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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
cristy739df912009-10-24 16:10:18 +00001754<p>It might be necessary to <a href="#repage" >+repage</a> the image prior to cropping the image to ensure the crop coordinate frame is relocated to the upper-left corner of the visible image.</p>
cristy3ed852e2009-09-05 21:47:34 +00001755
1756<div style="margin: auto;">
1757 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1758</div>
1759
1760<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>
1761
1762<p><em class="arg">Amount</em> defines the number of positions each
1763colormap entry is shifted.</p>
1764
1765
1766<div style="margin: auto;">
1767 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1768</div>
1769
1770<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>
1771
1772<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>
1773
1774
1775<p>For example, to log cache and blob events, use.</p>
1776
1777<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1778<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1779
1780<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1781
1782<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1783
1784<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1785
1786<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>
1787
1788
1789<div style="margin: auto;">
1790 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1791</div>
1792
1793<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>
1794
1795<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1796
1797<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1798
1799
1800<div style="margin: auto;">
1801 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1802</div>
1803
1804<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>
1805
1806<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>
1807
1808<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>
1809
1810<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1811
1812
1813<div style="margin: auto;">
1814 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1815</div>
1816
1817<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>
1818
1819<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>
1820
1821<p>The following definitions may be created:</p>
1822
1823<ul>
cristy48dd1af2009-10-02 01:21:56 +00001824<dt>jpeg:size=geometry</dt>
1825 <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 +00001826<dt>jp2:rate=value</dt>
1827 <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 />
1828<dt>mng:need-cacheoff</dt>
1829 <dd>turn playback caching off for streaming MNG.</dd><br />
1830<dt>png:bit-depth=value</dt>
1831<dt>png:color-type=value</dt>
1832 <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 />
1833<dt>ps:imagemask</dt>
1834 <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>
1835</ul>
1836
1837<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1838
1839<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1840<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>
1841
1842<p class="crtsnip">
1843-define registry:temporary-path=/data/tmp
1844</p>
1845
1846<div style="margin: auto;">
1847 <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>
1848</div>
1849
1850<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>
1851
1852<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>
1853
1854<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>
1855
1856
1857<div style="margin: auto;">
1858 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1859</div>
1860
1861<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>
1862
1863<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>
1864
1865
1866<div style="margin: auto;">
1867 <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>
1868</div>
1869
1870<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>
1871
1872<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>
1873
1874<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>
1875
1876<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>
1877
1878<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>
1879
1880<div style="margin: auto;">
1881 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1882</div>
1883
1884<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>
1885
1886<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>
1887
1888<div style="margin: auto;">
1889 <h4><a name="descend" id="descend"></a>-descend</h4>
1890</div>
1891
1892<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>
1893
1894<div style="margin: auto;">
1895 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1896</div>
1897
1898<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>
1899
1900<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>
1901
1902<div style="margin: auto;">
1903 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1904</div>
1905
1906<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>
1907
1908<div style="margin: auto;">
1909 <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>
1910</div>
1911
1912<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>
1913
1914<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1915will be used as a displacement map, which is used to displace the lookup of
1916what part of the 'background' image is seen at each point of the overlaid
1917area. Much like the displacement map is a 'lens' that redirects light shining
1918through it so as to present a distorted view the original 'background' image
1919behind it. </p>
1920
1921<p>Any perfect grey areas of the displacement map produce a zero
1922displacement of the image. Black areas produce the given maximum negative
1923displacement of the lookup point, while white produce a maximum positive
1924displacement of the lookup. </p>
1925
1926<p>Note that it is the lookup of the 'background' that is displaced, not a
1927displacement of the image itself. As such an area of the displacement map
1928containing 'white' will have the lookup point 'shifted' by a positive amount,
1929and thus generating a copy of the destination image to the right/downward from
1930the correct position. That is the image will look like it may have been
1931'shifted' in a negative left/upward direction. Understanding this is a very
1932important in understanding how displacement maps work. </p>
1933
1934<p>The given arguments define the maximum amount of displacement in pixels
1935that a particular map can produce. If the displacement scale is large enough
1936it is also posible to lookup parts of the 'background' image that lie well
1937outside the bounds of the displacement map itself. That is you could very
1938easilly copy a section of the original image from outside the overlay area
1939into the overlay area. </p>
1940
1941<p>The '%' flag makes the displacement scale relative to the size of the
1942overlay image (100% = half width/height of image). Using '!' switches
1943percentage arguments to refer to the destination image size instead.
1944these flags were added as of IM v6.5.3-5.</p>
1945
1946<p>Normally a single grayscale displacement map is provided, which with the
1947given scaling values will determine a single direction (vector) in which
1948displacements can occur (positivally or negativally). However, if you also
1949specify a third image which is normally used as a <em class="arg">mask</em>,
1950then the <em class="arg">composite image</em> will be used for horizontal X
1951displacement, while the <em class="arg">mask image</em> is used for vertical Y
1952displacement. This allows you to define completely different displacement
1953values for the X and Y directions, and allowing you to lookup any point within
1954the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1955any other nearby pixel, producing complex 2 dimentional displacements, rather
1956than a simple 1 dimentional vector displacements. </p>
1957
1958<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1959you can use the 'red' channel of the overlay image to specify the horizontal
1960or X displacement, and the 'green' channel for the vertical or Y displacement.
1961</p>
1962
1963<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1964mask the transparency of the destination image. However areas outside the
1965overlaid areas will not be effected. </p>
1966
1967
1968<div style="margin: auto;">
1969 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1970</div>
1971
1972<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>
1973
1974<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1975
1976<div style="margin: auto;">
1977 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1978</div>
1979
1980<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>
1981
1982<p>The layer disposal method defines the way each the displayed image is to be
1983modified after the current 'frame' of an animation has finished being
1984displayed (after its 'delay' period), but before the next frame on an
1985animation is to be overlaid onto the display. </p>
1986
1987<p>Here are the valid methods:</p>
1988
1989<pre class="text">
1990Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1991None 1 Do not dispose, just overlay next frame image.
1992Background 2 Clear the frame area with the background color.
1993Previous 3 Clear to the image prior to this frames overlay.
1994</pre>
1995
1996<p>You can also use the numbers given above, which is what the GIF format
1997uses internally to represent the above settings. </p>
1998
1999<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
2000
2001<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
2002resetting the layer disposal methods of images being read in. </p>
2003
2004<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
2005disposal method for images already in memory.</p>
2006
2007<div style="margin: auto;">
2008 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
2009</div>
2010
2011<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>
2012
2013
2014<div style="margin: auto;">
2015 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
2016</div>
2017
2018<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>
2019
2020<p>The opacity of the composite image is multiplied by the given percent, then
2021it is composited 'over' the main image. If <em class="arg">src_percent</em>
2022is greater than 100, start dissolving the main image so it will become
2023transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
2024are given, each image are dissolved to the percentages given. </p>
2025
2026<p>Note that dissolve percentages do not add, two opaque images dissolved
2027'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2028images, you would need to use dissolve values of '50,100'. </p>
2029
2030<div style="margin: auto;">
2031 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
2032</div>
2033
2034<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>
2035
2036<p>The <em class="arg">arguments</em> is a single string containing a list
2037of floating point numbers separated by commas or spaces. The number of
2038and meaning of the floating point values depends on the distortion <em
2039class="arg">method</em> being used. </p>
2040
2041<p>Choose from these distortion types:</p>
2042
2043<table class="doc">
2044 <tr valign="top">
2045 <th align="left" style="width: 8%">Method</th>
2046 <th align="left">Description</th>
2047 </tr>
2048
2049 <tr valign="top">
2050 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
2051 <br/>or &nbsp; <kbd>SRT</kbd></td>
2052 <td valign="top">
2053 Distort image by first scaling and rotating about a given 'center',
2054 before translating that 'center' to the new location, in that order. It
2055 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
2056 distortion, but without shearing effects. It also provides a good way
2057 of rotating and displacing a smaller image for tiling onto a larger
2058 background (IE 2-dimensional animations). <br/>
2059
2060 The number of arguments determine the specific meaning of each
2061 argument for the scales, rotation, and translation operations. <br/>
2062
2063 <table style="margin-left:auto; margin-right:auto;">
2064 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
2065 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
2066 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
2067 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2068 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
2069 <tr><td>5:</td>
2070 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
2071 <tr><td>6:</td>
2072 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
2073 <tr><td>7:</td>
2074 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
2075 &nbsp; NewX,NewY</em></td></tr>
2076 </table>
2077
2078 This is actually an alternative way of specifing a 2 dimensional linear
2079 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
2080
2081 <tr valign="top">
2082 <td valign="top"><kbd>Affine</kbd></td>
2083 <td valign="top">
2084 Distort the image linearly by moving a list of at least 3 or more sets
2085 of control points (as defined below). Idealy 3 sets or 12 floating
2086 point values are given allowing the image to be linearly scaled,
2087 rotated, sheared, and translated, according to those three points. See
2088 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
2089 distortions. <br/>
2090
2091 More than 3 sets given control point pairs (12 numbers) is least
2092 squares fitted to best match a lineary affine distortion. If only 2
2093 control point pairs (8 numbers) are given a two point image translation
2094 rotation and scaling is performed, without any posible shearing,
2095 flipping or changes in aspect ratio to the resulting image. If only one
2096 control point pair is provides the image is only translated, (which may
2097 be a floating point non-integer translation). <br/>
2098
2099 This distortion does not include any form of perspective distortion.
2100 </td>
2101
2102 </tr>
2103
2104 <tr valign="top">
2105 <td valign="top"><kbd>AffineProjection</kbd></td>
2106 <td valign="top">
2107 Linearly distort an image using the given Affine Matrix of 6
2108 pre-calculated coefficients forming a set of Affine Equations to map
2109 the source image to the destination image.
