not improve the optimization (for the next frame
3704 only), it will fall back to the results of the previous normal
3705 '<kbd>optimize-frame</kbd>' technique. </td>
3706 </tr>
3707
3708 <tr><td></td><td>There is the possibility that the change in the disposal style will
3709 result in a worsening in the optimization of later frames, though this
3710 is unlikely. In other words there no guarantee that it is better than
3711 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3712 however you can get a vast improvment in the final animation size. </td>
3713 </tr>
3714
3715 <tr valign="top">
3716 <td valign="top">optimize-transparency</td>
3717 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3718 overlay images with transparency, if it does not change the resulting
3719 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3720 </td>
3721 </tr>
3722
3723 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3724 into a smaller file size due to larger areas of one (transparent)
3725 color rather than a pattern of multiple colors repeating the current
3726 disposed image of the last frame. </td>
3727 </tr>
3728
3729 <tr valign="top">
3730 <td valign="top">remove-dups</td>
3731 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3732 images, so as to simplify layer overlays of coalesced animations.
3733 </td>
3734 </tr>
3735
3736 <tr><td></td><td>Usually this a result of using a constant time delay across the
3737 whole animation, or after a larger animation was split into smaller
3738 sub-animations. The duplicate frames could also have been used as
3739 part of some frame optimization methods. </td>
3740 </tr>
3741
3742 <tr valign="top">
3743 <td valign="top">remove-zero</td>
3744 <td valign="top">Remove any image with a zero time delay, unless ALL the
3745 images have a zero time delay (and is not a proper timed animation, a
3746 warning is then issued). </td>
3747 </tr>
3748
3749 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3750 partial intermediary updates between the frames that are actually
3751 displayed to users. These frames are usally added for improved frame
3752 optimization in GIF animations. </td>
3753 </tr>
3754
3755 <tr valign="top">
3756 <td valign="top">trim-bounds</td>
3757 <td valign="top">Find the bounds of all the images in the current
3758 image sequence, then adjust the offsets so all images are contained on
3759 a minimal positive canvas. None of the image data is modified, only
3760 there virtual canvas size and offset. The all the image is given
3761 the same canvas size, and and will have a positive offset, but will
3762 remain in the same position relative to each other. As a result of the
3763 minimal canvas size at least one image will touch every edge of that
3764 canvas. The image data however may be transparent.
3765 </td>
3766 </tr>
3767
3768 </tbody>
3769</table>
3770
3771<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3772
3773<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3774>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3775>-mosaic</a> are only aliases for the above methods. Also see <a
3776href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3777href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3778>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3779
3780
3781<div style="margin: auto;">
3782 <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>
3783</div>
3784
3785<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>
3786
3787<p>Given one, two or three values delimited with commas: black-point,
3788white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3789white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3790point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3791contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3792both black and white points are percentages of the full color range. Gamma
3793will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3794omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3795
3796<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3797the given '<kbd>black_point</kbd>' value in the original image is set to
3798zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3799<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3800to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3801adjusted. </p>
3802
3803<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3804adding the special '!' flag anywhere in the argument list, will cause the
3805operator to do the reverse of the level adjustment. That is a zero, or
3806<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3807adjusted to the given level values, allowing you to de-contrast, or compress
3808the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3809
3810<p>Only the channels defined by the current <a href="#channel">-channel</a>
3811setting are adjusted (defaults to RGB color channels only), allowing you to
3812limit the effect of this operator. </p>
3813
3814<p>Please note that the transparency channel is treated as 'matte'
3815values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3816
3817
3818<div style="margin: auto;">
3819 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3820 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3821</div>
3822
3823<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>
3824
3825<p>This function is exactly like <a href="#level">-level</a>, except that the
3826value value for each color channel is determined by the
3827'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3828described under the <a href="#fill">-fill</a> option). </p>
3829
3830<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3831is mapped to become 'black' and 'white' respectivally, with all the other
3832colors linearly adjusted (or clipped) to match that change. Each channel is
3833adjusted separatally using the channel values of the colors specified. </p>
3834
3835<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3836will map the image color 'black' and 'white' to the given colors
3837respectivally, resulting in a gradient (de-contrasting) tint of the image to
3838those colors. This can also be used to convert a plain gray-scale image into a
3839one using the gradient of colors specified. </p>
3840
3841<p>By supplying a single color with a comma separator either before or after
3842that color, will just replace the respective 'black' or 'white' point
3843respectivally. But if no comma separator is provided, the given color is
3844used for both the black and white color points, making the operator either
3845threshold the images around that color (- form) or set all colors to that
3846color (+ form). </p>
3847
3848
3849<div style="margin: auto;">
3850 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3851</div>
3852
3853<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>
3854
3855<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>
3856
3857<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>
3858
3859<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +00003860 -limit memory 32MiB -limit map 64MiB
cristy3ed852e2009-09-05 21:47:34 +00003861</p>
3862
3863<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3864
cristyd934d102009-10-10 12:55:13 +00003865<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
3866-----------------------------------------------------------------------
3867 768 3.8187GiB 2.864GiB 7.6375GiB 16EiB 2 unlimited</pre>
cristy3ed852e2009-09-05 21:47:34 +00003868</span></p>
3869<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>
3870
3871<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>
3872
3873<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>
3874
3875<p class="crtsnip">
3876-limit area 10mb
3877</p>
3878
3879<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>
3880
3881<p class="crtsnip">
3882-limit area 10mb -limit disk 500mb
3883</p>
3884
3885<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3886
3887<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>
3888
3889<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.
