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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
429<div style="margin: auto;">
430 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4>
431</div>
432
433<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust gamma level of image.</td><td style='text-align:right;'></td></tr></table>
434
435<div style="margin: auto;">
436 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4>
437</div>
438
439<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>
440
441<div style="margin: auto;">
442 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
443</div>
444
445<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>
446
447<div style="margin: auto;">
448 <h4><a name="average" id="average"></a>-average</h4>
449</div>
450
451<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>
452
453<p>An error results if the images are not identically sized.</p>
454
455<p>The sequence of images is terminated by the appearance of any option. If the <a href="#average">-average</a> option appears after all of the input images, all images are averaged.</p>
456
457<div style="margin: auto;">
458 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
459</div>
460
461<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>
462
463<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>
464
465<div style="margin: auto;">
466 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
467</div>
468
469<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>
470
471<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>
472
473<div style="margin: auto;">
474 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
475</div>
476
477<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>
478
479<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>
480
481<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>
482<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>
483
484<div style="margin: auto;">
485 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
486</div>
487
488<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>
489
490<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>
491
492<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>
493
494<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
495negative results without clipping to the color value range
496(0..QuantumRange).</p>
497
498<p>See the discussion on HDRI implementations of ImageMagick on the page
499<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.
500</p>
501
502<div style="margin: auto;">
503 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
504</div>
505
506<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>
507
508<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +0000509 <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 +0000510</div>
511
cristy5cadd612009-09-21 19:33:41 +0000512<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>
513
514<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.
515</p>
cristy3ed852e2009-09-05 21:47:34 +0000516
517
518<div style="margin: auto;">
519 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4>
520</div>
521
522<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>
523
524<p>Blend will average the images together ('plus') according to the
525percentages given and each pixels transparency. If only a single percentage
526value is given it sets the weight of the composite or 'source' image, while
527the background image is weighted by the exact opposite amount. That is a
528<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the
529'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p>
530
531
532<div style="margin: auto;">
533 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
534</div>
535
536<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>
537
538<div style="margin: auto;">
539 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
540</div>
541
542<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>
543
544<div style="margin: auto;">
545
546<div style="margin: auto;">
547 <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>
548</div>
549
550<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>
551
552<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
553
554<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
555</div>
556
557<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>
558
559<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>
560
561<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
562pixels which are outside the image proper are blurred into the final result.
563</p>
564
565
566<div style="margin: auto;">
567 <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>
568</div>
569
570<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>
571
572<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
573Average (EWA) of the source image, scaled according to the grayscale
574mapping. </p>
575
576<p>The ellipse is weighted with sigma set to the given <em class="arg"
577>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
578defaults to the <em class="arg" >Width</em> for a normal circular Guassian
579weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
580horizontal clock-wise. </p>
581
582<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
583pixels which are outside the image proper are blurred into the final result.
584</p>
585
586
587<div style="margin: auto;">
588 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
589</div>
590
591<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>
592
593<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>
594
595<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p>
596
597<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p>
598
599<div style="margin: auto;">
600 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
601</div>
602
603<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>
604
605<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
606
607<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
608
609<div style="margin: auto;">
610 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
611</div>
612
613<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the 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>
614
615<div style="margin: auto;">
616 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
617</div>
618
619<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>
620
621<div style="margin: auto;">
622 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
623</div>
624
625<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>
626
627<div style="margin: auto;">
628 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
629</div>
630
631<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>
632
633<p>Here is an example color correction collection:</p>
634
635<pre class="text">
636&lt;?xml version="1.0" encoding="UTF-8"?>
637&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
638 &lt;ColorCorrection id="cc06668">
639 &lt;SOPNode>
640 &lt;Slope> 0.9 1.2 0.5 &lt;/Slope>
641 &lt;Offset> 0.4 -0.5 0.6 &lt;/Offset>
642 &lt;Power> 1.0 0.8 1.5 &lt;/Power>
643 &lt;/SOPNode>
644 &lt;SATNode>
645 &lt;Saturation> 0.85 &lt;/Saturation>
646 &lt;/SATNode>
647 &lt;/ColorCorrection>
648&lt;/ColorCorrectionCollection>
649</pre>
650
651<div style="margin: auto;">
652 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
653</div>
654
655<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>
656
657<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>
658
659<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p>
660
661<p>The channels above can be specified as a comma-separated list or can be abbreviated as a
662concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', '<kbd>B</kbd>',
663'<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', '<kbd>M</kbd>', '<kbd>Y</kbd>',
664'<kbd>K</kbd>'.
665
666For example, to negate only the alpha channel of an image, use</p>
667<p class="crtsnip">
668 -channel Alpha -negate
669</p>
670
671<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
672'<kbd>RGB</kbd>', which specifies that operators act on all channels except
673the opacity channel. Using the option <a href="#channel" >+channel</a> will reset the value back to this default. </p>
674
675<p>Operators that are affected by the <a href="#channel" >-channel</a>
676setting include the following.
677<a href="#black-threshold">-black-threshold</a>,
678<a href="#blur">-blur</a>,
679<a href="#clut">-clut</a>,
680<a href="#combine">-combine</a>,
681<a href="#contrast-stretch">-contrast-stretch</a>,
682<a href="#evaluate">-evaluate</a>,
683<a href="#function">-function</a>,
684<a href="#fx">-fx</a>,
685<a href="#clut">-hald-clut</a>,
686<a href="#gaussian-blur">-gaussian-blur</a>,
687<a href="#motion-blur">-motion-blur</a>,
688<a href="#negate">-negate</a>,
689<a href="#normalize">-normalize</a>,
690<a href="#ordered-dither">-ordered-dither</a>,
691<a href="#radial-blur">-radial-blur</a>,
692<a href="#random-threshold">-random-threshold</a>,
693<a href="#separate">-separate</a>, and
694<a href="#white-threshold">-white-threshold</a>.
695</p>
696
697
698<div style="margin: auto;">
699 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
700</div>
701
702<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>
703
704<div style="margin: auto;">
705 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
706</div>
707
708<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>
709
710<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>
711
712<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>
713
714<div style="margin: auto;">
715 <h4><a name="clip" id="clip"></a>-clip</h4>
716</div>
717
718<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>
719
720<p>If a clipping path is present, it is applied to subsequent operations.</p>
721
722<p>For example, in the command</p>
723
724<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
725<p>only the pixels within the clipping path are negated.</p>
726
727<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
728
729<div style="margin: auto;">
730 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
731</div>
732
733<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>
734
735<div style="margin: auto;">
736 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
737</div>
738
739<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>
740
741<div style="margin: auto;">
742 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
743</div>
744
745<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>
746
747<p>Specify the image by its index in the sequence. The first image is index
7480. Negative indexes are relative to the end of the sequence; for example, &minus;1
749represents the last image of the sequence. Specify a range of images with a
750dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
751href="#clone">+clone</a> make a copy of the last image in the image
752sequence.</p>
753
754<div style="margin: auto;">
755 <h4><a name="clut" id="clut"></a>-clut</h4>
756</div>
757
758<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
759corresponding channel in the second image as a <b>c</b>olor
760<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
761
762<p>The second (LUT) image is ordinarily a gradient image containing the
763histogram mapping of how each channel should be modified. Typically it is a
764either a single row or column image of replacement color values. If larger
765than a single row or column, values are taken from a diagonal line from
766top-left to bottom-right corners.</p>
767
768<p>The lookup is further controlled by the <a
769href="#interpolate">-interpolate</a> setting, which is especially handy for an
770LUT which is not the full length needed by the ImageMagick installed Quality
771(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
772'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
773gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
774lookup of color values. </p>
775
776<p>This operator is especially suited to replacing a grayscale image with a
777specific color gradient from the CLUT image. </p>
778
779<p>Only the channel values defined by the <a href="#channel">-channel</a>
780setting will have their values replaced. In particular, since the default <a
781href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
782transparency (alpha/matte channel) is not affected, unless the <a
783href="#channel">-channel</a> setting is modified. When the alpha channel is
784set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
785as the other channels, implying that alpha/matte values are replaced using the
786alpha/matte values of the original image. </p>
787
788<p>If either the image being modified, or the lookup image, conatins no
789transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
790href="#channel">-channel</a> setting includes alpha replacement, then it is
791assumed that image represents a gray-scale graident which will be used for the
792replacement alpha values. That is you can use a gray-scale CLUT image to
793adjust a existing images alpha channel, or you can color a gray-scale image
794using colors form CLUT containing the desired colors, including transparency.
795</p>
796
797<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
798the lookup of the full color RGB value from a 2D representation of a 3D color
799cube. </p>
800
801
802<div style="margin: auto;">
803 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
804</div>
805
806<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>
807
808<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>
809
810<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>
811
812
813<div style="margin: auto;">
814 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
815</div>
816
817<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>
818
819<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>
820
821<div style="margin: auto;">
822 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
823</div>
824
825<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>
826
827<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
828
829<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>
830
831<div style="margin: auto;">
832 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
833</div>
834
835<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>
836
837<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>
838
839<div style="margin: auto;">
840 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
841</div>
842
843<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>
844
845<p>Choices are:</p>
846
847<pre class="text">
848 CMY
849 CMYK
850 Gray
851 HSB
852 HSL
853 HWB
854 Lab
855 Log
856 OHTA
857 Rec601Luma
858 Rec601YCbCr
859 Rec709Luma
860 Rec709YCbCr
861 RGB
862 sRGB
863 Transparent
864 XYZ
865 YCbCr
866 YCC
867 YIQ
868 YPbPr
869 YUV
870</pre>
871
872<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
873
874<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>
875
876<table class="doc">
877 <caption>Conversion Of RGB To Other Color Spaces</caption>
878 <tr><th align="left" valign="middle">CMY</th></tr>
879 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
880 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
881 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
882 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
883 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
884 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
885 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
886 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
887
888 <tr><th align="left" valign="middle">Gray</th></tr>
889 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
890
891 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
892 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
893 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
894 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
895
896 <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>
897 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
898 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
899 <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>
900
901 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
902 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
903 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
904 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
905
906 <tr><th align="left" valign="middle">LAB</th></tr>
907 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
908 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
909 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
910
911 <tr><th align="left" valign="middle">LOG</th></tr>
912 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
913 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
914 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
915
916 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
917 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
918 <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>
919 <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>
920
921 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
922 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
923
924 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
925 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
926 <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>
927 <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>
928
929 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
930 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
931
932 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
933 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
934 <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>
935 <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>
936
937 <tr><th align="left" valign="middle">sRGB</th></tr>
938 <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>
939 <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>
940 <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>
941
942 <tr><th align="left" valign="middle">XYZ</th></tr>
943 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
944 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
945 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
946
947 <tr><th align="left" valign="middle">YCC</th></tr>
948 <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>
949 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
950 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
951
952 <tr><th align="left" valign="middle">YCbCr</th></tr>
953 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
954 <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>
955 <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>
956
957 <tr><th align="left" valign="middle">YIQ</th></tr>
958 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
959 <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>
960 <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>
961
962 <tr><th align="left" valign="middle">YPbPr</th></tr>
963 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
964 <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>
965 <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>
966
967 <tr><th align="left" valign="middle">YUV</th></tr>
968 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
969 <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>
970 <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>
971</table>
972
973<div style="margin: auto;">
974 <h4><a name="combine" id="combine"></a>-combine</h4>
975</div>
976
977<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>
978
979<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>
980
981<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.
982</p>
983
984<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>
985<div style="margin: auto;">
986 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
987</div>
988
989<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>
990
991<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>
992
993<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>
994
995<p>For example,</p>
996
997<p class="crtsnip">
998 -comment "%m:%f %wx%h"
999</p>
1000
1001<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>
1002
1003<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>
1004
1005<div style="margin: auto;">
1006 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1007</div>
1008
1009<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>
1010
1011<p>The description of composition uses abstract terminology in order to allow
1012the description to be more precise, while avoiding constant values which are
1013specific to a particular build configuration. Each image pixel is represented
1014by red, green, and blue levels (which are equal for a gray pixel). The
1015build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1016value which may be stored, per pixel, in the red, green, or blue channels of
1017the image. Each image pixel may also optionally (if the image matte channel is
1018enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1019<em>transparent</em>, which may be used to determine the influence of the pixel
1020color when compositing the pixel with another image pixel. If the image matte
1021channel is disabled, then all pixels in the image are treated as opaque. The
1022color of an opaque pixel is fully visible while the color of a transparent
1023pixel color is entirely absent (pixel color is ignored).</p>
1024
1025<p>By definition, raster images have a rectangular shape. All image rows are of
1026equal length, as are all image columns. By treating the alpha channel as a
1027visual "mask" the rectangular image may be given a "shape" by treating the
1028alpha channel as a cookie-cutter for the image. This is done by setting the
1029pixels within the shape to be opaque, with pixels outside the shape set as
1030transparent. Pixels on the boundary of the shape may be between opaque and
1031transparent in order to provide antialiasing (visually smooth edges). The
1032description of the composition operators use this concept of image "shape" in
1033order to make the description of the operators easier to understand. While it
1034is convenient to describe the operators in terms of "shapes" they are by no
1035means limited to mask-style operations since they are based on continuous
1036floating-point mathematics rather than simple boolean operations.</p>
1037
1038<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1039
1040<table class="doc">
1041 <tbody>
1042 <tr valign="top">
1043 <th align="left" style="width: 8%">Method</th>
1044 <th align="left">Description</th>
1045 </tr>
1046
1047 <tr valign="top">
1048 <td valign="top">clear</td>
1049 <td valign="top">Both the color and the alpha of the destination are
1050 cleared. Neither the source nor the destination are used (except for
1051 destinations size and other meta-data which is always preserved.</td>
1052 </tr>
1053
1054 <tr valign="top">
1055 <td valign="top">src</td>
1056 <td valign="top">The source is copied to the destination. The destination
1057 is not used as input, though it is cleared.</td>
1058 </tr>
1059
1060 <tr valign="top">
1061 <td valign="top">dst</td>
1062 <td valign="top">The destination is left untouched. The source image is
1063 completely ignored.</td>
1064 </tr>
1065
1066 <tr valign="top">
1067 <td valign="top">src-over</td>
1068 <td valign="top">The source is composited over the destination. this is
1069 the default alpha blending compose method, when neither the compose
1070 setting is set, nor is set in the image meta-data.</td>
1071 </tr>
1072
1073 <tr valign="top">
1074 <td valign="top">dst-over</td>
1075 <td valign="top">The destination is composited over the source and the
1076 result replaces the destination.</td>
1077 </tr>
1078
1079 <tr valign="top">
1080 <td valign="top">src-in</td>
1081 <td valign="top">The part of the source lying inside of the destination
1082 replaces the destination.</td>
1083 </tr>
1084
1085 <tr valign="top">
1086 <td valign="top">dst-in</td>
1087 <td valign="top">The part of the destination lying inside of the source
1088 replaces the destination. Areas not overlaid are cleared.</td>
1089 </tr>
1090
1091 <tr valign="top">
1092 <td valign="top">src-out</td>
1093 <td valign="top">The part of the source lying outside of the destination
1094 replaces the destination.</td>
1095 </tr>
1096
1097 <tr valign="top">
1098 <td valign="top">dst-out</td>
1099 <td valign="top">The part of the destination lying outside of the source
1100 replaces the destination.</td>
1101 </tr>
1102
1103 <tr valign="top">
1104 <td valign="top">src-atop</td>
1105 <td valign="top">The part of the source lying inside of the destination is
1106 composited onto the destination.</td>
1107 </tr>
1108
1109 <tr valign="top">
1110 <td valign="top">dst-atop</td>
1111 <td valign="top">The part of the destination lying inside of the source is
1112 composited over the source and replaces the destination. Areas not
1113 overlaid are cleared. </td>
1114 </tr>
1115
1116 <tr valign="top">
1117 <td valign="top">xor</td>
1118 <td valign="top">The part of the source that lies outside of the
1119 destination is combined with the part of the destination that lies
1120 outside of the source. Source or Destination, but not both. </td>
1121 </tr>
1122
1123 </tbody>
1124</table>
1125
1126<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1127For example the defaul compose method can be specified as just 'Over'.</p>
1128
1129
1130<p>The following mathemathical composition methods are also available. </p>
1131
1132<p>Typically these use the default 'Over' alpha blending when transparencies
1133are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1134also composes the alpha channel using the same process as the color channels.