2110
2111 <div style="text-align: center"><em>
2112 s<sub>x</sub>, r<sub>x</sub>,
2113 r<sub>y</sub>, s<sub>y</sub>,
2114 t<sub>x</sub>, t<sub>y</sub>
2115 </em></div>
2116
2117 See <a href="#affine" >-affine</a> setting for more detail, and
2118 meanings of these coefficients. <br/>
2119
2120 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
2121 alternative methods of defining this distortion, with ImageMagick doing the
2122 calculations needed to generate the required coefficients. You can see
2123 the internally generated coefficients, by using a <a href="#verbose"
2124 >-verbose</a> setting. </td>
2125
2126 </tr>
2127
2128<!-- still under development, do not display - Anthony
2129 <tr valign="top">
2130 <td valign="top"><kbd>Bilinear</kbd></td>
2131 <td valign="top">
2132 Bilinear (reversed) Distortion, given a minimum of 4 sets of
2133 coordinate pairs, or 16 values (see below). Not that lines may not
2134 appear straight after distortion, though the distance between
2135 coordinates will remain consistant. </td>
2136 </tr>
2137-->
2138
2139 <tr valign="top">
2140 <td valign="top"><kbd>Perspective</kbd></td>
2141 <td valign="top">
2142 Perspective distort the images, using a list of 4 or more sets of
2143 control points (as defined below). More that 4 sets (16 numbers) of
2144 control points provide least squares fitting for more accurate
2145 distortions (for the purposes of image registration and panarama
2146 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2147 linear distortion. <br/>
2148
2149 Perspective Distorted images ensures that straight lines remain
2150 straight, but the scale of the distorted image will vary. The horizon
2151 is anti-aliased, and the 'sky' color may be set using the
2152 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2153 </tr>
2154
2155 <tr valign="top">
2156 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2157 <td valign="top">
2158 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2159 pre-calculated coefficients. You can get these coefficients by looking
2160 at the <a href="#verbose" >-verbose</a> output of a
2161 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2162 If the last two perspective scaling coefficients are zero, the
2163 remaining 6 represents a transposed 'Affine Matrix'. </td>
2164
2165 </tr>
2166
2167 <tr valign="top">
2168 <td valign="top"><kbd>Arc</kbd></td>
2169 <td valign="top">
2170 Arc the image (variation of polar mapping) over the angle given around
2171 a circle. <br/>
2172 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2173 <tr valign="top"><td>Argument</td>
2174 <td>Meaning</td></tr>
2175 <tr valign="top"><td><em>arc_angle</em></td>
2176 <td>The angle over which to arc the image side-to-side</td></tr>
2177 <tr valign="top"><td><em>rotate_angle</em></td>
2178 <td>Angle to rotate resulting image from vertical center</td></tr>
2179 <tr valign="top"><td><em>top_radius</em></td>
2180 <td>Set top edge of source image at this radius</td></tr>
2181 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2182 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2183 </table>
2184
2185 The resulting image is always resized to best fit the resulting image,
2186 (as if using <a href="#distort" >+distort</a>) while attempting to
2187 preserve scale and aspect ratio of the original image as much as
2188 possible with the arguments given by the user. All four arguments will
2189 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2190
2191 This a variation of a polar distortion designed to try to preserve the
2192 aspect ratio of the image rather than direct Cartesian to Polar
2193 conversion. </td>
2194 </tr>
2195
2196 <tr valign="top">
2197 <td valign="top"><kbd>Polar</kbd></td>
2198 <td valign="top">
2199 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2200 the image. that is the height of the input image is mapped to the
2201 radius limits, while the width is wrapped around between the
2202 angle limits. <br/>
2203
2204 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2205
2206 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2207 center to the center of the image, and the angles going from -180 (top)
2208 to +180 (top). If <em>Rmax</em> is given the special value of
2209 '<code>0</code>', the the distance from the center to the nearest edge
2210 is used for the radius of the output image, which will ensure the whole
2211 image is visible (though scaled smaller). However a special value of
2212 '<code>-1</code>' will use the distance from the center to the furthest
2213 corner, This may 'clip' the corners from the input rectangular image,
2214 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2215 the same arguments. <br/>
2216
2217 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2218 output image center will default to <code>0,0</code> of the virtual
2219 canvas, and the image size adjusted to ensure the whole input image is
2220 made visible in the output image on the virtual canvas. </td>
2221
2222 </tr>
2223
2224 <tr valign="top">
2225 <td valign="top"><kbd>DePolar</kbd></td>
2226 <td valign="top">
2227 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2228 but generates the reverse Polar to Cartesian distortion. <br/>
2229
2230 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2231 the corners of the input image. However using the special
2232 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2233 distance) will ensure the whole distorted image is preserved in the
2234 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2235 reverse the distortion re-producing the original.
2236
2237 Note that as this distortion requires the area resampling of a circular
2238 arc, which can not be handled by the builtin EWA resampling function.
2239 As such the normal EWA filters are turned off. It is recomended some
2240 form of 'super-sampling' image processing technique be used to produce
2241 a high quality result. </td>
2242
2243 </tr>
2244
2245 <tr valign="top">
2246 <td valign="top"><kbd>Barrel</kbd></td>
2247 <td valign="top">
2248 Given the four coefficients (A,B,C,D) as defined by <a
2249 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2250 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2251 correct radial lens distortions. That is in photographs, make straight
2252 lines straight again. <br/>
2253
2254 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2255 <em>X</em> , <em>Y</em> ] ] <br/>
2256 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2257 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2258 [ <em>X</em> , <em>Y</em> ] <br/>
2259 So that it forms the function <br/>
2260 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2261 <em>C</em>*r + <em>D</em> )<br/>
2262
2263 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2264 (defaulting to the center of the image). <br/>
2265 The second form is typically used to distort images, rather than
2266 correct lens distortions. <br/>
2267 </td>
2268
2269 </tr>
2270
2271 <tr valign="top">
2272 <td valign="top"><kbd>BarrelInverse</kbd></td>
2273 <td valign="top">
2274 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2275 arguments, and argument handling. However it uses the inverse
2276 of the radial polynomial,
2277 so that it forms the function <br/>
2278 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2279 <em>C</em>*r + <em>D</em> )
2280 </td>
2281 </tr>
2282
2283 <tr valign="top">
2284 <td valign="top"><kbd>Shepards</kbd></td>
2285 <td valign="top">
2286 Distort the given list control points (any number) using an Inverse
2287 Squared Distance Interpolation Method (<a
2288 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2289 >Shepards Method</a>). The control points in effect do 'localized'
2290 distortions of the image around the given control point. For best
2291 results extra control points should be added to 'lock' the positions of
2292 the corners and other unchanging parts of the image. <br/>
2293
2294 The distortion has been likened to 'taffy pulling' using nails, pins or
2295 sticks. It basically uses the <a href="#sparse-color"
2296 >-sparse-color</a> method of the same name to generate separate X and Y
2297 displacement maps (see <a href="#displace" >-displace</a>) for source
2298 image color look-up. </td>
2299
2300 </tr>
2301
2302</table>
2303
2304<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2305
2306<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2307'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2308defining how these points in the given image should be distorted in the
2309destination image. Each set of four floating point values represent a source
2310image coordinate, followed immediately by the destination image coordinate.
2311This produces a list of values such as...</p>
2312<div style="text-align: center"><em>
2313 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2314 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2315 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2316 ... &nbsp;
2317 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2318</em></div>
2319<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2320destination image. </p>
2321
2322<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2323needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2324perspective distortion of the built-in "rose:" image. Note how spaces were
2325used to group the 4 sets of coordinate pairs, to make it easier to read and
2326understand.</p>
2327
2328<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2329 convert rose: -virtual-pixel black \ <br/>
2330 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2331 rose_3d_rotated.gif</span></p>
2332<p>If more that the required number of coordinate pairs are given for a
2333distortion, the distortion method is 'least squares' fitted to
2334produce the best result for all the coordinate pairs given. If less than the
2335ideal number of points are given, the distort will generally fall back to a
2336simpler form of distortion that can handles the smaller number of coordinates
2337(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2338
2339<p>By using more coodinates you can make use of image registration tool to
2340find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2341of the distortion. Of course a bad coordinate pair can also make the 'fit'
2342worse. Caution is always advised. </p>
2343
2344<p>Colors are acquired from the source image according to the <a
2345href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2346magnified. However if the viewed image is minified (image becomes smaller), a
2347special area resampling function (added ImageMagick v6.3.5-9), is used to
2348produce a higher quality image. For example you can use a
2349'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2350way to the horizon. </p>
2351
2352<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2353 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2354 checks_tiled.jpg</span></p>
2355<p>Note that a infinitely tiled perspective images involving the horizon can
2356be very slow to generate due to the use of the high quality 'area resampling'
2357function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2358using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2359(recommended if you plan to use super-sampling instead). </p>
2360
2361<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2362'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2363will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2364pixels. If you do not what these pixels to be visible, set the color to match
2365the rest of the ground. </p>
2366
2367<p>The output image size will by default be the same as the input image. This
2368means that if the part of the distorted image falls outside the viewed area of
2369the 'distorted space', those parts is clipped and lost. However if you
2370use the plus form of the operator (<a href="#distort" >+distort</a>) the
2371operator will attempt (if posible) to show the whole of the distorted image,
2372while retaining a correct 'virtual canvas' offset, for image layering. This
2373offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2374if it is unwanted. </p>
2375
2376<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2377option:distort:viewport {geometry_string}</kbd>" setting which will specify
2378the size and the offset of the generated 'viewport' image of the distorted
2379image space.</p>
2380
2381<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2382{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2383that factor without changing the viewed contents of the distorted image. This
2384can be used either for 'super-sampling' the image for a higher quality result,
2385or for panning and zooming around the image (with appropriate viewport
2386changes, or post-distort cropping and resizing). </p>
2387
2388<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2389href="#distort" >-distort</a> to attempt to output the internal coefficients,
2390and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2391and debugging purposes. This many not be available for all distorts. </p>
2392
2393<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2394produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2395and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2396above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2397</p>
2398
2399
2400<div style="margin: auto;">
2401 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2402</div>
2403
2404<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>
2405
2406<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>
2407
2408<p>Dithering is turned on by default, to turn it off use the plus form of the
2409setting, <a href="#dither">+dither</a>. This will also also render PostScript
2410without text or graphic aliasing. Disabling dithering often (but not always)
2411leads to faster process, a smaller number of colors, but more cartoon like
2412image coloring. Generally resulting in 'color banding' effects in areas with
2413color gradients. </p>
2414
2415<p>The color reduction operators <a href="#colors">-colors</a>, <a
2416href="#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>
2417
2418<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>
2419
2420
2421<div style="margin: auto;">
2422 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2423</div>
2424
2425<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>
2426
2427<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>
2428
2429<p>The shape primitives:</p>
2430
2431<pre class="text">
2432 point x,y
2433 line x0,y0 x1,y1
2434 rectangle x0,y0 x1,y1
2435 roundRectangle x0,y0 x1,y1 wc,hc
2436 arc x0,y0 x1,y1 a0,a1
2437 ellipse x0,y0 rx,ry a0,a1
2438 circle x0,y0 x1,y1
2439 polyline x0,y0 ... xn,yn
2440 polygon x0,y0 ... xn,yn
2441 bezier x0,y0 ... xn,yn
2442 path path specification
2443 image operator x0,y0 w,h filename
2444</pre>
2445
2446<p>The text primitive:</p>
2447
2448<pre class="text">
2449 text x0,y0 string
2450</pre>
2451<p>The text gravity primitive:</p>
2452
2453<pre class="text">
2454 gravity NorthWest, North, NorthEast, West, Center,
2455 East, SouthWest, South, or SouthEast
2456</pre>
2457
2458<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>
2459
2460<p>The transformation primitives:</p>
2461
2462<pre class="text">
2463 rotate degrees
2464 translate dx,dy
2465 scale sx,sy
2466 skewX degrees
2467 skewY degrees
2468</pre>
2469
2470<p>The pixel operation primitives:</p>
2471
2472<pre class="text">
2473 color x0,y0 method
2474 matte x0,y0 method
2475</pre>
2476
2477<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>
2478
2479<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>
2480
2481<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2482
2483<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2484
2485<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>
2486
2487<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2488
2489<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>
2490
2491<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>
2492
2493<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>.
2494</p>
2495
2496<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2497
2498<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2499
2500<p class="crtsnip">
2501 -draw 'circle 100,100 150,150'
2502</p>
2503
2504<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
2505draw 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>
2506
2507<p class="crtsnip">
2508 -draw 'bezier 20,50 45,100 45,0 70,50'
2509</p>
2510<p class="crtsnip">
2511 -draw 'bezier 70,50 95,100 95,0 120,50'
2512</p>
2513
2514
2515<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>
2516
2517<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>
2518
2519<p class="crtsnip">
2520 -draw 'image SrcOver 100,100 225,225 image.jpg'
2521</p>
2522
2523<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>
2524
2525<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>
2526
2527<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2528
2529<p class="crtsnip">
2530 -draw 'text 100,100 "Works like magick!"'