3890</p>
3891
3892<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.
3893</p>
3894
3895<div style="margin: auto;">
3896 <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>
3897</div>
3898
3899<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>
3900
cristyd934d102009-10-10 12:55:13 +00003901<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>,
3902and uses a 'histogram bin' to determine the range of color values that needs to
3903be stretched. However it then stretchs those colors using the <a
3904href="#level" >-level</a> operator.</p>
3905
3906<p>As such while the initial determination may have 'binning' round off
3907effects, the image colors are stretched mathematically, rather than using the
3908histogram bins. This makes the operator more accurate. </p>
3909
3910<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of
3911'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near
3912perfect stretch of the color range. </p>
3913
3914<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
3915normalization of mathematical images. </p>
3916
3917<p>This operator is under review for re-development. </p>
3918
3919
cristy3ed852e2009-09-05 21:47:34 +00003920<div style="margin: auto;">
3921 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3922</div>
3923
3924<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>
3925
3926<div style="margin: auto;">
3927 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3928</div>
3929
3930<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>
3931
3932<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>
3933
3934<div style="margin: auto;">
3935 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3936</div>
3937
3938<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>
3939
3940<pre class="text">
3941 coder
3942 color
3943 configure
3944 delegate
3945 font
3946 format
3947 list
3948 log
3949 magic
3950 module
3951 resource
3952 threshold
3953</pre>
3954
3955<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>
3956
3957<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3958<div style="margin: auto;">
3959 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3960</div>
3961
3962<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>
3963
3964<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3965
3966<p>You can display the following components by embedding special format characters:</p>
3967
3968<pre class="text">
3969 %d domain
3970 %e event
3971 %f function
3972 %l line
3973 %m module
3974 %p process ID
3975 %r real CPU time
3976 %t wall clock time
3977 %u user CPU time
3978 %% percent sign
3979 \n newline
3980 \r carriage return
3981</pre>
3982
3983<p>For example:</p>
3984
3985<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>
3986<p>The default behavior is to print all of the components.</p>
3987
3988<div style="margin: auto;">
3989 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3990</div>
3991
3992<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>
3993
3994<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>
3995
3996<div style="margin: auto;">
3997 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3998</div>
3999
4000<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>
4001
4002<div style="margin: auto;">
4003 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
4004</div>
4005
4006<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>
4007
4008
4009<div style="margin: auto;">
4010 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
4011</div>
4012
4013<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>
4014
4015<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
4016
4017<pre class="text">
4018 best
4019 default
4020 gray
4021 red
4022 green
4023 blue
4024</pre>
4025
4026<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>
4027
4028
4029<div style="margin: auto;">
4030 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
4031</div>
4032
4033<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>
4034
4035<p>Here are the valid components of a map:</p>
4036
4037<pre class="text">
4038 r red pixel component
4039 g green pixel component
4040 b blue pixel component
4041 a alpha pixel component (0 is transparent)
4042 o opacity pixel component (0 is opaque)
4043 i grayscale intensity pixel component
4044 c cyan pixel component
4045 m magenta pixel component
4046 y yellow pixel component
4047 k black pixel component
4048 p pad component (always 0)
4049</pre>
4050
4051<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>
4052
4053<div style="margin: auto;">
4054 <h4><a name="mask" id="mask"></a>-mask
4055<em class="arg">filename</em></h4>
4056</div>
4057
4058<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>
4059
4060<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
4061
4062<div style="margin: auto;">
4063 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
4064</div>
4065
4066<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>
4067
4068<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4069
4070<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
4071
4072<div style="margin: auto;">
4073 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
4074</div>
4075
4076<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>
4077
4078<div style="margin: auto;">
4079 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
4080</div>
4081
4082<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>
4083
4084<p>Choose from:</p>
4085
4086<pre class="text">
4087 AE absolute number of differnet pixels
4088 MAE mean absolute error (normalized), average channel error distance
4089 MEPP mean error per pixel (normalized mean error, normalized peak error)
4090 MSE mean error squared, average of the channel error squared
4091 PAE peak absolute (normalize peak absolute)
4092 PSNR peak signal to noise ratio
4093 RMSE root mean squared (normalized root mean squared)
4094</pre>
4095
4096<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
4097controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
4098only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
4099size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
4100'similar'. </p>
4101
4102<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
4103('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
4104normalized) from the single comparision run. </p>
4105
4106<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
4107
4108
4109<div style="margin: auto;">
4110 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
4111</div>
4112
4113<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>
4114
4115<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
4116
4117<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
4118argument for a list of <a href="#mode" >-mode</a> arguments available
4119in your ImageMagick installation.</p>
4120
4121
4122<div style="margin: auto;">
4123 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
4124</div>
4125
4126<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>
4127
4128<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
4129missing values are taken to mean 100.</p>
4130
4131<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
4132means pure black, 50 is half as bright, 200 is twice as bright. To invert its
4133meaning <a href="#negate">-negate</a> the image before and after. </p>
4134
4135<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>
4136
4137<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
4138shades to purple, and so on. A value of either 0 or 200 results in a complete
4139180 degree rotation of the image. Using a value of 300 is a 360 degree
4140rotation resulting in no change to the original image. </p>
4141
4142<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>
4143
4144<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>
4145
4146<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>
4147<div style="margin: auto;">
4148 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
4149</div>
4150
4151<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>
4152
4153
4154<div style="margin: auto;">
4155 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
4156</div>
4157
4158<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>
4159
4160
4161<div style="margin: auto;">
4162 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4163</div>
4164
4165<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>
4166
4167<p>Both the image pixels and size are linearly interpolated to give the
4168appearance of a meta-morphosis from one image to the next, over all the images
4169in the current image list. The added images are the equivalent of a <a
4170href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4171argument determine how many images to interpolate between each image. </p>
4172
4173
4174<div style="margin: auto;">
4175 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4176</div>
4177
4178<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>
4179
4180
4181<div style="margin: auto;">
4182 <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>
4183</div>
4184
4185<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>
4186
4187<p>Blur with the given radius, standard deviation (sigma), and angle. The
4188angle given is the angle toward which the image is blurred. That is the
4189direction people would consider the object is coming from. </p>
4190
4191<p>Note that the blur is not uniform distribution, giving the motion a
4192definate sense of direction of movement. </p>
4193
4194<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4195pixels which are outside the image proper are blurred into the final result.
