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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
cristyb4c03bb2009-09-27 13:55:46 +0000675<p>Options that are affected by the <a href="#channel" >-channel</a> setting include the following.
cristy3ed852e2009-09-05 21:47:34 +0000676<a href="#black-threshold">-black-threshold</a>,
677<a href="#blur">-blur</a>,
cristyb4c03bb2009-09-27 13:55:46 +0000678<a href="#clamp">-clamp</a>,
cristy3ed852e2009-09-05 21:47:34 +0000679<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>,
cristyb4c03bb2009-09-27 13:55:46 +0000685<a href="#hald-clut">-hald-clut</a>,
cristy3ed852e2009-09-05 21:47:34 +0000686<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;">
cristyb4c03bb2009-09-27 13:55:46 +0000699 <h4><a name="clamp" id="clamp"></a>-clamp</h4>
700</div>
701
702<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Restrict image colors from 0 to the quantum depth.</td><td style='text-align:right;'></td></tr></table>
703
704<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +0000705 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
706</div>
707
708<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>
709
710<div style="margin: auto;">
711 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
712</div>
713
714<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>
715
716<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>
717
718<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>
719
720<div style="margin: auto;">
721 <h4><a name="clip" id="clip"></a>-clip</h4>
722</div>
723
724<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>
725
726<p>If a clipping path is present, it is applied to subsequent operations.</p>
727
728<p>For example, in the command</p>
729
730<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
731<p>only the pixels within the clipping path are negated.</p>
732
733<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
734
735<div style="margin: auto;">
736 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
737</div>
738
739<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>
740
741<div style="margin: auto;">
742 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
743</div>
744
745<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>
746
747<div style="margin: auto;">
748 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
749</div>
750
751<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>
752
753<p>Specify the image by its index in the sequence. The first image is index
7540. Negative indexes are relative to the end of the sequence; for example, &minus;1
755represents the last image of the sequence. Specify a range of images with a
756dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
757href="#clone">+clone</a> make a copy of the last image in the image
758sequence.</p>
759
760<div style="margin: auto;">
761 <h4><a name="clut" id="clut"></a>-clut</h4>
762</div>
763
764<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
765corresponding channel in the second image as a <b>c</b>olor
766<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
767
768<p>The second (LUT) image is ordinarily a gradient image containing the
769histogram mapping of how each channel should be modified. Typically it is a
770either a single row or column image of replacement color values. If larger
771than a single row or column, values are taken from a diagonal line from
772top-left to bottom-right corners.</p>
773
774<p>The lookup is further controlled by the <a
775href="#interpolate">-interpolate</a> setting, which is especially handy for an
776LUT which is not the full length needed by the ImageMagick installed Quality
777(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
778'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
779gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
780lookup of color values. </p>
781
782<p>This operator is especially suited to replacing a grayscale image with a
783specific color gradient from the CLUT image. </p>
784
785<p>Only the channel values defined by the <a href="#channel">-channel</a>
786setting will have their values replaced. In particular, since the default <a
787href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
788transparency (alpha/matte channel) is not affected, unless the <a
789href="#channel">-channel</a> setting is modified. When the alpha channel is
790set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
791as the other channels, implying that alpha/matte values are replaced using the
792alpha/matte values of the original image. </p>
793
794<p>If either the image being modified, or the lookup image, conatins no
795transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
796href="#channel">-channel</a> setting includes alpha replacement, then it is
797assumed that image represents a gray-scale graident which will be used for the
798replacement alpha values. That is you can use a gray-scale CLUT image to
799adjust a existing images alpha channel, or you can color a gray-scale image
800using colors form CLUT containing the desired colors, including transparency.
801</p>
802
803<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
804the lookup of the full color RGB value from a 2D representation of a 3D color
805cube. </p>
806
807
808<div style="margin: auto;">
809 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
810</div>
811
812<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>
813
814<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>
815
816<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>
817
818
819<div style="margin: auto;">
820 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
821</div>
822
823<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>
824
825<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>
826
827<div style="margin: auto;">
828 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
829</div>
830
831<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>
832
833<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
834
835<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>
836
837<div style="margin: auto;">
838 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
839</div>
840
841<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>
842
843<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>
844
845<div style="margin: auto;">
846 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
847</div>
848
849<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>
850
851<p>Choices are:</p>
852
853<pre class="text">
854 CMY
855 CMYK
856 Gray
857 HSB
858 HSL
859 HWB
860 Lab
861 Log
862 OHTA
863 Rec601Luma
864 Rec601YCbCr
865 Rec709Luma
866 Rec709YCbCr
867 RGB
868 sRGB
869 Transparent
870 XYZ
871 YCbCr
872 YCC
873 YIQ
874 YPbPr
875 YUV
876</pre>
877
878<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
879
880<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>
881
882<table class="doc">
883 <caption>Conversion Of RGB To Other Color Spaces</caption>
884 <tr><th align="left" valign="middle">CMY</th></tr>
885 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
886 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
887 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
888 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
889 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
890 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
891 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
892 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
893
894 <tr><th align="left" valign="middle">Gray</th></tr>
895 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
896
897 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
898 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
899 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
900 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
901
902 <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>
903 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
904 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
905 <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>
906
907 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
908 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
909 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
910 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
911
912 <tr><th align="left" valign="middle">LAB</th></tr>
913 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
914 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
915 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
916
917 <tr><th align="left" valign="middle">LOG</th></tr>
918 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
919 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
920 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
921
922 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
923 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
924 <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>
925 <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>
926
927 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
928 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
929
930 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
931 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
932 <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>
933 <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>
934
935 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
936 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
937
938 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
939 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
940 <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>
941 <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>
942
943 <tr><th align="left" valign="middle">sRGB</th></tr>
944 <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>
945 <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>
946 <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>
947
948 <tr><th align="left" valign="middle">XYZ</th></tr>
949 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
950 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
951 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
952
953 <tr><th align="left" valign="middle">YCC</th></tr>
954 <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>
955 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
956 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
957
958 <tr><th align="left" valign="middle">YCbCr</th></tr>
959 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
960 <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>
961 <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>
962
963 <tr><th align="left" valign="middle">YIQ</th></tr>
964 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
965 <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>
966 <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>
967
968 <tr><th align="left" valign="middle">YPbPr</th></tr>
969 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
970 <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>
971 <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>
972
973 <tr><th align="left" valign="middle">YUV</th></tr>
974 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
975 <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>
976 <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>
977</table>
978
979<div style="margin: auto;">
980 <h4><a name="combine" id="combine"></a>-combine</h4>
981</div>
982
983<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>
984
985<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>
986
987<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.
988</p>
989
990<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>
991<div style="margin: auto;">
992 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
993</div>
994
995<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>
996
997<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>
998
999<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>
1000
1001<p>For example,</p>
1002
1003<p class="crtsnip">
1004 -comment "%m:%f %wx%h"
1005</p>
1006
1007<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>
1008
1009<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>
1010
1011<div style="margin: auto;">
1012 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1013</div>
1014
1015<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>
1016
1017<p>The description of composition uses abstract terminology in order to allow
1018the description to be more precise, while avoiding constant values which are
1019specific to a particular build configuration. Each image pixel is represented
1020by red, green, and blue levels (which are equal for a gray pixel). The
1021build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1022value which may be stored, per pixel, in the red, green, or blue channels of
1023the image. Each image pixel may also optionally (if the image matte channel is
1024enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1025<em>transparent</em>, which may be used to determine the influence of the pixel
1026color when compositing the pixel with another image pixel. If the image matte
1027channel is disabled, then all pixels in the image are treated as opaque. The
1028color of an opaque pixel is fully visible while the color of a transparent
1029pixel color is entirely absent (pixel color is ignored).</p>
1030
1031<p>By definition, raster images have a rectangular shape. All image rows are of
1032equal length, as are all image columns. By treating the alpha channel as a
1033visual "mask" the rectangular image may be given a "shape" by treating the
1034alpha channel as a cookie-cutter for the image. This is done by setting the
1035pixels within the shape to be opaque, with pixels outside the shape set as
1036transparent. Pixels on the boundary of the shape may be between opaque and
1037transparent in order to provide antialiasing (visually smooth edges). The
1038description of the composition operators use this concept of image "shape" in
1039order to make the description of the operators easier to understand. While it
1040is convenient to describe the operators in terms of "shapes" they are by no
1041means limited to mask-style operations since they are based on continuous
1042floating-point mathematics rather than simple boolean operations.</p>
1043
1044<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1045
1046<table class="doc">
1047 <tbody>
1048 <tr valign="top">
1049 <th align="left" style="width: 8%">Method</th>
1050 <th align="left">Description</th>
1051 </tr>
1052
1053 <tr valign="top">
1054 <td valign="top">clear</td>
1055 <td valign="top">Both the color and the alpha of the destination are
1056 cleared. Neither the source nor the destination are used (except for
1057 destinations size and other meta-data which is always preserved.</td>
1058 </tr>
1059
1060 <tr valign="top">
1061 <td valign="top">src</td>
1062 <td valign="top">The source is copied to the destination. The destination
1063 is not used as input, though it is cleared.</td>
1064 </tr>
1065
1066 <tr valign="top">
1067 <td valign="top">dst</td>
1068 <td valign="top">The destination is left untouched. The source image is
1069 completely ignored.</td>
1070 </tr>
1071
1072 <tr valign="top">
1073 <td valign="top">src-over</td>
1074 <td valign="top">The source is composited over the destination. this is
1075 the default alpha blending compose method, when neither the compose
1076 setting is set, nor is set in the image meta-data.</td>
1077 </tr>
1078
1079 <tr valign="top">
1080 <td valign="top">dst-over</td>
1081 <td valign="top">The destination is composited over the source and the
1082 result replaces the destination.</td>
1083 </tr>
1084
1085 <tr valign="top">
1086 <td valign="top">src-in</td>
1087 <td valign="top">The part of the source lying inside of the destination
1088 replaces the destination.</td>
1089 </tr>
1090
1091 <tr valign="top">
1092 <td valign="top">dst-in</td>
1093 <td valign="top">The part of the destination lying inside of the source
1094 replaces the destination. Areas not overlaid are cleared.</td>
1095 </tr>
1096
1097 <tr valign="top">
1098 <td valign="top">src-out</td>
1099 <td valign="top">The part of the source lying outside of the destination
1100 replaces the destination.</td>
1101 </tr>
1102
1103 <tr valign="top">
1104 <td valign="top">dst-out</td>
1105 <td valign="top">The part of the destination lying outside of the source
1106 replaces the destination.</td>
1107 </tr>
1108
1109 <tr valign="top">
1110 <td valign="top">src-atop</td>
1111 <td valign="top">The part of the source lying inside of the destination is
1112 composited onto the destination.</td>
1113 </tr>
1114
1115 <tr valign="top">
1116 <td valign="top">dst-atop</td>
1117 <td valign="top">The part of the destination lying inside of the source is
1118 composited over the source and replaces the destination. Areas not
1119 overlaid are cleared. </td>
1120 </tr>
1121
1122 <tr valign="top">
1123 <td valign="top">xor</td>
1124 <td valign="top">The part of the source that lies outside of the
1125 destination is combined with the part of the destination that lies
1126 outside of the source. Source or Destination, but not both. </td>
1127 </tr>
1128
1129 </tbody>
1130</table>
1131
1132<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1133For example the defaul compose method can be specified as just 'Over'.</p>
1134
1135
1136<p>The following mathemathical composition methods are also available. </p>
1137
1138<p>Typically these use the default 'Over' alpha blending when transparencies
1139are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1140also composes the alpha channel using the same process as the color channels.