2531</p>
2532
2533<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2534
2535<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>
2536
2537<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2538
2539<p>The <kbd>scale</kbd> primitive scales them.</p>
2540
2541<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>
2542
2543<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
2544matrix.</p>
2545
2546<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>
2547
2548<pre class="text">
2549 point
2550 replace
2551 floodfill
2552 filltoborder
2553 reset
2554</pre>
2555
2556<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>
2557
2558<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>
2559
2560<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>
2561
2562<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2563
2564<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2565
2566
2567<div style="margin: auto;">
2568 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2569</div>
2570
2571<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>
2572
2573<div style="margin: auto;">
2574 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2575</div>
2576
2577<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>
2578
2579<div style="margin: auto;">
2580 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2581</div>
2582
2583<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>
2584
2585<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2586
2587<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2588
2589<div style="margin: auto;">
2590 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2591</div>
2592
2593<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>
2594
2595<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>
2596
2597<div style="margin: auto;">
2598 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2599</div>
2600
2601<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>
2602
2603<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2604
2605<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2606
2607
2608<div style="margin: auto;">
2609 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2610</div>
2611
2612<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>
2613
2614
2615<div style="margin: auto;">
2616 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2617</div>
2618
2619<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>
2620
2621<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>
2622
2623<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2624
2625<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>
2626
2627<div style="margin: auto;">
2628 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2629</div>
2630
2631<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>
2632
2633<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>
2634
2635<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>
2636
2637<table class="doc">
2638 <col width="25%" />
2639 <col width="75%" />
2640 <thead>
2641 <tr>
2642 <th><em class="arg">operator</em></th>
2643 <th>Summary (see further below for details)</th>
2644 </tr>
2645 </thead>
2646 <tbody>
2647
2648 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2649 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2650 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2651 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2652 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2653 <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>
2654 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2655 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2656 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2657 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2658 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2659 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2660 <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>
2661 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2662 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2663 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2664 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2665
2666 <tr><td>&nbsp;</td></tr>
2667
2668 <tr><td>Gaussian-noise</td></tr>
2669 <tr><td>Impulse-noise</td></tr>
2670 <tr><td>Laplacian-noise</td></tr>
2671 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2672 <tr><td>PoissonNoise</td></tr>
2673 <tr><td>Uniform-noise</td></tr>
2674
2675 <tr><td>&nbsp;</td></tr>
2676
2677 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2678 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2679 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2680 </tbody>
2681 </table>
2682
2683<p>The specified functions are applied only to each previously set <a
2684href="#channel" >-channel</a> in the image. If necessary, the results of the
2685calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2686class="QR">QuantumRange</em>]. The transparency channel of the image is
2687represented as a 'alpha' values (0 = fully transparent), so, for example, a
2688<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2689semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2690as a percentage of the <em class="QR">QuantumRange</em>.</p>
2691
2692<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2693<a href="#list">-list evaluate</a>.</p>
2694
2695<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2696<kbd>Multiply</kbd> methods can also be achieved using either the <a
2697href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2698appropriate argument, to linearly modify the overall range of color values.
2699Please note, however, that <a href="#level" >-level</a> treats transparency as
2700'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2701'alpha' values.</p>
2702
2703<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>
2704
2705<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>
2706
2707 <div style="text-align:center;">
2708 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2709 </div>
2710
2711<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2712normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2713href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2714to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2715with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2716with <kbd>Pow</kbd>.</p>
2717
2718<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2719converts the image values into a value according to a (co)sine wave function.
2720The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2721is biased 50% and normalized by 50% so as to fit in the respective color value
2722range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2723function (its frequency), and thus determines the number of 'waves' that will
2724be generated over the input color range. For example, if the <em
2725class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2726class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2727then the effective period is the <em>half</em> the <em
2728class="QR">QuantumRange</em>.
2729
2730 <div style="text-align:center;">
2731 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2732 </div>
2733
2734See also the <a href="#function" >-function</a> operator, which is a
2735multi-value version of evaluate. </P>
2736
2737
2738<div style="margin: auto;">
2739 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2740</div>
2741
2742<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>
2743
2744<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>
2745
2746<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>
2747
2748<div style="margin: auto;">
2749 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2750</div>
2751
2752<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>
2753
2754<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2755
2756<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>
2757
2758<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>
2759<p>then the image will be <em>resized</em> to the specified dimensions instead,
2760equivalent to:</p>
2761
2762<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>
2763<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>
2764
2765<div style="margin: auto;">
2766 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2767</div>
2768
2769<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>
2770
2771<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).
2772</p>
2773
2774<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>.
2775</p>
2776
2777<div style="margin: auto;">
2778 <h4><a name="fft" id="fft"></a>-fft</h4>
2779</div>
2780
2781<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>
2782
2783<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>
2784
2785<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>
2786
2787<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>
2788
2789<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2790<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>
2791
2792<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2793<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>
2794
2795<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>
2796
2797<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>
2798
2799<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2800 -evaluate log 1000 fft_image_spectrum.png</span></p>
2801<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>
2802
2803<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2804
2805<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>
2806
2807<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>
2808
2809<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>
2810
2811<p>See the discussion on HDRI implementations of ImageMagick on the page
2812<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.
2813</p>
2814
2815
2816<div style="margin: auto;">
2817 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2818</div>
2819
2820<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>
2821
2822<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>
2823
2824<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2825
2826<p>For example,</p>
2827
2828<p class="crtsnip">
2829 -fill blue
2830</p>
2831<p class="crtsnip">
2832 -fill "#ddddff"
2833</p>
2834<p class="crtsnip">
2835 -fill "rgb(255,255,255)"
2836</p>
2837
2838<p>See <a href="#draw">-draw</a> for further details.</p>
2839
2840<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2841
2842<div style="margin: auto;">
2843 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2844</div>
2845
2846<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>
2847
2848<p>Use this option to affect the resizing operation of an image (see <a
2849href="#resize">-resize</a>). For example you can use a simple resize filter
2850such as:</p>
2851
2852<pre class="text">
2853 Point Hermite Cubic
2854 Box Gaussian Catrom
2855 Triangle Quadratic Mitchell
2856</pre>
2857
2858<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2859by default <kbd>blackman</kbd>-windowed. However these filters define a
2860windowing filter for the Sinc or Bessel filter function, as appropriate for
2861the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2862>-resize</a>). Windowed filters include: </p>
2863
2864<pre class="text">
2865 Lanczos Hamming Parzen
2866 Blackman Kaiser Welsh
2867 Hanning Bartlett Bohman
2868</pre>
2869
2870<p>Also one special self-windowing filter is also provided
2871<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2872on the current 'support' or 'lobes' expert settings (see below).</p>
2873
2874<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>
2875
2876<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2877
2878<p>You can modify how the filter behaves as it scales your image through the
2879use of these expert settings:</p>
2880
2881<dl class="doc">
2882<dt>-set filter:blur <em>factor</em></dt>
2883<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2884 blurry or &lt; 1.0 for sharp.</dd>
2885
2886<dt>-set filter:support <em>radius</em></dt>
2887<dd>Set the filter support radius.</dd>
2888
2889<dt>-set filter:lobes <em>count</em></dt>
2890<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2891 alternative way of specifying the 'support' range of the filter.</dd>
2892
2893<dt>-set filter:b <em>b-spline_factor</em></dt>
2894<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2895<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2896 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2897 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2898 are defined, the other is set so as to generate a 'Keys' type cubic
2899 filter.
2900
2901<dt>-set filter:filter <em>filter</em></dt>
2902<dd>Use this function directly as the scaling filter. This will allow
2903 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2904 rather than as its normal usage as a windowing function for 'Sinc' or
2905 'Bessel'. If defined, no windowing function is used, unless the following
2906 expert setting is also defined.</dd>
2907
2908<dt>-set filter:window <em>filter</em></dt>
2909<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2910 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2911 support range) with the given filter. This allows you to use a filter that
2912 is not normally used as a windowing function, such as <kbd>box</kbd>,
2913 (which effectivally turns off the windowing function). </dd>
2914
2915</dl>
2916
2917<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2918
2919<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2920 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2921 -resize 150% image.jpg</span></p>
2922<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2923
2924<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2925 -resize 150% image.jpg</span></p>
2926<p>Note that the use of expert options (except for 'blur' with simple resize
2927filters), are provided for image processing experts who have studied and
2928understood how resize filters work. Without this knowledge, and an
2929understanding of the defination of the actual filters involved, using expert
2930settings are more likely to be detremental to your image resizing.</p>
2931
2932
2933<div style="margin: auto;">
2934 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2935</div>
2936
2937<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>
2938
2939
2940<div style="margin: auto;">
2941 <h4><a name="flip" id="flip"></a>-flip</h4>
2942</div>
2943
2944<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>
2945
2946<p>reflect the scanlines in the vertical direction.</p>
2947
2948<div style="margin: auto;">
2949 <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>
2950</div>
2951
2952<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>
2953
2954<div style="margin: auto;">
2955 <h4><a name="flop" id="flop"></a>-flop</h4>
2956</div>
2957
2958<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>
2959
2960<p>reflect the scanlines in the horizontal direction.</p>
2961
2962
2963<div style="margin: auto;">
2964 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2965</div>
2966
2967<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>
2968
2969<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>
2970
2971<p>In addition to the fonts specified by the above pre-defined list, you can
2972also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2973is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2974<kbd>x:fixed</kbd> is X11 font.</p>
2975
2976<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>
2977
2978
2979<div style="margin: auto;">
2980 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2981</div>
2982
2983<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>
2984
2985<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2986
2987<p>The default foreground color is black.</p>
2988
2989<div style="margin: auto;">
2990 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2991</div>
2992
2993<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>
2994
2995<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>
2996
2997<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>
2998
2999<div style="margin: auto;">
3000 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
3001</div>
3002
3003<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>
3004
3005<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>
3006
3007<div style="margin: auto;">
3008 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
3009</div>
3010
3011<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>
3012
3013<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
3014
3015<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>
3016
3017
3018<div style="margin: auto;">
3019 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
3020</div>
3021
3022<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>
3023
3024<div style="margin: auto;">
3025 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
3026</div>
3027
3028<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>
3029
3030<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>
3031
3032<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>
3033
3034<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>
3035
3036<pre class="text">
3037 Polynomial
3038 Sinusoid
3039 Arcsin
3040 Arctan
3041</pre>
3042
3043<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
3044
3045<dl class="doc">
3046<dt><kbd>Polynomial</kbd></dt>
3047<dd>
3048<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>
3049
3050<div style="text-align: center">
3051 -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>
3052</div>
3053
3054<p>will invoke a polynomial function given by</p>
3055
3056<div style="text-align: center">
3057 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
3058 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
3059 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
3060</div>
3061
3062<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
3063
3064<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>
3065
3066<table class="doc">
3067 <col width="35%" />
3068 <col width="35%" />
3069 <col width="30%" />
3070 <tr>
3071 <td>-evaluate Set <em class="arg">value</em> </td>
3072 <td>-function Polynomial <em class="arg">value</em></td>
3073 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
3074 </tr>
3075 <tr>
3076 <td>-evaluate Add <em class="arg">value</em> </td>
3077 <td>-function Polynomial 1,<em class="arg">value</em></td>
3078 </tr>
3079 <tr>
3080 <td>-evaluate Subtract <em class="arg">value</em> </td>
3081 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
3082 </tr>
3083 <tr>
3084 <td>-evaluate Multiply <em class="arg">value</em> </td>
3085 <td>-function Polynomial <em class="arg">value</em>,0</td>
3086 </tr>
3087 <tr>
3088 <td>+level black% x white%</td>
3089 <td>-function Polynomial A,B</td>
3090 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3091 </tr>
3092</table>
3093
3094<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>
3095</dd>
3096
3097<dt><kbd>Sinusoid</kbd></dt>
3098<dd>
3099<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>
3100
3101<div style="text-align: center">
3102 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
3103</div>
3104
3105<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>
3106
3107<div style="text-align: center">
3108<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>
3109</div>
3110
3111<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>
3112
3113<p class="crtsnip">
3114 -function Sinusoid 3,-90,.2,.7
3115</p>
3116
3117<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>
3118
3119<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>
3120
3121<table class="doc">
3122 <tr>
3123 <td>-evaluate Sin <em class="arg">freq</em> </td>
3124 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
3125 </tr>
3126 <tr>
3127 <td>-evaluate Cos <em class="arg">freq</em> </td>
3128 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
3129 </tr>
3130</table>
3131</dd>
3132
3133<dt><kbd>ArcSin</kbd></dt>
3134<dd>
3135<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
3136and can be used to generate cylindrical distortion and displacement maps.