1135This allows them to be used for special image masking techniques. </p>
1136
1137<table class="doc">
1138 <tbody>
1139 <tr valign="top">
1140 <th align="left" style="width: 8%">Method</th>
1141 <th align="left">Description</th>
1142 </tr>
1143
1144 <tr valign="top">
1145 <td valign="top">multiply</td>
1146 <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>
1147 </tr>
1148
1149 <tr valign="top">
1150 <td valign="top">screen</td>
1151 <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>
1152 </tr>
1153
1154 <tr valign="top">
1155 <td valign="top">plus</td>
1156 <td valign="top">The source is added to the destination and replaces the
1157 destination. This operator is useful for averaging or a controled
1158 merger of two images, rather than a direct overlay.</td>
1159 </tr>
1160
1161 <tr valign="top">
1162 <td valign="top">add</td>
1163 <td valign="top">As per 'plus' but transparency data is treated as matte
1164 values. As such any transparent areas in either image remain
1165 transparent. </td>
1166 </tr>
1167
1168 <tr valign="top">
1169 <td valign="top">minus</td>
1170 <td valign="top">Subtract the colors in the source image from the
1171 destination image. When transparency is involved, opaque areas is
1172 subtracted from any destination opaque areas. </td>
1173 </tr>
1174
1175 <tr valign="top">
1176 <td valign="top">subtract</td>
1177 <td valign="top">Subtract the colors in the source image from the
1178 destination image. When transparency is involved transparent areas are
1179 subtracted, so only the opaque areas in the source remain opaque in
1180 the destination image. </td>
1181 </tr>
1182
1183 <tr valign="top">
1184 <td valign="top">difference</td>
1185 <td valign="top">Subtracts the darker of the two constituent colors from
1186 the lighter. Painting with white inverts the destination color.
1187 Painting with black produces no change.</td>
1188 </tr>
1189
1190 <tr valign="top">
1191 <td valign="top">exclusion</td>
1192 <td valign="top">Produces an effect similar to that of 'difference', but
1193 appears as lower contrast. Painting with white inverts the
1194 destination color. Painting with black produces no change.</td>
1195 </tr>
1196
1197 <tr valign="top">
1198 <td valign="top">darken</td>
1199 <td valign="top">Selects the darker of the destination and source colors.
1200 The destination is replaced with the source when the source is darker,
1201 otherwise it is left unchanged.</td>
1202 </tr>
1203
1204 <tr valign="top">
1205 <td valign="top">lighten</td>
1206 <td valign="top">Selects the lighter of the destination and source colors.
1207 The destination is replaced with the source when the source is
1208 lighter, otherwise it is left unchanged. </td>
1209 </tr>
1210
1211 <tr valign="top">
1212 <td valign="top">linear-dodge</td>
1213 <td valign="top">This is equivelent to 'Plus' in that the color channels
1214 are simply added, however it does not 'Plus' the alpha channel, but
1215 uses the normal 'Over' alpha blending, which transparencies are
1216 involved. Produces a sort of additive multiply-like result. Added
1217 ImageMagick version 6.5.4-3. </td>
1218 </tr>
1219
1220 <tr valign="top">
1221 <td valign="top">linear-burn</td>
1222 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1223 Sort of a additive 'Screen' of the images. Added ImageMagick version
1224 6.5.4-3. </td>
1225 </tr>
1226
1227 <tr valign="top">
1228 <td valign="top">color-dodge</td>
1229 <td valign="top">Brightens the destination color to reflect the source
1230 color. Painting with black produces no change.</td>
1231 </tr>
1232
1233 <tr valign="top">
1234 <td valign="top">color-burn</td>
1235 <td valign="top">Darkens the destination color to reflect the source
1236 color. Painting with white produces no change. Fixed in ImageMagick
1237 version 6.5.4-3. </td>
1238 </tr>
1239
1240 <tr valign="top">
1241 <td valign="top">overlay</td>
1242 <td valign="top">Multiplies or screens the colors, dependent on the
1243 destination color. Source colors overlay the destination whilst
1244 preserving its highlights and shadows. The destination color is not
1245 replaced, but is mixed with the source color to reflect the lightness
1246 or darkness of the destination.</td>
1247 </tr>
1248
1249 <tr valign="top">
1250 <td valign="top">hard-light</td>
1251 <td valign="top">Multiplies or screens the colors, dependent on the source
1252 color value. If the source color is lighter than 0.5, the destination
1253 is lightened as if it were screened. If the source color is darker
1254 than 0.5, the destination is darkened, as if it were multiplied. The
1255 degree of lightening or darkening is proportional to the difference
1256 between the source color and 0.5. If it is equal to 0.5 the
1257 destination is unchanged. Painting with pure black or white produces
1258 black or white.</td>
1259 </tr>
1260
1261
1262 <tr valign="top">
1263 <td valign="top">linear-light</td>
1264 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1265 instead. Increases contrast slightly with an impact on the
1266 foreground's tonal values.</td>
1267 </tr>
1268
1269 <tr valign="top">
1270 <td valign="top">soft-light</td>
1271 <td valign="top">Darkens or lightens the colors, dependent on the source
1272 color value. If the source color is lighter than 0.5, the destination
1273 is lightened. If the source color is darker than 0.5, the destination
1274 is darkened, as if it were burned in. The degree of darkening or
1275 lightening is proportional to the difference between the source color
1276 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1277 with pure black or white produces a distinctly darker or lighter area,
1278 but does not result in pure black or white. Fixed in ImageMagick
1279 version 6.5.4-3. </td>
1280 </tr>
1281
1282 <tr valign="top">
1283 <td valign="top">pegtop-light</td>
1284 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1285 continuious mathematical formula rather than two conditionally
1286 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1287 </tr>
1288
1289 <tr valign="top">
1290 <td valign="top">vivid-light</td>
1291 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1292 primary and secondary colors in the image. Added ImageMagick version
1293 6.5.4-3. </td>
1294 </tr>
1295
1296 <tr valign="top">
1297 <td valign="top">pin-light</td>
1298 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1299 to similate the effects of a strong 'pinhole' light source. Added
1300 ImageMagick version 6.5.4-3. </td>
1301 </tr>
1302
1303 </tbody>
1304</table>
1305
1306
1307<p>Also included are these special purpose compose methods:</p>
1308
1309<table class="doc">
1310 <tbody>
1311 <tr valign="top">
1312 <th align="left" style="width: 8%">Method</th>
1313 <th align="left">Description</th>
1314 </tr>
1315
1316 <tr valign="top">
1317 <td valign="top">copy-*</td>
1318 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1319 Magenta, Yellow, Black, or Opacity) in the source image to the
1320 same channel in the destination image. If the channel specified
1321 does not exist in the source image, (which can only happen for methods,
1322 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1323 assumed that the source image is a special grayscale channel image
1324 of the values to be copied. </td>
1325 </tr>
1326
1327 <tr valign="top">
1328 <td valign="top">change-mask</td>
1329 <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>
1330 </tr>
1331 </tbody>
1332</table>
1333
1334<p>On top of these composed methods are a few special ones that not only require
1335the two images that are being merged or overlaid, but have some extra numerical
1336arguments, which are tabled below. </p>
1337
1338<p>In the "<code>composite</code>" command these composition methods are
1339selected using special options with the arguments needed. They are usually,
1340but not always, the same name as the composte 'method' they use, and replaces
1341the normal use of the <a href="#compose" >-compose</a> setting in the
1342"<code>composite</code>" command. For example... </p>
1343
1344<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1345<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1346these extra arguments to its <a href="#composite" >-composite</a> operator,
1347using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1348these special argumented <a href="#compose" >-compose</a> methods, those the
1349argument and the method both need to be set separatally. For example... </p>
1350
1351<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1352<p>The following is a table of these special 'argumented' compose methods,
1353with a brief summary of what they do. For more details see the equivalent
1354"composite" command option name. </p>
1355
1356<table class="doc">
1357 <tbody>
1358 <tr valign="top">
1359 <th align="left" style="width: 8%">Method</th>
1360 <th align="left">Description</th>
1361 </tr>
1362
1363 <tr valign="top">
1364 <td valign="top">dissolve</td>
1365 <td valign="top">Arguments:
1366 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1367 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1368 <br>Dissolve the 'source' image by the percentage given before overlaying
1369 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1370 greater than 100, it starts dissolving the main image so it will
1371 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1372 both percentages are given, each image are dissolved to the
1373 percentages given.
1374 </td>
1375 </tr>
1376
1377 <tr valign="top">
1378 <td valign="top">blend</td>
1379 <td valign="top">Arguments:
1380 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1381 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1382 <br>Average the images together ('plus') according to the percentages
1383 given and each pixels transparency. If only a single percentage value
1384 is given it sets the weight of the composite or 'source' image, while
1385 the background image is weighted by the exact opposite amount. That is
1386 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1387 the 'destination' image. Thus it is equivalent to <kbd>-blend
1388 30x70</kbd>.
1389 </td>
1390 </tr>
1391
1392 <tr valign="top">
1393 <td valign="top">mathematics</td>
1394 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1395 <br>Not available in "<code>composite</code>" at this time.
1396 <br>Merge the source and destination images according to the formula
1397 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1398 <br>Can be used to generate a custom composition method that would
1399 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1400 DIY image operator. Added to ImageMagick version 6.5.4-3.
1401 </td>
1402 </tr>
1403
1404 <tr valign="top">
1405 <td valign="top">modulate</td>
1406 <td valign="top">Arguments:
1407 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1408 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1409 <br>Take a grayscale image (with alpha mask) and modify the destination
1410 image's brightness according to watermark image's grayscale value and
1411 the <em class="arg">brightness</em> percentage. The destinations
1412 color saturation attribute is just direct modified by the <em
1413 class="arg">saturation</em> percentage, which defaults to 100 percent
1414 (no color change).
1415
1416 </td>
1417 </tr>
1418
1419 <tr valign="top">
1420 <td valign="top">displace</td>
1421 <td valign="top">Arguments:
1422 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1423 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1424 <br>With this option, the 'overlay' image, and optionally the 'mask'
1425 image, is used as a relative displacement map, which is used to
1426 displace the lookup of what part of the destination image is seen at
1427 each point of the overlaid area. Much like the displacement map is a
1428 'lens' that distorts the original 'background' image behind it.
1429 <br><br>
1430 The X-scale is modilated by the 'red' channel of the overlay image
1431 while the Y-scale is modulated by the green channel, (the mask image
1432 if given is rolled into green channel of the overlay image. This
1433 separation allows you to modulate the X and Y lookup displacement
1434 separatally allowing you to di 2 dimentional displacements, rather
1435 than 1 dimentional verctored displacements (using grayscale image).
1436 <br><br>
1437 If the overlay image contains transparency this is used as a mask
1438 of the resulting image to remove 'invalid' pixels.
1439 <br><br>
1440 The '%' flag makes the displacement scale relative to the size of the
1441 overlay image (100% = half width/height of image). Using '!' switches
1442 percentage arguments to refer to the destination image size instead.
1443 <br><br>
1444 Special flags were added Added to ImageMagick version 6.5.3-5.
1445 </td>
1446 </tr>
1447
1448 <tr valign="top">
1449 <td valign="top">distort</td>
1450 <td valign="top">Arguments:
1451 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1452 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1453 <br>Not available in "<code>composite</code>" at this time.
1454 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1455 relative to the center of the overlay (or that given). Basically
1456 allows you to generate absolute distortion maps where 'black' will
1457 look up the left/top edge, and 'white' looks up the bottom/right
1458 edge of the destination image, according to the scale given.
1459 <br><br>
1460 The '!' flag not only switches percentage scaling, to use the
1461 destination image, but also the image the center offset of the lookup.
1462 This means the overlay can lookup a completely different region of the
1463 destination image.
1464 <br><br>
1465 Added to ImageMagick version 6.5.3-5.
1466 </td>
1467 </tr>
1468
1469 <tr valign="top">
1470 <td valign="top">blur</td>
1471 <td valign="top">Arguments:
1472 <em class="arg">Width</em>[x<em class="arg">Height</em
1473 >[+<em class="arg">Angle</em>]]
1474 <br>Equivalent to "<code>composite</code>"
1475 <a href="#blur-composite">-blur</a>
1476 <br>A Variable Blur Mapping Composition method, where each pixel in the
1477 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1478 with an ellipse (typically a circle) of the given sigma size, scaled
1479 according to overlay (source image) grayscale mapping.
1480 <br><br>
1481 As per 'Displace' and 'Distort', the red channel will modulate the
1482 width of the ellipse, while the green channel will modulate the height
1483 of the ellipse. However at this time the ellipse angle is not
1484 modulated though this may be a future posibility (perhaps with a
1485 special flag to enable use of blur channel for this purpose).