4196</p>
4197
4198<div style="margin: auto;">
4199 <h4><a name="name" id="name"></a>-name</h4>
4200</div>
4201
4202<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>
4203<div style="margin: auto;">
4204 <h4><a name="negate" id="negate"></a>-negate</h4>
4205</div>
4206
4207<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>
4208
4209<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>
4210
4211<div style="margin: auto;">
4212 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4213 +noise <em class="arg">type</em></h4>
4214</div>
4215
4216<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>
4217
4218<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>
4219
4220<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>
4221
4222<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>
4223
4224<pre class="text">
4225Gaussian
4226Impulse
4227Laplacian
4228Multiplicative
4229Poisson
4230Random
4231Uniform
4232</pre>
4233
4234<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4235
cristy83543962009-10-16 19:04:28 +00004236<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos
4237the use of a controlling value to specify teh amount of noise that should be
4238added to an image. </p>
4239
cristy3ed852e2009-09-05 21:47:34 +00004240
4241<div style="margin: auto;">
4242 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4243</div>
4244
4245<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>
4246
cristyd934d102009-10-10 12:55:13 +00004247<p>The intensity values are stretched to cover the entire range of possible
4248values. While doing so, black-out at most <em>2%</em> of the pixels and
4249white-out at most <em>1%</em> of the pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00004250
cristyd934d102009-10-10 12:55:13 +00004251<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a>
4252is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>.
4253(Before this version, it was equivalent to <a href="#contrast-stretch"
4254>-contrast-stretch 2%x99%</a>).</p>
cristy3ed852e2009-09-05 21:47:34 +00004255
cristyd934d102009-10-10 12:55:13 +00004256<p>All the channels are normalized in concert by the came amount so as to
4257preserve color integrity, when the default <a href="#channel" >+channel</a>
4258setting is in use. Specifing any other <a href="#channel" >-channel</a>
4259setting will normalize the RGB channels independently.</p>
4260
4261<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details.
4262Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization
cristy83543962009-10-16 19:04:28 +00004263that is better suited to mathematically generated images. </p>
cristyd934d102009-10-10 12:55:13 +00004264
4265<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00004266
4267
4268<div style="margin: auto;">
4269 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4270</div>
4271
cristyd934d102009-10-10 12:55:13 +00004272<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
4273class="arg">threshold map</em> specified, and a uniform color map with the
4274given 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 +00004275
4276<p>You can choose from these standard threshold maps:</p>
4277
4278<pre class="text">
cristyd934d102009-10-10 12:55:13 +00004279 threshold
cristy3ed852e2009-09-05 21:47:34 +00004280 checks
4281 o2x2
4282 o3x3
4283 o4x4
4284 o8x8
4285 h4x4a
4286 h6x6a
4287 h8x8a
4288 h4x4o
4289 h6x6o
4290 h8x8o
4291 h16x16o
4292</pre>
4293
cristyd934d102009-10-10 12:55:13 +00004294<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the
4295'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or
4296'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither
4297pattern. Or you can define your own <em class="arg" >threshold map</em> in a
4298personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
cristy3ed852e2009-09-05 21:47:34 +00004299
cristyd934d102009-10-10 12:55:13 +00004300<p>To print a complete list of threshold, use the <a href="#list" >-list
4301threshold</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004302
cristyd934d102009-10-10 12:55:13 +00004303<p>It is recommended that the <a href="#map" >+map</a> operator be used after
4304applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of
cristy3ed852e2009-09-05 21:47:34 +00004305colors an animated image sequence, to less that 256 colors. This ensures that
4306a common or global color table is used when saving the result to a color
4307limited file format such as GIF. </p>
4308
cristyd934d102009-10-10 12:55:13 +00004309<p>Note that at this time the exact same threshold dithering map is used for
4310all color channels, no attempt is made to offset or rotate the map for
4311different channels is made, to create an offset printing effect. (possible
4312future expansion) </p>
cristy3ed852e2009-09-05 21:47:34 +00004313
4314
4315<div style="margin: auto;">
4316 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4317</div>
4318
4319<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>
4320
cristyd934d102009-10-10 12:55:13 +00004321<p>The <em class="arg" >color</em> argument is defined using the format
4322described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz"
4323>-fuzz</a> setting can be used to match and replace colors similar to the one
4324given.</p>
cristy3ed852e2009-09-05 21:47:34 +00004325
cristyd934d102009-10-10 12:55:13 +00004326<p>The <a href="#transparent" >-transparent</a> operator is exactly the same
4327as <a href="#opaque" >-opaque</a> but makes the matching color transparent,
cristy3ed852e2009-09-05 21:47:34 +00004328rather than the same as the current <a href="#fill">-fill</a> color. </p>
4329
cristyd934d102009-10-10 12:55:13 +00004330<p>Use <em class="arg" >+opaque</em> to paint any pixel that does not match
4331the target color.</p>
4332
4333
cristy3ed852e2009-09-05 21:47:34 +00004334
4335<div style="margin: auto;">
4336 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4337</div>
4338
4339<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>
4340
4341<p>Choose from these orientations:</p>
4342
4343<pre class="text">
4344 bottom-left
4345 bottom-right
4346 left-bottom
4347 left-top
4348 right-bottom
4349 right-top
4350 top-left
4351 top-right
4352 undefined
4353</pre>
4354
cristyd934d102009-10-10 12:55:13 +00004355<p>To print a complete list of orientations, use the <a href="#list" >-list
4356orientation</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004357
4358
4359<div style="margin: auto;">
4360 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4361 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4362 +page
4363 </h4>
4364</div>
4365
4366<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>
4367
4368<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>
4369
4370<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>
4371
4372<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>
4373<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4374<thead>
4375 <tr valign="top">
4376 <th align="center"><em class="arg">media</em></th>
4377 <th align="center"><em class="arg">width</em></th>
4378 <th align="center"><em class="arg">height</em></th>
4379 </tr>
4380</thead>
4381<tbody>