3137The curve can be adjusted relative to both the input values and output range
3138of values.
3139
3140<div style="text-align: center">
3141 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3142</div>
3143
3144<p>with all values given in terms of noramlize color values (0.0 for black,
31451.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3146for bout input (<em class="arg">width</em>), and output (<em
3147class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3148
3149<div style="text-align: center">
3150<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>
3151</div>
3152
3153</dd>
3154
3155<dt><kbd>ArcTan</kbd></dt>
3156<dd>
3157<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3158limit values at infinities, though a center using the given slope value.
3159All these values can be adjusted via the arguments.
3160
3161<div style="text-align: center">
3162 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3163</div>
3164
3165<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3166</p>
3167
3168<div style="text-align: center">
3169<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>
3170</div>
3171
3172</dd>
3173
3174</dl>
3175
3176
3177<div style="margin: auto;">
3178 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3179</div>
3180
3181<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>
3182
3183<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>
3184
3185<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>
3186
3187
3188<div style="margin: auto;">
3189 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3190</div>
3191
3192<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>
3193
3194<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>
3195
3196<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3197
3198
3199<div style="margin: auto;">
3200 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3201</div>
3202
3203<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>
3204
3205<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>
3206
3207<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>
3208
3209<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>
3210
3211<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>
3212
3213<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3214
3215<div style="margin: auto;">
3216 <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>
3217</div>
3218
3219<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>
3220
3221<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3222
3223<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3224</div>
3225
3226<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>
3227
3228<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3229full 2-dimentional convolution is used to generate the weighted average of the
3230neighbouring pixels. </p>
3231
3232<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3233pixels which are outside the image proper are blurred into the final result.
3234</p>
3235
3236
3237<div style="margin: auto;">
3238 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3239</div>
3240
3241<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>
3242
3243<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>
3244
3245<div style="margin: auto;">
3246 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3247</div>
3248
3249<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>
3250
3251<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3252<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3253<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3254list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3255installation.</p>
3256
3257<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>
3258
3259<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>
3260
3261<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>
3262
3263<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>
3264<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>
3265
3266<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>
3267
3268
3269<div style="margin: auto;">
3270 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3271</div>
3272
3273<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>
3274
3275
3276<div style="margin: auto;">
3277 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3278</div>
3279
3280<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>
3281
3282<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3283dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3284can apply any color transformation to the Hald image and then use this option
3285to apply the transform to the image. </p>
3286
3287<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3288<p>This option provides a convenient method for you to use Gimp or Photoshop
3289to make color corrections to the Hald CLUT image and subsequently apply them
3290to multiple images using an ImageMagick script. </p>
3291
3292<p>Note that the representation is only of the normal RGB color space and that
3293the whole color value triplet is used for the interpolated lookup of the
3294represented Hald color cube image. Because of this the operation is not <a
3295href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3296images transparency or alpha/matte channel.</p>
3297
3298<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3299of the individual color channels, usally involving a simplier gray-scale
3300image. E.g: gray-scale to color replacement, or modification by a histogram
3301mapping. </p>
3302
3303
3304<div style="margin: auto;">
3305 <h4><a name="help" id="help"></a>-help</h4>
3306</div>
3307
3308<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>
3309
3310<div style="margin: auto;">
3311 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3312</div>
3313
3314<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>
3315
3316<div style="margin: auto;">
3317 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3318</div>
3319
3320<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>
3321
3322<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>
3323
3324<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>
3325
3326<div style="margin: auto;">
3327 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3328</div>
3329
3330<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>
3331
3332<div style="margin: auto;">
3333 <h4><a name="identify" id="identify"></a>-identify</h4>
3334</div>
3335
3336<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>
3337
3338<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>
3339
3340<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>
3341
3342<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3343amounts of image properties are displayed including image statistics, profiles,
3344image histogram, and others.</p>
3345
3346<div style="margin: auto;">
3347 <h4><a name="ift" id="ift"></a>-ift</h4>
3348</div>
3349
3350<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>
3351
3352<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>
3353
3354<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>
3355
3356<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3357<p>or</p>
3358
3359<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>
3360
3361<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.
3362
3363<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3364
3365<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.
3366
3367<div style="margin: auto;">
3368 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3369</div>
3370
3371<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>
3372
3373<div style="margin: auto;">
3374 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3375</div>
3376
3377<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>
3378
3379<div style="margin: auto;">
3380 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3381</div>
3382
3383<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>
3384
3385<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>
3386
3387<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>
3388
3389<div style="margin: auto;">
3390 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3391</div>
3392
3393<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>
3394
3395<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>
3396
3397<p>The default intent is undefined.</p>
3398
3399<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3400
3401<div style="margin: auto;">
3402 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3403</div>
3404
3405<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>
3406
3407<p>Choose from:</p>
3408
3409<pre class="text">
3410 none
3411 line
3412 plane
3413 partition
3414 JPEG
3415 GIF
3416 PNG
3417</pre>
3418
3419<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>
3420
3421<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3422
3423<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3424
3425<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3426
3427<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3428image.G, and image.B).</p>
3429
3430<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>
3431image.</p>
3432
3433<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3434
3435<div style="margin: auto;">
3436 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3437</div>
3438
3439<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>
3440
3441<p>When looking up the color of a pixel using a non-interger floating point
3442value, you typically fall in between the pixel colors defined by the source
3443image. This setting determines how the color is determined from the colors of
3444the pixels surrounding that point. That is how to determine the color of a
3445point that falls between two, or even four different colored pixels. </p>
3446
3447<pre class="text">
3448 integer: The color of the top-left pixel (floor function)
3449 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3450 average: The average color of the surrounding four pixels
3451 bilinear A double linear interpolation of pixels (the default)
3452 mesh Divide area into two flat triangular interpolations
3453 bicubic Fitted bicubic-spines of surrounding 16 pixels
3454 spline Direct spline curves (colors are blurred)
3455 filter Use resize <a href="#filter">-filter</a> settings
3456</pre>
3457
3458<p>This most important for distortion operators such as <a href="#distort"
3459>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3460>-transform</a> and <a href="#fx" >-fx</a>. </p>
3461
3462<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3463
3464<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3465lookup for positions outside the boundaries of the image. </p>
3466
3467
3468<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003469 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3470</div>
3471
3472<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>
3473
3474<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003475 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3476</div>
3477
3478<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>
3479
3480<div style="margin: auto;">
3481 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3482</div>
3483
3484<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>
3485
3486<div style="margin: auto;">
3487 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3488</div>
3489
3490<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>
3491
3492<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>
3493
3494<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>
3495
3496<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>
3497
3498<p>For example,</p>
3499
3500<p class="crtsnip">
3501 -label "%m:%f %wx%h" bird.miff
3502</p>
3503
3504<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>
3505
3506<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>
3507
3508<p>The label font can be specified with <a href="#font">-font</a>, and the
3509other font attribute settings.</p>
3510
3511<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>
3512
3513
3514<div style="margin: auto;">
3515 <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>
3516</div>
3517
3518<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>
3519
3520<p>Adaptively threshold each pixel based on the value of pixels in a
3521surrounding window. If the current pixel is lighter than this average plus
3522the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3523black. Small variations in pixel values such as found in scanned documents
3524can be ignored if offset is positive. A negative offset will make it more
3525sensitive to those small variations. </p>
3526
3527<p>This is commonly used to threshold images with an uneven background. It is
3528based on the assumption that average color of the small window is the
3529the local background color, from which to separate the forground color. </p>
3530
3531
3532<div style="margin: auto;">
3533 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3534</div>
3535
3536<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>
3537
3538<p>Perform various image operation methods to a ordered sequence of images
3539which may represent either a set of overlaid 'image layers', a GIF disposal
3540animation, or a fully-'coalesced' animation sequence. </p>
3541
3542<table class="doc">
3543 <tbody>
3544 <tr valign="top">
3545 <th align="left" style="width: 8%">Method</th>
3546 <th align="left">Description</th>
3547 </tr>
3548
3549 <tr valign="top">
3550 <td valign="top">compare-any</td>
3551 <td valign="top">Crop the second and later frames to the smallest rectangle
3552 that contains all the differences between the two images. No GIF <a
3553 href="#dispose" >-dispose</a> methods are taken into account. </td>
3554 </tr>
3555
3556 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3557 >-deconstruct</a> operator, and does not preserve animations normal
3558 working, especially when animation used layer disposal methods such as
3559 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3560 </tr>
3561
3562 <tr valign="top">
3563 <td valign="top">compare-clear</td>
3564 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3565 opaque pixels which become transparent in the second frame. That is the
3566 smallest image needed to mask or erase pixels for the next frame. </td>
3567 </tr>
3568
3569 <tr valign="top">
3570 <td valign="top">compare-overlay</td>
3571 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3572 extra color to the next image, as a result of overlaying color pixels.
3573 That is the smallest single overlaid image to add or change colors. </td>
3574 </tr>
3575
3576 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3577 composition method '<kbd>change-mask</kbd>', to reduce the image to
3578 just the pixels that need to be overlaid. </td>
3579 </tr>
3580
3581 <tr valign="top">
3582 <td valign="top">coalesce</td>
3583 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3584 >-coalesce</a> operator. Apply the layer disposal methods set in the
3585 current image sequence to form a fully defined animation sequence, as
3586 it should be displayed. Effectively converting a GIF animation into a
3587 'film strip'-like animation. </td>
3588 </tr>
3589
3590 <tr valign="top">
3591 <td valign="top">composite</td>
3592 <td valign="top">Alpha Composition of two image lists, separated by a
3593 "<kbd>null:</kbd>" image, with the destination image list first, and
3594 the source images last. An image from each list are composited
3595 together until one list is finished. The separator image and source
3596 image lists are removed. </td>
3597 </tr>
3598
3599
3600 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3601 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3602 size of the first image in each list. Unlike a normal <a
3603 href="#composite" >-composite</a> operation, the canvas offset is also
3604 added to the final composite positioning of each image. </td>
3605 </tr>
3606
3607 <tr><td></td><td>If one of the image lists only contains one image, that image is
3608 applied to all the images in the other image list, regardless of which
3609 list it is. In this case it is the image meta-data of the list which
3610 preserved. </td>
3611 </tr>
3612
3613
3614 <tr valign="top">
3615 <td valign="top">dispose</td>
3616 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3617 the animation after the layer disposal method has been applied, before
3618 the next sub-frame image is overlaid. That is the 'dispose' image that
3619 results from the application of the GIF <a href="#dispose"
3620 >-dispose</a> method. This allows you to check what
3621 is going wrong with a particular animation you may be developing.