1486 <br><br>
1487 Added to ImageMagick version 6.5.4-0.
1488 </td>
1489 </tr>
1490
1491 </tbody>
1492</table>
1493
1494<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1495
1496
1497<div style="margin: auto;">
1498 <h4><a name="composite" id="composite"></a>-composite</h4>
1499</div>
1500
1501<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>
1502
1503<p>Take the first image 'destination' and overlay the second 'source' image
1504according to the current <a href="#compose">-compose</a> setting. The location
1505of the 'source' or 'overlay' image is controlled according to <a
1506href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1507settings. </p>
1508
1509<p>If a third image is given this is treated as a gray-scale 'mask' image
1510relative to the first 'destination' image. This mask will limit what parts of
1511the destination can be modified by the image composition. However for the
1512'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1513Y-displacement image instead. </p>
1514
1515<p>If a <a href="#compose">-compose</a> method requires extra numerical
1516arguments or flags these can be provided by setting the <a
1517href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1518appropriatally for the compose method. </p>
1519
1520<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1521image outside the overlay area. You can disable this by setting the special <a
1522href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1523to '<kbd>false</kbd>'. </p>
1524
1525
1526<div style="margin: auto;">
1527 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1528</div>
1529
1530<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>
1531
1532<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>
1533
1534<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1535
1536<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>
1537
1538<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>
1539
1540<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>
1541
1542<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>
1543
1544<div style="margin: auto;">
1545 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1546</div>
1547
1548<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>
1549
1550<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>
1551
1552<p>For a more pronounced effect you can repeat the option:</p>
1553
1554<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1555<div style="margin: auto;">
1556 <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>
1557</div>
1558
1559<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>
1560
1561<p>While performing the stretch, black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">white-point %</em> pixels.</p>
1562
1563<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch">-contrast-stretch</a> will black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">total pixels minus white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">100% minus white-point %</em> pixels.</p>
1564
1565<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that the image's
1566min and max values are stretched to 0 and <em class="QR">QuantumRange</em>, respectively, without any loss of data due to burn-out at either end. This is not the same as <a href="#normalize">-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p>
1567
1568<p>The channels are stretched in concert. Specify <a href="#channel">-channel</a> to normalize the RGB channels individually.</p>
1569
1570
1571<div style="margin: auto;">
1572 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1573</div>
1574
1575<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>
1576
1577<p>The <em class="arg">kernel</em> is a square matrix specified as a comma-separated list of integers (with no spaces), ordered left-to right, starting with the top row. Presently, only odd-dimensioned kernels are supported, and therefore the number of entries in the specified <em class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 7<sup>2</sup>=49, etc. </p>
1578
1579<p>Note that the <a href="../www/command-line-options.html#convolve">&#x2011;convolve</a> operator supports the <a href="../www/command-line-options.html#bias">&#x2011;bias</a> setting. This option shifts the convolution so that positive and negative results are relative to a user-specified bias value. This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values is clipped at zero.
1580</p>
1581
1582<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,
1583as ImageMagick is able to store/handle any negative results without
1584clipping to the color value range (0..QuantumRange).</p>
1585
1586<p>See the discussion on HDRI implementations of ImageMagick on the page
1587<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.
1588</p>
1589
1590<div style="margin: auto;">
1591 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1592</div>
1593
1594<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>
1595
1596<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>
1597
1598<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>
1599
1600<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>
1601
1602<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>
1603
1604<p>By adding a exclamation character flag to the geometry argument, the
1605cropped images virtual canvas page size and offset is set as if the
1606geometry argument was a viewport or window. This means the canvas page size
1607is set to exactly the same size you specified, the image offset set
1608relative top left corner of the region cropped. </p>
1609
1610<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1611special single pixel transparent 'missed' image is returned, and a 'crop
1612missed' warning given. </p>
1613
1614
1615<div style="margin: auto;">
1616 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1617</div>
1618
1619<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>
1620
1621<p><em class="arg">Amount</em> defines the number of positions each
1622colormap entry is shifted.</p>
1623
1624
1625<div style="margin: auto;">
1626 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1627</div>
1628
1629<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>
1630
1631<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>
1632
1633
1634<p>For example, to log cache and blob events, use.</p>
1635
1636<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1637<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1638
1639<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1640
1641<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1642
1643<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1644
1645<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>
1646
1647
1648<div style="margin: auto;">
1649 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1650</div>
1651
1652<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>
1653
1654<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1655
1656<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1657
1658
1659<div style="margin: auto;">
1660 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1661</div>
1662
1663<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>
1664
1665<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>
1666
1667<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>
1668
1669<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1670
1671
1672<div style="margin: auto;">
1673 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1674</div>
1675
1676<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>
1677
1678<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>
1679
1680<p>The following definitions may be created:</p>
1681
1682<ul>
1683<dt>jp2:rate=value</dt>
1684 <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 />
1685<dt>mng:need-cacheoff</dt>
1686 <dd>turn playback caching off for streaming MNG.</dd><br />
1687<dt>png:bit-depth=value</dt>
1688<dt>png:color-type=value</dt>
1689 <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 />
1690<dt>ps:imagemask</dt>
1691 <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>
1692</ul>
1693
1694<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1695
1696<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1697<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>
1698
1699<p class="crtsnip">
1700-define registry:temporary-path=/data/tmp
1701</p>
1702
1703<div style="margin: auto;">
1704 <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>
1705</div>
1706
1707<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>
1708
1709<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>
1710
1711<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>
1712
1713
1714<div style="margin: auto;">
1715 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1716</div>
1717
1718<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>
1719
1720<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>
1721
1722
1723<div style="margin: auto;">
1724 <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>
1725</div>
1726
1727<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>
1728
1729<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>
1730
1731<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>
1732
1733<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>
1734
1735<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>
1736
1737<div style="margin: auto;">
1738 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1739</div>
1740
1741<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>
1742
1743<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>
1744
1745<div style="margin: auto;">
1746 <h4><a name="descend" id="descend"></a>-descend</h4>
1747</div>
1748
1749<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>
1750
1751<div style="margin: auto;">
1752 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1753</div>
1754
1755<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>
1756
1757<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>
1758
1759<div style="margin: auto;">
1760 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1761</div>
1762
1763<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>
1764
1765<div style="margin: auto;">
1766 <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>
1767</div>
1768
1769<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>
1770
1771<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1772will be used as a displacement map, which is used to displace the lookup of
1773what part of the 'background' image is seen at each point of the overlaid
1774area. Much like the displacement map is a 'lens' that redirects light shining
1775through it so as to present a distorted view the original 'background' image
1776behind it. </p>
1777
1778<p>Any perfect grey areas of the displacement map produce a zero
1779displacement of the image. Black areas produce the given maximum negative
1780displacement of the lookup point, while white produce a maximum positive
1781displacement of the lookup. </p>
1782
1783<p>Note that it is the lookup of the 'background' that is displaced, not a
1784displacement of the image itself. As such an area of the displacement map
1785containing 'white' will have the lookup point 'shifted' by a positive amount,
1786and thus generating a copy of the destination image to the right/downward from
1787the correct position. That is the image will look like it may have been
1788'shifted' in a negative left/upward direction. Understanding this is a very
1789important in understanding how displacement maps work. </p>
1790
1791<p>The given arguments define the maximum amount of displacement in pixels
1792that a particular map can produce. If the displacement scale is large enough
1793it is also posible to lookup parts of the 'background' image that lie well
1794outside the bounds of the displacement map itself. That is you could very
1795easilly copy a section of the original image from outside the overlay area
1796into the overlay area. </p>
1797
1798<p>The '%' flag makes the displacement scale relative to the size of the
1799overlay image (100% = half width/height of image). Using '!' switches
1800percentage arguments to refer to the destination image size instead.
1801these flags were added as of IM v6.5.3-5.</p>
1802
1803<p>Normally a single grayscale displacement map is provided, which with the
1804given scaling values will determine a single direction (vector) in which
1805displacements can occur (positivally or negativally). However, if you also
1806specify a third image which is normally used as a <em class="arg">mask</em>,
1807then the <em class="arg">composite image</em> will be used for horizontal X
1808displacement, while the <em class="arg">mask image</em> is used for vertical Y
1809displacement. This allows you to define completely different displacement
1810values for the X and Y directions, and allowing you to lookup any point within
1811the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1812any other nearby pixel, producing complex 2 dimentional displacements, rather
1813than a simple 1 dimentional vector displacements. </p>
1814
1815<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1816you can use the 'red' channel of the overlay image to specify the horizontal
1817or X displacement, and the 'green' channel for the vertical or Y displacement.
1818</p>
1819
1820<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1821mask the transparency of the destination image. However areas outside the
1822overlaid areas will not be effected. </p>
1823
1824
1825<div style="margin: auto;">
1826 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1827</div>
1828
1829<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>
1830
1831<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1832
1833<div style="margin: auto;">
1834 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1835</div>
1836
1837<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>
1838
1839<p>The layer disposal method defines the way each the displayed image is to be
1840modified after the current 'frame' of an animation has finished being
1841displayed (after its 'delay' period), but before the next frame on an
1842animation is to be overlaid onto the display. </p>
1843
1844<p>Here are the valid methods:</p>
1845
1846<pre class="text">
1847Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1848None 1 Do not dispose, just overlay next frame image.
1849Background 2 Clear the frame area with the background color.
1850Previous 3 Clear to the image prior to this frames overlay.
1851</pre>
1852
1853<p>You can also use the numbers given above, which is what the GIF format
1854uses internally to represent the above settings. </p>
1855
1856<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1857
1858<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1859resetting the layer disposal methods of images being read in. </p>
1860
1861<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1862disposal method for images already in memory.</p>
1863
1864<div style="margin: auto;">
1865 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1866</div>
1867
1868<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>
1869
1870
1871<div style="margin: auto;">
1872 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
1873</div>
1874
1875<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>
1876
1877<p>The opacity of the composite image is multiplied by the given percent, then
1878it is composited 'over' the main image. If <em class="arg">src_percent</em>
1879is greater than 100, start dissolving the main image so it will become
1880transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
1881are given, each image are dissolved to the percentages given. </p>
1882
1883<p>Note that dissolve percentages do not add, two opaque images dissolved
1884'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
1885images, you would need to use dissolve values of '50,100'. </p>
1886
1887<div style="margin: auto;">
1888 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
1889</div>
1890
1891<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>
1892
1893<p>The <em class="arg">arguments</em> is a single string containing a list
1894of floating point numbers separated by commas or spaces. The number of
1895and meaning of the floating point values depends on the distortion <em
1896class="arg">method</em> being used. </p>
1897
1898<p>Choose from these distortion types:</p>
1899
1900<table class="doc">
1901 <tr valign="top">
1902 <th align="left" style="width: 8%">Method</th>
1903 <th align="left">Description</th>
1904 </tr>
1905
1906 <tr valign="top">
1907 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
1908 <br/>or &nbsp; <kbd>SRT</kbd></td>
1909 <td valign="top">
1910 Distort image by first scaling and rotating about a given 'center',
1911 before translating that 'center' to the new location, in that order. It
1912 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
1913 distortion, but without shearing effects. It also provides a good way
1914 of rotating and displacing a smaller image for tiling onto a larger
1915 background (IE 2-dimensional animations). <br/>
1916
1917 The number of arguments determine the specific meaning of each
1918 argument for the scales, rotation, and translation operations. <br/>
1919
1920 <table style="margin-left:auto; margin-right:auto;">
1921 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
1922 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
1923 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
1924 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1925 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
1926 <tr><td>5:</td>
1927 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1928 <tr><td>6:</td>
1929 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
1930 <tr><td>7:</td>
1931 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
1932 &nbsp; NewX,NewY</em></td></tr>
1933 </table>
1934
1935 This is actually an alternative way of specifing a 2 dimensional linear
1936 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
1937
1938 <tr valign="top">
1939 <td valign="top"><kbd>Affine</kbd></td>
1940 <td valign="top">
1941 Distort the image linearly by moving a list of at least 3 or more sets
1942 of control points (as defined below). Idealy 3 sets or 12 floating
1943 point values are given allowing the image to be linearly scaled,
1944 rotated, sheared, and translated, according to those three points. See
1945 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
1946 distortions. <br/>
1947
1948 More than 3 sets given control point pairs (12 numbers) is least
1949 squares fitted to best match a lineary affine distortion. If only 2
1950 control point pairs (8 numbers) are given a two point image translation
1951 rotation and scaling is performed, without any posible shearing,
1952 flipping or changes in aspect ratio to the resulting image. If only one
1953 control point pair is provides the image is only translated, (which may
1954 be a floating point non-integer translation). <br/>
1955
1956 This distortion does not include any form of perspective distortion.
1957 </td>
1958
1959 </tr>
1960
1961 <tr valign="top">
1962 <td valign="top"><kbd>AffineProjection</kbd></td>
1963 <td valign="top">
1964 Linearly distort an image using the given Affine Matrix of 6
1965 pre-calculated coefficients forming a set of Affine Equations to map
1966 the source image to the destination image.
1967
1968 <div style="text-align: center"><em>
1969 s<sub>x</sub>, r<sub>x</sub>,
1970 r<sub>y</sub>, s<sub>y</sub>,
1971 t<sub>x</sub>, t<sub>y</sub>
1972 </em></div>
1973
1974 See <a href="#affine" >-affine</a> setting for more detail, and
1975 meanings of these coefficients. <br/>
1976
1977 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
1978 alternative methods of defining this distortion, with ImageMagick doing the
1979 calculations needed to generate the required coefficients. You can see
1980 the internally generated coefficients, by using a <a href="#verbose"
1981 >-verbose</a> setting. </td>
1982
1983 </tr>
1984
1985<!-- still under development, do not display - Anthony
1986 <tr valign="top">
1987 <td valign="top"><kbd>Bilinear</kbd></td>
1988 <td valign="top">
1989 Bilinear (reversed) Distortion, given a minimum of 4 sets of
1990 coordinate pairs, or 16 values (see below). Not that lines may not
1991 appear straight after distortion, though the distance between
1992 coordinates will remain consistant. </td>
1993 </tr>
1994-->
1995
1996 <tr valign="top">
1997 <td valign="top"><kbd>Perspective</kbd></td>
1998 <td valign="top">
1999 Perspective distort the images, using a list of 4 or more sets of
2000 control points (as defined below). More that 4 sets (16 numbers) of
2001 control points provide least squares fitting for more accurate
2002 distortions (for the purposes of image registration and panarama
2003 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2004 linear distortion. <br/>
2005
2006 Perspective Distorted images ensures that straight lines remain
2007 straight, but the scale of the distorted image will vary. The horizon
2008 is anti-aliased, and the 'sky' color may be set using the
2009 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2010 </tr>
2011
2012 <tr valign="top">
2013 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2014 <td valign="top">
2015 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2016 pre-calculated coefficients. You can get these coefficients by looking
2017 at the <a href="#verbose" >-verbose</a> output of a
2018 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2019 If the last two perspective scaling coefficients are zero, the
2020 remaining 6 represents a transposed 'Affine Matrix'. </td>
2021
2022 </tr>
2023
2024 <tr valign="top">
2025 <td valign="top"><kbd>Arc</kbd></td>
2026 <td valign="top">
2027 Arc the image (variation of polar mapping) over the angle given around
2028 a circle. <br/>
2029 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2030 <tr valign="top"><td>Argument</td>
2031 <td>Meaning</td></tr>
2032 <tr valign="top"><td><em>arc_angle</em></td>
2033 <td>The angle over which to arc the image side-to-side</td></tr>
2034 <tr valign="top"><td><em>rotate_angle</em></td>
2035 <td>Angle to rotate resulting image from vertical center</td></tr>
2036 <tr valign="top"><td><em>top_radius</em></td>
2037 <td>Set top edge of source image at this radius</td></tr>
2038 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2039 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2040 </table>
2041
2042 The resulting image is always resized to best fit the resulting image,
2043 (as if using <a href="#distort" >+distort</a>) while attempting to
2044 preserve scale and aspect ratio of the original image as much as
2045 possible with the arguments given by the user. All four arguments will
2046 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2047
2048 This a variation of a polar distortion designed to try to preserve the
2049 aspect ratio of the image rather than direct Cartesian to Polar
2050 conversion. </td>
2051 </tr>
2052
2053 <tr valign="top">
2054 <td valign="top"><kbd>Polar</kbd></td>
2055 <td valign="top">
2056 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2057 the image. that is the height of the input image is mapped to the
2058 radius limits, while the width is wrapped around between the
2059 angle limits. <br/>
2060
2061 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2062
2063 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2064 center to the center of the image, and the angles going from -180 (top)
2065 to +180 (top). If <em>Rmax</em> is given the special value of
2066 '<code>0</code>', the the distance from the center to the nearest edge
2067 is used for the radius of the output image, which will ensure the whole
2068 image is visible (though scaled smaller). However a special value of
2069 '<code>-1</code>' will use the distance from the center to the furthest
2070 corner, This may 'clip' the corners from the input rectangular image,
2071 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2072 the same arguments. <br/>
2073
2074 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2075 output image center will default to <code>0,0</code> of the virtual
2076 canvas, and the image size adjusted to ensure the whole input image is
2077 made visible in the output image on the virtual canvas. </td>
2078
2079 </tr>
2080
2081 <tr valign="top">
2082 <td valign="top"><kbd>DePolar</kbd></td>
2083 <td valign="top">
2084 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2085 but generates the reverse Polar to Cartesian distortion. <br/>
2086
2087 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2088 the corners of the input image. However using the special
2089 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2090 distance) will ensure the whole distorted image is preserved in the
2091 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2092 reverse the distortion re-producing the original.