4382<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4383<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4384<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4385<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4386<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4387<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4388<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4389<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4390<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4391<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4392<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4393<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4394<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4395<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4396<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4397<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4398<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4399<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4400<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4401<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4402<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4403<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4404<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4405<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4406<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4407<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4408<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4409<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4410<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4411<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4412<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4413<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4414<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4415<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4416<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4417<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4418<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4419<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4420</tbody>
4421</table>
4422
4423
4424
4425
4426<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>
4427
4428<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>
4429
4430<p>The default page dimensions for a TEXT image is 612x792.</p>
4431
4432<p>This option is used in concert with <a href="#density">-density</a>.</p>
4433
4434<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4435
4436<div style="margin: auto;">
4437 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4438</div>
4439
4440<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>
4441
4442<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>
4443
4444<div style="margin: auto;">
4445 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4446
4447<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>
4448
4449<div style="margin: auto;">
4450 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4451</div>
4452
4453<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>
4454
4455<p>Pause for the specified number of seconds before repeating the animation.</p>
4456
4457<div style="margin: auto;">
4458 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4459</div>
4460
4461<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>
4462
4463<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4464
4465<div style="margin: auto;">
4466 <h4><a name="ping" id="ping"></a>-ping</h4>
4467</div>
4468
4469<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>
4470
4471<div style="margin: auto;">
4472 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4473</div>
4474
4475<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>
4476
4477<div style="margin: auto;">
4478 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4479</div>
4480
4481<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>
4482
4483<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4484
4485<div style="margin: auto;">
4486 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4487</div>
4488
4489<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>
4490
4491<div style="margin: auto;">
4492 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4493</div>
4494
4495<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>
4496
4497<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>
4498
4499<pre class="text">
4500 Rotate
4501 Shear
4502 Roll
4503 Hue
4504 Saturation
4505 Brightness
4506 Gamma
4507 Spiff
4508 Dull
4509 Grayscale
4510 Quantize
4511 Despeckle
4512 ReduceNoise
4513 Add Noise
4514 Sharpen
4515 Blur
4516 Threshold
4517 EdgeDetect
4518 Spread
4519 Shade
4520 Raise
4521 Segment
4522 Solarize
4523 Swirl
4524 Implode
4525 Wave
4526 OilPaint
4527 CharcoalDrawing
4528 JPEG
4529</pre>
4530
4531<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4532
4533<p>The default preview is <kbd>JPEG</kbd>.</p>
4534
4535<div style="margin: auto;">
4536 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4537</div>
4538
4539<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>
4540
4541<div style="margin: auto;">
4542 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4543</div>
4544
4545<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>
4546
4547<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>
4548
4549<div style="margin: auto;">
4550 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4551 +profile <em class="arg">profile_name</em></h4>
4552</div>
4553
4554<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>
4555
4556<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>
4557
4558<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>
4559
4560<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>
4561
4562<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>
4563
4564<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4565
4566<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4567<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>
4568
4569<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>
4570<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4571CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4572</p>
4573
4574<div style="margin: auto;">
4575 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4576</div>
4577
4578<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>
4579
4580<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>
4581
4582<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>
4583
4584<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>
4585
4586<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>
4587
4588<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4589
4590<pre class="text">
4591 0: none
4592 1: sub
4593 2: up
4594 3: average
4595 4: Paeth
4596</pre>
4597
4598<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>
4599
4600<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4601
4602<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>
4603
4604<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>
4605
4606<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4607
4608<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>
4609
4610<div style="margin: auto;">
4611 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4612</div>
4613
4614<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>
4615
4616<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4617
4618
4619<div style="margin: auto;">
4620 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4621</div>
4622
4623<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>
4624
4625<div style="margin: auto;">
4626 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4627</div>
4628
4629<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>
4630
4631<p>Note that this is actually a rotational blur rather than a radial and as
4632such actually mis-named. </p>
4633
4634<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4635pixels which are outside the image proper are blurred into the final result.
4636</p>
4637
4638
4639<div style="margin: auto;">
4640 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4641</div>
4642
4643<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>
4644
4645<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>.