1141This allows them to be used for special image masking techniques. </p>
1142
1143<table class="doc">
1144 <tbody>
1145 <tr valign="top">
1146 <th align="left" style="width: 8%">Method</th>
1147 <th align="left">Description</th>
1148 </tr>
1149
1150 <tr valign="top">
1151 <td valign="top">multiply</td>
1152 <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>
1153 </tr>
1154
1155 <tr valign="top">
1156 <td valign="top">screen</td>
1157 <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>
1158 </tr>
1159
1160 <tr valign="top">
1161 <td valign="top">plus</td>
1162 <td valign="top">The source is added to the destination and replaces the
1163 destination. This operator is useful for averaging or a controled
1164 merger of two images, rather than a direct overlay.</td>
1165 </tr>
1166
1167 <tr valign="top">
1168 <td valign="top">add</td>
1169 <td valign="top">As per 'plus' but transparency data is treated as matte
1170 values. As such any transparent areas in either image remain
1171 transparent. </td>
1172 </tr>
1173
1174 <tr valign="top">
1175 <td valign="top">minus</td>
1176 <td valign="top">Subtract the colors in the source image from the
1177 destination image. When transparency is involved, opaque areas is
1178 subtracted from any destination opaque areas. </td>
1179 </tr>
1180
1181 <tr valign="top">
1182 <td valign="top">subtract</td>
1183 <td valign="top">Subtract the colors in the source image from the
1184 destination image. When transparency is involved transparent areas are
1185 subtracted, so only the opaque areas in the source remain opaque in
1186 the destination image. </td>
1187 </tr>
1188
1189 <tr valign="top">
1190 <td valign="top">difference</td>
1191 <td valign="top">Subtracts the darker of the two constituent colors from
1192 the lighter. Painting with white inverts the destination color.
1193 Painting with black produces no change.</td>
1194 </tr>
1195
1196 <tr valign="top">
1197 <td valign="top">exclusion</td>
1198 <td valign="top">Produces an effect similar to that of 'difference', but
1199 appears as lower contrast. Painting with white inverts the
1200 destination color. Painting with black produces no change.</td>
1201 </tr>
1202
1203 <tr valign="top">
1204 <td valign="top">darken</td>
1205 <td valign="top">Selects the darker of the destination and source colors.
1206 The destination is replaced with the source when the source is darker,
1207 otherwise it is left unchanged.</td>
1208 </tr>
1209
1210 <tr valign="top">
1211 <td valign="top">lighten</td>
1212 <td valign="top">Selects the lighter of the destination and source colors.
1213 The destination is replaced with the source when the source is
1214 lighter, otherwise it is left unchanged. </td>
1215 </tr>
1216
1217 <tr valign="top">
1218 <td valign="top">linear-dodge</td>
1219 <td valign="top">This is equivelent to 'Plus' in that the color channels
1220 are simply added, however it does not 'Plus' the alpha channel, but
1221 uses the normal 'Over' alpha blending, which transparencies are
1222 involved. Produces a sort of additive multiply-like result. Added
1223 ImageMagick version 6.5.4-3. </td>
1224 </tr>
1225
1226 <tr valign="top">
1227 <td valign="top">linear-burn</td>
1228 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1229 Sort of a additive 'Screen' of the images. Added ImageMagick version
1230 6.5.4-3. </td>
1231 </tr>
1232
1233 <tr valign="top">
1234 <td valign="top">color-dodge</td>
1235 <td valign="top">Brightens the destination color to reflect the source
1236 color. Painting with black produces no change.</td>
1237 </tr>
1238
1239 <tr valign="top">
1240 <td valign="top">color-burn</td>
1241 <td valign="top">Darkens the destination color to reflect the source
1242 color. Painting with white produces no change. Fixed in ImageMagick
1243 version 6.5.4-3. </td>
1244 </tr>
1245
1246 <tr valign="top">
1247 <td valign="top">overlay</td>
1248 <td valign="top">Multiplies or screens the colors, dependent on the
1249 destination color. Source colors overlay the destination whilst
1250 preserving its highlights and shadows. The destination color is not
1251 replaced, but is mixed with the source color to reflect the lightness
1252 or darkness of the destination.</td>
1253 </tr>
1254
1255 <tr valign="top">
1256 <td valign="top">hard-light</td>
1257 <td valign="top">Multiplies or screens the colors, dependent on the source
1258 color value. If the source color is lighter than 0.5, the destination
1259 is lightened as if it were screened. If the source color is darker
1260 than 0.5, the destination is darkened, as if it were multiplied. The
1261 degree of lightening or darkening is proportional to the difference
1262 between the source color and 0.5. If it is equal to 0.5 the
1263 destination is unchanged. Painting with pure black or white produces
1264 black or white.</td>
1265 </tr>
1266
1267
1268 <tr valign="top">
1269 <td valign="top">linear-light</td>
1270 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1271 instead. Increases contrast slightly with an impact on the
1272 foreground's tonal values.</td>
1273 </tr>
1274
1275 <tr valign="top">
1276 <td valign="top">soft-light</td>
1277 <td valign="top">Darkens or lightens the colors, dependent on the source
1278 color value. If the source color is lighter than 0.5, the destination
1279 is lightened. If the source color is darker than 0.5, the destination
1280 is darkened, as if it were burned in. The degree of darkening or
1281 lightening is proportional to the difference between the source color
1282 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1283 with pure black or white produces a distinctly darker or lighter area,
1284 but does not result in pure black or white. Fixed in ImageMagick
1285 version 6.5.4-3. </td>
1286 </tr>
1287
1288 <tr valign="top">
1289 <td valign="top">pegtop-light</td>
1290 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1291 continuious mathematical formula rather than two conditionally
1292 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1293 </tr>
1294
1295 <tr valign="top">
1296 <td valign="top">vivid-light</td>
1297 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1298 primary and secondary colors in the image. Added ImageMagick version
1299 6.5.4-3. </td>
1300 </tr>
1301
1302 <tr valign="top">
1303 <td valign="top">pin-light</td>
1304 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1305 to similate the effects of a strong 'pinhole' light source. Added
1306 ImageMagick version 6.5.4-3. </td>
1307 </tr>
1308
1309 </tbody>
1310</table>
1311
1312
1313<p>Also included are these special purpose compose methods:</p>
1314
1315<table class="doc">
1316 <tbody>
1317 <tr valign="top">
1318 <th align="left" style="width: 8%">Method</th>
1319 <th align="left">Description</th>
1320 </tr>
1321
1322 <tr valign="top">
1323 <td valign="top">copy-*</td>
1324 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1325 Magenta, Yellow, Black, or Opacity) in the source image to the
1326 same channel in the destination image. If the channel specified
1327 does not exist in the source image, (which can only happen for methods,
1328 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1329 assumed that the source image is a special grayscale channel image
1330 of the values to be copied. </td>
1331 </tr>
1332
1333 <tr valign="top">
1334 <td valign="top">change-mask</td>
1335 <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>
1336 </tr>
1337 </tbody>
1338</table>
1339
1340<p>On top of these composed methods are a few special ones that not only require
1341the two images that are being merged or overlaid, but have some extra numerical
1342arguments, which are tabled below. </p>
1343
1344<p>In the "<code>composite</code>" command these composition methods are
1345selected using special options with the arguments needed. They are usually,
1346but not always, the same name as the composte 'method' they use, and replaces
1347the normal use of the <a href="#compose" >-compose</a> setting in the
1348"<code>composite</code>" command. For example... </p>
1349
1350<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1351<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1352these extra arguments to its <a href="#composite" >-composite</a> operator,
1353using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1354these special argumented <a href="#compose" >-compose</a> methods, those the
1355argument and the method both need to be set separatally. For example... </p>
1356
1357<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1358<p>The following is a table of these special 'argumented' compose methods,
1359with a brief summary of what they do. For more details see the equivalent
1360"composite" command option name. </p>
1361
1362<table class="doc">
1363 <tbody>
1364 <tr valign="top">
1365 <th align="left" style="width: 8%">Method</th>
1366 <th align="left">Description</th>
1367 </tr>
1368
1369 <tr valign="top">
1370 <td valign="top">dissolve</td>
1371 <td valign="top">Arguments:
1372 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1373 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1374 <br>Dissolve the 'source' image by the percentage given before overlaying
1375 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1376 greater than 100, it starts dissolving the main image so it will
1377 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1378 both percentages are given, each image are dissolved to the
1379 percentages given.
1380 </td>
1381 </tr>
1382
1383 <tr valign="top">
1384 <td valign="top">blend</td>
1385 <td valign="top">Arguments:
1386 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1387 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1388 <br>Average the images together ('plus') according to the percentages
1389 given and each pixels transparency. If only a single percentage value
1390 is given it sets the weight of the composite or 'source' image, while
1391 the background image is weighted by the exact opposite amount. That is
1392 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1393 the 'destination' image. Thus it is equivalent to <kbd>-blend
1394 30x70</kbd>.
1395 </td>
1396 </tr>
1397
1398 <tr valign="top">
1399 <td valign="top">mathematics</td>
1400 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1401 <br>Not available in "<code>composite</code>" at this time.
1402 <br>Merge the source and destination images according to the formula
1403 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1404 <br>Can be used to generate a custom composition method that would
1405 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1406 DIY image operator. Added to ImageMagick version 6.5.4-3.
1407 </td>
1408 </tr>
1409
1410 <tr valign="top">
1411 <td valign="top">modulate</td>
1412 <td valign="top">Arguments:
1413 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1414 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1415 <br>Take a grayscale image (with alpha mask) and modify the destination
1416 image's brightness according to watermark image's grayscale value and
1417 the <em class="arg">brightness</em> percentage. The destinations
1418 color saturation attribute is just direct modified by the <em
1419 class="arg">saturation</em> percentage, which defaults to 100 percent
1420 (no color change).
1421
1422 </td>
1423 </tr>
1424
1425 <tr valign="top">
1426 <td valign="top">displace</td>
1427 <td valign="top">Arguments:
1428 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1429 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1430 <br>With this option, the 'overlay' image, and optionally the 'mask'
1431 image, is used as a relative displacement map, which is used to
1432 displace the lookup of what part of the destination image is seen at
1433 each point of the overlaid area. Much like the displacement map is a
1434 'lens' that distorts the original 'background' image behind it.
1435 <br><br>
1436 The X-scale is modilated by the 'red' channel of the overlay image
1437 while the Y-scale is modulated by the green channel, (the mask image
1438 if given is rolled into green channel of the overlay image. This
1439 separation allows you to modulate the X and Y lookup displacement
1440 separatally allowing you to di 2 dimentional displacements, rather
1441 than 1 dimentional verctored displacements (using grayscale image).
1442 <br><br>
1443 If the overlay image contains transparency this is used as a mask
1444 of the resulting image to remove 'invalid' pixels.
1445 <br><br>
1446 The '%' flag makes the displacement scale relative to the size of the
1447 overlay image (100% = half width/height of image). Using '!' switches
1448 percentage arguments to refer to the destination image size instead.
1449 <br><br>
1450 Special flags were added Added to ImageMagick version 6.5.3-5.
1451 </td>
1452 </tr>
1453
1454 <tr valign="top">
1455 <td valign="top">distort</td>
1456 <td valign="top">Arguments:
1457 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1458 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1459 <br>Not available in "<code>composite</code>" at this time.