2093
2094 Note that as this distortion requires the area resampling of a circular
2095 arc, which can not be handled by the builtin EWA resampling function.
2096 As such the normal EWA filters are turned off. It is recomended some
2097 form of 'super-sampling' image processing technique be used to produce
2098 a high quality result. </td>
2099
2100 </tr>
2101
2102 <tr valign="top">
2103 <td valign="top"><kbd>Barrel</kbd></td>
2104 <td valign="top">
2105 Given the four coefficients (A,B,C,D) as defined by <a
2106 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2107 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2108 correct radial lens distortions. That is in photographs, make straight
2109 lines straight again. <br/>
2110
2111 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2112 <em>X</em> , <em>Y</em> ] ] <br/>
2113 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2114 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2115 [ <em>X</em> , <em>Y</em> ] <br/>
2116 So that it forms the function <br/>
2117 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2118 <em>C</em>*r + <em>D</em> )<br/>
2119
2120 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2121 (defaulting to the center of the image). <br/>
2122 The second form is typically used to distort images, rather than
2123 correct lens distortions. <br/>
2124 </td>
2125
2126 </tr>
2127
2128 <tr valign="top">
2129 <td valign="top"><kbd>BarrelInverse</kbd></td>
2130 <td valign="top">
2131 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2132 arguments, and argument handling. However it uses the inverse
2133 of the radial polynomial,
2134 so that it forms the function <br/>
2135 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2136 <em>C</em>*r + <em>D</em> )
2137 </td>
2138 </tr>
2139
2140 <tr valign="top">
2141 <td valign="top"><kbd>Shepards</kbd></td>
2142 <td valign="top">
2143 Distort the given list control points (any number) using an Inverse
2144 Squared Distance Interpolation Method (<a
2145 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2146 >Shepards Method</a>). The control points in effect do 'localized'
2147 distortions of the image around the given control point. For best
2148 results extra control points should be added to 'lock' the positions of
2149 the corners and other unchanging parts of the image. <br/>
2150
2151 The distortion has been likened to 'taffy pulling' using nails, pins or
2152 sticks. It basically uses the <a href="#sparse-color"
2153 >-sparse-color</a> method of the same name to generate separate X and Y
2154 displacement maps (see <a href="#displace" >-displace</a>) for source
2155 image color look-up. </td>
2156
2157 </tr>
2158
2159</table>
2160
2161<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2162
2163<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2164'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2165defining how these points in the given image should be distorted in the
2166destination image. Each set of four floating point values represent a source
2167image coordinate, followed immediately by the destination image coordinate.
2168This produces a list of values such as...</p>
2169<div style="text-align: center"><em>
2170 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2171 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2172 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2173 ... &nbsp;
2174 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2175</em></div>
2176<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2177destination image. </p>
2178
2179<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2180needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2181perspective distortion of the built-in "rose:" image. Note how spaces were
2182used to group the 4 sets of coordinate pairs, to make it easier to read and
2183understand.</p>
2184
2185<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2186 convert rose: -virtual-pixel black \ <br/>
2187 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2188 rose_3d_rotated.gif</span></p>
2189<p>If more that the required number of coordinate pairs are given for a
2190distortion, the distortion method is 'least squares' fitted to
2191produce the best result for all the coordinate pairs given. If less than the
2192ideal number of points are given, the distort will generally fall back to a
2193simpler form of distortion that can handles the smaller number of coordinates
2194(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2195
2196<p>By using more coodinates you can make use of image registration tool to
2197find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2198of the distortion. Of course a bad coordinate pair can also make the 'fit'
2199worse. Caution is always advised. </p>
2200
2201<p>Colors are acquired from the source image according to the <a
2202href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2203magnified. However if the viewed image is minified (image becomes smaller), a
2204special area resampling function (added ImageMagick v6.3.5-9), is used to
2205produce a higher quality image. For example you can use a
2206'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2207way to the horizon. </p>
2208
2209<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2210 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2211 checks_tiled.jpg</span></p>
2212<p>Note that a infinitely tiled perspective images involving the horizon can
2213be very slow to generate due to the use of the high quality 'area resampling'
2214function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2215using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2216(recommended if you plan to use super-sampling instead). </p>
2217
2218<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2219'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2220will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2221pixels. If you do not what these pixels to be visible, set the color to match
2222the rest of the ground. </p>
2223
2224<p>The output image size will by default be the same as the input image. This
2225means that if the part of the distorted image falls outside the viewed area of
2226the 'distorted space', those parts is clipped and lost. However if you
2227use the plus form of the operator (<a href="#distort" >+distort</a>) the
2228operator will attempt (if posible) to show the whole of the distorted image,
2229while retaining a correct 'virtual canvas' offset, for image layering. This
2230offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2231if it is unwanted. </p>
2232
2233<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2234option:distort:viewport {geometry_string}</kbd>" setting which will specify
2235the size and the offset of the generated 'viewport' image of the distorted
2236image space.</p>
2237
2238<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2239{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2240that factor without changing the viewed contents of the distorted image. This
2241can be used either for 'super-sampling' the image for a higher quality result,
2242or for panning and zooming around the image (with appropriate viewport
2243changes, or post-distort cropping and resizing). </p>
2244
2245<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2246href="#distort" >-distort</a> to attempt to output the internal coefficients,
2247and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2248and debugging purposes. This many not be available for all distorts. </p>
2249
2250<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2251produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2252and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2253above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2254</p>
2255
2256
2257<div style="margin: auto;">
2258 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2259</div>
2260
2261<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>
2262
2263<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>
2264
2265<p>Dithering is turned on by default, to turn it off use the plus form of the
2266setting, <a href="#dither">+dither</a>. This will also also render PostScript
2267without text or graphic aliasing. Disabling dithering often (but not always)
2268leads to faster process, a smaller number of colors, but more cartoon like
2269image coloring. Generally resulting in 'color banding' effects in areas with
2270color gradients. </p>
2271
2272<p>The color reduction operators <a href="#colors">-colors</a>, <a
2273href="#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>
2274
2275<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>
2276
2277
2278<div style="margin: auto;">
2279 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2280</div>
2281
2282<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>
2283
2284<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>
2285
2286<p>The shape primitives:</p>
2287
2288<pre class="text">
2289 point x,y
2290 line x0,y0 x1,y1
2291 rectangle x0,y0 x1,y1
2292 roundRectangle x0,y0 x1,y1 wc,hc
2293 arc x0,y0 x1,y1 a0,a1
2294 ellipse x0,y0 rx,ry a0,a1
2295 circle x0,y0 x1,y1
2296 polyline x0,y0 ... xn,yn
2297 polygon x0,y0 ... xn,yn
2298 bezier x0,y0 ... xn,yn
2299 path path specification
2300 image operator x0,y0 w,h filename
2301</pre>
2302
2303<p>The text primitive:</p>
2304
2305<pre class="text">
2306 text x0,y0 string
2307</pre>
2308<p>The text gravity primitive:</p>
2309
2310<pre class="text">
2311 gravity NorthWest, North, NorthEast, West, Center,
2312 East, SouthWest, South, or SouthEast
2313</pre>
2314
2315<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>
2316
2317<p>The transformation primitives:</p>
2318
2319<pre class="text">
2320 rotate degrees
2321 translate dx,dy
2322 scale sx,sy
2323 skewX degrees
2324 skewY degrees
2325</pre>
2326
2327<p>The pixel operation primitives:</p>
2328
2329<pre class="text">
2330 color x0,y0 method
2331 matte x0,y0 method
2332</pre>
2333
2334<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>
2335
2336<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>
2337
2338<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2339
2340<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2341
2342<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>
2343
2344<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2345
2346<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>
2347
2348<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>
2349
2350<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>.
2351</p>
2352
2353<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2354
2355<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2356
2357<p class="crtsnip">
2358 -draw 'circle 100,100 150,150'
2359</p>
2360
2361<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
2362draw 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>
2363
2364<p class="crtsnip">
2365 -draw 'bezier 20,50 45,100 45,0 70,50'
2366</p>
2367<p class="crtsnip">
2368 -draw 'bezier 70,50 95,100 95,0 120,50'
2369</p>
2370
2371
2372<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>
2373
2374<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>
2375
2376<p class="crtsnip">
2377 -draw 'image SrcOver 100,100 225,225 image.jpg'
2378</p>
2379
2380<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>
2381
2382<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>
2383
2384<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2385
2386<p class="crtsnip">
2387 -draw 'text 100,100 "Works like magick!"'
2388</p>
2389
2390<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2391
2392<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>
2393
2394<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2395
2396<p>The <kbd>scale</kbd> primitive scales them.</p>
2397
2398<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>
2399
2400<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
2401matrix.</p>
2402
2403<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>
2404
2405<pre class="text">
2406 point
2407 replace
2408 floodfill
2409 filltoborder
2410 reset
2411</pre>
2412
2413<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>
2414
2415<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>
2416
2417<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>
2418
2419<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2420
2421<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2422
2423
2424<div style="margin: auto;">
2425 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2426</div>
2427
2428<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>
2429
2430<div style="margin: auto;">
2431 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2432</div>
2433
2434<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>
2435
2436<div style="margin: auto;">
2437 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2438</div>
2439
2440<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>
2441
2442<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2443
2444<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2445
2446<div style="margin: auto;">
2447 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2448</div>
2449
2450<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>
2451
2452<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>
2453
2454<div style="margin: auto;">
2455 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2456</div>
2457
2458<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>
2459
2460<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2461
2462<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2463
2464
2465<div style="margin: auto;">
2466 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2467</div>
2468
2469<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>
2470
2471
2472<div style="margin: auto;">
2473 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2474</div>
2475
2476<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>
2477
2478<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>
2479
2480<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2481
2482<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>
2483
2484<div style="margin: auto;">
2485 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2486</div>
2487
2488<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>
2489
2490<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>
2491
2492<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>
2493
2494<table class="doc">
2495 <col width="25%" />
2496 <col width="75%" />
2497 <thead>
2498 <tr>
2499 <th><em class="arg">operator</em></th>
2500 <th>Summary (see further below for details)</th>
2501 </tr>
2502 </thead>
2503 <tbody>
2504
2505 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2506 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2507 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2508 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2509 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2510 <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>
2511 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2512 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2513 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2514 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2515 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2516 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2517 <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>
2518 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2519 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2520 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2521 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2522
2523 <tr><td>&nbsp;</td></tr>
2524
2525 <tr><td>Gaussian-noise</td></tr>
2526 <tr><td>Impulse-noise</td></tr>
2527 <tr><td>Laplacian-noise</td></tr>
2528 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2529 <tr><td>PoissonNoise</td></tr>
2530 <tr><td>Uniform-noise</td></tr>
2531
2532 <tr><td>&nbsp;</td></tr>
2533
2534 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2535 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2536 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2537 </tbody>
2538 </table>
2539
2540<p>The specified functions are applied only to each previously set <a
2541href="#channel" >-channel</a> in the image. If necessary, the results of the
2542calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2543class="QR">QuantumRange</em>]. The transparency channel of the image is
2544represented as a 'alpha' values (0 = fully transparent), so, for example, a
2545<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2546semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2547as a percentage of the <em class="QR">QuantumRange</em>.</p>
2548
2549<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2550<a href="#list">-list evaluate</a>.</p>
2551
2552<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2553<kbd>Multiply</kbd> methods can also be achieved using either the <a
2554href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2555appropriate argument, to linearly modify the overall range of color values.
2556Please note, however, that <a href="#level" >-level</a> treats transparency as
2557'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2558'alpha' values.</p>
2559
2560<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>
2561
2562<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>
2563
2564 <div style="text-align:center;">
2565 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2566 </div>
2567
2568<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2569normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2570href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2571to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2572with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2573with <kbd>Pow</kbd>.</p>
2574
2575<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2576converts the image values into a value according to a (co)sine wave function.
2577The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2578is biased 50% and normalized by 50% so as to fit in the respective color value
2579range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2580function (its frequency), and thus determines the number of 'waves' that will
2581be generated over the input color range. For example, if the <em
2582class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2583class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2584then the effective period is the <em>half</em> the <em
2585class="QR">QuantumRange</em>.
2586
2587 <div style="text-align:center;">
2588 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2589 </div>
2590
2591See also the <a href="#function" >-function</a> operator, which is a
2592multi-value version of evaluate. </P>
2593
2594
2595<div style="margin: auto;">
2596 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2597</div>
2598
2599<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>
2600
2601<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>
2602
2603<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>
2604
2605<div style="margin: auto;">
2606 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2607</div>
2608
2609<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>
2610
2611<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2612
2613<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>
2614
2615<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>
2616<p>then the image will be <em>resized</em> to the specified dimensions instead,
2617equivalent to:</p>
2618
2619<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>
2620<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>
2621
2622<div style="margin: auto;">
2623 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2624</div>
2625
2626<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>
2627
2628<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).
2629</p>
2630
2631<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>.
2632</p>
2633
2634<div style="margin: auto;">
2635 <h4><a name="fft" id="fft"></a>-fft</h4>
2636</div>
2637
2638<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>
2639
2640<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>
2641
2642<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>
2643
2644<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>
2645
2646<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2647<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>
2648
2649<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2650<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>
2651
2652<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>
2653
2654<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>
2655
2656<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2657 -evaluate log 1000 fft_image_spectrum.png</span></p>
2658<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>
2659
2660<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2661
2662<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>
2663
2664<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>
2665
2666<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>
2667
2668<p>See the discussion on HDRI implementations of ImageMagick on the page
2669<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.