4646</p>
4647
4648<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4649
4650<div style="margin: auto;">
4651 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4652</div>
4653
4654<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>
4655
4656<div style="margin: auto;">
4657 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4658</div>
4659
4660<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>
4661
4662<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.
4663</p>
4664
4665<div style="margin: auto;">
4666 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4667</div>
4668
4669<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>
4670
4671<div style="margin: auto;">
4672 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4673</div>
4674
4675<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>
4676
4677<div style="margin: auto;">
4678 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4679</div>
4680
4681<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>
4682
4683<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4684the given colors are dithered over the image as necessary, otherwise the closest
4685color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4686
4687<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4688images in the current image sequence, all the images will have the same color
4689table. That means that when saved to a file format such as GIF, it will use
4690that color table as a single common or global color table, for all the images,
4691without requiring extra local color tables. </p>
4692
4693<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4694sequence to use a common color map over all the images. This equivalent to
4695appending all the images together (without extra background colors) and color
4696reducing those images using <a href="#colors">-colors</a> with a 256 color
4697limit, then <a href="#remap">-remap</a> those colors over the original list of
4698images. This ensures all the images follow a single color map. </p>
4699
4700<p>If the number of colors over all the images is less than 256, then <a
4701href="#remap">+remap</a> should not perform any color reduction or dithering, as
4702no color changes are needed. In that case, its only effect is to force the use
4703of a global color table. This recommended after using either <a
4704href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4705reduce the number of colors in an animated image sequence. </p>
4706
4707<div style="margin: auto;">
4708 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4709</div>
4710
4711<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>
4712
4713<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>
4714
4715<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>
4716
4717<div style="margin: auto;">
4718 <h4><a name="remote" id="remote"></a>-remote</h4>
4719</div>
4720
4721<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>
4722
4723<p>The only command recognized is the name of an image file to load.</p>
4724
4725<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>
4726
4727<div style="margin: auto;">
4728 <h4><a name="render" id="render"></a>-render</h4>
4729</div>
4730
4731<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>
4732
4733<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>
4734
4735<div style="margin: auto;">
4736<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4737</div>
4738
4739<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>
4740
4741<p>This option is like <a href="#page">-page</a> but acts as an image operator
4742rather than a setting. You can separately set the canvas size or the offset
4743of the image on that canvas by only providing those components. </p>
4744
4745<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>
4746
4747<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4748offset to move the image relative to its previous position. This useful for
4749animation sequences. </p>
4750
4751<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4752recalculate the canvas size so the image (at its current offset) will appear
4753completely on that canvas (unless it has a negative offset).</p>
4754
4755<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4756canvas meta-data from the images. </p>
4757
4758<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4759directly assign virtual canvas meta-data. </p>
4760
4761
4762<div style="margin: auto;">
4763 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4764</div>
4765
4766<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>
4767
4768<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>
4769
4770<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>
4771
4772<div style="margin: auto;">
4773 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4774</div>
4775
4776<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>
4777
4778<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>
4779
4780<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>
4781
4782<div style="margin: auto;">
4783 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4784</div>
4785
4786<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>
4787
4788<div style="margin: auto;">
4789 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4790</div>
4791
4792<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>
4793
4794
4795<div style="margin: auto;">
4796 <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>
4797</div>
4798
4799<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>
4800
4801<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>
4802
4803
4804<div style="margin: auto;">
4805 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4806</div>
4807
4808<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>
4809
4810<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>
4811
4812<p>Empty triangles in the corners, left over from rotating the image, are
4813filled with the <kbd>background</kbd> color. </p>
4814
4815<p>See also the <a href="#distort">-distort</a> operator and specifically the
4816'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4817
4818
4819<div style="margin: auto;">
4820 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4821</div>
4822
4823<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>
4824
4825<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>
4826
4827<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>
4828
4829
4830<div style="margin: auto;">
4831 <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>
4832</div>
4833
4834<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>
4835
4836<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>
4837
4838<div style="margin: auto;">
4839 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4840</div>
4841
4842<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>
4843
4844<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>
4845
4846<div style="margin: auto;">
4847 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4848</div>
4849
4850<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>
4851
4852<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4853
4854<div style="margin: auto;">
4855 <h4><a name="screen" id="screen"></a>-screen</h4>
4856</div>
4857
4858<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>
4859
4860<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>
4861
4862<div style="margin: auto;">
4863 <h4><a name="seed" id="seed"></a>-seed</h4>
4864</div>
4865
4866<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>
4867
4868<div style="margin: auto;">
4869 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4870</div>
4871
4872<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>
4873
4874<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>
4875
4876<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>
4877
4878<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4879of the color clusters is returned.</p>
4880
4881
4882<div style="margin: auto;">
4883 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4884</div>
4885
4886<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>
4887
4888<div style="margin: auto;">
4889 <h4><a name="separate" id="separate"></a>-separate</h4>
4890</div>
4891
4892<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>
4893
4894<div style="margin: auto;">
4895 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4896</div>
4897
4898<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>
4899
4900<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4901
4902<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>
4903
4904<div style="margin: auto;">
4905 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4906</div>
4907
4908<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>
4909
4910<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>
4911
4912<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>
4913<p>The <a href="#repage">-repage</a> operator will also set the
4914'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4915separately set the virtual canvas's size and offset components, and also allows
4916relative offset changes, and automatic canvas size re-calculating. The above
4917<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4918virtual canvas (page) meta-data. </p>
4919
4920<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>
4921
4922<div style="margin: auto;">
4923 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4924</div>
4925
4926<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>
4927
4928<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>
4929
4930<div style="margin: auto;">
4931 <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>
4932</div>
4933
4934<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>
4935
4936<div style="margin: auto;">
4937 <h4><a name="shared-memory"
4938id="shared-memory"></a>-shared-memory</h4>
4939</div>
4940
4941<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>
4942
4943<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>