3622 </td>
3623 </tr>
3624
3625 <tr valign="top">
3626 <td valign="top">flatten</td>
3627 <td valign="top">Create a canvas the size of the first images virtual
3628 canvas using the current <a href="#background" >-background</a> color,
3629 and <a href="#compose" >-compose</a> each image in turn onto that
3630 canvas. Images falling outside that canvas is clipped. Final
3631 image will have a zero virtual canvas offset. </td>
3632 </tr>
3633
3634 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3635 overlaying all the prepared image layers into a final image. </td>
3636 </tr>
3637
3638 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3639 canvas with real pixels, or to underlay a opaque color to remove
3640 transparency from an image.</td>
3641 </tr>
3642
3643
3644 <tr valign="top">
3645 <td valign="top">merge</td>
3646 <td valign="top">As 'flatten' method but merging all the given image
3647 layers into a new layer image just large enough to hold all the image
3648 without clipping or extra space. The new images virtual offset will
3649 prevere the position of the new layer, even if this offset is
3650 negative. the virtual canvas size of the first image is preserved.
3651 </td>
3652 </tr>
3653
3654 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3655 as few image file formats handle them correctly. </td>
3656 </tr>
3657
3658 <tr valign="top">
3659 <td valign="top">mosaic</td>
3660 <td valign="top">As 'flatten' method but expanding the initial canvas size
3661 of the first image so as to hold all the image layers. However as a
3662 virtual canvas is 'locked' to the origin, by defination, image layers
3663 with a negative offsets will still be clipped by the top and left
3664 edges.</td>
3665 </tr>
3666
3667 <tr><td></td><td>This method is commonly used to layout individual image using various
3668 offset but without knowning the final canvas size. The resulting image
3669 will, like 'flatten' not have any virtual offset, so can be saved to
3670 any image file format. </td>
3671 </tr>
3672
3673
3674 <tr valign="top">
3675 <td valign="top">optimize</td>
3676 <td valign="top">Optimize a coalesced animation, into GIF animation using
3677 a number of general techniques. This currently a short cut to
3678 apply both the '<kbd>optimize-frame</kbd>', and
3679 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3680 include other optimization methods as they are developed. </td>
3681 </tr>
3682
3683 <tr valign="top">
3684 <td valign="top">optimize-frame</td>
3685 <td valign="top">Optimize a coalesced animation, into GIF animation by
3686 reducing the number of pixels per frame as much as possible by
3687 attempting to pick the best layer disposal method to use, while ensuring
3688 the result will continue to animate properly. </td>
3689 </tr>
3690
3691 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3692 then no reasonably fast GIF optimization algorithm can do this.
3693 However this does seem to do better than most other GIF frame
3694 optimizers seen. </td>
3695 </tr>
3696
3697 <tr valign="top">
3698 <td valign="top">optimize-plus</td>
3699 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3700 overall optimization by adding extra frames to the animation, without
3701 changing the final look or timing of the animation. The frames are
3702 added to attempt to separate the clearing of pixels from the
3703 overlaying of new additional pixels from one animation frame to the
3704 next. If this does not improve the optimization (for the next frame
3705 only), it will fall back to the results of the previous normal
3706 '<kbd>optimize-frame</kbd>' technique. </td>
3707 </tr>
3708
3709 <tr><td></td><td>There is the possibility that the change in the disposal style will
3710 result in a worsening in the optimization of later frames, though this
3711 is unlikely. In other words there no guarantee that it is better than
3712 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3713 however you can get a vast improvment in the final animation size. </td>
3714 </tr>
3715
3716 <tr valign="top">
3717 <td valign="top">optimize-transparency</td>
3718 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3719 overlay images with transparency, if it does not change the resulting
3720 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3721 </td>
3722 </tr>
3723
3724 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3725 into a smaller file size due to larger areas of one (transparent)
3726 color rather than a pattern of multiple colors repeating the current
3727 disposed image of the last frame. </td>
3728 </tr>
3729
3730 <tr valign="top">
3731 <td valign="top">remove-dups</td>
3732 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3733 images, so as to simplify layer overlays of coalesced animations.
3734 </td>
3735 </tr>
3736
3737 <tr><td></td><td>Usually this a result of using a constant time delay across the
3738 whole animation, or after a larger animation was split into smaller
3739 sub-animations. The duplicate frames could also have been used as
3740 part of some frame optimization methods. </td>
3741 </tr>
3742
3743 <tr valign="top">
3744 <td valign="top">remove-zero</td>
3745 <td valign="top">Remove any image with a zero time delay, unless ALL the
3746 images have a zero time delay (and is not a proper timed animation, a
3747 warning is then issued). </td>
3748 </tr>
3749
3750 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3751 partial intermediary updates between the frames that are actually
3752 displayed to users. These frames are usally added for improved frame
3753 optimization in GIF animations. </td>
3754 </tr>
3755
3756 <tr valign="top">
3757 <td valign="top">trim-bounds</td>
3758 <td valign="top">Find the bounds of all the images in the current
3759 image sequence, then adjust the offsets so all images are contained on
3760 a minimal positive canvas. None of the image data is modified, only
3761 there virtual canvas size and offset. The all the image is given
3762 the same canvas size, and and will have a positive offset, but will
3763 remain in the same position relative to each other. As a result of the
3764 minimal canvas size at least one image will touch every edge of that
3765 canvas. The image data however may be transparent.
3766 </td>
3767 </tr>
3768
3769 </tbody>
3770</table>
3771
3772<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3773
3774<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3775>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3776>-mosaic</a> are only aliases for the above methods. Also see <a
3777href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3778href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3779>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3780
3781
3782<div style="margin: auto;">
3783 <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>
3784</div>
3785
3786<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>
3787
3788<p>Given one, two or three values delimited with commas: black-point,
3789white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3790white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3791point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3792contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3793both black and white points are percentages of the full color range. Gamma
3794will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3795omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3796
3797<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3798the given '<kbd>black_point</kbd>' value in the original image is set to
3799zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3800<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3801to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3802adjusted. </p>
3803
3804<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3805adding the special '!' flag anywhere in the argument list, will cause the
3806operator to do the reverse of the level adjustment. That is a zero, or
3807<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3808adjusted to the given level values, allowing you to de-contrast, or compress
3809the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3810
3811<p>Only the channels defined by the current <a href="#channel">-channel</a>
3812setting are adjusted (defaults to RGB color channels only), allowing you to
3813limit the effect of this operator. </p>
3814
3815<p>Please note that the transparency channel is treated as 'matte'
3816values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3817
3818
3819<div style="margin: auto;">
3820 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3821 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3822</div>
3823
3824<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash seperated colors.</td><td style='text-align:right;'></td></tr></table>
3825
3826<p>This function is exactly like <a href="#level">-level</a>, except that the
3827value value for each color channel is determined by the
3828'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3829described under the <a href="#fill">-fill</a> option). </p>
3830
3831<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3832is mapped to become 'black' and 'white' respectivally, with all the other
3833colors linearly adjusted (or clipped) to match that change. Each channel is
3834adjusted separatally using the channel values of the colors specified. </p>
3835
3836<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3837will map the image color 'black' and 'white' to the given colors
3838respectivally, resulting in a gradient (de-contrasting) tint of the image to
3839those colors. This can also be used to convert a plain gray-scale image into a
3840one using the gradient of colors specified. </p>
3841
3842<p>By supplying a single color with a comma separator either before or after
3843that color, will just replace the respective 'black' or 'white' point
3844respectivally. But if no comma separator is provided, the given color is
3845used for both the black and white color points, making the operator either
3846threshold the images around that color (- form) or set all colors to that
3847color (+ form). </p>
3848
3849
3850<div style="margin: auto;">
3851 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3852</div>
3853
3854<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>
3855
3856<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>
3857
3858<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>
3859
3860<p class="crtsnip">
cristyd934d102009-10-10 12:55:13 +00003861 -limit memory 32MiB -limit map 64MiB
cristy3ed852e2009-09-05 21:47:34 +00003862</p>
3863
3864<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3865
cristyd934d102009-10-10 12:55:13 +00003866<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
3867-----------------------------------------------------------------------
3868 768 3.8187GiB 2.864GiB 7.6375GiB 16EiB 2 unlimited</pre>
cristy3ed852e2009-09-05 21:47:34 +00003869</span></p>
3870<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>
3871
3872<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>
3873
3874<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>
3875
3876<p class="crtsnip">
3877-limit area 10mb
3878</p>
3879
3880<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>
3881
3882<p class="crtsnip">
3883-limit area 10mb -limit disk 500mb
3884</p>
3885
3886<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3887
3888<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>
3889
3890<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.
3891</p>
3892
3893<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.