2670</p>
2671
2672
2673<div style="margin: auto;">
2674 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2675</div>
2676
2677<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>
2678
2679<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>
2680
2681<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2682
2683<p>For example,</p>
2684
2685<p class="crtsnip">
2686 -fill blue
2687</p>
2688<p class="crtsnip">
2689 -fill "#ddddff"
2690</p>
2691<p class="crtsnip">
2692 -fill "rgb(255,255,255)"
2693</p>
2694
2695<p>See <a href="#draw">-draw</a> for further details.</p>
2696
2697<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2698
2699<div style="margin: auto;">
2700 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2701</div>
2702
2703<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>
2704
2705<p>Use this option to affect the resizing operation of an image (see <a
2706href="#resize">-resize</a>). For example you can use a simple resize filter
2707such as:</p>
2708
2709<pre class="text">
2710 Point Hermite Cubic
2711 Box Gaussian Catrom
2712 Triangle Quadratic Mitchell
2713</pre>
2714
2715<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2716by default <kbd>blackman</kbd>-windowed. However these filters define a
2717windowing filter for the Sinc or Bessel filter function, as appropriate for
2718the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2719>-resize</a>). Windowed filters include: </p>
2720
2721<pre class="text">
2722 Lanczos Hamming Parzen
2723 Blackman Kaiser Welsh
2724 Hanning Bartlett Bohman
2725</pre>
2726
2727<p>Also one special self-windowing filter is also provided
2728<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2729on the current 'support' or 'lobes' expert settings (see below).</p>
2730
2731<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>
2732
2733<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2734
2735<p>You can modify how the filter behaves as it scales your image through the
2736use of these expert settings:</p>
2737
2738<dl class="doc">
2739<dt>-set filter:blur <em>factor</em></dt>
2740<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2741 blurry or &lt; 1.0 for sharp.</dd>
2742
2743<dt>-set filter:support <em>radius</em></dt>
2744<dd>Set the filter support radius.</dd>
2745
2746<dt>-set filter:lobes <em>count</em></dt>
2747<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2748 alternative way of specifying the 'support' range of the filter.</dd>
2749
2750<dt>-set filter:b <em>b-spline_factor</em></dt>
2751<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2752<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2753 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2754 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2755 are defined, the other is set so as to generate a 'Keys' type cubic
2756 filter.
2757
2758<dt>-set filter:filter <em>filter</em></dt>
2759<dd>Use this function directly as the scaling filter. This will allow
2760 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2761 rather than as its normal usage as a windowing function for 'Sinc' or
2762 'Bessel'. If defined, no windowing function is used, unless the following
2763 expert setting is also defined.</dd>
2764
2765<dt>-set filter:window <em>filter</em></dt>
2766<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2767 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2768 support range) with the given filter. This allows you to use a filter that
2769 is not normally used as a windowing function, such as <kbd>box</kbd>,
2770 (which effectivally turns off the windowing function). </dd>
2771
2772</dl>
2773
2774<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2775
2776<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2777 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2778 -resize 150% image.jpg</span></p>
2779<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2780
2781<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2782 -resize 150% image.jpg</span></p>
2783<p>Note that the use of expert options (except for 'blur' with simple resize
2784filters), are provided for image processing experts who have studied and
2785understood how resize filters work. Without this knowledge, and an
2786understanding of the defination of the actual filters involved, using expert
2787settings are more likely to be detremental to your image resizing.</p>
2788
2789
2790<div style="margin: auto;">
2791 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2792</div>
2793
2794<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>
2795
2796
2797<div style="margin: auto;">
2798 <h4><a name="flip" id="flip"></a>-flip</h4>
2799</div>
2800
2801<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>
2802
2803<p>reflect the scanlines in the vertical direction.</p>
2804
2805<div style="margin: auto;">
2806 <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>
2807</div>
2808
2809<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>
2810
2811<div style="margin: auto;">
2812 <h4><a name="flop" id="flop"></a>-flop</h4>
2813</div>
2814
2815<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>
2816
2817<p>reflect the scanlines in the horizontal direction.</p>
2818
2819
2820<div style="margin: auto;">
2821 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2822</div>
2823
2824<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>
2825
2826<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>
2827
2828<p>In addition to the fonts specified by the above pre-defined list, you can
2829also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2830is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2831<kbd>x:fixed</kbd> is X11 font.</p>
2832
2833<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>
2834
2835
2836<div style="margin: auto;">
2837 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2838</div>
2839
2840<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>
2841
2842<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2843
2844<p>The default foreground color is black.</p>
2845
2846<div style="margin: auto;">
2847 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2848</div>
2849
2850<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>
2851
2852<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>
2853
2854<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>
2855
2856<div style="margin: auto;">
2857 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2858</div>
2859
2860<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>
2861
2862<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>
2863
2864<div style="margin: auto;">
2865 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2866</div>
2867
2868<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>
2869
2870<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
2871
2872<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>
2873
2874
2875<div style="margin: auto;">
2876 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
2877</div>
2878
2879<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>
2880
2881<div style="margin: auto;">
2882 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
2883</div>
2884
2885<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>
2886
2887<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>
2888
2889<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>
2890
2891<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>
2892
2893<pre class="text">
2894 Polynomial
2895 Sinusoid
2896 Arcsin
2897 Arctan
2898</pre>
2899
2900<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
2901
2902<dl class="doc">
2903<dt><kbd>Polynomial</kbd></dt>
2904<dd>
2905<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>
2906
2907<div style="text-align: center">
2908 -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>
2909</div>
2910
2911<p>will invoke a polynomial function given by</p>
2912
2913<div style="text-align: center">
2914 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
2915 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
2916 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
2917</div>
2918
2919<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
2920
2921<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>
2922
2923<table class="doc">
2924 <col width="35%" />
2925 <col width="35%" />
2926 <col width="30%" />
2927 <tr>
2928 <td>-evaluate Set <em class="arg">value</em> </td>
2929 <td>-function Polynomial <em class="arg">value</em></td>
2930 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
2931 </tr>
2932 <tr>
2933 <td>-evaluate Add <em class="arg">value</em> </td>
2934 <td>-function Polynomial 1,<em class="arg">value</em></td>
2935 </tr>
2936 <tr>
2937 <td>-evaluate Subtract <em class="arg">value</em> </td>
2938 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
2939 </tr>
2940 <tr>
2941 <td>-evaluate Multiply <em class="arg">value</em> </td>
2942 <td>-function Polynomial <em class="arg">value</em>,0</td>
2943 </tr>
2944 <tr>
2945 <td>+level black% x white%</td>
2946 <td>-function Polynomial A,B</td>
2947 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
2948 </tr>
2949</table>
2950
2951<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>
2952</dd>
2953
2954<dt><kbd>Sinusoid</kbd></dt>
2955<dd>
2956<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>
2957
2958<div style="text-align: center">
2959 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
2960</div>
2961
2962<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>
2963
2964<div style="text-align: center">
2965<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>
2966</div>
2967
2968<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>
2969
2970<p class="crtsnip">
2971 -function Sinusoid 3,-90,.2,.7
2972</p>
2973
2974<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>
2975
2976<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>
2977
2978<table class="doc">
2979 <tr>
2980 <td>-evaluate Sin <em class="arg">freq</em> </td>
2981 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
2982 </tr>
2983 <tr>
2984 <td>-evaluate Cos <em class="arg">freq</em> </td>
2985 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
2986 </tr>
2987</table>
2988</dd>
2989
2990<dt><kbd>ArcSin</kbd></dt>
2991<dd>
2992<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
2993and can be used to generate cylindrical distortion and displacement maps.
2994The curve can be adjusted relative to both the input values and output range
2995of values.
2996
2997<div style="text-align: center">
2998 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
2999</div>
3000
3001<p>with all values given in terms of noramlize color values (0.0 for black,
30021.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3003for bout input (<em class="arg">width</em>), and output (<em
3004class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3005
3006<div style="text-align: center">
3007<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>
3008</div>
3009
3010</dd>
3011
3012<dt><kbd>ArcTan</kbd></dt>
3013<dd>
3014<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3015limit values at infinities, though a center using the given slope value.
3016All these values can be adjusted via the arguments.
3017
3018<div style="text-align: center">
3019 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3020</div>
3021
3022<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3023</p>
3024
3025<div style="text-align: center">
3026<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>
3027</div>
3028
3029</dd>
3030
3031</dl>
3032
3033
3034<div style="margin: auto;">
3035 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3036</div>
3037
3038<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>
3039
3040<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>
3041
3042<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>
3043
3044
3045<div style="margin: auto;">
3046 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3047</div>
3048
3049<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>
3050
3051<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>
3052
3053<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3054
3055
3056<div style="margin: auto;">
3057 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3058</div>
3059
3060<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>
3061
3062<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>
3063
3064<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>
3065
3066<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>
3067
3068<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>
3069
3070<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3071
3072<div style="margin: auto;">
3073 <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>
3074</div>
3075
3076<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>
3077
3078<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3079
3080<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3081</div>
3082
3083<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>
3084
3085<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3086full 2-dimentional convolution is used to generate the weighted average of the
3087neighbouring pixels. </p>
3088
3089<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3090pixels which are outside the image proper are blurred into the final result.
3091</p>
3092
3093
3094<div style="margin: auto;">
3095 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3096</div>
3097
3098<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>
3099
3100<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>
3101
3102<div style="margin: auto;">
3103 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3104</div>
3105
3106<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>
3107
3108<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3109<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3110<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3111list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3112installation.</p>
3113
3114<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>
3115
3116<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>
3117
3118<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>
3119
3120<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>
3121<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>
3122
3123<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>
3124
3125
3126<div style="margin: auto;">
3127 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3128</div>
3129
3130<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>
3131
3132
3133<div style="margin: auto;">
3134 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3135</div>
3136
3137<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>
3138
3139<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3140dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3141can apply any color transformation to the Hald image and then use this option
3142to apply the transform to the image. </p>
3143
3144<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3145<p>This option provides a convenient method for you to use Gimp or Photoshop
3146to make color corrections to the Hald CLUT image and subsequently apply them
3147to multiple images using an ImageMagick script. </p>
3148
3149<p>Note that the representation is only of the normal RGB color space and that
3150the whole color value triplet is used for the interpolated lookup of the
3151represented Hald color cube image. Because of this the operation is not <a
3152href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3153images transparency or alpha/matte channel.</p>
3154
3155<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3156of the individual color channels, usally involving a simplier gray-scale
3157image. E.g: gray-scale to color replacement, or modification by a histogram
3158mapping. </p>
3159
3160
3161<div style="margin: auto;">
3162 <h4><a name="help" id="help"></a>-help</h4>
3163</div>
3164
3165<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>
3166
3167<div style="margin: auto;">
3168 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3169</div>
3170
3171<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>
3172
3173<div style="margin: auto;">
3174 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3175</div>
3176
3177<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>
3178
3179<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>
3180
3181<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>
3182
3183<div style="margin: auto;">
3184 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3185</div>
3186
3187<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>
3188
3189<div style="margin: auto;">
3190 <h4><a name="identify" id="identify"></a>-identify</h4>
3191</div>
3192
3193<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>
3194
3195<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>
3196
3197<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>
3198
3199<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3200amounts of image properties are displayed including image statistics, profiles,
3201image histogram, and others.</p>
3202
3203<div style="margin: auto;">
3204 <h4><a name="ift" id="ift"></a>-ift</h4>
3205</div>
3206
3207<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>
3208
3209<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>
3210
3211<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>
3212
3213<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3214<p>or</p>
3215
3216<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>
3217
3218<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.
3219
3220<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3221
3222<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.
3223
3224<div style="margin: auto;">
3225 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3226</div>
3227
3228<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>
3229
3230<div style="margin: auto;">
3231 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3232</div>
3233
3234<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>
3235
3236<div style="margin: auto;">
3237 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3238</div>
3239
3240<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>
3241
3242<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>
3243
3244<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>
3245
3246<div style="margin: auto;">
3247 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3248</div>
3249
3250<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>
3251
3252<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>
3253
3254<p>The default intent is undefined.</p>
3255
3256<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3257
3258<div style="margin: auto;">
3259 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3260</div>
3261
3262<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>
3263
3264<p>Choose from:</p>
3265
3266<pre class="text">
3267 none
3268 line
3269 plane
3270 partition
3271 JPEG
3272 GIF
3273 PNG
3274</pre>
3275
3276<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>
3277
3278<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3279
3280<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3281
3282<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3283
3284<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3285image.G, and image.B).</p>
3286
3287<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>
3288image.</p>
3289
3290<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3291
3292<div style="margin: auto;">
3293 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3294</div>
3295
3296<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>
3297
3298<p>When looking up the color of a pixel using a non-interger floating point
3299value, you typically fall in between the pixel colors defined by the source
3300image. This setting determines how the color is determined from the colors of
3301the pixels surrounding that point. That is how to determine the color of a
3302point that falls between two, or even four different colored pixels. </p>
3303
3304<pre class="text">
3305 integer: The color of the top-left pixel (floor function)
3306 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3307 average: The average color of the surrounding four pixels
3308 bilinear A double linear interpolation of pixels (the default)
3309 mesh Divide area into two flat triangular interpolations
3310 bicubic Fitted bicubic-spines of surrounding 16 pixels
3311 spline Direct spline curves (colors are blurred)
3312 filter Use resize <a href="#filter">-filter</a> settings
3313</pre>
3314
3315<p>This most important for distortion operators such as <a href="#distort"
3316>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3317>-transform</a> and <a href="#fx" >-fx</a>. </p>
3318
3319<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3320
3321<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3322lookup for positions outside the boundaries of the image. </p>
3323
3324
3325<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003326 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3327</div>
3328
3329<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>
3330
3331<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003332 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3333</div>
3334
3335<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>
3336
3337<div style="margin: auto;">
3338 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3339</div>
3340
3341<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>
3342
3343<div style="margin: auto;">
3344 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3345</div>
3346
3347<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>
3348
3349<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>
3350
3351<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>
3352
3353<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>
3354
3355<p>For example,</p>
3356
3357<p class="crtsnip">
3358 -label "%m:%f %wx%h" bird.miff
3359</p>
3360
3361<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>
3362
3363<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>
3364
3365<p>The label font can be specified with <a href="#font">-font</a>, and the
3366other font attribute settings.</p>
3367
3368<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>
3369
3370
3371<div style="margin: auto;">
3372 <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>
3373</div>
3374
3375<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>
3376
3377<p>Adaptively threshold each pixel based on the value of pixels in a
3378surrounding window. If the current pixel is lighter than this average plus
3379the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3380black. Small variations in pixel values such as found in scanned documents
3381can be ignored if offset is positive. A negative offset will make it more
3382sensitive to those small variations. </p>
3383
3384<p>This is commonly used to threshold images with an uneven background. It is
3385based on the assumption that average color of the small window is the
3386the local background color, from which to separate the forground color. </p>
3387
3388
3389<div style="margin: auto;">
3390 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3391</div>
3392
3393<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>
3394
3395<p>Perform various image operation methods to a ordered sequence of images
3396which may represent either a set of overlaid 'image layers', a GIF disposal
3397animation, or a fully-'coalesced' animation sequence. </p>
3398
3399<table class="doc">
3400 <tbody>
3401 <tr valign="top">
3402 <th align="left" style="width: 8%">Method</th>
3403 <th align="left">Description</th>
3404 </tr>
3405
3406 <tr valign="top">
3407 <td valign="top">compare-any</td>
3408 <td valign="top">Crop the second and later frames to the smallest rectangle
3409 that contains all the differences between the two images. No GIF <a
3410 href="#dispose" >-dispose</a> methods are taken into account. </td>
3411 </tr>
3412
3413 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3414 >-deconstruct</a> operator, and does not preserve animations normal
3415 working, especially when animation used layer disposal methods such as
3416 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3417 </tr>
3418
3419 <tr valign="top">
3420 <td valign="top">compare-clear</td>
3421 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3422 opaque pixels which become transparent in the second frame. That is the
3423 smallest image needed to mask or erase pixels for the next frame. </td>
3424 </tr>
3425
3426 <tr valign="top">
3427 <td valign="top">compare-overlay</td>
3428 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3429 extra color to the next image, as a result of overlaying color pixels.