1460 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1461 relative to the center of the overlay (or that given). Basically
1462 allows you to generate absolute distortion maps where 'black' will
1463 look up the left/top edge, and 'white' looks up the bottom/right
1464 edge of the destination image, according to the scale given.
1465 <br><br>
1466 The '!' flag not only switches percentage scaling, to use the
1467 destination image, but also the image the center offset of the lookup.
1468 This means the overlay can lookup a completely different region of the
1469 destination image.
1470 <br><br>
1471 Added to ImageMagick version 6.5.3-5.
1472 </td>
1473 </tr>
1474
1475 <tr valign="top">
1476 <td valign="top">blur</td>
1477 <td valign="top">Arguments:
1478 <em class="arg">Width</em>[x<em class="arg">Height</em
1479 >[+<em class="arg">Angle</em>]]
1480 <br>Equivalent to "<code>composite</code>"
1481 <a href="#blur-composite">-blur</a>
1482 <br>A Variable Blur Mapping Composition method, where each pixel in the
1483 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1484 with an ellipse (typically a circle) of the given sigma size, scaled
1485 according to overlay (source image) grayscale mapping.
1486 <br><br>
1487 As per 'Displace' and 'Distort', the red channel will modulate the
1488 width of the ellipse, while the green channel will modulate the height
1489 of the ellipse. However at this time the ellipse angle is not
1490 modulated though this may be a future posibility (perhaps with a
1491 special flag to enable use of blur channel for this purpose).
1492 <br><br>
1493 Added to ImageMagick version 6.5.4-0.
1494 </td>
1495 </tr>
1496
1497 </tbody>
1498</table>
1499
1500<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1501
1502
1503<div style="margin: auto;">
1504 <h4><a name="composite" id="composite"></a>-composite</h4>
1505</div>
1506
1507<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>
1508
1509<p>Take the first image 'destination' and overlay the second 'source' image
1510according to the current <a href="#compose">-compose</a> setting. The location
1511of the 'source' or 'overlay' image is controlled according to <a
1512href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1513settings. </p>
1514
1515<p>If a third image is given this is treated as a gray-scale 'mask' image
1516relative to the first 'destination' image. This mask will limit what parts of
1517the destination can be modified by the image composition. However for the
1518'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1519Y-displacement image instead. </p>
1520
1521<p>If a <a href="#compose">-compose</a> method requires extra numerical
1522arguments or flags these can be provided by setting the <a
1523href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1524appropriatally for the compose method. </p>
1525
1526<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1527image outside the overlay area. You can disable this by setting the special <a
1528href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1529to '<kbd>false</kbd>'. </p>
1530
1531
1532<div style="margin: auto;">
1533 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1534</div>
1535
1536<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>
1537
1538<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>
1539
1540<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1541
1542<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>
1543
1544<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>
1545
1546<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>
1547
1548<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>
1549
1550<div style="margin: auto;">
1551 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1552</div>
1553
1554<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>
1555
1556<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>
1557
1558<p>For a more pronounced effect you can repeat the option:</p>
1559
1560<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1561<div style="margin: auto;">
1562 <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>
1563</div>
1564
1565<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>
1566
1567<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>
1568
1569<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>
1570
1571<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that the image's
1572min 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>
1573
1574<p>The channels are stretched in concert. Specify <a href="#channel">-channel</a> to normalize the RGB channels individually.</p>
1575
1576
1577<div style="margin: auto;">
1578 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1579</div>
1580
1581<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>
1582
1583<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>
1584
1585<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.
1586</p>
1587
1588<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,
1589as ImageMagick is able to store/handle any negative results without
1590clipping to the color value range (0..QuantumRange).</p>
1591
1592<p>See the discussion on HDRI implementations of ImageMagick on the page
1593<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.
1594</p>
1595
1596<div style="margin: auto;">
1597 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1598</div>
1599
1600<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>
1601
1602<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>
1603
1604<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>
1605
1606<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>
1607
1608<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>
1609
1610<p>By adding a exclamation character flag to the geometry argument, the
1611cropped images virtual canvas page size and offset is set as if the
1612geometry argument was a viewport or window. This means the canvas page size
1613is set to exactly the same size you specified, the image offset set
1614relative top left corner of the region cropped. </p>
1615
1616<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1617special single pixel transparent 'missed' image is returned, and a 'crop
1618missed' warning given. </p>
1619
1620
1621<div style="margin: auto;">
1622 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1623</div>
1624
1625<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>
1626
1627<p><em class="arg">Amount</em> defines the number of positions each
1628colormap entry is shifted.</p>
1629
1630
1631<div style="margin: auto;">
1632 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1633</div>
1634
1635<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>
1636
1637<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>
1638
1639
1640<p>For example, to log cache and blob events, use.</p>
1641
1642<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1643<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1644
1645<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1646
1647<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1648
1649<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1650
1651<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>
1652
1653
1654<div style="margin: auto;">
1655 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1656</div>
1657
1658<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>
1659
1660<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1661
1662<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1663
1664
1665<div style="margin: auto;">
1666 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1667</div>
1668
1669<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>
1670
1671<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>
1672
1673<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>
1674
1675<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1676
1677
1678<div style="margin: auto;">
1679 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1680</div>
1681
1682<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>
1683
1684<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>
1685
1686<p>The following definitions may be created:</p>
1687
1688<ul>
cristy48dd1af2009-10-02 01:21:56 +00001689<dt>jpeg:size=geometry</dt>
1690 <dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. It is most useful for increasing performance and reducing the memory requirements when reducing the size of a large JPEG image.</dd><br />
cristy3ed852e2009-09-05 21:47:34 +00001691<dt>jp2:rate=value</dt>
1692 <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 />
1693<dt>mng:need-cacheoff</dt>
1694 <dd>turn playback caching off for streaming MNG.</dd><br />
1695<dt>png:bit-depth=value</dt>
1696<dt>png:color-type=value</dt>
1697 <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 />
1698<dt>ps:imagemask</dt>
1699 <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>
1700</ul>
1701
1702<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1703
1704<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1705<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>
1706
1707<p class="crtsnip">
1708-define registry:temporary-path=/data/tmp
1709</p>
1710
1711<div style="margin: auto;">
1712 <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>
1713</div>
1714
1715<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>
1716
1717<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>
1718
1719<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>
1720
1721
1722<div style="margin: auto;">
1723 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1724</div>
1725
1726<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>
1727
1728<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>
1729
1730
1731<div style="margin: auto;">
1732 <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>
1733</div>
1734
1735<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>
1736
1737<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>
1738
1739<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>
1740
1741<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>
1742
1743<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>
1744
1745<div style="margin: auto;">
1746 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1747</div>
1748
1749<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>
1750
1751<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>
1752
1753<div style="margin: auto;">
1754 <h4><a name="descend" id="descend"></a>-descend</h4>
1755</div>
1756
1757<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>
1758
1759<div style="margin: auto;">
1760 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1761</div>
1762
1763<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>
1764
1765<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>
1766
1767<div style="margin: auto;">
1768 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1769</div>
1770
1771<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>
1772
1773<div style="margin: auto;">
1774 <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>
1775</div>
1776
1777<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>
1778
1779<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1780will be used as a displacement map, which is used to displace the lookup of
1781what part of the 'background' image is seen at each point of the overlaid
1782area. Much like the displacement map is a 'lens' that redirects light shining
1783through it so as to present a distorted view the original 'background' image
1784behind it. </p>
1785
1786<p>Any perfect grey areas of the displacement map produce a zero
1787displacement of the image. Black areas produce the given maximum negative
1788displacement of the lookup point, while white produce a maximum positive
1789displacement of the lookup. </p>
1790
1791<p>Note that it is the lookup of the 'background' that is displaced, not a
1792displacement of the image itself. As such an area of the displacement map
1793containing 'white' will have the lookup point 'shifted' by a positive amount,
1794and thus generating a copy of the destination image to the right/downward from
1795the correct position. That is the image will look like it may have been
1796'shifted' in a negative left/upward direction. Understanding this is a very
1797important in understanding how displacement maps work. </p>
1798
1799<p>The given arguments define the maximum amount of displacement in pixels
1800that a particular map can produce. If the displacement scale is large enough
1801it is also posible to lookup parts of the 'background' image that lie well
1802outside the bounds of the displacement map itself. That is you could very
1803easilly copy a section of the original image from outside the overlay area
1804into the overlay area. </p>
1805
1806<p>The '%' flag makes the displacement scale relative to the size of the
1807overlay image (100% = half width/height of image). Using '!' switches
1808percentage arguments to refer to the destination image size instead.
1809these flags were added as of IM v6.5.3-5.</p>
1810
1811<p>Normally a single grayscale displacement map is provided, which with the
1812given scaling values will determine a single direction (vector) in which
1813displacements can occur (positivally or negativally). However, if you also
1814specify a third image which is normally used as a <em class="arg">mask</em>,
1815then the <em class="arg">composite image</em> will be used for horizontal X
1816displacement, while the <em class="arg">mask image</em> is used for vertical Y
1817displacement. This allows you to define completely different displacement
1818values for the X and Y directions, and allowing you to lookup any point within
1819the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1820any other nearby pixel, producing complex 2 dimentional displacements, rather
1821than a simple 1 dimentional vector displacements. </p>
1822
1823<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1824you can use the 'red' channel of the overlay image to specify the horizontal
1825or X displacement, and the 'green' channel for the vertical or Y displacement.
1826</p>
1827
1828<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1829mask the transparency of the destination image. However areas outside the
1830overlaid areas will not be effected. </p>
1831
1832
1833<div style="margin: auto;">
1834 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1835</div>
1836
1837<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>
1838
1839<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1840
1841<div style="margin: auto;">
1842 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1843</div>
1844
1845<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>
1846
1847<p>The layer disposal method defines the way each the displayed image is to be
1848modified after the current 'frame' of an animation has finished being
1849displayed (after its 'delay' period), but before the next frame on an
1850animation is to be overlaid onto the display. </p>
1851
1852<p>Here are the valid methods:</p>
1853
1854<pre class="text">
1855Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1856None 1 Do not dispose, just overlay next frame image.
1857Background 2 Clear the frame area with the background color.
1858Previous 3 Clear to the image prior to this frames overlay.