4944
4945<div style="margin: auto;">
4946 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4947</div>
4948
4949<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>
4950
4951<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4952
4953<div style="margin: auto;">
4954 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4955</div>
4956
4957<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>
4958
4959<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>
4960
4961<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>
4962
4963<div style="margin: auto;">
4964 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4965</div>
4966
4967<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>
4968
4969<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>
4970
4971<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>
4972
4973<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>
4974
4975<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>
4976
4977<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>
4978<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>
4979
4980<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4981<div style="margin: auto;">
4982 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4983</div>
4984
4985<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>
4986
4987<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>
4988
4989<div style="margin: auto;">
4990 <h4><a name="silent" id="silent"></a>-silent</h4>
4991</div>
4992
4993<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>
4994
4995<div style="margin: auto;">
4996 <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>
4997</div>
4998
4999<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>
5000
5001<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>
5002
5003<p>For Photo CD images, choose from these sizes:</p>
5004
5005<pre class="text">
5006 192x128
5007 384x256
5008 768x512
5009 1536x1024
5010 3072x2048
5011</pre>
5012
cristy3ed852e2009-09-05 21:47:34 +00005013<div style="margin: auto;">
5014 <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>
5015</div>
5016
5017<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>
5018
5019<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>
5020
5021<div style="margin: auto;">
5022 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
5023</div>
5024
5025<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>
5026
5027<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
5028
5029<div style="margin: auto;">
5030 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
5031</div>
5032
5033<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>
5034
5035<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
5036
5037<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
5038
5039<div style="margin: auto;">
5040 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
5041 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
5042</div>
5043
5044<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>
5045
5046
5047<table class="doc">
5048 <tbody>
5049 <tr valign="top">
5050 <th align="left" style="width: 8%">Method</th>
5051 <th align="left">Description</th>
5052 </tr>
5053
5054 <tr valign="top">
5055 <td valign="top">voronoi</td>
5056 <td valign="top">Simply map each pixel to the to nearest color point
5057 given. The result are polygonal 'cells' of solid color. </td>
5058 </tr>
5059
5060 <tr valign="top">
5061 <td valign="top">shepards</td>
5062 <td valign="top">Colors points basied on the ratio of inverse distance
5063 squared. Generating spots of color in a sea of the average of
5064 colors. </td>
5065 </tr>
5066
5067 <tr valign="top">
5068 <td valign="top">barycentric</td>
5069 <td valign="top">three point triangle of color given 3 points.
5070 Giving only 2 points will form a linear gradient between those points.
5071 Gradient is however not restricted to just the triangle or line. </td>
5072 </tr>
5073
5074 <tr valign="top">
5075 <td valign="top">bilinear</td>
5076 <td valign="top">Like barycentric but for 4 points. Less than 4 points
5077 fall back to barycentric. </td>
5078 </tr>
5079
5080 </tbody>
5081</table>
5082
5083<p>The points are placed according to the images location on the virtual
5084canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
5085offset), and do not actually have to exist on the given image, but may be
5086some point beyond the edge of the image. All points are floating point values.
5087</p>
5088
5089<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
5090modified, whcih means the matte/alpha transparency channel is not effected by
5091default. If enabled, the image also needs a the matte/alpha channel to be
5092enabled for this operator to effect an images transparency. This is typical
5093transparency handling for images. </p>
5094
5095<p>All the above methods when given a single point of color will replace all
5096the colors in the image with the color given, regardless of the point. This is
5097logical, and provides an alternative technique to recolor a image to some
5098default value. </p>
5099
5100
5101<div style="margin: auto;">
5102 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
5103</div>
5104
5105<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>
5106
5107<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>
5108
5109<div style="margin: auto;">
5110 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
5111</div>
5112
5113<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>
5114
5115<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>
5116
5117<div style="margin: auto;">
5118 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
5119</div>
5120
5121<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>
5122
5123<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>
5124
5125<div style="margin: auto;">
5126 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
5127</div>
5128
5129<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>
5130
5131<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>
5132
5133<div style="margin: auto;">
5134 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
5135</div>
5136
5137<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>
5138
5139<pre class="text">
5140 char store pixels as unsigned characters
5141 double store pixels as doubles
5142 float store pixels as floats
5143 integer store pixels as integers
5144 long store pixels as longs
5145 quantum store pixels in the native depth of your ImageMagick distribution
5146 short store pixels as unsigned shorts
5147</pre>
5148
5149<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
5150values range from 0 to the maximum value the storage type can support.</p>
5151
5152<div style="margin: auto;">
5153 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
5154</div>
5155
5156<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>
5157
5158<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>
5159
5160<pre class="text">
5161 Any
5162 Condensed
5163 Expanded
5164 ExtraCondensed
5165 ExtraExpanded
5166 Normal
5167 SemiCondensed
5168 SemiExpanded
5169 UltraCondensed
5170 UltraExpanded
5171</pre>
5172
5173<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
5174
5175<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>
5176
5177<div style="margin: auto;">
5178 <h4><a name="strip" id="strip"></a>-strip</h4>
5179</div>
5180
5181<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>
5182
5183<div style="margin: auto;">
5184 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
5185</div>
5186
5187<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when stroking a graphic primitive.</td><td style='text-align:right;'></td></tr></table>
5188
5189<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5190
5191<p>See <a href="#draw">-draw</a> for further details.</p>
5192
5193<div style="margin: auto;">
5194 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5195</div>
5196
5197<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>
5198
5199<p>See <a href="#draw">-draw</a> for further details.</p>
5200
5201<div style="margin: auto;">
5202 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5203</div>
5204
5205<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>
5206
5207<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>
5208
5209<pre class="text">
5210 Any
5211 Italic
5212 Normal
5213 Oblique
5214</pre>
5215
5216<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>
5217
5218<div style="margin: auto;">
5219 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5220</div>
5221
5222<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>
5223
5224<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>
5225
5226<div style="margin: auto;">
5227 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5228</div>
5229
5230<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>
5231
5232<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5233
5234<div style="margin: auto;">
5235 <h4><a name="taint" id="taint"></a>-taint</h4>
5236</div>
5237
5238<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>
5239
5240<div style="margin: auto;">
5241 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5242</div>
5243
5244<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>
5245
5246<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>
5247
5248<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>
5249
5250<div style="margin: auto;">
5251 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5252</div>
5253
5254<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>
5255
5256<div style="margin: auto;">
5257 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5258</div>
5259
5260<!-- {<em class="arg">green,blue,opacity</em>}
5261<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>
5262-->
5263
5264<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>
5265
5266<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>
5267
5268<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.