3430 That is the smallest single overlaid image to add or change colors. </td>
3431 </tr>
3432
3433 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3434 composition method '<kbd>change-mask</kbd>', to reduce the image to
3435 just the pixels that need to be overlaid. </td>
3436 </tr>
3437
3438 <tr valign="top">
3439 <td valign="top">coalesce</td>
3440 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3441 >-coalesce</a> operator. Apply the layer disposal methods set in the
3442 current image sequence to form a fully defined animation sequence, as
3443 it should be displayed. Effectively converting a GIF animation into a
3444 'film strip'-like animation. </td>
3445 </tr>
3446
3447 <tr valign="top">
3448 <td valign="top">composite</td>
3449 <td valign="top">Alpha Composition of two image lists, separated by a
3450 "<kbd>null:</kbd>" image, with the destination image list first, and
3451 the source images last. An image from each list are composited
3452 together until one list is finished. The separator image and source
3453 image lists are removed. </td>
3454 </tr>
3455
3456
3457 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3458 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3459 size of the first image in each list. Unlike a normal <a
3460 href="#composite" >-composite</a> operation, the canvas offset is also
3461 added to the final composite positioning of each image. </td>
3462 </tr>
3463
3464 <tr><td></td><td>If one of the image lists only contains one image, that image is
3465 applied to all the images in the other image list, regardless of which
3466 list it is. In this case it is the image meta-data of the list which
3467 preserved. </td>
3468 </tr>
3469
3470
3471 <tr valign="top">
3472 <td valign="top">dispose</td>
3473 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3474 the animation after the layer disposal method has been applied, before
3475 the next sub-frame image is overlaid. That is the 'dispose' image that
3476 results from the application of the GIF <a href="#dispose"
3477 >-dispose</a> method. This allows you to check what
3478 is going wrong with a particular animation you may be developing.
3479 </td>
3480 </tr>
3481
3482 <tr valign="top">
3483 <td valign="top">flatten</td>
3484 <td valign="top">Create a canvas the size of the first images virtual
3485 canvas using the current <a href="#background" >-background</a> color,
3486 and <a href="#compose" >-compose</a> each image in turn onto that
3487 canvas. Images falling outside that canvas is clipped. Final
3488 image will have a zero virtual canvas offset. </td>
3489 </tr>
3490
3491 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3492 overlaying all the prepared image layers into a final image. </td>
3493 </tr>
3494
3495 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3496 canvas with real pixels, or to underlay a opaque color to remove
3497 transparency from an image.</td>
3498 </tr>
3499
3500
3501 <tr valign="top">
3502 <td valign="top">merge</td>
3503 <td valign="top">As 'flatten' method but merging all the given image
3504 layers into a new layer image just large enough to hold all the image
3505 without clipping or extra space. The new images virtual offset will
3506 prevere the position of the new layer, even if this offset is
3507 negative. the virtual canvas size of the first image is preserved.
3508 </td>
3509 </tr>
3510
3511 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3512 as few image file formats handle them correctly. </td>
3513 </tr>
3514
3515 <tr valign="top">
3516 <td valign="top">mosaic</td>
3517 <td valign="top">As 'flatten' method but expanding the initial canvas size
3518 of the first image so as to hold all the image layers. However as a
3519 virtual canvas is 'locked' to the origin, by defination, image layers
3520 with a negative offsets will still be clipped by the top and left
3521 edges.</td>
3522 </tr>
3523
3524 <tr><td></td><td>This method is commonly used to layout individual image using various
3525 offset but without knowning the final canvas size. The resulting image
3526 will, like 'flatten' not have any virtual offset, so can be saved to
3527 any image file format. </td>
3528 </tr>
3529
3530
3531 <tr valign="top">
3532 <td valign="top">optimize</td>
3533 <td valign="top">Optimize a coalesced animation, into GIF animation using
3534 a number of general techniques. This currently a short cut to
3535 apply both the '<kbd>optimize-frame</kbd>', and
3536 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3537 include other optimization methods as they are developed. </td>
3538 </tr>
3539
3540 <tr valign="top">
3541 <td valign="top">optimize-frame</td>
3542 <td valign="top">Optimize a coalesced animation, into GIF animation by
3543 reducing the number of pixels per frame as much as possible by
3544 attempting to pick the best layer disposal method to use, while ensuring
3545 the result will continue to animate properly. </td>
3546 </tr>
3547
3548 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3549 then no reasonably fast GIF optimization algorithm can do this.
3550 However this does seem to do better than most other GIF frame
3551 optimizers seen. </td>
3552 </tr>
3553
3554 <tr valign="top">
3555 <td valign="top">optimize-plus</td>
3556 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3557 overall optimization by adding extra frames to the animation, without
3558 changing the final look or timing of the animation. The frames are
3559 added to attempt to separate the clearing of pixels from the
3560 overlaying of new additional pixels from one animation frame to the
3561 next. If this does not improve the optimization (for the next frame
3562 only), it will fall back to the results of the previous normal
3563 '<kbd>optimize-frame</kbd>' technique. </td>
3564 </tr>
3565
3566 <tr><td></td><td>There is the possibility that the change in the disposal style will
3567 result in a worsening in the optimization of later frames, though this
3568 is unlikely. In other words there no guarantee that it is better than
3569 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3570 however you can get a vast improvment in the final animation size. </td>
3571 </tr>
3572
3573 <tr valign="top">
3574 <td valign="top">optimize-transparency</td>
3575 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3576 overlay images with transparency, if it does not change the resulting
3577 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3578 </td>
3579 </tr>
3580
3581 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3582 into a smaller file size due to larger areas of one (transparent)
3583 color rather than a pattern of multiple colors repeating the current
3584 disposed image of the last frame. </td>
3585 </tr>
3586
3587 <tr valign="top">
3588 <td valign="top">remove-dups</td>
3589 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3590 images, so as to simplify layer overlays of coalesced animations.
3591 </td>
3592 </tr>
3593
3594 <tr><td></td><td>Usually this a result of using a constant time delay across the
3595 whole animation, or after a larger animation was split into smaller
3596 sub-animations. The duplicate frames could also have been used as
3597 part of some frame optimization methods. </td>
3598 </tr>
3599
3600 <tr valign="top">
3601 <td valign="top">remove-zero</td>
3602 <td valign="top">Remove any image with a zero time delay, unless ALL the
3603 images have a zero time delay (and is not a proper timed animation, a
3604 warning is then issued). </td>
3605 </tr>
3606
3607 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3608 partial intermediary updates between the frames that are actually
3609 displayed to users. These frames are usally added for improved frame
3610 optimization in GIF animations. </td>
3611 </tr>
3612
3613 <tr valign="top">
3614 <td valign="top">trim-bounds</td>
3615 <td valign="top">Find the bounds of all the images in the current
3616 image sequence, then adjust the offsets so all images are contained on
3617 a minimal positive canvas. None of the image data is modified, only
3618 there virtual canvas size and offset. The all the image is given
3619 the same canvas size, and and will have a positive offset, but will
3620 remain in the same position relative to each other. As a result of the
3621 minimal canvas size at least one image will touch every edge of that
3622 canvas. The image data however may be transparent.
3623 </td>
3624 </tr>
3625
3626 </tbody>
3627</table>
3628
3629<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3630
3631<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3632>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3633>-mosaic</a> are only aliases for the above methods. Also see <a
3634href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3635href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3636>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3637
3638
3639<div style="margin: auto;">
3640 <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>
3641</div>
3642
3643<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>
3644
3645<p>Given one, two or three values delimited with commas: black-point,
3646white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3647white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3648point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3649contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3650both black and white points are percentages of the full color range. Gamma
3651will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3652omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3653
3654<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3655the given '<kbd>black_point</kbd>' value in the original image is set to
3656zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3657<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3658to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3659adjusted. </p>
3660
3661<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3662adding the special '!' flag anywhere in the argument list, will cause the
3663operator to do the reverse of the level adjustment. That is a zero, or
3664<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3665adjusted to the given level values, allowing you to de-contrast, or compress
3666the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3667
3668<p>Only the channels defined by the current <a href="#channel">-channel</a>
3669setting are adjusted (defaults to RGB color channels only), allowing you to
3670limit the effect of this operator. </p>
3671
3672<p>Please note that the transparency channel is treated as 'matte'
3673values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3674
3675
3676<div style="margin: auto;">
3677 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3678 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3679</div>
3680
3681<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>
3682
3683<p>This function is exactly like <a href="#level">-level</a>, except that the
3684value value for each color channel is determined by the
3685'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3686described under the <a href="#fill">-fill</a> option). </p>
3687
3688<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3689is mapped to become 'black' and 'white' respectivally, with all the other
3690colors linearly adjusted (or clipped) to match that change. Each channel is
3691adjusted separatally using the channel values of the colors specified. </p>
3692
3693<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3694will map the image color 'black' and 'white' to the given colors
3695respectivally, resulting in a gradient (de-contrasting) tint of the image to
3696those colors. This can also be used to convert a plain gray-scale image into a
3697one using the gradient of colors specified. </p>
3698
3699<p>By supplying a single color with a comma separator either before or after
3700that color, will just replace the respective 'black' or 'white' point
3701respectivally. But if no comma separator is provided, the given color is
3702used for both the black and white color points, making the operator either
3703threshold the images around that color (- form) or set all colors to that
3704color (+ form). </p>
3705
3706
3707<div style="margin: auto;">
3708 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3709</div>
3710
3711<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>
3712
3713<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>
3714
3715<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>
3716
3717<p class="crtsnip">
3718 -limit memory 32mb -limit map 64mb
3719</p>
3720
3721<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3722
3723<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
3724-------------------------------------------------------------------
3725 768 3.8187gb 2.864gb 7.6375gb 16eb 2 unlimited</pre>
3726</span></p>
3727<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>
3728
3729<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>
3730
3731<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>
3732
3733<p class="crtsnip">
3734-limit area 10mb
3735</p>
3736
3737<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>
3738
3739<p class="crtsnip">
3740-limit area 10mb -limit disk 500mb
3741</p>
3742
3743<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3744
3745<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>
3746
3747<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.
3748</p>
3749
3750<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.
3751</p>
3752
3753<div style="margin: auto;">
3754 <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>
3755</div>
3756
3757<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>
3758
3759<div style="margin: auto;">
3760 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3761</div>
3762
3763<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>
3764
3765<div style="margin: auto;">
3766 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3767</div>
3768
3769<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>
3770
3771<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>
3772
3773<div style="margin: auto;">
3774 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3775</div>
3776
3777<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>
3778
3779<pre class="text">
3780 coder
3781 color
3782 configure
3783 delegate
3784 font
3785 format
3786 list
3787 log
3788 magic
3789 module
3790 resource
3791 threshold
3792</pre>
3793
3794<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>
3795
3796<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3797<div style="margin: auto;">
3798 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3799</div>
3800
3801<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>
3802
3803<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3804
3805<p>You can display the following components by embedding special format characters:</p>
3806
3807<pre class="text">
3808 %d domain
3809 %e event
3810 %f function
3811 %l line
3812 %m module
3813 %p process ID
3814 %r real CPU time
3815 %t wall clock time
3816 %u user CPU time
3817 %% percent sign
3818 \n newline
3819 \r carriage return
3820</pre>
3821
3822<p>For example:</p>
3823
3824<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>
3825<p>The default behavior is to print all of the components.</p>
3826
3827<div style="margin: auto;">
3828 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3829</div>
3830
3831<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>
3832
3833<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>
3834
3835<div style="margin: auto;">
3836 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3837</div>
3838
3839<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>
3840
3841<div style="margin: auto;">
3842 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
3843</div>
3844
3845<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>
3846
3847
3848<div style="margin: auto;">
3849 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
3850</div>
3851
3852<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>
3853
3854<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
3855
3856<pre class="text">
3857 best
3858 default
3859 gray
3860 red
3861 green
3862 blue
3863</pre>
3864
3865<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>
3866
3867
3868<div style="margin: auto;">
3869 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
3870</div>
3871
3872<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>
3873
3874<p>Here are the valid components of a map:</p>
3875
3876<pre class="text">
3877 r red pixel component
3878 g green pixel component
3879 b blue pixel component
3880 a alpha pixel component (0 is transparent)
3881 o opacity pixel component (0 is opaque)
3882 i grayscale intensity pixel component
3883 c cyan pixel component
3884 m magenta pixel component
3885 y yellow pixel component
3886 k black pixel component
3887 p pad component (always 0)
3888</pre>
3889
3890<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>
3891
3892<div style="margin: auto;">
3893 <h4><a name="mask" id="mask"></a>-mask
3894<em class="arg">filename</em></h4>
3895</div>
3896
3897<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>
3898
3899<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
3900
3901<div style="margin: auto;">
3902 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
3903</div>
3904
3905<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>
3906
3907<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
3908
3909<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
3910
3911<div style="margin: auto;">
3912 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
3913</div>
3914
3915<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>
3916
3917<div style="margin: auto;">
3918 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
3919</div>
3920
3921<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>
3922
3923<p>Choose from:</p>
3924
3925<pre class="text">
3926 AE absolute number of differnet pixels
3927 MAE mean absolute error (normalized), average channel error distance
3928 MEPP mean error per pixel (normalized mean error, normalized peak error)
3929 MSE mean error squared, average of the channel error squared
3930 PAE peak absolute (normalize peak absolute)
3931 PSNR peak signal to noise ratio
3932 RMSE root mean squared (normalized root mean squared)
3933</pre>
3934
3935<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
3936controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
3937only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
3938size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
3939'similar'. </p>
3940
3941<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
3942('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
3943normalized) from the single comparision run. </p>
3944
3945<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
3946
3947
3948<div style="margin: auto;">
3949 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
3950</div>
3951
3952<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>
3953
3954<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
3955
3956<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
3957argument for a list of <a href="#mode" >-mode</a> arguments available
3958in your ImageMagick installation.</p>
3959
3960
3961<div style="margin: auto;">
3962 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
3963</div>
3964
3965<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>
3966
3967<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
3968missing values are taken to mean 100.</p>
3969
3970<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
3971means pure black, 50 is half as bright, 200 is twice as bright. To invert its
3972meaning <a href="#negate">-negate</a> the image before and after. </p>
3973
3974<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>
3975
3976<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
3977shades to purple, and so on. A value of either 0 or 200 results in a complete
3978180 degree rotation of the image. Using a value of 300 is a 360 degree
3979rotation resulting in no change to the original image. </p>
3980
3981<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>
3982
3983<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>
3984
3985<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>
3986<div style="margin: auto;">
3987 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
3988</div>
3989
3990<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>
3991
3992
3993<div style="margin: auto;">
3994 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
3995</div>
3996
3997<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>
3998
3999
4000<div style="margin: auto;">
4001 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4002</div>
4003
4004<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>
4005
4006<p>Both the image pixels and size are linearly interpolated to give the
4007appearance of a meta-morphosis from one image to the next, over all the images
4008in the current image list. The added images are the equivalent of a <a
4009href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4010argument determine how many images to interpolate between each image. </p>
4011
4012
4013<div style="margin: auto;">
4014 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4015</div>
4016
4017<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>
4018
4019
4020<div style="margin: auto;">
4021 <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>
4022</div>
4023
4024<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>
4025
4026<p>Blur with the given radius, standard deviation (sigma), and angle. The
4027angle given is the angle toward which the image is blurred. That is the
4028direction people would consider the object is coming from. </p>
4029
4030<p>Note that the blur is not uniform distribution, giving the motion a
4031definate sense of direction of movement. </p>
4032
4033<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4034pixels which are outside the image proper are blurred into the final result.