1859</pre>
1860
1861<p>You can also use the numbers given above, which is what the GIF format
1862uses internally to represent the above settings. </p>
1863
1864<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1865
1866<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1867resetting the layer disposal methods of images being read in. </p>
1868
1869<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1870disposal method for images already in memory.</p>
1871
1872<div style="margin: auto;">
1873 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1874</div>
1875
1876<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>
1877
1878
1879<div style="margin: auto;">
1880 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
1881</div>
1882
1883<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>
1884
1885<p>The opacity of the composite image is multiplied by the given percent, then
1886it is composited 'over' the main image. If <em class="arg">src_percent</em>
1887is greater than 100, start dissolving the main image so it will become
1888transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
1889are given, each image are dissolved to the percentages given. </p>
1890
1891<p>Note that dissolve percentages do not add, two opaque images dissolved
1892'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
1893images, you would need to use dissolve values of '50,100'. </p>
1894
1895<div style="margin: auto;">
1896 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
1897</div>
1898
1899<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>
1900
1901<p>The <em class="arg">arguments</em> is a single string containing a list
1902of floating point numbers separated by commas or spaces. The number of
1903and meaning of the floating point values depends on the distortion <em
1904class="arg">method</em> being used. </p>
1905
1906<p>Choose from these distortion types:</p>
1907
1908<table class="doc">
1909 <tr valign="top">
1910 <th align="left" style="width: 8%">Method</th>
1911 <th align="left">Description</th>
1912 </tr>
1913
1914 <tr valign="top">
1915 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
1916 <br/>or &nbsp; <kbd>SRT</kbd></td>
1917 <td valign="top">
1918 Distort image by first scaling and rotating about a given 'center',
1919 before translating that 'center' to the new location, in that order. It
1920 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
1921 distortion, but without shearing effects. It also provides a good way
1922 of rotating and displacing a smaller image for tiling onto a larger
1923 background (IE 2-dimensional animations). <br/>
1924
1925 The number of arguments determine the specific meaning of each
1926 argument for the scales, rotation, and translation operations. <br/>
1927
1928 <table style="margin-left:auto; margin-right:auto;">
1929 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
1930 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
1931 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
1932 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1933 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
1934 <tr><td>5:</td>
1935 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1936 <tr><td>6:</td>
1937 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
1938 <tr><td>7:</td>
1939 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
1940 &nbsp; NewX,NewY</em></td></tr>
1941 </table>
1942
1943 This is actually an alternative way of specifing a 2 dimensional linear
1944 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
1945
1946 <tr valign="top">
1947 <td valign="top"><kbd>Affine</kbd></td>
1948 <td valign="top">
1949 Distort the image linearly by moving a list of at least 3 or more sets
1950 of control points (as defined below). Idealy 3 sets or 12 floating
1951 point values are given allowing the image to be linearly scaled,
1952 rotated, sheared, and translated, according to those three points. See
1953 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
1954 distortions. <br/>
1955
1956 More than 3 sets given control point pairs (12 numbers) is least
1957 squares fitted to best match a lineary affine distortion. If only 2
1958 control point pairs (8 numbers) are given a two point image translation
1959 rotation and scaling is performed, without any posible shearing,
1960 flipping or changes in aspect ratio to the resulting image. If only one
1961 control point pair is provides the image is only translated, (which may
1962 be a floating point non-integer translation). <br/>
1963
1964 This distortion does not include any form of perspective distortion.
1965 </td>
1966
1967 </tr>
1968
1969 <tr valign="top">
1970 <td valign="top"><kbd>AffineProjection</kbd></td>
1971 <td valign="top">
1972 Linearly distort an image using the given Affine Matrix of 6
1973 pre-calculated coefficients forming a set of Affine Equations to map
1974 the source image to the destination image.
1975
1976 <div style="text-align: center"><em>
1977 s<sub>x</sub>, r<sub>x</sub>,
1978 r<sub>y</sub>, s<sub>y</sub>,
1979 t<sub>x</sub>, t<sub>y</sub>
1980 </em></div>
1981
1982 See <a href="#affine" >-affine</a> setting for more detail, and
1983 meanings of these coefficients. <br/>
1984
1985 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
1986 alternative methods of defining this distortion, with ImageMagick doing the
1987 calculations needed to generate the required coefficients. You can see
1988 the internally generated coefficients, by using a <a href="#verbose"
1989 >-verbose</a> setting. </td>
1990
1991 </tr>
1992
1993<!-- still under development, do not display - Anthony
1994 <tr valign="top">
1995 <td valign="top"><kbd>Bilinear</kbd></td>
1996 <td valign="top">
1997 Bilinear (reversed) Distortion, given a minimum of 4 sets of
1998 coordinate pairs, or 16 values (see below). Not that lines may not
1999 appear straight after distortion, though the distance between
2000 coordinates will remain consistant. </td>
2001 </tr>
2002-->
2003
2004 <tr valign="top">
2005 <td valign="top"><kbd>Perspective</kbd></td>
2006 <td valign="top">
2007 Perspective distort the images, using a list of 4 or more sets of
2008 control points (as defined below). More that 4 sets (16 numbers) of
2009 control points provide least squares fitting for more accurate
2010 distortions (for the purposes of image registration and panarama
2011 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
2012 linear distortion. <br/>
2013
2014 Perspective Distorted images ensures that straight lines remain
2015 straight, but the scale of the distorted image will vary. The horizon
2016 is anti-aliased, and the 'sky' color may be set using the
2017 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2018 </tr>
2019
2020 <tr valign="top">
2021 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2022 <td valign="top">
2023 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2024 pre-calculated coefficients. You can get these coefficients by looking
2025 at the <a href="#verbose" >-verbose</a> output of a
2026 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2027 If the last two perspective scaling coefficients are zero, the
2028 remaining 6 represents a transposed 'Affine Matrix'. </td>
2029
2030 </tr>
2031
2032 <tr valign="top">
2033 <td valign="top"><kbd>Arc</kbd></td>
2034 <td valign="top">
2035 Arc the image (variation of polar mapping) over the angle given around
2036 a circle. <br/>
2037 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2038 <tr valign="top"><td>Argument</td>
2039 <td>Meaning</td></tr>
2040 <tr valign="top"><td><em>arc_angle</em></td>
2041 <td>The angle over which to arc the image side-to-side</td></tr>
2042 <tr valign="top"><td><em>rotate_angle</em></td>
2043 <td>Angle to rotate resulting image from vertical center</td></tr>
2044 <tr valign="top"><td><em>top_radius</em></td>
2045 <td>Set top edge of source image at this radius</td></tr>
2046 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2047 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2048 </table>
2049
2050 The resulting image is always resized to best fit the resulting image,
2051 (as if using <a href="#distort" >+distort</a>) while attempting to
2052 preserve scale and aspect ratio of the original image as much as
2053 possible with the arguments given by the user. All four arguments will
2054 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2055
2056 This a variation of a polar distortion designed to try to preserve the
2057 aspect ratio of the image rather than direct Cartesian to Polar
2058 conversion. </td>
2059 </tr>
2060
2061 <tr valign="top">
2062 <td valign="top"><kbd>Polar</kbd></td>
2063 <td valign="top">
2064 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2065 the image. that is the height of the input image is mapped to the
2066 radius limits, while the width is wrapped around between the
2067 angle limits. <br/>
2068
2069 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2070
2071 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2072 center to the center of the image, and the angles going from -180 (top)
2073 to +180 (top). If <em>Rmax</em> is given the special value of
2074 '<code>0</code>', the the distance from the center to the nearest edge
2075 is used for the radius of the output image, which will ensure the whole
2076 image is visible (though scaled smaller). However a special value of
2077 '<code>-1</code>' will use the distance from the center to the furthest
2078 corner, This may 'clip' the corners from the input rectangular image,
2079 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2080 the same arguments. <br/>
2081
2082 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2083 output image center will default to <code>0,0</code> of the virtual
2084 canvas, and the image size adjusted to ensure the whole input image is
2085 made visible in the output image on the virtual canvas. </td>
2086
2087 </tr>
2088
2089 <tr valign="top">
2090 <td valign="top"><kbd>DePolar</kbd></td>
2091 <td valign="top">
2092 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2093 but generates the reverse Polar to Cartesian distortion. <br/>
2094
2095 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2096 the corners of the input image. However using the special
2097 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2098 distance) will ensure the whole distorted image is preserved in the
2099 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2100 reverse the distortion re-producing the original.
2101
2102 Note that as this distortion requires the area resampling of a circular
2103 arc, which can not be handled by the builtin EWA resampling function.
2104 As such the normal EWA filters are turned off. It is recomended some
2105 form of 'super-sampling' image processing technique be used to produce
2106 a high quality result. </td>
2107
2108 </tr>
2109
2110 <tr valign="top">
2111 <td valign="top"><kbd>Barrel</kbd></td>
2112 <td valign="top">
2113 Given the four coefficients (A,B,C,D) as defined by <a
2114 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2115 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2116 correct radial lens distortions. That is in photographs, make straight
2117 lines straight again. <br/>
2118
2119 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2120 <em>X</em> , <em>Y</em> ] ] <br/>
2121 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2122 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2123 [ <em>X</em> , <em>Y</em> ] <br/>
2124 So that it forms the function <br/>
2125 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2126 <em>C</em>*r + <em>D</em> )<br/>
2127
2128 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2129 (defaulting to the center of the image). <br/>
2130 The second form is typically used to distort images, rather than
2131 correct lens distortions. <br/>
2132 </td>
2133
2134 </tr>
2135
2136 <tr valign="top">
2137 <td valign="top"><kbd>BarrelInverse</kbd></td>
2138 <td valign="top">
2139 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2140 arguments, and argument handling. However it uses the inverse
2141 of the radial polynomial,
2142 so that it forms the function <br/>
2143 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2144 <em>C</em>*r + <em>D</em> )
2145 </td>
2146 </tr>
2147
2148 <tr valign="top">
2149 <td valign="top"><kbd>Shepards</kbd></td>
2150 <td valign="top">
2151 Distort the given list control points (any number) using an Inverse
2152 Squared Distance Interpolation Method (<a
2153 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2154 >Shepards Method</a>). The control points in effect do 'localized'
2155 distortions of the image around the given control point. For best
2156 results extra control points should be added to 'lock' the positions of
2157 the corners and other unchanging parts of the image. <br/>
2158
2159 The distortion has been likened to 'taffy pulling' using nails, pins or
2160 sticks. It basically uses the <a href="#sparse-color"
2161 >-sparse-color</a> method of the same name to generate separate X and Y
2162 displacement maps (see <a href="#displace" >-displace</a>) for source
2163 image color look-up. </td>
2164
2165 </tr>
2166
2167</table>
2168
2169<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2170
2171<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2172'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2173defining how these points in the given image should be distorted in the
2174destination image. Each set of four floating point values represent a source
2175image coordinate, followed immediately by the destination image coordinate.