3894</p>
3895
3896<div style="margin: auto;">
3897 <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>
3898</div>
3899
3900<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>
3901
cristyd934d102009-10-10 12:55:13 +00003902<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>,
3903and uses a 'histogram bin' to determine the range of color values that needs to
3904be stretched. However it then stretchs those colors using the <a
3905href="#level" >-level</a> operator.</p>
3906
3907<p>As such while the initial determination may have 'binning' round off
3908effects, the image colors are stretched mathematically, rather than using the
3909histogram bins. This makes the operator more accurate. </p>
3910
3911<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of
3912'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near
3913perfect stretch of the color range. </p>
3914
3915<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect'
3916normalization of mathematical images. </p>
3917
3918<p>This operator is under review for re-development. </p>
3919
3920
cristy3ed852e2009-09-05 21:47:34 +00003921<div style="margin: auto;">
3922 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3923</div>
3924
3925<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>
3926
3927<div style="margin: auto;">
3928 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3929</div>
3930
3931<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>
3932
3933<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>
3934
3935<div style="margin: auto;">
3936 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3937</div>
3938
3939<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>
3940
3941<pre class="text">
3942 coder
3943 color
3944 configure
3945 delegate
3946 font
3947 format
3948 list
3949 log
3950 magic
3951 module
3952 resource
3953 threshold
3954</pre>
3955
3956<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>
3957
3958<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3959<div style="margin: auto;">
3960 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3961</div>
3962
3963<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>
3964
3965<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3966
3967<p>You can display the following components by embedding special format characters:</p>
3968
3969<pre class="text">
3970 %d domain
3971 %e event
3972 %f function
3973 %l line
3974 %m module
3975 %p process ID
3976 %r real CPU time
3977 %t wall clock time
3978 %u user CPU time
3979 %% percent sign
3980 \n newline
3981 \r carriage return
3982</pre>
3983
3984<p>For example:</p>
3985
3986<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>
3987<p>The default behavior is to print all of the components.</p>
3988
3989<div style="margin: auto;">
3990 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3991</div>
3992
3993<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>
3994
3995<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>
3996
3997<div style="margin: auto;">
3998 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3999</div>
4000
4001<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>
4002
4003<div style="margin: auto;">
4004 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
4005</div>
4006
4007<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>
4008
4009
4010<div style="margin: auto;">
4011 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
4012</div>
4013
4014<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>
4015
4016<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
4017
4018<pre class="text">
4019 best
4020 default
4021 gray
4022 red
4023 green
4024 blue
4025</pre>
4026
4027<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>
4028
4029
4030<div style="margin: auto;">
4031 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
4032</div>
4033
4034<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>
4035
4036<p>Here are the valid components of a map:</p>
4037
4038<pre class="text">
4039 r red pixel component
4040 g green pixel component
4041 b blue pixel component
4042 a alpha pixel component (0 is transparent)
4043 o opacity pixel component (0 is opaque)
4044 i grayscale intensity pixel component
4045 c cyan pixel component
4046 m magenta pixel component
4047 y yellow pixel component
4048 k black pixel component
4049 p pad component (always 0)
4050</pre>
4051
4052<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>
4053
4054<div style="margin: auto;">
4055 <h4><a name="mask" id="mask"></a>-mask
4056<em class="arg">filename</em></h4>
4057</div>
4058
4059<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>
4060
4061<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
4062
4063<div style="margin: auto;">
4064 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
4065</div>
4066
4067<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>
4068
4069<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4070
4071<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
4072
4073<div style="margin: auto;">
4074 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
4075</div>
4076
4077<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>
4078
4079<div style="margin: auto;">
4080 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
4081</div>
4082
4083<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>
4084
4085<p>Choose from:</p>
4086
4087<pre class="text">
4088 AE absolute number of differnet pixels
4089 MAE mean absolute error (normalized), average channel error distance
4090 MEPP mean error per pixel (normalized mean error, normalized peak error)
4091 MSE mean error squared, average of the channel error squared
4092 PAE peak absolute (normalize peak absolute)
4093 PSNR peak signal to noise ratio
4094 RMSE root mean squared (normalized root mean squared)
4095</pre>
4096
4097<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
4098controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
4099only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
4100size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
4101'similar'. </p>
4102
4103<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
4104('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
4105normalized) from the single comparision run. </p>
4106
4107<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
4108
4109
4110<div style="margin: auto;">
4111 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
4112</div>
4113
4114<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>
4115
4116<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
4117
4118<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
4119argument for a list of <a href="#mode" >-mode</a> arguments available
4120in your ImageMagick installation.</p>
4121
4122
4123<div style="margin: auto;">
4124 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
4125</div>
4126
4127<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>
4128
4129<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
4130missing values are taken to mean 100.</p>
4131
4132<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
4133means pure black, 50 is half as bright, 200 is twice as bright. To invert its
4134meaning <a href="#negate">-negate</a> the image before and after. </p>
4135
4136<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>
4137
4138<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
4139shades to purple, and so on. A value of either 0 or 200 results in a complete
4140180 degree rotation of the image. Using a value of 300 is a 360 degree
4141rotation resulting in no change to the original image. </p>
4142
4143<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>
4144
4145<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>
4146
4147<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>
4148<div style="margin: auto;">
4149 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
4150</div>
4151
4152<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>
4153
4154
4155<div style="margin: auto;">
4156 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
4157</div>
4158
4159<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>
4160
4161
4162<div style="margin: auto;">
4163 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4164</div>
4165
4166<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>
4167
4168<p>Both the image pixels and size are linearly interpolated to give the
4169appearance of a meta-morphosis from one image to the next, over all the images
4170in the current image list. The added images are the equivalent of a <a
4171href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4172argument determine how many images to interpolate between each image. </p>
4173
4174
4175<div style="margin: auto;">
4176 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4177</div>
4178
4179<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>
4180
4181
4182<div style="margin: auto;">
4183 <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>
4184</div>
4185
4186<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>
4187
4188<p>Blur with the given radius, standard deviation (sigma), and angle. The
4189angle given is the angle toward which the image is blurred. That is the
4190direction people would consider the object is coming from. </p>
4191
4192<p>Note that the blur is not uniform distribution, giving the motion a
4193definate sense of direction of movement. </p>
4194
4195<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4196pixels which are outside the image proper are blurred into the final result.
4197</p>
4198
4199<div style="margin: auto;">
4200 <h4><a name="name" id="name"></a>-name</h4>
4201</div>
4202
4203<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>
4204<div style="margin: auto;">
4205 <h4><a name="negate" id="negate"></a>-negate</h4>
4206</div>
4207
4208<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>
4209
4210<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>
4211
4212<div style="margin: auto;">
4213 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4214 +noise <em class="arg">type</em></h4>
4215</div>
4216
4217<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>
4218
4219<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>
4220
4221<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>
4222
4223<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>
4224
4225<pre class="text">
4226Gaussian
4227Impulse
4228Laplacian
4229Multiplicative
4230Poisson
4231Random
4232Uniform
4233</pre>
4234
4235<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4236
cristy83543962009-10-16 19:04:28 +00004237<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos
4238the use of a controlling value to specify teh amount of noise that should be
4239added to an image. </p>
4240
cristy3ed852e2009-09-05 21:47:34 +00004241
4242<div style="margin: auto;">
4243 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4244</div>
4245
4246<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>
4247
cristyd934d102009-10-10 12:55:13 +00004248<p>The intensity values are stretched to cover the entire range of possible
4249values. While doing so, black-out at most <em>2%</em> of the pixels and
4250white-out at most <em>1%</em> of the pixels.</p>
cristy3ed852e2009-09-05 21:47:34 +00004251
cristyd934d102009-10-10 12:55:13 +00004252<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a>
4253is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>.
4254(Before this version, it was equivalent to <a href="#contrast-stretch"
4255>-contrast-stretch 2%x99%</a>).</p>
cristy3ed852e2009-09-05 21:47:34 +00004256
cristyd934d102009-10-10 12:55:13 +00004257<p>All the channels are normalized in concert by the came amount so as to
4258preserve color integrity, when the default <a href="#channel" >+channel</a>
4259setting is in use. Specifing any other <a href="#channel" >-channel</a>
4260setting will normalize the RGB channels independently.</p>
4261
4262<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details.
4263Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization
cristy83543962009-10-16 19:04:28 +00004264that is better suited to mathematically generated images. </p>
cristyd934d102009-10-10 12:55:13 +00004265
4266<p>This operator is under review for re-development. </p>
cristy3ed852e2009-09-05 21:47:34 +00004267
4268
4269<div style="margin: auto;">
4270 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4271</div>
4272
cristyd934d102009-10-10 12:55:13 +00004273<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
4274class="arg">threshold map</em> specified, and a uniform color map with the
4275given 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 +00004276
4277<p>You can choose from these standard threshold maps:</p>
4278
4279<pre class="text">
cristyd934d102009-10-10 12:55:13 +00004280 threshold
cristy3ed852e2009-09-05 21:47:34 +00004281 checks
4282 o2x2
4283 o3x3
4284 o4x4
4285 o8x8
4286 h4x4a
4287 h6x6a
4288 h8x8a
4289 h4x4o
4290 h6x6o
4291 h8x8o
4292 h16x16o
4293</pre>
4294
cristyd934d102009-10-10 12:55:13 +00004295<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the
4296'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or
4297'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither
4298pattern. Or you can define your own <em class="arg" >threshold map</em> in a
4299personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
cristy3ed852e2009-09-05 21:47:34 +00004300
cristyd934d102009-10-10 12:55:13 +00004301<p>To print a complete list of threshold, use the <a href="#list" >-list
4302threshold</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004303
cristyd934d102009-10-10 12:55:13 +00004304<p>It is recommended that the <a href="#map" >+map</a> operator be used after
4305applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of
cristy3ed852e2009-09-05 21:47:34 +00004306colors an animated image sequence, to less that 256 colors. This ensures that
4307a common or global color table is used when saving the result to a color
4308limited file format such as GIF. </p>
4309
cristyd934d102009-10-10 12:55:13 +00004310<p>Note that at this time the exact same threshold dithering map is used for
4311all color channels, no attempt is made to offset or rotate the map for
4312different channels is made, to create an offset printing effect. (possible
4313future expansion) </p>
cristy3ed852e2009-09-05 21:47:34 +00004314
4315
4316<div style="margin: auto;">
4317 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4318</div>
4319
4320<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>
4321
cristyd934d102009-10-10 12:55:13 +00004322<p>The <em class="arg" >color</em> argument is defined using the format
4323described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz"
4324>-fuzz</a> setting can be used to match and replace colors similar to the one
4325given.</p>
cristy3ed852e2009-09-05 21:47:34 +00004326
cristyd934d102009-10-10 12:55:13 +00004327<p>The <a href="#transparent" >-transparent</a> operator is exactly the same
4328as <a href="#opaque" >-opaque</a> but makes the matching color transparent,
cristy3ed852e2009-09-05 21:47:34 +00004329rather than the same as the current <a href="#fill">-fill</a> color. </p>
4330
cristyd934d102009-10-10 12:55:13 +00004331<p>Use <em class="arg" >+opaque</em> to paint any pixel that does not match
4332the target color.</p>
4333
4334
cristy3ed852e2009-09-05 21:47:34 +00004335
4336<div style="margin: auto;">
4337 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4338</div>
4339
4340<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>
4341
4342<p>Choose from these orientations:</p>
4343
4344<pre class="text">
4345 bottom-left
4346 bottom-right
4347 left-bottom
4348 left-top
4349 right-bottom
4350 right-top
4351 top-left
4352 top-right
4353 undefined
4354</pre>
4355
cristyd934d102009-10-10 12:55:13 +00004356<p>To print a complete list of orientations, use the <a href="#list" >-list
4357orientation</a> option.</p>
cristy3ed852e2009-09-05 21:47:34 +00004358
4359
4360<div style="margin: auto;">
4361 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4362 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4363 +page
4364 </h4>
4365</div>
4366
4367<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>
4368
4369<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>
4370
4371<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>
4372
4373<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>
4374<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4375<thead>
4376 <tr valign="top">
4377 <th align="center"><em class="arg">media</em></th>
4378 <th align="center"><em class="arg">width</em></th>
4379 <th align="center"><em class="arg">height</em></th>
4380 </tr>
4381</thead>
4382<tbody>
4383<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4384<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4385<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4386<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4387<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4388<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4389<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4390<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4391<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4392<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4393<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4394<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4395<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4396<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4397<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4398<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4399<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4400<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4401<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4402<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4403<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4404<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4405<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4406<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4407<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4408<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4409<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4410<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4411<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4412<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4413<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4414<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4415<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4416<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4417<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4418<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4419<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4420<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4421</tbody>
4422</table>
4423
4424
4425
4426
4427<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>
4428
4429<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>
4430
4431<p>The default page dimensions for a TEXT image is 612x792.</p>
4432
4433<p>This option is used in concert with <a href="#density">-density</a>.</p>
4434
4435<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4436
4437<div style="margin: auto;">
4438 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4439</div>
4440
4441<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>
4442
4443<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>
4444
4445<div style="margin: auto;">
4446 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4447
4448<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>
4449
4450<div style="margin: auto;">
4451 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4452</div>
4453
4454<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>
4455
4456<p>Pause for the specified number of seconds before repeating the animation.</p>
4457
4458<div style="margin: auto;">
4459 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4460</div>
4461
4462<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>
4463
4464<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4465
4466<div style="margin: auto;">
4467 <h4><a name="ping" id="ping"></a>-ping</h4>
4468</div>
4469
4470<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>
4471
4472<div style="margin: auto;">
4473 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4474</div>
4475
4476<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>
4477
4478<div style="margin: auto;">
4479 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4480</div>
4481
4482<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>
4483
4484<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4485
4486<div style="margin: auto;">
4487 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4488</div>
4489
4490<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>
4491
4492<div style="margin: auto;">
4493 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4494</div>
4495
4496<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>
4497
4498<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>
4499
4500<pre class="text">
4501 Rotate
4502 Shear
4503 Roll
4504 Hue
4505 Saturation
4506 Brightness
4507 Gamma
4508 Spiff
4509 Dull
4510 Grayscale
4511 Quantize
4512 Despeckle
4513 ReduceNoise
4514 Add Noise
4515 Sharpen
4516 Blur
4517 Threshold
4518 EdgeDetect
4519 Spread
4520 Shade
4521 Raise
4522 Segment
4523 Solarize
4524 Swirl
4525 Implode
4526 Wave
4527 OilPaint
4528 CharcoalDrawing
4529 JPEG
4530</pre>
4531
4532<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4533
4534<p>The default preview is <kbd>JPEG</kbd>.</p>
4535
4536<div style="margin: auto;">
4537 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4538</div>
4539
4540<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>
4541
4542<div style="margin: auto;">
4543 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4544</div>
4545
4546<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>
4547
4548<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>
4549
4550<div style="margin: auto;">
4551 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4552 +profile <em class="arg">profile_name</em></h4>
4553</div>
4554
4555<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>
4556
4557<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>
4558
4559<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>
4560
4561<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>
4562
4563<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>
4564
4565<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4566
4567<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4568<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>
4569
4570<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>
4571<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4572CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4573</p>
4574
4575<div style="margin: auto;">
4576 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4577</div>
4578
4579<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>
4580
4581<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>
4582
4583<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>
4584
4585<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>
4586
4587<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>
4588
4589<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4590
4591<pre class="text">
4592 0: none
4593 1: sub
4594 2: up
4595 3: average
4596 4: Paeth
4597</pre>
4598
4599<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>
4600
4601<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4602
4603<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>
4604
4605<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>
4606
4607<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4608
4609<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>
4610
4611<div style="margin: auto;">
4612 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4613</div>
4614
4615<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>
4616
4617<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4618
4619
4620<div style="margin: auto;">
4621 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4622</div>
4623
4624<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>
4625
4626<div style="margin: auto;">
4627 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4628</div>
4629
4630<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>
4631
4632<p>Note that this is actually a rotational blur rather than a radial and as
4633such actually mis-named. </p>
4634
4635<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4636pixels which are outside the image proper are blurred into the final result.