4035</p>
4036
4037<div style="margin: auto;">
4038 <h4><a name="name" id="name"></a>-name</h4>
4039</div>
4040
4041<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>
4042<div style="margin: auto;">
4043 <h4><a name="negate" id="negate"></a>-negate</h4>
4044</div>
4045
4046<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>
4047
4048<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>
4049
4050<div style="margin: auto;">
4051 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4052 +noise <em class="arg">type</em></h4>
4053</div>
4054
4055<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>
4056
4057<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>
4058
4059<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>
4060
4061<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>
4062
4063<pre class="text">
4064Gaussian
4065Impulse
4066Laplacian
4067Multiplicative
4068Poisson
4069Random
4070Uniform
4071</pre>
4072
4073<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4074
4075
4076<div style="margin: auto;">
4077 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4078</div>
4079
4080<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>
4081
4082<p>The intensity values are stretched to cover the entire range of possible values. While doing so, black-out at most <em>2%</em> of the pixels and white-out at most <em>1%</em> of the pixels.</p>
4083
4084<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. (Before this
4085version, it was equivalent to <a href="#contrast-stretch">-contrast-stretch 2%x99%)</a></p>
4086
4087<p>All the channels are normalized in concert by the came amount so as to preserve color integrity. Specify <a href="#channel">-channel</a> to normalize the RGB channels independently.</p>
4088
4089
4090<div style="margin: auto;">
4091 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4092</div>
4093
4094<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dither the image using a pre-defined ordered dither <em class="arg">threshold map</em> specified, and a uniform color map with the number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table>
4095
4096<p>You can choose from these standard threshold maps:</p>
4097
4098<pre class="text">
4099 checks
4100 o2x2
4101 o3x3
4102 o4x4
4103 o8x8
4104 h4x4a
4105 h6x6a
4106 h8x8a
4107 h4x4o
4108 h6x6o
4109 h8x8o
4110 h16x16o
4111</pre>
4112
4113<p>The '<kbd>o</kbd>' are ordered diffused pixel threshold maps, while the
4114'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled,
4115or 'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord
4116dither pattern. Or you can define your own <em class="arg">threshold
4117map</em> in a personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
4118
4119<p>To print a complete list of threshold, use the <a href="#list">-list threshold</a> option.</p>
4120
4121<p>It is recommended that the <a href="#map">+map</a> operator be used after
4122applying <a href="#ordered-dither">-ordered-dither</a> to reduce the number of
4123colors an animated image sequence, to less that 256 colors. This ensures that
4124a common or global color table is used when saving the result to a color
4125limited file format such as GIF. </p>
4126
4127<p>Note that at this time the exact same map is used for all color channels, no
4128attempt is made to offset or rotate the dither map for different channels is
4129made, at this point in time. (possible future expansion) </p>
4130
4131
4132<div style="margin: auto;">
4133 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4134</div>
4135
4136<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>
4137
4138<p>The <em class="arg">color</em> argument is defined using the format
4139described under the <a href="#fill">-fill</a> option.
4140The <a href="#fuzz">-fuzz</a> setting can be used to match and replace colors similar
4141to the one given.</p>
4142
4143<p>The <a href="#transparent">-transparent</a> operator is exactly the same
4144as <a href="#opaque">-opaque</a> but makes the matching color transparent,
4145rather than the same as the current <a href="#fill">-fill</a> color. </p>
4146
4147<p>Use <em class="arg">+opaque</em> to paint any pixel that does not match the target color.</p>
4148
4149<div style="margin: auto;">
4150 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4151</div>
4152
4153<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>
4154
4155<p>Choose from these orientations:</p>
4156
4157<pre class="text">
4158 bottom-left
4159 bottom-right
4160 left-bottom
4161 left-top
4162 right-bottom
4163 right-top
4164 top-left
4165 top-right
4166 undefined
4167</pre>
4168
4169<p>To print a complete list of orientations, use the <a href="#list">-list orientation</a> option.</p>
4170
4171
4172<div style="margin: auto;">
4173 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4174 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4175 +page
4176 </h4>
4177</div>
4178
4179<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>
4180
4181<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>
4182
4183<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>
4184
4185<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>
4186<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4187<thead>
4188 <tr valign="top">
4189 <th align="center"><em class="arg">media</em></th>
4190 <th align="center"><em class="arg">width</em></th>
4191 <th align="center"><em class="arg">height</em></th>
4192 </tr>
4193</thead>
4194<tbody>
4195<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4196<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4197<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4198<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4199<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4200<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4201<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4202<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4203<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4204<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4205<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4206<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4207<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4208<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4209<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4210<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4211<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4212<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4213<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4214<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4215<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4216<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4217<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4218<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4219<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4220<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4221<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4222<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4223<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4224<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4225<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4226<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4227<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4228<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4229<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4230<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4231<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4232<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4233</tbody>
4234</table>
4235
4236
4237
4238
4239<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>
4240
4241<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>
4242
4243<p>The default page dimensions for a TEXT image is 612x792.</p>
4244
4245<p>This option is used in concert with <a href="#density">-density</a>.</p>
4246
4247<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4248
4249<div style="margin: auto;">
4250 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4251</div>
4252
4253<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>
4254
4255<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>
4256
4257<div style="margin: auto;">
4258 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4259
4260<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>
4261
4262<div style="margin: auto;">
4263 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4264</div>
4265
4266<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>
4267
4268<p>Pause for the specified number of seconds before repeating the animation.</p>
4269
4270<div style="margin: auto;">
4271 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4272</div>
4273
4274<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>
4275
4276<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4277
4278<div style="margin: auto;">
4279 <h4><a name="ping" id="ping"></a>-ping</h4>
4280</div>
4281
4282<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>
4283
4284<div style="margin: auto;">
4285 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4286</div>
4287
4288<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>
4289
4290<div style="margin: auto;">
4291 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4292</div>
4293
4294<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>
4295
4296<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4297
4298<div style="margin: auto;">
4299 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4300</div>
4301
4302<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>
4303
4304<div style="margin: auto;">
4305 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4306</div>
4307
4308<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>
4309
4310<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>
4311
4312<pre class="text">
4313 Rotate
4314 Shear
4315 Roll
4316 Hue
4317 Saturation
4318 Brightness
4319 Gamma
4320 Spiff
4321 Dull
4322 Grayscale
4323 Quantize
4324 Despeckle
4325 ReduceNoise
4326 Add Noise
4327 Sharpen
4328 Blur
4329 Threshold
4330 EdgeDetect
4331 Spread
4332 Shade
4333 Raise
4334 Segment
4335 Solarize
4336 Swirl
4337 Implode
4338 Wave
4339 OilPaint
4340 CharcoalDrawing
4341 JPEG
4342</pre>
4343
4344<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4345
4346<p>The default preview is <kbd>JPEG</kbd>.</p>
4347
4348<div style="margin: auto;">
4349 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4350</div>
4351
4352<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>
4353
4354<div style="margin: auto;">
4355 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4356</div>
4357
4358<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>
4359
4360<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>
4361
4362<div style="margin: auto;">
4363 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4364 +profile <em class="arg">profile_name</em></h4>
4365</div>
4366
4367<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>
4368
4369<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>
4370
4371<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>
4372
4373<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>
4374
4375<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>
4376
4377<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4378
4379<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4380<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>
4381
4382<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>
4383<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4384CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4385</p>
4386
4387<div style="margin: auto;">
4388 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4389</div>
4390
4391<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>
4392
4393<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>
4394
4395<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>
4396
4397<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>
4398
4399<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>
4400
4401<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4402
4403<pre class="text">
4404 0: none
4405 1: sub
4406 2: up
4407 3: average
4408 4: Paeth
4409</pre>
4410
4411<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>
4412
4413<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4414
4415<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>
4416
4417<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>
4418
4419<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4420
4421<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>
4422
4423<div style="margin: auto;">
4424 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4425</div>
4426
4427<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>
4428
4429<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4430
4431
4432<div style="margin: auto;">
4433 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4434</div>
4435
4436<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>
4437
4438<div style="margin: auto;">
4439 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4440</div>
4441
4442<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>
4443
4444<p>Note that this is actually a rotational blur rather than a radial and as
4445such actually mis-named. </p>
4446
4447<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4448pixels which are outside the image proper are blurred into the final result.
4449</p>
4450
4451
4452<div style="margin: auto;">
4453 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4454</div>
4455
4456<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>
4457
4458<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>.
4459</p>
4460
4461<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4462
4463<div style="margin: auto;">
4464 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4465</div>
4466
4467<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>
4468
4469<div style="margin: auto;">
4470 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4471</div>
4472
4473<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>
4474
4475<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.
4476</p>
4477
4478<div style="margin: auto;">
4479 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4480</div>
4481
4482<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>
4483
4484<div style="margin: auto;">
4485 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4486</div>
4487
4488<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>
4489
4490<div style="margin: auto;">
4491 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4492</div>
4493
4494<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>
4495
4496<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4497the given colors are dithered over the image as necessary, otherwise the closest
4498color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4499
4500<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4501images in the current image sequence, all the images will have the same color
4502table. That means that when saved to a file format such as GIF, it will use
4503that color table as a single common or global color table, for all the images,
4504without requiring extra local color tables. </p>
4505
4506<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4507sequence to use a common color map over all the images. This equivalent to
4508appending all the images together (without extra background colors) and color
4509reducing those images using <a href="#colors">-colors</a> with a 256 color
4510limit, then <a href="#remap">-remap</a> those colors over the original list of
4511images. This ensures all the images follow a single color map. </p>
4512
4513<p>If the number of colors over all the images is less than 256, then <a
4514href="#remap">+remap</a> should not perform any color reduction or dithering, as
4515no color changes are needed. In that case, its only effect is to force the use
4516of a global color table. This recommended after using either <a
4517href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4518reduce the number of colors in an animated image sequence. </p>
4519
4520<div style="margin: auto;">
4521 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4522</div>
4523
4524<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>
4525
4526<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>
4527
4528<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>
4529
4530<div style="margin: auto;">
4531 <h4><a name="remote" id="remote"></a>-remote</h4>
4532</div>
4533
4534<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>
4535
4536<p>The only command recognized is the name of an image file to load.</p>
4537
4538<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>
4539
4540<div style="margin: auto;">
4541 <h4><a name="render" id="render"></a>-render</h4>
4542</div>
4543
4544<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>
4545
4546<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>
4547
4548<div style="margin: auto;">
4549<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4550</div>
4551
4552<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>
4553
4554<p>This option is like <a href="#page">-page</a> but acts as an image operator
4555rather than a setting. You can separately set the canvas size or the offset
4556of the image on that canvas by only providing those components. </p>
4557
4558<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>
4559
4560<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4561offset to move the image relative to its previous position. This useful for
4562animation sequences. </p>
4563
4564<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4565recalculate the canvas size so the image (at its current offset) will appear
4566completely on that canvas (unless it has a negative offset).</p>
4567
4568<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4569canvas meta-data from the images. </p>
4570
4571<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4572directly assign virtual canvas meta-data. </p>
4573
4574
4575<div style="margin: auto;">
4576 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4577</div>
4578
4579<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>
4580
4581<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>
4582
4583<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>
4584
4585<div style="margin: auto;">
4586 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4587</div>
4588
4589<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>
4590
4591<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>
4592
4593<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>
4594
4595<div style="margin: auto;">
4596 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4597</div>
4598
4599<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>
4600
4601<div style="margin: auto;">
4602 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4603</div>
4604
4605<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>
4606
4607
4608<div style="margin: auto;">
4609 <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>
4610</div>
4611
4612<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>
4613
4614<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>
4615
4616
4617<div style="margin: auto;">
4618 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4619</div>
4620
4621<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>
4622
4623<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>
4624
4625<p>Empty triangles in the corners, left over from rotating the image, are
4626filled with the <kbd>background</kbd> color. </p>
4627
4628<p>See also the <a href="#distort">-distort</a> operator and specifically the
4629'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4630
4631
4632<div style="margin: auto;">
4633 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4634</div>
4635
4636<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>
4637
4638<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>
4639
4640<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>
4641
4642
4643<div style="margin: auto;">
4644 <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>
4645</div>
4646
4647<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>
4648
4649<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>
4650
4651<div style="margin: auto;">
4652 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4653</div>
4654
4655<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>
4656
4657<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>
4658
4659<div style="margin: auto;">
4660 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4661</div>
4662
4663<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>
4664
4665<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4666
4667<div style="margin: auto;">
4668 <h4><a name="screen" id="screen"></a>-screen</h4>
4669</div>
4670
4671<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>
4672
4673<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>
4674
4675<div style="margin: auto;">
4676 <h4><a name="seed" id="seed"></a>-seed</h4>
4677</div>
4678
4679<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>
4680
4681<div style="margin: auto;">
4682 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4683</div>
4684
4685<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>
4686
4687<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>
4688
4689<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>
4690
4691<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4692of the color clusters is returned.</p>
4693
4694
4695<div style="margin: auto;">
4696 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4697</div>
4698
4699<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>
4700
4701<div style="margin: auto;">
4702 <h4><a name="separate" id="separate"></a>-separate</h4>
4703</div>
4704
4705<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>
4706
4707<div style="margin: auto;">
4708 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4709</div>
4710
4711<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>
4712
4713<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4714
4715<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>
4716
4717<div style="margin: auto;">
4718 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4719</div>
4720
4721<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>
4722
4723<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>
4724
4725<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>
4726<p>The <a href="#repage">-repage</a> operator will also set the
4727'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4728separately set the virtual canvas's size and offset components, and also allows
4729relative offset changes, and automatic canvas size re-calculating. The above
4730<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4731virtual canvas (page) meta-data. </p>
4732
4733<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>
4734
4735<div style="margin: auto;">
4736 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4737</div>
4738
4739<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>
4740
4741<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>
4742
4743<div style="margin: auto;">
4744 <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>
4745</div>
4746
4747<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>
4748
4749<div style="margin: auto;">
4750 <h4><a name="shared-memory"
4751id="shared-memory"></a>-shared-memory</h4>
4752</div>
4753
4754<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>
4755
4756<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>
4757
4758<div style="margin: auto;">
4759 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4760</div>
4761
4762<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>
4763
4764<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4765
4766<div style="margin: auto;">
4767 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4768</div>
4769
4770<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>
4771
4772<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>
4773
4774<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>
4775
4776<div style="margin: auto;">
4777 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4778</div>
4779
4780<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>
4781
4782<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>
4783
4784<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>
4785
4786<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>
4787
4788<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>
4789
4790<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>
4791<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>
4792
4793<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4794<div style="margin: auto;">
4795 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4796</div>
4797
4798<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>
4799
4800<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>
4801
4802<div style="margin: auto;">
4803 <h4><a name="silent" id="silent"></a>-silent</h4>
4804</div>
4805
4806<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>
4807
4808<div style="margin: auto;">
4809 <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>
4810</div>
4811
4812<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>
4813
4814<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>
4815
4816<p>For Photo CD images, choose from these sizes:</p>
4817
4818<pre class="text">
4819 192x128
4820 384x256
4821 768x512
4822 1536x1024
4823 3072x2048
4824</pre>
4825
cristy3ed852e2009-09-05 21:47:34 +00004826<div style="margin: auto;">
4827 <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>
4828</div>
4829
4830<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>
4831
4832<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>
4833
4834<div style="margin: auto;">
4835 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
4836</div>
4837
4838<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>
4839
4840<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
4841
4842<div style="margin: auto;">
4843 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
4844</div>
4845
4846<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>
4847
4848<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4849
4850<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
4851
4852<div style="margin: auto;">
4853 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
4854 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
4855</div>
4856
4857<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>
4858
4859
4860<table class="doc">
4861 <tbody>
4862 <tr valign="top">
4863 <th align="left" style="width: 8%">Method</th>
4864 <th align="left">Description</th>
4865 </tr>
4866
4867 <tr valign="top">
4868 <td valign="top">voronoi</td>
4869 <td valign="top">Simply map each pixel to the to nearest color point
4870 given. The result are polygonal 'cells' of solid color. </td>
4871 </tr>
4872
4873 <tr valign="top">
4874 <td valign="top">shepards</td>
4875 <td valign="top">Colors points basied on the ratio of inverse distance
4876 squared. Generating spots of color in a sea of the average of
4877 colors. </td>
4878 </tr>
4879
4880 <tr valign="top">
4881 <td valign="top">barycentric</td>
4882 <td valign="top">three point triangle of color given 3 points.