2176This produces a list of values such as...</p>
2177<div style="text-align: center"><em>
2178 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2179 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2180 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2181 ... &nbsp;
2182 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2183</em></div>
2184<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2185destination image. </p>
2186
2187<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2188needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2189perspective distortion of the built-in "rose:" image. Note how spaces were
2190used to group the 4 sets of coordinate pairs, to make it easier to read and
2191understand.</p>
2192
2193<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2194 convert rose: -virtual-pixel black \ <br/>
2195 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2196 rose_3d_rotated.gif</span></p>
2197<p>If more that the required number of coordinate pairs are given for a
2198distortion, the distortion method is 'least squares' fitted to
2199produce the best result for all the coordinate pairs given. If less than the
2200ideal number of points are given, the distort will generally fall back to a
2201simpler form of distortion that can handles the smaller number of coordinates
2202(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2203
2204<p>By using more coodinates you can make use of image registration tool to
2205find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2206of the distortion. Of course a bad coordinate pair can also make the 'fit'
2207worse. Caution is always advised. </p>
2208
2209<p>Colors are acquired from the source image according to the <a
2210href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2211magnified. However if the viewed image is minified (image becomes smaller), a
2212special area resampling function (added ImageMagick v6.3.5-9), is used to
2213produce a higher quality image. For example you can use a
2214'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2215way to the horizon. </p>
2216
2217<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2218 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2219 checks_tiled.jpg</span></p>
2220<p>Note that a infinitely tiled perspective images involving the horizon can
2221be very slow to generate due to the use of the high quality 'area resampling'
2222function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2223using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2224(recommended if you plan to use super-sampling instead). </p>
2225
2226<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2227'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2228will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2229pixels. If you do not what these pixels to be visible, set the color to match
2230the rest of the ground. </p>
2231
2232<p>The output image size will by default be the same as the input image. This
2233means that if the part of the distorted image falls outside the viewed area of
2234the 'distorted space', those parts is clipped and lost. However if you
2235use the plus form of the operator (<a href="#distort" >+distort</a>) the
2236operator will attempt (if posible) to show the whole of the distorted image,
2237while retaining a correct 'virtual canvas' offset, for image layering. This
2238offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2239if it is unwanted. </p>
2240
2241<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2242option:distort:viewport {geometry_string}</kbd>" setting which will specify
2243the size and the offset of the generated 'viewport' image of the distorted
2244image space.</p>
2245
2246<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2247{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2248that factor without changing the viewed contents of the distorted image. This
2249can be used either for 'super-sampling' the image for a higher quality result,
2250or for panning and zooming around the image (with appropriate viewport
2251changes, or post-distort cropping and resizing). </p>
2252
2253<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2254href="#distort" >-distort</a> to attempt to output the internal coefficients,
2255and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2256and debugging purposes. This many not be available for all distorts. </p>
2257
2258<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2259produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2260and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2261above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2262</p>
2263
2264
2265<div style="margin: auto;">
2266 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2267</div>
2268
2269<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>
2270
2271<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>
2272
2273<p>Dithering is turned on by default, to turn it off use the plus form of the
2274setting, <a href="#dither">+dither</a>. This will also also render PostScript
2275without text or graphic aliasing. Disabling dithering often (but not always)
2276leads to faster process, a smaller number of colors, but more cartoon like
2277image coloring. Generally resulting in 'color banding' effects in areas with
2278color gradients. </p>
2279
2280<p>The color reduction operators <a href="#colors">-colors</a>, <a
2281href="#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>
2282
2283<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>
2284
2285
2286<div style="margin: auto;">
2287 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2288</div>
2289
2290<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>
2291
2292<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>
2293
2294<p>The shape primitives:</p>
2295
2296<pre class="text">
2297 point x,y
2298 line x0,y0 x1,y1
2299 rectangle x0,y0 x1,y1
2300 roundRectangle x0,y0 x1,y1 wc,hc
2301 arc x0,y0 x1,y1 a0,a1
2302 ellipse x0,y0 rx,ry a0,a1
2303 circle x0,y0 x1,y1
2304 polyline x0,y0 ... xn,yn
2305 polygon x0,y0 ... xn,yn
2306 bezier x0,y0 ... xn,yn
2307 path path specification
2308 image operator x0,y0 w,h filename
2309</pre>
2310
2311<p>The text primitive:</p>
2312
2313<pre class="text">
2314 text x0,y0 string
2315</pre>
2316<p>The text gravity primitive:</p>
2317
2318<pre class="text">
2319 gravity NorthWest, North, NorthEast, West, Center,
2320 East, SouthWest, South, or SouthEast
2321</pre>
2322
2323<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>
2324
2325<p>The transformation primitives:</p>
2326
2327<pre class="text">
2328 rotate degrees
2329 translate dx,dy
2330 scale sx,sy
2331 skewX degrees
2332 skewY degrees
2333</pre>
2334
2335<p>The pixel operation primitives:</p>
2336
2337<pre class="text">
2338 color x0,y0 method
2339 matte x0,y0 method
2340</pre>
2341
2342<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>
2343
2344<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>
2345
2346<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2347
2348<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2349
2350<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>
2351
2352<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2353
2354<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>
2355
2356<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>
2357
2358<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>.
2359</p>
2360
2361<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2362
2363<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2364
2365<p class="crtsnip">
2366 -draw 'circle 100,100 150,150'
2367</p>
2368
2369<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
2370draw 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>
2371
2372<p class="crtsnip">
2373 -draw 'bezier 20,50 45,100 45,0 70,50'
2374</p>
2375<p class="crtsnip">
2376 -draw 'bezier 70,50 95,100 95,0 120,50'
2377</p>
2378
2379
2380<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>
2381
2382<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>
2383
2384<p class="crtsnip">
2385 -draw 'image SrcOver 100,100 225,225 image.jpg'
2386</p>
2387
2388<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>
2389
2390<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>
2391
2392<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2393
2394<p class="crtsnip">
2395 -draw 'text 100,100 "Works like magick!"'
2396</p>
2397
2398<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2399
2400<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>
2401
2402<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2403
2404<p>The <kbd>scale</kbd> primitive scales them.</p>
2405
2406<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>
2407
2408<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
2409matrix.</p>
2410
2411<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>
2412
2413<pre class="text">
2414 point
2415 replace
2416 floodfill
2417 filltoborder
2418 reset
2419</pre>
2420
2421<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>
2422
2423<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>
2424
2425<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>
2426
2427<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2428
2429<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2430
2431
2432<div style="margin: auto;">
2433 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2434</div>
2435
2436<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>
2437
2438<div style="margin: auto;">
2439 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2440</div>
2441
2442<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>
2443
2444<div style="margin: auto;">
2445 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2446</div>
2447
2448<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>
2449
2450<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2451
2452<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2453
2454<div style="margin: auto;">
2455 <h4><a name="encoding" id="encoding"></a>-encoding <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 the text encoding.</td><td style='text-align:right;'></td></tr></table>
2459
2460<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>
2461
2462<div style="margin: auto;">
2463 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2464</div>
2465
2466<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>
2467
2468<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2469
2470<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2471
2472
2473<div style="margin: auto;">
2474 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2475</div>
2476
2477<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>
2478
2479
2480<div style="margin: auto;">
2481 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2482</div>
2483
2484<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>
2485
2486<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>
2487
2488<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2489
2490<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>
2491
2492<div style="margin: auto;">
2493 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2494</div>
2495
2496<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>
2497
2498<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>
2499
2500<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>
2501
2502<table class="doc">
2503 <col width="25%" />
2504 <col width="75%" />
2505 <thead>
2506 <tr>
2507 <th><em class="arg">operator</em></th>
2508 <th>Summary (see further below for details)</th>
2509 </tr>
2510 </thead>
2511 <tbody>
2512
2513 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2514 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2515 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2516 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2517 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2518 <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>
2519 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2520 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2521 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2522 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2523 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2524 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2525 <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>
2526 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2527 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2528 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2529 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2530
2531 <tr><td>&nbsp;</td></tr>
2532
2533 <tr><td>Gaussian-noise</td></tr>
2534 <tr><td>Impulse-noise</td></tr>
2535 <tr><td>Laplacian-noise</td></tr>
2536 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2537 <tr><td>PoissonNoise</td></tr>
2538 <tr><td>Uniform-noise</td></tr>
2539
2540 <tr><td>&nbsp;</td></tr>
2541
2542 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2543 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2544 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2545 </tbody>
2546 </table>
2547
2548<p>The specified functions are applied only to each previously set <a
2549href="#channel" >-channel</a> in the image. If necessary, the results of the
2550calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2551class="QR">QuantumRange</em>]. The transparency channel of the image is
2552represented as a 'alpha' values (0 = fully transparent), so, for example, a
2553<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2554semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2555as a percentage of the <em class="QR">QuantumRange</em>.</p>
2556
2557<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2558<a href="#list">-list evaluate</a>.</p>
2559
2560<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2561<kbd>Multiply</kbd> methods can also be achieved using either the <a
2562href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2563appropriate argument, to linearly modify the overall range of color values.
2564Please note, however, that <a href="#level" >-level</a> treats transparency as
2565'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2566'alpha' values.</p>
2567
2568<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>
2569
2570<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>
2571
2572 <div style="text-align:center;">
2573 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2574 </div>
2575
2576<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2577normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2578href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2579to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2580with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2581with <kbd>Pow</kbd>.</p>
2582
2583<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2584converts the image values into a value according to a (co)sine wave function.
2585The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2586is biased 50% and normalized by 50% so as to fit in the respective color value
2587range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2588function (its frequency), and thus determines the number of 'waves' that will
2589be generated over the input color range. For example, if the <em
2590class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2591class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2592then the effective period is the <em>half</em> the <em
2593class="QR">QuantumRange</em>.
2594
2595 <div style="text-align:center;">
2596 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2597 </div>
2598
2599See also the <a href="#function" >-function</a> operator, which is a
2600multi-value version of evaluate. </P>
2601
2602
2603<div style="margin: auto;">
2604 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2605</div>
2606
2607<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>
2608
2609<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>
2610
2611<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>
2612
2613<div style="margin: auto;">
2614 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2615</div>
2616
2617<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>
2618
2619<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2620
2621<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>
2622
2623<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>
2624<p>then the image will be <em>resized</em> to the specified dimensions instead,
2625equivalent to:</p>
2626
2627<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>
2628<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>
2629
2630<div style="margin: auto;">
2631 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2632</div>
2633
2634<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>
2635
2636<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).
2637</p>
2638
2639<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>.
2640</p>
2641
2642<div style="margin: auto;">
2643 <h4><a name="fft" id="fft"></a>-fft</h4>
2644</div>
2645
2646<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>
2647
2648<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>
2649
2650<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>
2651
2652<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>
2653
2654<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2655<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>
2656
2657<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2658<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>
2659
2660<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>
2661
2662<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>
2663
2664<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2665 -evaluate log 1000 fft_image_spectrum.png</span></p>
2666<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>
2667
2668<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2669
2670<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>
2671
2672<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>
2673
2674<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>
2675
2676<p>See the discussion on HDRI implementations of ImageMagick on the page
2677<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.
2678</p>
2679
2680
2681<div style="margin: auto;">
2682 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2683</div>
2684
2685<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>
2686
2687<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>
2688
2689<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2690
2691<p>For example,</p>
2692
2693<p class="crtsnip">
2694 -fill blue
2695</p>
2696<p class="crtsnip">
2697 -fill "#ddddff"
2698</p>
2699<p class="crtsnip">
2700 -fill "rgb(255,255,255)"
2701</p>
2702
2703<p>See <a href="#draw">-draw</a> for further details.</p>
2704
2705<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2706
2707<div style="margin: auto;">
2708 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2709</div>
2710
2711<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>
2712
2713<p>Use this option to affect the resizing operation of an image (see <a
2714href="#resize">-resize</a>). For example you can use a simple resize filter
2715such as:</p>
2716
2717<pre class="text">
2718 Point Hermite Cubic
2719 Box Gaussian Catrom
2720 Triangle Quadratic Mitchell
2721</pre>
2722
2723<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2724by default <kbd>blackman</kbd>-windowed. However these filters define a
2725windowing filter for the Sinc or Bessel filter function, as appropriate for
2726the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2727>-resize</a>). Windowed filters include: </p>
2728
2729<pre class="text">
2730 Lanczos Hamming Parzen
2731 Blackman Kaiser Welsh
2732 Hanning Bartlett Bohman
2733</pre>
2734
2735<p>Also one special self-windowing filter is also provided
2736<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2737on the current 'support' or 'lobes' expert settings (see below).</p>
2738
2739<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>
2740
2741<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2742
2743<p>You can modify how the filter behaves as it scales your image through the
2744use of these expert settings:</p>
2745
2746<dl class="doc">
2747<dt>-set filter:blur <em>factor</em></dt>
2748<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2749 blurry or &lt; 1.0 for sharp.</dd>
2750
2751<dt>-set filter:support <em>radius</em></dt>
2752<dd>Set the filter support radius.</dd>
2753
2754<dt>-set filter:lobes <em>count</em></dt>
2755<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2756 alternative way of specifying the 'support' range of the filter.</dd>
2757
2758<dt>-set filter:b <em>b-spline_factor</em></dt>
2759<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2760<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2761 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2762 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2763 are defined, the other is set so as to generate a 'Keys' type cubic
2764 filter.