4637</p>
4638
4639
4640<div style="margin: auto;">
4641 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4642</div>
4643
4644<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>
4645
4646<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>.
4647</p>
4648
4649<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4650
4651<div style="margin: auto;">
4652 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4653</div>
4654
4655<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>
4656
4657<div style="margin: auto;">
4658 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4659</div>
4660
4661<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>
4662
4663<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.
4664</p>
4665
4666<div style="margin: auto;">
4667 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4668</div>
4669
4670<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>
4671
4672<div style="margin: auto;">
4673 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4674</div>
4675
4676<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>
4677
4678<div style="margin: auto;">
4679 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4680</div>
4681
4682<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>
4683
4684<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4685the given colors are dithered over the image as necessary, otherwise the closest
4686color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4687
4688<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4689images in the current image sequence, all the images will have the same color
4690table. That means that when saved to a file format such as GIF, it will use
4691that color table as a single common or global color table, for all the images,
4692without requiring extra local color tables. </p>
4693
4694<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4695sequence to use a common color map over all the images. This equivalent to
4696appending all the images together (without extra background colors) and color
4697reducing those images using <a href="#colors">-colors</a> with a 256 color
4698limit, then <a href="#remap">-remap</a> those colors over the original list of
4699images. This ensures all the images follow a single color map. </p>
4700
4701<p>If the number of colors over all the images is less than 256, then <a
4702href="#remap">+remap</a> should not perform any color reduction or dithering, as
4703no color changes are needed. In that case, its only effect is to force the use
4704of a global color table. This recommended after using either <a
4705href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4706reduce the number of colors in an animated image sequence. </p>
4707
4708<div style="margin: auto;">
4709 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4710</div>
4711
4712<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>
4713
4714<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>
4715
4716<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>
4717
4718<div style="margin: auto;">
4719 <h4><a name="remote" id="remote"></a>-remote</h4>
4720</div>
4721
4722<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>
4723
4724<p>The only command recognized is the name of an image file to load.</p>
4725
4726<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>
4727
4728<div style="margin: auto;">
4729 <h4><a name="render" id="render"></a>-render</h4>
4730</div>
4731
4732<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>
4733
4734<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>
4735
4736<div style="margin: auto;">
4737<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4738</div>
4739
4740<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>
4741
4742<p>This option is like <a href="#page">-page</a> but acts as an image operator
4743rather than a setting. You can separately set the canvas size or the offset
4744of the image on that canvas by only providing those components. </p>
4745
4746<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>
4747
4748<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4749offset to move the image relative to its previous position. This useful for
4750animation sequences. </p>
4751
4752<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4753recalculate the canvas size so the image (at its current offset) will appear
4754completely on that canvas (unless it has a negative offset).</p>
4755
4756<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4757canvas meta-data from the images. </p>
4758
4759<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4760directly assign virtual canvas meta-data. </p>
4761
4762
4763<div style="margin: auto;">
4764 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4765</div>
4766
4767<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>
4768
4769<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>
4770
4771<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>
4772
4773<div style="margin: auto;">
4774 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4775</div>
4776
4777<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>
4778
4779<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>
4780
4781<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>
4782
4783<div style="margin: auto;">
4784 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4785</div>
4786
4787<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>
4788
4789<div style="margin: auto;">
4790 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4791</div>
4792
4793<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>
4794
4795
4796<div style="margin: auto;">
4797 <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>
4798</div>
4799
4800<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>
4801
4802<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>
4803
4804
4805<div style="margin: auto;">
4806 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4807</div>
4808
4809<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>
4810
4811<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>
4812
4813<p>Empty triangles in the corners, left over from rotating the image, are
4814filled with the <kbd>background</kbd> color. </p>
4815
4816<p>See also the <a href="#distort">-distort</a> operator and specifically the
4817'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4818
4819
4820<div style="margin: auto;">
4821 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4822</div>
4823
4824<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>
4825
4826<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>
4827
4828<p>See <a href="../www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p>
4829
4830
4831<div style="margin: auto;">
4832 <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>
4833</div>
4834
4835<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>
4836
4837<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>
4838
4839<div style="margin: auto;">
4840 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4841</div>
4842
4843<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>
4844
4845<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>
4846
4847<div style="margin: auto;">
4848 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4849</div>
4850
4851<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>
4852
4853<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4854
4855<div style="margin: auto;">
4856 <h4><a name="screen" id="screen"></a>-screen</h4>
4857</div>
4858
4859<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>
4860
4861<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>
4862
4863<div style="margin: auto;">
4864 <h4><a name="seed" id="seed"></a>-seed</h4>
4865</div>
4866
4867<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>
4868
4869<div style="margin: auto;">
4870 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4871</div>
4872
4873<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>
4874
4875<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>
4876
4877<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>
4878
4879<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4880of the color clusters is returned.</p>
4881
4882
4883<div style="margin: auto;">
4884 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4885</div>
4886
4887<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Selectively blur pixels within a contrast threshold.</td><td style='text-align:right;'></td></tr></table>
4888
4889<div style="margin: auto;">
4890 <h4><a name="separate" id="separate"></a>-separate</h4>
4891</div>
4892
4893<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>
4894
4895<div style="margin: auto;">
4896 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4897</div>
4898
4899<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>
4900
4901<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4902
4903<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>
4904
4905<div style="margin: auto;">
4906 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4907</div>
4908
4909<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>
4910
4911<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>
4912
4913<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>
4914<p>The <a href="#repage">-repage</a> operator will also set the
4915'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4916separately set the virtual canvas's size and offset components, and also allows
4917relative offset changes, and automatic canvas size re-calculating. The above
4918<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4919virtual canvas (page) meta-data. </p>
4920
4921<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>
4922
4923<div style="margin: auto;">
4924 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4925</div>
4926
4927<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>
4928
4929<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>
4930
4931<div style="margin: auto;">
4932 <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>
4933</div>
4934
4935<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>
4936
4937<div style="margin: auto;">
4938 <h4><a name="shared-memory"
4939id="shared-memory"></a>-shared-memory</h4>
4940</div>
4941
4942<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>
4943
4944<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>
4945
4946<div style="margin: auto;">
4947 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4948</div>
4949
4950<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>
4951
4952<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4953
4954<div style="margin: auto;">
4955 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4956</div>
4957
4958<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>
4959
4960<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>
4961
4962<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>
4963
4964<div style="margin: auto;">
4965 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4966</div>
4967
4968<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>
4969
4970<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>
4971
4972<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>
4973
4974<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>
4975
4976<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>
4977
4978<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>
4979<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>
4980
4981<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4982<div style="margin: auto;">
4983 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4984</div>
4985
4986<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>
4987
4988<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>
4989
4990<div style="margin: auto;">
4991 <h4><a name="silent" id="silent"></a>-silent</h4>
4992</div>
4993
4994<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>
4995
4996<div style="margin: auto;">
4997 <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>
4998</div>
4999
5000<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>
5001
5002<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>
5003
5004<p>For Photo CD images, choose from these sizes:</p>
5005
5006<pre class="text">
5007 192x128
5008 384x256
5009 768x512
5010 1536x1024
5011 3072x2048
5012</pre>
5013
cristy3ed852e2009-09-05 21:47:34 +00005014<div style="margin: auto;">
5015 <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>
5016</div>
5017
5018<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>
5019
5020<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>
5021
5022<div style="margin: auto;">
5023 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
5024</div>
5025
5026<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>
5027
5028<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
5029
5030<div style="margin: auto;">
5031 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
5032</div>
5033
5034<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>
5035
5036<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
5037
5038<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
5039
5040<div style="margin: auto;">
5041 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
5042 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
5043</div>
5044
5045<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>
5046
5047
5048<table class="doc">
5049 <tbody>
5050 <tr valign="top">
5051 <th align="left" style="width: 8%">Method</th>
5052 <th align="left">Description</th>
5053 </tr>
5054
5055 <tr valign="top">
5056 <td valign="top">voronoi</td>
5057 <td valign="top">Simply map each pixel to the to nearest color point
5058 given. The result are polygonal 'cells' of solid color. </td>
5059 </tr>
5060
5061 <tr valign="top">
5062 <td valign="top">shepards</td>
5063 <td valign="top">Colors points basied on the ratio of inverse distance
5064 squared. Generating spots of color in a sea of the average of
5065 colors. </td>
5066 </tr>
5067
5068 <tr valign="top">
5069 <td valign="top">barycentric</td>
5070 <td valign="top">three point triangle of color given 3 points.
5071 Giving only 2 points will form a linear gradient between those points.
5072 Gradient is however not restricted to just the triangle or line. </td>
5073 </tr>
5074
5075 <tr valign="top">
5076 <td valign="top">bilinear</td>
5077 <td valign="top">Like barycentric but for 4 points. Less than 4 points
5078 fall back to barycentric. </td>
5079 </tr>
5080
5081 </tbody>
5082</table>
5083
5084<p>The points are placed according to the images location on the virtual
5085canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
5086offset), and do not actually have to exist on the given image, but may be
5087some point beyond the edge of the image. All points are floating point values.