4883 Giving only 2 points will form a linear gradient between those points.
4884 Gradient is however not restricted to just the triangle or line. </td>
4885 </tr>
4886
4887 <tr valign="top">
4888 <td valign="top">bilinear</td>
4889 <td valign="top">Like barycentric but for 4 points. Less than 4 points
4890 fall back to barycentric. </td>
4891 </tr>
4892
4893 </tbody>
4894</table>
4895
4896<p>The points are placed according to the images location on the virtual
4897canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
4898offset), and do not actually have to exist on the given image, but may be
4899some point beyond the edge of the image. All points are floating point values.
4900</p>
4901
4902<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
4903modified, whcih means the matte/alpha transparency channel is not effected by
4904default. If enabled, the image also needs a the matte/alpha channel to be
4905enabled for this operator to effect an images transparency. This is typical
4906transparency handling for images. </p>
4907
4908<p>All the above methods when given a single point of color will replace all
4909the colors in the image with the color given, regardless of the point. This is
4910logical, and provides an alternative technique to recolor a image to some
4911default value. </p>
4912
4913
4914<div style="margin: auto;">
4915 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
4916</div>
4917
4918<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>
4919
4920<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>
4921
4922<div style="margin: auto;">
4923 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
4924</div>
4925
4926<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>
4927
4928<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>
4929
4930<div style="margin: auto;">
4931 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
4932</div>
4933
4934<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>
4935
4936<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>
4937
4938<div style="margin: auto;">
4939 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
4940</div>
4941
4942<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>
4943
4944<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>
4945
4946<div style="margin: auto;">
4947 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
4948</div>
4949
4950<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>
4951
4952<pre class="text">
4953 char store pixels as unsigned characters
4954 double store pixels as doubles
4955 float store pixels as floats
4956 integer store pixels as integers
4957 long store pixels as longs
4958 quantum store pixels in the native depth of your ImageMagick distribution
4959 short store pixels as unsigned shorts
4960</pre>
4961
4962<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
4963values range from 0 to the maximum value the storage type can support.</p>
4964
4965<div style="margin: auto;">
4966 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
4967</div>
4968
4969<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>
4970
4971<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>
4972
4973<pre class="text">
4974 Any
4975 Condensed
4976 Expanded
4977 ExtraCondensed
4978 ExtraExpanded
4979 Normal
4980 SemiCondensed
4981 SemiExpanded
4982 UltraCondensed
4983 UltraExpanded
4984</pre>
4985
4986<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
4987
4988<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>
4989
4990<div style="margin: auto;">
4991 <h4><a name="strip" id="strip"></a>-strip</h4>
4992</div>
4993
4994<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>
4995
4996<div style="margin: auto;">
4997 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
4998</div>
4999
5000<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>
5001
5002<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5003
5004<p>See <a href="#draw">-draw</a> for further details.</p>
5005
5006<div style="margin: auto;">
5007 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5008</div>
5009
5010<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>
5011
5012<p>See <a href="#draw">-draw</a> for further details.</p>
5013
5014<div style="margin: auto;">
5015 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5016</div>
5017
5018<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>
5019
5020<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>
5021
5022<pre class="text">
5023 Any
5024 Italic
5025 Normal
5026 Oblique
5027</pre>
5028
5029<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>
5030
5031<div style="margin: auto;">
5032 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5033</div>
5034
5035<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>
5036
5037<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>
5038
5039<div style="margin: auto;">
5040 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5041</div>
5042
5043<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>
5044
5045<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5046
5047<div style="margin: auto;">
5048 <h4><a name="taint" id="taint"></a>-taint</h4>
5049</div>
5050
5051<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>
5052
5053<div style="margin: auto;">
5054 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5055</div>
5056
5057<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>
5058
5059<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>
5060
5061<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>
5062
5063<div style="margin: auto;">
5064 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5065</div>
5066
5067<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>
5068
5069<div style="margin: auto;">
5070 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5071</div>
5072
5073<!-- {<em class="arg">green,blue,opacity</em>}
5074<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>
5075-->
5076
5077<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>
5078
5079<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>
5080
5081<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.
5082</p>
5083
5084<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>
5085
5086<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5087<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>
5088
5089
5090<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>
5091<p>Note that the values of the transparency channel is treated as 'matte'
5092values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5093
5094<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>.
5095</p>
5096
5097<div style="margin: auto;">
5098 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5099</div>
5100
5101<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>
5102
5103<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>
5104
5105<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>
5106
5107<div style="margin: auto;">
5108 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5109</div>
5110
5111<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>
5112
5113<div style="margin: auto;">
5114 <h4>-tile <em class="arg">geometry</em></h4>
5115</div>
5116
5117<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>
5118
5119<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>
5120
5121<div style="margin: auto;">
5122 <h4>-tile</h4>
5123</div>
5124
5125<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>
5126
5127<div style="margin: auto;">
5128 <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>
5129</div>
5130
5131<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>
5132
5133<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>
5134
5135<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>
5136
5137<div style="margin: auto;">
5138 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5139</div>
5140
5141<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>
5142
5143<p>Tint the image with the fill color.</p>
5144
5145<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>
5146
5147<div style="margin: auto;">
5148 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5149</div>
5150
5151<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>
5152
5153<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>
5154
5155<p>For example,</p>
5156
5157<p class="crtsnip">
5158 -title "%m:%f %wx%h"
5159</p>
5160
5161<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>
5162
5163
5164<div style="margin: auto;">
5165 <h4><a name="transform" id="transform"></a>-transform</h4>
5166</div>
5167
5168<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>
5169
5170<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5171
5172<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>
5173<div style="margin: auto;">
5174 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5175</div>
5176
5177<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>
5178
5179<p>The <em class="arg">color</em> argument is defined using the format
5180described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5181>-fuzz</a> setting can be used to match and replace colors similar to the one
5182given. </p>
5183
5184<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5185href="#transparent" >-transparent</a> but replaces the matching color same as
5186the current <a href="#fill">-fill</a> color setting. </p>
5187
5188<p>This does not define the 'transparency color' used for color-mapped image
5189formats, such as GIF. For that use <a href="#transparent-color"
5190>-transparent-color</a> </p>
5191
5192<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5193paint any pixel that does not match the target color, with the fill color.</p>
5194
5195
5196<div style="margin: auto;">
5197 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5198</div>
5199
5200<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>
5201
5202<p>Sometimes this is used for saving to image formats such as
5203GIF and PNG8 which uses this color to represent boolean transparency. This
5204does not make a color transparent, it only defines what color the transparent
5205color is in the color palette of the saved image. Use <a
5206href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5207
5208<p>This option allows you to have both an opaque visible color, as well as a
5209transparent color of the same color value without conflict. That is, you can
5210use the same color for both the transparent and opaque color areas within an
5211image. This, in turn, frees to you to select a transparent color that is
5212appropriate when an image is displayed by an application that does not handle a
5213transparent color index, while allowing ImageMagick to correctly handle images of this
5214type. </p>
5215
5216<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5217
5218<div style="margin: auto;">
5219 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5220</div>
5221
5222<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>
5223
5224<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5225</p>
5226
5227<div style="margin: auto;">
5228 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5229</div>
5230
5231<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>
5232
5233
5234<div style="margin: auto;">
5235 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5236</div>
5237
5238<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>
5239
5240<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>
5241
5242<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>
5243
5244<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>
5245
5246<div style="margin: auto;">
5247 <h4><a name="trim" id="trim"></a>-trim</h4>
5248</div>
5249
5250<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>
5251
5252<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>
5253
5254<p>The page or virtual canvas information of the image is preserved allowing
5255you to extract the result of the <a href="#trim">-trim</a> operation from the
5256image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5257information if it is unwanted.</p>
5258
5259<p>If the trimmed image 'disappears' an warning is produced, and a special
5260single pixel transparent 'missed' image is returned, in the same way as when a
5261<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5262
5263
5264<div style="margin: auto;">
5265 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5266</div>
5267
5268<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>
5269 <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>
5270
5271<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>
5272
5273<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5274<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>
5275
5276<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5277
5278<div style="margin: auto;">
5279 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5280</div>
5281
5282<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the color of the annotation bounding box.</td><td style='text-align:right;'></td></tr></table>
5283
5284<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5285
5286<p>See <a href="#draw">-draw</a> for further details.</p>
5287
5288
5289<div style="margin: auto;">
5290 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5291</div>
5292
5293<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>
5294
5295<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>
5296
5297
5298<div style="margin: auto;">
5299 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5300</div>
5301
5302<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>
5303
5304
5305<div style="margin: auto;">
5306 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5307</div>
5308
5309<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>
5310
5311<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>
5312
5313
5314<div style="margin: auto;">
5315 <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>
5316</div>
5317
5318<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>
5319
5320<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>
5321
5322<p>The parameters are:</p>
5323
5324<pre class="text">
5325 radius: The radius of the Gaussian, in pixels, not counting the center
5326 pixel (default 0).
5327 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5328 amount: The fraction of the difference between the original and the blur
5329 image that is added back into the original (default 1.0).
5330 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5331 difference amount (default 0.05).
5332</pre>
5333
5334
5335<div style="margin: auto;">
5336 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5337</div>
5338
5339<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>
5340
5341
5342<div style="margin: auto;">
5343 <h4><a name="version" id="version"></a>-version</h4>
5344</div>
5345
5346<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>
5347
5348
5349<div style="margin: auto;">
5350 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5351</div>
5352
5353<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>
5354
5355
5356<div style="margin: auto;">
5357 <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>
5358</div>
5359
5360<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>
5361
5362
5363<div style="margin: auto;">
5364 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5365</div>
5366
5367<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>
5368
5369<p>This option defines what color source should be used if and when a color
5370lookup completely 'misses' the source image. The color(s) that appear to
5371surround the source image. Generally this color is derived from the source
5372image, but could also be set to a specify background color. </p>
5373
5374<p>Choose from these methods:</p>
5375
5376<pre class="text">
5377 background: the area surrounding the image is the background color
5378 black: the area surrounding the image is black
5379 checker-tile: alternate squares with image and background color
5380 dither: non-random 32x32 dithered pattern
5381 edge: extend the edge pixel toward infinity
5382 gray: the area surrounding the image is gray
5383 horizontal-tile: horizontally tile the image, background color above/below
5384 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5385 mirror: mirror tile the image
5386 random: choose a random pixel from the image
5387 tile: tile the image (default)
5388 transparent: the area surrounding the image is transparent blackness
5389 vertical-tile: vertically tile the image, sides are background color
5390 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5391 white: the area surrounding the image is white
5392</pre>
5393
5394<p>The default value is "edge".</p>
5395
5396<p>This most important for distortion operators such as <a href="#distort"
5397>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5398However it also effects operations that may access pixels just outside the
5399image proper, such as <a href="#convolve">-convolve</a>, <a
5400href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5401
5402<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5403
5404
5405<div style="margin: auto;">
5406 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5407</div>
5408
5409<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>
5410
5411<p>Choose from these visual classes:</p>
5412
5413<pre class="text">
5414 StaticGray
5415 GrayScale
5416 StaticColor
5417 PseudoColor
5418 TrueColor
5419 DirectColor
5420 default
5421 visual id
5422</pre>
5423
5424<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>
5425
5426
5427<div style="margin: auto;">
5428 <h4><a name="watermark" id="watermark"></a>-watermark <em
5429 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5430</div>
5431
5432<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
5433saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5434
5435<p>Take a grayscale image (with alpha mask) and modify the destination image's
5436brightness according to watermark image's grayscale value and the <em
5437class="arg">brightness</em> percentage. The destinations color saturation
5438attribute is just direct modified by the <em class="arg">saturation</em>
5439percentage, which defaults to 100 percent (no color change). </p>
5440
5441
5442<div style="margin: auto;">
5443 <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>
5444</div>
5445
5446<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>
5447
5448<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5449
5450<div style="margin: auto;">
5451 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5452</div>
5453
5454<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>
5455
5456<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>
5457
5458<table class="doc">
5459 <col width="25%" />
5460 <col width="75%" />
5461 <thead>
5462 <tr>
5463 <th><em class="arg">fontWeight</em></th>
5464 <th>Description</th>
5465 </tr>
5466 </thead>
5467 <tbody>
5468 <tr><td>All </td> <td>No effect. </td></tr>
5469 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5470 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5471 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5472 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5473 </tbody>
5474 </table>
5475
5476<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5477
5478<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>
5479
5480<div style="margin: auto;">
5481 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5482</div>
5483
5484<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>
5485
5486<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005487 <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 +00005488</div>
5489
cristy5cadd612009-09-21 19:33:41 +00005490<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>
5491
5492<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.
5493</p>
cristy3ed852e2009-09-05 21:47:34 +00005494
5495<div style="margin: auto;">
5496 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5497</div>
5498
5499<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>
5500
5501<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>
5502
5503<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>
5504
5505<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>
5506
5507<div style="margin: auto;">
5508 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5509</div>
5510
5511<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>
5512
5513<div style="margin: auto;">
5514 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5515</div>
5516
5517<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>
5518 <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>
5519
5520<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5521
cristyf3bb4782009-09-08 13:10:04 +00005522
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