2765
2766<dt>-set filter:filter <em>filter</em></dt>
2767<dd>Use this function directly as the scaling filter. This will allow
2768 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2769 rather than as its normal usage as a windowing function for 'Sinc' or
2770 'Bessel'. If defined, no windowing function is used, unless the following
2771 expert setting is also defined.</dd>
2772
2773<dt>-set filter:window <em>filter</em></dt>
2774<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2775 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2776 support range) with the given filter. This allows you to use a filter that
2777 is not normally used as a windowing function, such as <kbd>box</kbd>,
2778 (which effectivally turns off the windowing function). </dd>
2779
2780</dl>
2781
2782<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2783
2784<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2785 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2786 -resize 150% image.jpg</span></p>
2787<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2788
2789<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2790 -resize 150% image.jpg</span></p>
2791<p>Note that the use of expert options (except for 'blur' with simple resize
2792filters), are provided for image processing experts who have studied and
2793understood how resize filters work. Without this knowledge, and an
2794understanding of the defination of the actual filters involved, using expert
2795settings are more likely to be detremental to your image resizing.</p>
2796
2797
2798<div style="margin: auto;">
2799 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2800</div>
2801
2802<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>
2803
2804
2805<div style="margin: auto;">
2806 <h4><a name="flip" id="flip"></a>-flip</h4>
2807</div>
2808
2809<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>
2810
2811<p>reflect the scanlines in the vertical direction.</p>
2812
2813<div style="margin: auto;">
2814 <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>
2815</div>
2816
2817<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>
2818
2819<div style="margin: auto;">
2820 <h4><a name="flop" id="flop"></a>-flop</h4>
2821</div>
2822
2823<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>
2824
2825<p>reflect the scanlines in the horizontal direction.</p>
2826
2827
2828<div style="margin: auto;">
2829 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2830</div>
2831
2832<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>
2833
2834<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>
2835
2836<p>In addition to the fonts specified by the above pre-defined list, you can
2837also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2838is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2839<kbd>x:fixed</kbd> is X11 font.</p>
2840
2841<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>
2842
2843
2844<div style="margin: auto;">
2845 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2846</div>
2847
2848<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>
2849
2850<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2851
2852<p>The default foreground color is black.</p>
2853
2854<div style="margin: auto;">
2855 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2856</div>
2857
2858<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>
2859
2860<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>
2861
2862<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>
2863
2864<div style="margin: auto;">
2865 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2866</div>
2867
2868<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>
2869
2870<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>
2871
2872<div style="margin: auto;">
2873 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2874</div>
2875
2876<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>
2877
2878<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
2879
2880<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>
2881
2882
2883<div style="margin: auto;">
2884 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
2885</div>
2886
2887<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>
2888
2889<div style="margin: auto;">
2890 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
2891</div>
2892
2893<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>
2894
2895<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>
2896
2897<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>
2898
2899<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>
2900
2901<pre class="text">
2902 Polynomial
2903 Sinusoid
2904 Arcsin
2905 Arctan
2906</pre>
2907
2908<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
2909
2910<dl class="doc">
2911<dt><kbd>Polynomial</kbd></dt>
2912<dd>
2913<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>
2914
2915<div style="text-align: center">
2916 -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>
2917</div>
2918
2919<p>will invoke a polynomial function given by</p>
2920
2921<div style="text-align: center">
2922 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
2923 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
2924 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
2925</div>
2926
2927<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
2928
2929<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>
2930
2931<table class="doc">
2932 <col width="35%" />
2933 <col width="35%" />
2934 <col width="30%" />
2935 <tr>
2936 <td>-evaluate Set <em class="arg">value</em> </td>
2937 <td>-function Polynomial <em class="arg">value</em></td>
2938 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
2939 </tr>
2940 <tr>
2941 <td>-evaluate Add <em class="arg">value</em> </td>
2942 <td>-function Polynomial 1,<em class="arg">value</em></td>
2943 </tr>
2944 <tr>
2945 <td>-evaluate Subtract <em class="arg">value</em> </td>
2946 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
2947 </tr>
2948 <tr>
2949 <td>-evaluate Multiply <em class="arg">value</em> </td>
2950 <td>-function Polynomial <em class="arg">value</em>,0</td>
2951 </tr>
2952 <tr>
2953 <td>+level black% x white%</td>
2954 <td>-function Polynomial A,B</td>
2955 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
2956 </tr>
2957</table>
2958
2959<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>
2960</dd>
2961
2962<dt><kbd>Sinusoid</kbd></dt>
2963<dd>
2964<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>
2965
2966<div style="text-align: center">
2967 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
2968</div>
2969
2970<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>
2971
2972<div style="text-align: center">
2973<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>
2974</div>
2975
2976<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>
2977
2978<p class="crtsnip">
2979 -function Sinusoid 3,-90,.2,.7
2980</p>
2981
2982<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>
2983
2984<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>
2985
2986<table class="doc">
2987 <tr>
2988 <td>-evaluate Sin <em class="arg">freq</em> </td>
2989 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
2990 </tr>
2991 <tr>
2992 <td>-evaluate Cos <em class="arg">freq</em> </td>
2993 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
2994 </tr>
2995</table>
2996</dd>
2997
2998<dt><kbd>ArcSin</kbd></dt>
2999<dd>
3000<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
3001and can be used to generate cylindrical distortion and displacement maps.
3002The curve can be adjusted relative to both the input values and output range
3003of values.
3004
3005<div style="text-align: center">
3006 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3007</div>
3008
3009<p>with all values given in terms of noramlize color values (0.0 for black,
30101.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3011for bout input (<em class="arg">width</em>), and output (<em
3012class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3013
3014<div style="text-align: center">
3015<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>
3016</div>
3017
3018</dd>
3019
3020<dt><kbd>ArcTan</kbd></dt>
3021<dd>
3022<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3023limit values at infinities, though a center using the given slope value.
3024All these values can be adjusted via the arguments.
3025
3026<div style="text-align: center">
3027 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3028</div>
3029
3030<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3031</p>
3032
3033<div style="text-align: center">
3034<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>
3035</div>
3036
3037</dd>
3038
3039</dl>
3040
3041
3042<div style="margin: auto;">
3043 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3044</div>
3045
3046<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>
3047
3048<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>
3049
3050<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>
3051
3052
3053<div style="margin: auto;">
3054 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3055</div>
3056
3057<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>
3058
3059<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>
3060
3061<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3062
3063
3064<div style="margin: auto;">
3065 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3066</div>
3067
3068<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>
3069
3070<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>
3071
3072<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>
3073
3074<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>
3075
3076<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>
3077
3078<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3079
3080<div style="margin: auto;">
3081 <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>
3082</div>
3083
3084<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>
3085
3086<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3087
3088<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3089</div>
3090
3091<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>
3092
3093<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3094full 2-dimentional convolution is used to generate the weighted average of the
3095neighbouring pixels. </p>
3096
3097<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3098pixels which are outside the image proper are blurred into the final result.
3099</p>
3100
3101
3102<div style="margin: auto;">
3103 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3104</div>
3105
3106<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>
3107
3108<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>
3109
3110<div style="margin: auto;">
3111 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3112</div>
3113
3114<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>
3115
3116<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3117<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3118<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3119list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3120installation.</p>
3121
3122<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>
3123
3124<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>
3125
3126<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>
3127
3128<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>
3129<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>
3130
3131<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>
3132
3133
3134<div style="margin: auto;">
3135 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3136</div>
3137
3138<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>
3139
3140
3141<div style="margin: auto;">
3142 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3143</div>
3144
3145<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>
3146
3147<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3148dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3149can apply any color transformation to the Hald image and then use this option
3150to apply the transform to the image. </p>
3151
3152<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3153<p>This option provides a convenient method for you to use Gimp or Photoshop
3154to make color corrections to the Hald CLUT image and subsequently apply them
3155to multiple images using an ImageMagick script. </p>
3156
3157<p>Note that the representation is only of the normal RGB color space and that
3158the whole color value triplet is used for the interpolated lookup of the
3159represented Hald color cube image. Because of this the operation is not <a
3160href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3161images transparency or alpha/matte channel.</p>
3162
3163<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3164of the individual color channels, usally involving a simplier gray-scale
3165image. E.g: gray-scale to color replacement, or modification by a histogram
3166mapping. </p>
3167
3168
3169<div style="margin: auto;">
3170 <h4><a name="help" id="help"></a>-help</h4>
3171</div>
3172
3173<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>
3174
3175<div style="margin: auto;">
3176 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3177</div>
3178
3179<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>
3180
3181<div style="margin: auto;">
3182 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3183</div>
3184
3185<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>
3186
3187<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>
3188
3189<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>
3190
3191<div style="margin: auto;">
3192 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3193</div>
3194
3195<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>
3196
3197<div style="margin: auto;">
3198 <h4><a name="identify" id="identify"></a>-identify</h4>
3199</div>
3200
3201<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>
3202
3203<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>
3204
3205<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>
3206
3207<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3208amounts of image properties are displayed including image statistics, profiles,
3209image histogram, and others.</p>
3210
3211<div style="margin: auto;">
3212 <h4><a name="ift" id="ift"></a>-ift</h4>
3213</div>
3214
3215<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>
3216
3217<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>
3218
3219<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>
3220
3221<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3222<p>or</p>
3223
3224<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>
3225
3226<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.
3227
3228<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3229
3230<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.