5269</p>
5270
5271<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>
5272
5273<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5274<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>
5275
5276
5277<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>
5278<p>Note that the values of the transparency channel is treated as 'matte'
5279values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5280
5281<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>.
5282</p>
5283
5284<div style="margin: auto;">
5285 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <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%'>Create a thumbnail of the image.</td><td style='text-align:right;'></td></tr></table>
5289
5290<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>
5291
5292<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>
5293
5294<div style="margin: auto;">
5295 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5296</div>
5297
5298<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>
5299
5300<div style="margin: auto;">
5301 <h4>-tile <em class="arg">geometry</em></h4>
5302</div>
5303
5304<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>
5305
5306<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>
5307
5308<div style="margin: auto;">
5309 <h4>-tile</h4>
5310</div>
5311
5312<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>
5313
5314<div style="margin: auto;">
5315 <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>
5316</div>
5317
5318<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>
5319
5320<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>
5321
5322<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>
5323
5324<div style="margin: auto;">
5325 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5326</div>
5327
5328<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>
5329
5330<p>Tint the image with the fill color.</p>
5331
5332<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>
5333
5334<div style="margin: auto;">
5335 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5336</div>
5337
5338<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>
5339
5340<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>
5341
5342<p>For example,</p>
5343
5344<p class="crtsnip">
5345 -title "%m:%f %wx%h"
5346</p>
5347
5348<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>
5349
5350
5351<div style="margin: auto;">
5352 <h4><a name="transform" id="transform"></a>-transform</h4>
5353</div>
5354
5355<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>
5356
5357<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5358
5359<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>
5360<div style="margin: auto;">
5361 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5362</div>
5363
5364<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>
5365
5366<p>The <em class="arg">color</em> argument is defined using the format
5367described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5368>-fuzz</a> setting can be used to match and replace colors similar to the one
5369given. </p>
5370
5371<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5372href="#transparent" >-transparent</a> but replaces the matching color same as
5373the current <a href="#fill">-fill</a> color setting. </p>
5374
5375<p>This does not define the 'transparency color' used for color-mapped image
5376formats, such as GIF. For that use <a href="#transparent-color"
5377>-transparent-color</a> </p>
5378
5379<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5380paint any pixel that does not match the target color, with the fill color.</p>
5381
5382
5383<div style="margin: auto;">
5384 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5385</div>
5386
5387<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>
5388
5389<p>Sometimes this is used for saving to image formats such as
5390GIF and PNG8 which uses this color to represent boolean transparency. This
5391does not make a color transparent, it only defines what color the transparent
5392color is in the color palette of the saved image. Use <a
5393href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5394
5395<p>This option allows you to have both an opaque visible color, as well as a
5396transparent color of the same color value without conflict. That is, you can
5397use the same color for both the transparent and opaque color areas within an
5398image. This, in turn, frees to you to select a transparent color that is
5399appropriate when an image is displayed by an application that does not handle a
5400transparent color index, while allowing ImageMagick to correctly handle images of this
5401type. </p>
5402
5403<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5404
5405<div style="margin: auto;">
5406 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5407</div>
5408
5409<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>
5410
5411<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5412</p>
5413
5414<div style="margin: auto;">
5415 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5416</div>
5417
5418<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>
5419
5420
5421<div style="margin: auto;">
5422 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5423</div>
5424
5425<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>
5426
5427<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>
5428
5429<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>
5430
5431<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>
5432
5433<div style="margin: auto;">
5434 <h4><a name="trim" id="trim"></a>-trim</h4>
5435</div>
5436
5437<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>
5438
5439<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>
5440
5441<p>The page or virtual canvas information of the image is preserved allowing
5442you to extract the result of the <a href="#trim">-trim</a> operation from the
5443image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5444information if it is unwanted.</p>
5445
5446<p>If the trimmed image 'disappears' an warning is produced, and a special
5447single pixel transparent 'missed' image is returned, in the same way as when a
5448<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5449
5450
5451<div style="margin: auto;">
5452 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5453</div>
5454
5455<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>
5456 <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>
5457
5458<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>
5459
5460<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5461<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>
5462
5463<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5464
5465<div style="margin: auto;">
5466 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5467</div>
5468
5469<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>
5470
5471<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5472
5473<p>See <a href="#draw">-draw</a> for further details.</p>
5474
5475
5476<div style="margin: auto;">
5477 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5478</div>
5479
5480<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>
5481
5482<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>
5483
5484
5485<div style="margin: auto;">
5486 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5487</div>
5488
5489<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>
5490
5491
5492<div style="margin: auto;">
5493 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5494</div>
5495
5496<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>
5497
5498<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>
5499
5500
5501<div style="margin: auto;">
5502 <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>
5503</div>
5504
5505<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>
5506
5507<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>
5508
5509<p>The parameters are:</p>
5510
5511<pre class="text">
5512 radius: The radius of the Gaussian, in pixels, not counting the center
5513 pixel (default 0).