5088</p>
5089
5090<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
5091modified, whcih means the matte/alpha transparency channel is not effected by
5092default. If enabled, the image also needs a the matte/alpha channel to be
5093enabled for this operator to effect an images transparency. This is typical
5094transparency handling for images. </p>
5095
5096<p>All the above methods when given a single point of color will replace all
5097the colors in the image with the color given, regardless of the point. This is
5098logical, and provides an alternative technique to recolor a image to some
5099default value. </p>
5100
5101
5102<div style="margin: auto;">
5103 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
5104</div>
5105
5106<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>
5107
5108<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>
5109
5110<div style="margin: auto;">
5111 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
5112</div>
5113
5114<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>
5115
5116<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>
5117
5118<div style="margin: auto;">
5119 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
5120</div>
5121
5122<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>
5123
5124<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>
5125
5126<div style="margin: auto;">
5127 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
5128</div>
5129
5130<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>
5131
5132<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>
5133
5134<div style="margin: auto;">
5135 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
5136</div>
5137
5138<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>
5139
5140<pre class="text">
5141 char store pixels as unsigned characters
5142 double store pixels as doubles
5143 float store pixels as floats
5144 integer store pixels as integers
5145 long store pixels as longs
5146 quantum store pixels in the native depth of your ImageMagick distribution
5147 short store pixels as unsigned shorts
5148</pre>
5149
5150<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
5151values range from 0 to the maximum value the storage type can support.</p>
5152
5153<div style="margin: auto;">
5154 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
5155</div>
5156
5157<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>
5158
5159<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>
5160
5161<pre class="text">
5162 Any
5163 Condensed
5164 Expanded
5165 ExtraCondensed
5166 ExtraExpanded
5167 Normal
5168 SemiCondensed
5169 SemiExpanded
5170 UltraCondensed
5171 UltraExpanded
5172</pre>
5173
5174<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
5175
5176<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>
5177
5178<div style="margin: auto;">
5179 <h4><a name="strip" id="strip"></a>-strip</h4>
5180</div>
5181
5182<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>
5183
5184<div style="margin: auto;">
5185 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
5186</div>
5187
5188<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>
5189
5190<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5191
5192<p>See <a href="#draw">-draw</a> for further details.</p>
5193
5194<div style="margin: auto;">
5195 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5196</div>
5197
5198<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>
5199
5200<p>See <a href="#draw">-draw</a> for further details.</p>
5201
5202<div style="margin: auto;">
5203 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5204</div>
5205
5206<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>
5207
5208<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>
5209
5210<pre class="text">
5211 Any
5212 Italic
5213 Normal
5214 Oblique
5215</pre>
5216
5217<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>
5218
5219<div style="margin: auto;">
5220 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5221</div>
5222
5223<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>
5224
5225<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>
5226
5227<div style="margin: auto;">
5228 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5229</div>
5230
5231<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>
5232
5233<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5234
5235<div style="margin: auto;">
5236 <h4><a name="taint" id="taint"></a>-taint</h4>
5237</div>
5238
5239<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>
5240
5241<div style="margin: auto;">
5242 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5243</div>
5244
5245<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>
5246
5247<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>
5248
5249<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>
5250
5251<div style="margin: auto;">
5252 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5253</div>
5254
5255<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>
5256
5257<div style="margin: auto;">
5258 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5259</div>
5260
5261<!-- {<em class="arg">green,blue,opacity</em>}
5262<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>
5263-->
5264
5265<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>
5266
5267<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>
5268
5269<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.
5270</p>
5271
5272<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>
5273
5274<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5275<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>
5276
5277
5278<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>
5279<p>Note that the values of the transparency channel is treated as 'matte'
5280values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5281
5282<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>.
5283</p>
5284
5285<div style="margin: auto;">
5286 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5287</div>
5288
5289<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>
5290
5291<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>
5292
5293<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>
5294
5295<div style="margin: auto;">
5296 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5297</div>
5298
5299<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>
5300
5301<div style="margin: auto;">
5302 <h4>-tile <em class="arg">geometry</em></h4>
5303</div>
5304
5305<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>
5306
5307<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>
5308
5309<div style="margin: auto;">
5310 <h4>-tile</h4>
5311</div>
5312
5313<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>
5314
5315<div style="margin: auto;">
5316 <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>
5317</div>
5318
5319<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>
5320
5321<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>
5322
5323<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>
5324
5325<div style="margin: auto;">
5326 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5327</div>
5328
5329<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>
5330
5331<p>Tint the image with the fill color.</p>
5332
5333<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>
5334
5335<div style="margin: auto;">
5336 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5337</div>
5338
5339<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>
5340
5341<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>
5342
5343<p>For example,</p>
5344
5345<p class="crtsnip">
5346 -title "%m:%f %wx%h"
5347</p>
5348
5349<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>
5350
5351
5352<div style="margin: auto;">
5353 <h4><a name="transform" id="transform"></a>-transform</h4>
5354</div>
5355
5356<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>
5357
5358<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5359
5360<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>
5361<div style="margin: auto;">
5362 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5363</div>
5364
5365<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>
5366
5367<p>The <em class="arg">color</em> argument is defined using the format
5368described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5369>-fuzz</a> setting can be used to match and replace colors similar to the one
5370given. </p>
5371
5372<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5373href="#transparent" >-transparent</a> but replaces the matching color same as
5374the current <a href="#fill">-fill</a> color setting. </p>
5375
5376<p>This does not define the 'transparency color' used for color-mapped image
5377formats, such as GIF. For that use <a href="#transparent-color"
5378>-transparent-color</a> </p>
5379
5380<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5381paint any pixel that does not match the target color, with the fill color.</p>
5382
5383
5384<div style="margin: auto;">
5385 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5386</div>
5387
5388<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>
5389
5390<p>Sometimes this is used for saving to image formats such as
5391GIF and PNG8 which uses this color to represent boolean transparency. This
5392does not make a color transparent, it only defines what color the transparent
5393color is in the color palette of the saved image. Use <a
5394href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5395
5396<p>This option allows you to have both an opaque visible color, as well as a
5397transparent color of the same color value without conflict. That is, you can
5398use the same color for both the transparent and opaque color areas within an
5399image. This, in turn, frees to you to select a transparent color that is
5400appropriate when an image is displayed by an application that does not handle a
5401transparent color index, while allowing ImageMagick to correctly handle images of this
5402type. </p>
5403
5404<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5405
5406<div style="margin: auto;">
5407 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5408</div>
5409
5410<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>
5411
5412<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5413</p>
5414
5415<div style="margin: auto;">
5416 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5417</div>
5418
5419<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>
5420
5421
5422<div style="margin: auto;">
5423 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5424</div>
5425
5426<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>
5427
5428<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>
5429
5430<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>
5431
5432<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>
5433
5434<div style="margin: auto;">
5435 <h4><a name="trim" id="trim"></a>-trim</h4>
5436</div>
5437
5438<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>
5439
5440<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>
5441
5442<p>The page or virtual canvas information of the image is preserved allowing
5443you to extract the result of the <a href="#trim">-trim</a> operation from the
5444image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5445information if it is unwanted.</p>
5446
5447<p>If the trimmed image 'disappears' an warning is produced, and a special
5448single pixel transparent 'missed' image is returned, in the same way as when a
5449<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5450
5451
5452<div style="margin: auto;">
5453 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5454</div>
5455
5456<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>
5457 <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>
5458
5459<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>
5460
5461<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5462<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>
5463
5464<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5465
5466<div style="margin: auto;">
5467 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5468</div>
5469
5470<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>
5471
5472<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5473
5474<p>See <a href="#draw">-draw</a> for further details.</p>
5475
5476
5477<div style="margin: auto;">
5478 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5479</div>
5480
5481<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>
5482
5483<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>
5484
5485
5486<div style="margin: auto;">
5487 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5488</div>
5489
5490<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>
5491
5492
5493<div style="margin: auto;">
5494 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5495</div>
5496
5497<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>
5498
5499<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>
5500
5501
5502<div style="margin: auto;">
5503 <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>
5504</div>
5505
5506<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>
5507
5508<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>
5509
5510<p>The parameters are:</p>
5511
5512<pre class="text">
5513 radius: The radius of the Gaussian, in pixels, not counting the center
5514 pixel (default 0).
5515 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5516 amount: The fraction of the difference between the original and the blur
5517 image that is added back into the original (default 1.0).
5518 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5519 difference amount (default 0.05).
5520</pre>
5521
5522
5523<div style="margin: auto;">
5524 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5525</div>
5526
5527<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>
5528
5529
5530<div style="margin: auto;">
5531 <h4><a name="version" id="version"></a>-version</h4>
5532</div>
5533
5534<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>
5535
5536
5537<div style="margin: auto;">
5538 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5539</div>
5540
5541<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>
5542
5543
5544<div style="margin: auto;">
5545 <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>
5546</div>
5547
5548<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>
5549
5550
5551<div style="margin: auto;">
5552 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5553</div>
5554
5555<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>
5556
5557<p>This option defines what color source should be used if and when a color
5558lookup completely 'misses' the source image. The color(s) that appear to
5559surround the source image. Generally this color is derived from the source
5560image, but could also be set to a specify background color. </p>
5561
5562<p>Choose from these methods:</p>
5563
5564<pre class="text">
5565 background: the area surrounding the image is the background color
5566 black: the area surrounding the image is black
5567 checker-tile: alternate squares with image and background color
5568 dither: non-random 32x32 dithered pattern
5569 edge: extend the edge pixel toward infinity
5570 gray: the area surrounding the image is gray
5571 horizontal-tile: horizontally tile the image, background color above/below
5572 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5573 mirror: mirror tile the image
5574 random: choose a random pixel from the image
5575 tile: tile the image (default)
5576 transparent: the area surrounding the image is transparent blackness
5577 vertical-tile: vertically tile the image, sides are background color
5578 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5579 white: the area surrounding the image is white
5580</pre>
5581
5582<p>The default value is "edge".</p>
5583
5584<p>This most important for distortion operators such as <a href="#distort"
5585>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5586However it also effects operations that may access pixels just outside the
5587image proper, such as <a href="#convolve">-convolve</a>, <a
5588href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5589
5590<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5591
5592
5593<div style="margin: auto;">
5594 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5595</div>
5596
5597<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>
5598
5599<p>Choose from these visual classes:</p>
5600
5601<pre class="text">
5602 StaticGray
5603 GrayScale
5604 StaticColor
5605 PseudoColor
5606 TrueColor
5607 DirectColor
5608 default
5609 visual id
5610</pre>
5611
5612<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>
5613
5614
5615<div style="margin: auto;">
5616 <h4><a name="watermark" id="watermark"></a>-watermark <em
5617 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5618</div>
5619
5620<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
5621saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5622
5623<p>Take a grayscale image (with alpha mask) and modify the destination image's
5624brightness according to watermark image's grayscale value and the <em
5625class="arg">brightness</em> percentage. The destinations color saturation
5626attribute is just direct modified by the <em class="arg">saturation</em>
5627percentage, which defaults to 100 percent (no color change). </p>
5628
5629
5630<div style="margin: auto;">
5631 <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>
5632</div>
5633
5634<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>
5635
5636<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5637
5638<div style="margin: auto;">
5639 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5640</div>
5641
5642<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>
5643
5644<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>
5645
5646<table class="doc">
5647 <col width="25%" />
5648 <col width="75%" />
5649 <thead>
5650 <tr>
5651 <th><em class="arg">fontWeight</em></th>
5652 <th>Description</th>
5653 </tr>
5654 </thead>
5655 <tbody>
5656 <tr><td>All </td> <td>No effect. </td></tr>
5657 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5658 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5659 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5660 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5661 </tbody>
5662 </table>
5663
5664<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5665
5666<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>
5667
5668<div style="margin: auto;">
5669 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5670</div>
5671
5672<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>
5673
5674<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005675 <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 +00005676</div>
5677
cristy5cadd612009-09-21 19:33:41 +00005678<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>
5679
5680<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.
5681</p>
cristy3ed852e2009-09-05 21:47:34 +00005682
5683<div style="margin: auto;">
5684 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5685</div>
5686
5687<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>
5688
5689<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>
5690
5691<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>
5692
5693<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>
5694
5695<div style="margin: auto;">
5696 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5697</div>
5698
5699<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>
5700
5701<div style="margin: auto;">
5702 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5703</div>
5704
5705<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>
5706 <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>
5707
5708<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5709
cristyf3bb4782009-09-08 13:10:04 +00005710
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5724 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span>
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