3231
3232<div style="margin: auto;">
3233 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3234</div>
3235
3236<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>
3237
3238<div style="margin: auto;">
3239 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3240</div>
3241
3242<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>
3243
3244<div style="margin: auto;">
3245 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3246</div>
3247
3248<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>
3249
3250<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>
3251
3252<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>
3253
3254<div style="margin: auto;">
3255 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3256</div>
3257
3258<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>
3259
3260<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>
3261
3262<p>The default intent is undefined.</p>
3263
3264<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3265
3266<div style="margin: auto;">
3267 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3268</div>
3269
3270<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>
3271
3272<p>Choose from:</p>
3273
3274<pre class="text">
3275 none
3276 line
3277 plane
3278 partition
3279 JPEG
3280 GIF
3281 PNG
3282</pre>
3283
3284<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>
3285
3286<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3287
3288<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3289
3290<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3291
3292<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3293image.G, and image.B).</p>
3294
3295<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>
3296image.</p>
3297
3298<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3299
3300<div style="margin: auto;">
3301 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3302</div>
3303
3304<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>
3305
3306<p>When looking up the color of a pixel using a non-interger floating point
3307value, you typically fall in between the pixel colors defined by the source
3308image. This setting determines how the color is determined from the colors of
3309the pixels surrounding that point. That is how to determine the color of a
3310point that falls between two, or even four different colored pixels. </p>
3311
3312<pre class="text">
3313 integer: The color of the top-left pixel (floor function)
3314 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3315 average: The average color of the surrounding four pixels
3316 bilinear A double linear interpolation of pixels (the default)
3317 mesh Divide area into two flat triangular interpolations
3318 bicubic Fitted bicubic-spines of surrounding 16 pixels
3319 spline Direct spline curves (colors are blurred)
3320 filter Use resize <a href="#filter">-filter</a> settings
3321</pre>
3322
3323<p>This most important for distortion operators such as <a href="#distort"
3324>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3325>-transform</a> and <a href="#fx" >-fx</a>. </p>
3326
3327<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3328
3329<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3330lookup for positions outside the boundaries of the image. </p>
3331
3332
3333<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003334 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3335</div>
3336
3337<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>
3338
3339<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003340 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3341</div>
3342
3343<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>
3344
3345<div style="margin: auto;">
3346 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3347</div>
3348
3349<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>
3350
3351<div style="margin: auto;">
3352 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3353</div>
3354
3355<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>
3356
3357<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>
3358
3359<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>
3360
3361<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>
3362
3363<p>For example,</p>
3364
3365<p class="crtsnip">
3366 -label "%m:%f %wx%h" bird.miff
3367</p>
3368
3369<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>
3370
3371<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>
3372
3373<p>The label font can be specified with <a href="#font">-font</a>, and the
3374other font attribute settings.</p>
3375
3376<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>
3377
3378
3379<div style="margin: auto;">
3380 <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>
3381</div>
3382
3383<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>
3384
3385<p>Adaptively threshold each pixel based on the value of pixels in a
3386surrounding window. If the current pixel is lighter than this average plus
3387the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3388black. Small variations in pixel values such as found in scanned documents
3389can be ignored if offset is positive. A negative offset will make it more
3390sensitive to those small variations. </p>
3391
3392<p>This is commonly used to threshold images with an uneven background. It is
3393based on the assumption that average color of the small window is the
3394the local background color, from which to separate the forground color. </p>
3395
3396
3397<div style="margin: auto;">
3398 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3399</div>
3400
3401<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>
3402
3403<p>Perform various image operation methods to a ordered sequence of images
3404which may represent either a set of overlaid 'image layers', a GIF disposal
3405animation, or a fully-'coalesced' animation sequence. </p>
3406
3407<table class="doc">
3408 <tbody>
3409 <tr valign="top">
3410 <th align="left" style="width: 8%">Method</th>
3411 <th align="left">Description</th>
3412 </tr>
3413
3414 <tr valign="top">
3415 <td valign="top">compare-any</td>
3416 <td valign="top">Crop the second and later frames to the smallest rectangle
3417 that contains all the differences between the two images. No GIF <a
3418 href="#dispose" >-dispose</a> methods are taken into account. </td>
3419 </tr>
3420
3421 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3422 >-deconstruct</a> operator, and does not preserve animations normal
3423 working, especially when animation used layer disposal methods such as
3424 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3425 </tr>
3426
3427 <tr valign="top">
3428 <td valign="top">compare-clear</td>
3429 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3430 opaque pixels which become transparent in the second frame. That is the
3431 smallest image needed to mask or erase pixels for the next frame. </td>
3432 </tr>
3433
3434 <tr valign="top">
3435 <td valign="top">compare-overlay</td>
3436 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3437 extra color to the next image, as a result of overlaying color pixels.
3438 That is the smallest single overlaid image to add or change colors. </td>
3439 </tr>
3440
3441 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3442 composition method '<kbd>change-mask</kbd>', to reduce the image to
3443 just the pixels that need to be overlaid. </td>
3444 </tr>
3445
3446 <tr valign="top">
3447 <td valign="top">coalesce</td>
3448 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3449 >-coalesce</a> operator. Apply the layer disposal methods set in the
3450 current image sequence to form a fully defined animation sequence, as
3451 it should be displayed. Effectively converting a GIF animation into a
3452 'film strip'-like animation. </td>
3453 </tr>
3454
3455 <tr valign="top">
3456 <td valign="top">composite</td>
3457 <td valign="top">Alpha Composition of two image lists, separated by a
3458 "<kbd>null:</kbd>" image, with the destination image list first, and
3459 the source images last. An image from each list are composited
3460 together until one list is finished. The separator image and source
3461 image lists are removed. </td>
3462 </tr>
3463
3464
3465 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3466 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3467 size of the first image in each list. Unlike a normal <a
3468 href="#composite" >-composite</a> operation, the canvas offset is also
3469 added to the final composite positioning of each image. </td>
3470 </tr>
3471
3472 <tr><td></td><td>If one of the image lists only contains one image, that image is
3473 applied to all the images in the other image list, regardless of which
3474 list it is. In this case it is the image meta-data of the list which
3475 preserved. </td>
3476 </tr>
3477
3478
3479 <tr valign="top">
3480 <td valign="top">dispose</td>
3481 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3482 the animation after the layer disposal method has been applied, before
3483 the next sub-frame image is overlaid. That is the 'dispose' image that
3484 results from the application of the GIF <a href="#dispose"
3485 >-dispose</a> method. This allows you to check what
3486 is going wrong with a particular animation you may be developing.
3487 </td>
3488 </tr>
3489
3490 <tr valign="top">
3491 <td valign="top">flatten</td>
3492 <td valign="top">Create a canvas the size of the first images virtual
3493 canvas using the current <a href="#background" >-background</a> color,
3494 and <a href="#compose" >-compose</a> each image in turn onto that
3495 canvas. Images falling outside that canvas is clipped. Final
3496 image will have a zero virtual canvas offset. </td>
3497 </tr>
3498
3499 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3500 overlaying all the prepared image layers into a final image. </td>
3501 </tr>
3502
3503 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3504 canvas with real pixels, or to underlay a opaque color to remove
3505 transparency from an image.</td>
3506 </tr>
3507
3508
3509 <tr valign="top">
3510 <td valign="top">merge</td>
3511 <td valign="top">As 'flatten' method but merging all the given image
3512 layers into a new layer image just large enough to hold all the image
3513 without clipping or extra space. The new images virtual offset will
3514 prevere the position of the new layer, even if this offset is
3515 negative. the virtual canvas size of the first image is preserved.
3516 </td>
3517 </tr>
3518
3519 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3520 as few image file formats handle them correctly. </td>
3521 </tr>
3522
3523 <tr valign="top">
3524 <td valign="top">mosaic</td>
3525 <td valign="top">As 'flatten' method but expanding the initial canvas size
3526 of the first image so as to hold all the image layers. However as a
3527 virtual canvas is 'locked' to the origin, by defination, image layers
3528 with a negative offsets will still be clipped by the top and left
3529 edges.</td>
3530 </tr>
3531
3532 <tr><td></td><td>This method is commonly used to layout individual image using various
3533 offset but without knowning the final canvas size. The resulting image
3534 will, like 'flatten' not have any virtual offset, so can be saved to
3535 any image file format. </td>
3536 </tr>
3537
3538
3539 <tr valign="top">
3540 <td valign="top">optimize</td>
3541 <td valign="top">Optimize a coalesced animation, into GIF animation using
3542 a number of general techniques. This currently a short cut to
3543 apply both the '<kbd>optimize-frame</kbd>', and
3544 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3545 include other optimization methods as they are developed. </td>
3546 </tr>
3547
3548 <tr valign="top">
3549 <td valign="top">optimize-frame</td>
3550 <td valign="top">Optimize a coalesced animation, into GIF animation by
3551 reducing the number of pixels per frame as much as possible by
3552 attempting to pick the best layer disposal method to use, while ensuring
3553 the result will continue to animate properly. </td>
3554 </tr>
3555
3556 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3557 then no reasonably fast GIF optimization algorithm can do this.
3558 However this does seem to do better than most other GIF frame
3559 optimizers seen. </td>
3560 </tr>
3561
3562 <tr valign="top">
3563 <td valign="top">optimize-plus</td>
3564 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3565 overall optimization by adding extra frames to the animation, without
3566 changing the final look or timing of the animation. The frames are
3567 added to attempt to separate the clearing of pixels from the
3568 overlaying of new additional pixels from one animation frame to the
3569 next. If this does not improve the optimization (for the next frame
3570 only), it will fall back to the results of the previous normal
3571 '<kbd>optimize-frame</kbd>' technique. </td>
3572 </tr>
3573
3574 <tr><td></td><td>There is the possibility that the change in the disposal style will
3575 result in a worsening in the optimization of later frames, though this
3576 is unlikely. In other words there no guarantee that it is better than
3577 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3578 however you can get a vast improvment in the final animation size. </td>
3579 </tr>
3580
3581 <tr valign="top">
3582 <td valign="top">optimize-transparency</td>
3583 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3584 overlay images with transparency, if it does not change the resulting
3585 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3586 </td>
3587 </tr>
3588
3589 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3590 into a smaller file size due to larger areas of one (transparent)
3591 color rather than a pattern of multiple colors repeating the current
3592 disposed image of the last frame. </td>
3593 </tr>
3594
3595 <tr valign="top">
3596 <td valign="top">remove-dups</td>
3597 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3598 images, so as to simplify layer overlays of coalesced animations.
3599 </td>
3600 </tr>
3601
3602 <tr><td></td><td>Usually this a result of using a constant time delay across the
3603 whole animation, or after a larger animation was split into smaller
3604 sub-animations. The duplicate frames could also have been used as
3605 part of some frame optimization methods. </td>
3606 </tr>
3607
3608 <tr valign="top">
3609 <td valign="top">remove-zero</td>
3610 <td valign="top">Remove any image with a zero time delay, unless ALL the
3611 images have a zero time delay (and is not a proper timed animation, a
3612 warning is then issued). </td>
3613 </tr>
3614
3615 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3616 partial intermediary updates between the frames that are actually
3617 displayed to users. These frames are usally added for improved frame
3618 optimization in GIF animations. </td>
3619 </tr>
3620
3621 <tr valign="top">
3622 <td valign="top">trim-bounds</td>
3623 <td valign="top">Find the bounds of all the images in the current
3624 image sequence, then adjust the offsets so all images are contained on
3625 a minimal positive canvas. None of the image data is modified, only
3626 there virtual canvas size and offset. The all the image is given
3627 the same canvas size, and and will have a positive offset, but will
3628 remain in the same position relative to each other. As a result of the
3629 minimal canvas size at least one image will touch every edge of that
3630 canvas. The image data however may be transparent.
3631 </td>
3632 </tr>
3633
3634 </tbody>
3635</table>
3636
3637<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3638
3639<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3640>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3641>-mosaic</a> are only aliases for the above methods. Also see <a
3642href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3643href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3644>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3645
3646
3647<div style="margin: auto;">
3648 <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>
3649</div>
3650
3651<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>
3652
3653<p>Given one, two or three values delimited with commas: black-point,
3654white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3655white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3656point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3657contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3658both black and white points are percentages of the full color range. Gamma
3659will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3660omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3661
3662<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3663the given '<kbd>black_point</kbd>' value in the original image is set to
3664zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3665<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3666to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3667adjusted. </p>
3668
3669<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3670adding the special '!' flag anywhere in the argument list, will cause the
3671operator to do the reverse of the level adjustment. That is a zero, or
3672<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3673adjusted to the given level values, allowing you to de-contrast, or compress
3674the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3675
3676<p>Only the channels defined by the current <a href="#channel">-channel</a>
3677setting are adjusted (defaults to RGB color channels only), allowing you to
3678limit the effect of this operator. </p>
3679
3680<p>Please note that the transparency channel is treated as 'matte'
3681values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3682
3683
3684<div style="margin: auto;">
3685 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3686 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3687</div>
3688
3689<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>
3690
3691<p>This function is exactly like <a href="#level">-level</a>, except that the
3692value value for each color channel is determined by the
3693'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3694described under the <a href="#fill">-fill</a> option). </p>
3695
3696<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3697is mapped to become 'black' and 'white' respectivally, with all the other
3698colors linearly adjusted (or clipped) to match that change. Each channel is
3699adjusted separatally using the channel values of the colors specified. </p>
3700
3701<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3702will map the image color 'black' and 'white' to the given colors
3703respectivally, resulting in a gradient (de-contrasting) tint of the image to
3704those colors. This can also be used to convert a plain gray-scale image into a
3705one using the gradient of colors specified. </p>
3706
3707<p>By supplying a single color with a comma separator either before or after
3708that color, will just replace the respective 'black' or 'white' point
3709respectivally. But if no comma separator is provided, the given color is
3710used for both the black and white color points, making the operator either
3711threshold the images around that color (- form) or set all colors to that
3712color (+ form). </p>
3713
3714
3715<div style="margin: auto;">
3716 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3717</div>
3718
3719<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>
3720
3721<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>
3722
3723<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>
3724
3725<p class="crtsnip">
3726 -limit memory 32mb -limit map 64mb
3727</p>
3728
3729<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3730
3731<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
3732-------------------------------------------------------------------
3733 768 3.8187gb 2.864gb 7.6375gb 16eb 2 unlimited</pre>
3734</span></p>
3735<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>
3736
3737<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>
3738
3739<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>
3740
3741<p class="crtsnip">
3742-limit area 10mb
3743</p>
3744
3745<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>
3746
3747<p class="crtsnip">
3748-limit area 10mb -limit disk 500mb
3749</p>
3750
3751<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3752
3753<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>
3754
3755<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.