5514 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5515 amount: The fraction of the difference between the original and the blur
5516 image that is added back into the original (default 1.0).
5517 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5518 difference amount (default 0.05).
5519</pre>
5520
5521
5522<div style="margin: auto;">
5523 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5524</div>
5525
5526<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>
5527
5528
5529<div style="margin: auto;">
5530 <h4><a name="version" id="version"></a>-version</h4>
5531</div>
5532
5533<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>
5534
5535
5536<div style="margin: auto;">
5537 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5538</div>
5539
5540<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>
5541
5542
5543<div style="margin: auto;">
5544 <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>
5545</div>
5546
5547<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>
5548
5549
5550<div style="margin: auto;">
5551 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5552</div>
5553
5554<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>
5555
5556<p>This option defines what color source should be used if and when a color
5557lookup completely 'misses' the source image. The color(s) that appear to
5558surround the source image. Generally this color is derived from the source
5559image, but could also be set to a specify background color. </p>
5560
5561<p>Choose from these methods:</p>
5562
5563<pre class="text">
5564 background: the area surrounding the image is the background color
5565 black: the area surrounding the image is black
5566 checker-tile: alternate squares with image and background color
5567 dither: non-random 32x32 dithered pattern
5568 edge: extend the edge pixel toward infinity
5569 gray: the area surrounding the image is gray
5570 horizontal-tile: horizontally tile the image, background color above/below
5571 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5572 mirror: mirror tile the image
5573 random: choose a random pixel from the image
5574 tile: tile the image (default)
5575 transparent: the area surrounding the image is transparent blackness
5576 vertical-tile: vertically tile the image, sides are background color
5577 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5578 white: the area surrounding the image is white
5579</pre>
5580
5581<p>The default value is "edge".</p>
5582
5583<p>This most important for distortion operators such as <a href="#distort"
5584>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5585However it also effects operations that may access pixels just outside the
5586image proper, such as <a href="#convolve">-convolve</a>, <a
5587href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5588
5589<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5590
5591
5592<div style="margin: auto;">
5593 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5594</div>
5595
5596<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>
5597
5598<p>Choose from these visual classes:</p>
5599
5600<pre class="text">
5601 StaticGray
5602 GrayScale
5603 StaticColor
5604 PseudoColor
5605 TrueColor
5606 DirectColor
5607 default
5608 visual id
5609</pre>
5610
5611<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>
5612
5613
5614<div style="margin: auto;">
5615 <h4><a name="watermark" id="watermark"></a>-watermark <em
5616 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5617</div>
5618
5619<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
5620saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5621
5622<p>Take a grayscale image (with alpha mask) and modify the destination image's
5623brightness according to watermark image's grayscale value and the <em
5624class="arg">brightness</em> percentage. The destinations color saturation
5625attribute is just direct modified by the <em class="arg">saturation</em>
5626percentage, which defaults to 100 percent (no color change). </p>
5627
5628
5629<div style="margin: auto;">
5630 <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>
5631</div>
5632
5633<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>
5634
5635<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5636
5637<div style="margin: auto;">
5638 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5639</div>
5640
5641<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>
5642
5643<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>
5644
5645<table class="doc">
5646 <col width="25%" />
5647 <col width="75%" />
5648 <thead>
5649 <tr>
5650 <th><em class="arg">fontWeight</em></th>
5651 <th>Description</th>
5652 </tr>
5653 </thead>
5654 <tbody>
5655 <tr><td>All </td> <td>No effect. </td></tr>
5656 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5657 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5658 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5659 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5660 </tbody>
5661 </table>
5662
5663<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5664
5665<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>
5666
5667<div style="margin: auto;">
5668 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5669</div>
5670
5671<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>
5672
5673<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005674 <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 +00005675</div>
5676
cristy5cadd612009-09-21 19:33:41 +00005677<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>
5678
5679<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.
5680</p>
cristy3ed852e2009-09-05 21:47:34 +00005681
5682<div style="margin: auto;">
5683 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5684</div>
5685
5686<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>
5687
5688<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>
5689
5690<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>
5691
5692<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>
5693
5694<div style="margin: auto;">
5695 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5696</div>
5697
5698<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>
5699
5700<div style="margin: auto;">
5701 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5702</div>
5703
5704<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>
5705 <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>
5706
5707<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5708
cristyf3bb4782009-09-08 13:10:04 +00005709
5710</div>
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cristy83543962009-10-16 19:04:28 +00005717 <a href="http://studio.webbyland.com/ImageMagick/MagickStudio/scripts/MagickStudio.cgi">Studio</a>
cristyf3bb4782009-09-08 13:10:04 +00005718 </span>
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5723 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
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