3756</p>
3757
3758<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.
3759</p>
3760
3761<div style="margin: auto;">
3762 <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>
3763</div>
3764
3765<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>
3766
3767<div style="margin: auto;">
3768 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3769</div>
3770
3771<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>
3772
3773<div style="margin: auto;">
3774 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3775</div>
3776
3777<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>
3778
3779<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>
3780
3781<div style="margin: auto;">
3782 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3783</div>
3784
3785<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>
3786
3787<pre class="text">
3788 coder
3789 color
3790 configure
3791 delegate
3792 font
3793 format
3794 list
3795 log
3796 magic
3797 module
3798 resource
3799 threshold
3800</pre>
3801
3802<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>
3803
3804<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3805<div style="margin: auto;">
3806 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3807</div>
3808
3809<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>
3810
3811<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3812
3813<p>You can display the following components by embedding special format characters:</p>
3814
3815<pre class="text">
3816 %d domain
3817 %e event
3818 %f function
3819 %l line
3820 %m module
3821 %p process ID
3822 %r real CPU time
3823 %t wall clock time
3824 %u user CPU time
3825 %% percent sign
3826 \n newline
3827 \r carriage return
3828</pre>
3829
3830<p>For example:</p>
3831
3832<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>
3833<p>The default behavior is to print all of the components.</p>
3834
3835<div style="margin: auto;">
3836 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3837</div>
3838
3839<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>
3840
3841<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>
3842
3843<div style="margin: auto;">
3844 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3845</div>
3846
3847<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>
3848
3849<div style="margin: auto;">
3850 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
3851</div>
3852
3853<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>
3854
3855
3856<div style="margin: auto;">
3857 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
3858</div>
3859
3860<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>
3861
3862<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
3863
3864<pre class="text">
3865 best
3866 default
3867 gray
3868 red
3869 green
3870 blue
3871</pre>
3872
3873<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>
3874
3875
3876<div style="margin: auto;">
3877 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
3878</div>
3879
3880<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>
3881
3882<p>Here are the valid components of a map:</p>
3883
3884<pre class="text">
3885 r red pixel component
3886 g green pixel component
3887 b blue pixel component
3888 a alpha pixel component (0 is transparent)
3889 o opacity pixel component (0 is opaque)
3890 i grayscale intensity pixel component
3891 c cyan pixel component
3892 m magenta pixel component
3893 y yellow pixel component
3894 k black pixel component
3895 p pad component (always 0)
3896</pre>
3897
3898<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>
3899
3900<div style="margin: auto;">
3901 <h4><a name="mask" id="mask"></a>-mask
3902<em class="arg">filename</em></h4>
3903</div>
3904
3905<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>
3906
3907<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
3908
3909<div style="margin: auto;">
3910 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
3911</div>
3912
3913<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>
3914
3915<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
3916
3917<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
3918
3919<div style="margin: auto;">
3920 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
3921</div>
3922
3923<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>
3924
3925<div style="margin: auto;">
3926 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
3927</div>
3928
3929<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>
3930
3931<p>Choose from:</p>
3932
3933<pre class="text">
3934 AE absolute number of differnet pixels
3935 MAE mean absolute error (normalized), average channel error distance
3936 MEPP mean error per pixel (normalized mean error, normalized peak error)
3937 MSE mean error squared, average of the channel error squared
3938 PAE peak absolute (normalize peak absolute)
3939 PSNR peak signal to noise ratio
3940 RMSE root mean squared (normalized root mean squared)
3941</pre>
3942
3943<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
3944controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
3945only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
3946size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
3947'similar'. </p>
3948
3949<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
3950('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
3951normalized) from the single comparision run. </p>
3952
3953<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
3954
3955
3956<div style="margin: auto;">
3957 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
3958</div>
3959
3960<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>
3961
3962<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
3963
3964<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
3965argument for a list of <a href="#mode" >-mode</a> arguments available
3966in your ImageMagick installation.</p>
3967
3968
3969<div style="margin: auto;">
3970 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
3971</div>
3972
3973<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>
3974
3975<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
3976missing values are taken to mean 100.</p>
3977
3978<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
3979means pure black, 50 is half as bright, 200 is twice as bright. To invert its
3980meaning <a href="#negate">-negate</a> the image before and after. </p>
3981
3982<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>
3983
3984<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
3985shades to purple, and so on. A value of either 0 or 200 results in a complete
3986180 degree rotation of the image. Using a value of 300 is a 360 degree
3987rotation resulting in no change to the original image. </p>
3988
3989<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>
3990
3991<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>
3992
3993<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>
3994<div style="margin: auto;">
3995 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
3996</div>
3997
3998<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>
3999
4000
4001<div style="margin: auto;">
4002 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
4003</div>
4004
4005<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>
4006
4007
4008<div style="margin: auto;">
4009 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
4010</div>
4011
4012<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>
4013
4014<p>Both the image pixels and size are linearly interpolated to give the
4015appearance of a meta-morphosis from one image to the next, over all the images
4016in the current image list. The added images are the equivalent of a <a
4017href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4018argument determine how many images to interpolate between each image. </p>
4019
4020
4021<div style="margin: auto;">
4022 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4023</div>
4024
4025<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>
4026
4027
4028<div style="margin: auto;">
4029 <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>
4030</div>
4031
4032<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>
4033
4034<p>Blur with the given radius, standard deviation (sigma), and angle. The
4035angle given is the angle toward which the image is blurred. That is the
4036direction people would consider the object is coming from. </p>
4037
4038<p>Note that the blur is not uniform distribution, giving the motion a
4039definate sense of direction of movement. </p>
4040
4041<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4042pixels which are outside the image proper are blurred into the final result.
4043</p>
4044
4045<div style="margin: auto;">
4046 <h4><a name="name" id="name"></a>-name</h4>
4047</div>
4048
4049<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>
4050<div style="margin: auto;">
4051 <h4><a name="negate" id="negate"></a>-negate</h4>
4052</div>
4053
4054<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>
4055
4056<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>
4057
4058<div style="margin: auto;">
4059 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4060 +noise <em class="arg">type</em></h4>
4061</div>
4062
4063<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>
4064
4065<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>
4066
4067<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>
4068
4069<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>
4070
4071<pre class="text">
4072Gaussian
4073Impulse
4074Laplacian
4075Multiplicative
4076Poisson
4077Random
4078Uniform
4079</pre>
4080
4081<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4082
4083
4084<div style="margin: auto;">
4085 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4086</div>
4087
4088<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>
4089
4090<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>
4091
4092<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
4093version, it was equivalent to <a href="#contrast-stretch">-contrast-stretch 2%x99%)</a></p>
4094
4095<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>
4096
4097
4098<div style="margin: auto;">
4099 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4100</div>
4101
4102<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>
4103
4104<p>You can choose from these standard threshold maps:</p>
4105
4106<pre class="text">
4107 checks
4108 o2x2
4109 o3x3
4110 o4x4
4111 o8x8
4112 h4x4a
4113 h6x6a
4114 h8x8a
4115 h4x4o
4116 h6x6o
4117 h8x8o
4118 h16x16o
4119</pre>
4120
4121<p>The '<kbd>o</kbd>' are ordered diffused pixel threshold maps, while the
4122'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled,
4123or 'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord
4124dither pattern. Or you can define your own <em class="arg">threshold
4125map</em> in a personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
4126
4127<p>To print a complete list of threshold, use the <a href="#list">-list threshold</a> option.</p>
4128
4129<p>It is recommended that the <a href="#map">+map</a> operator be used after
4130applying <a href="#ordered-dither">-ordered-dither</a> to reduce the number of
4131colors an animated image sequence, to less that 256 colors. This ensures that
4132a common or global color table is used when saving the result to a color
4133limited file format such as GIF. </p>
4134
4135<p>Note that at this time the exact same map is used for all color channels, no
4136attempt is made to offset or rotate the dither map for different channels is
4137made, at this point in time. (possible future expansion) </p>
4138
4139
4140<div style="margin: auto;">
4141 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4142</div>
4143
4144<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>
4145
4146<p>The <em class="arg">color</em> argument is defined using the format
4147described under the <a href="#fill">-fill</a> option.
4148The <a href="#fuzz">-fuzz</a> setting can be used to match and replace colors similar
4149to the one given.</p>
4150
4151<p>The <a href="#transparent">-transparent</a> operator is exactly the same
4152as <a href="#opaque">-opaque</a> but makes the matching color transparent,
4153rather than the same as the current <a href="#fill">-fill</a> color. </p>
4154
4155<p>Use <em class="arg">+opaque</em> to paint any pixel that does not match the target color.</p>
4156
4157<div style="margin: auto;">
4158 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4159</div>
4160
4161<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>
4162
4163<p>Choose from these orientations:</p>
4164
4165<pre class="text">
4166 bottom-left
4167 bottom-right
4168 left-bottom
4169 left-top
4170 right-bottom
4171 right-top
4172 top-left
4173 top-right
4174 undefined
4175</pre>
4176
4177<p>To print a complete list of orientations, use the <a href="#list">-list orientation</a> option.</p>
4178
4179
4180<div style="margin: auto;">
4181 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4182 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4183 +page
4184 </h4>
4185</div>
4186
4187<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>
4188
4189<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>
4190
4191<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>
4192
4193<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>
4194<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4195<thead>
4196 <tr valign="top">
4197 <th align="center"><em class="arg">media</em></th>
4198 <th align="center"><em class="arg">width</em></th>
4199 <th align="center"><em class="arg">height</em></th>
4200 </tr>
4201</thead>
4202<tbody>
4203<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4204<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4205<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4206<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4207<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4208<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4209<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4210<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4211<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4212<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4213<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4214<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4215<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4216<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4217<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4218<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4219<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4220<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4221<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4222<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4223<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4224<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4225<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4226<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4227<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4228<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4229<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4230<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4231<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4232<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4233<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4234<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4235<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4236<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4237<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4238<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4239<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4240<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4241</tbody>
4242</table>
4243
4244
4245
4246
4247<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>
4248
4249<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>
4250
4251<p>The default page dimensions for a TEXT image is 612x792.</p>
4252
4253<p>This option is used in concert with <a href="#density">-density</a>.</p>
4254
4255<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4256
4257<div style="margin: auto;">
4258 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4259</div>
4260
4261<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>
4262
4263<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>
4264
4265<div style="margin: auto;">
4266 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4267
4268<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>
4269
4270<div style="margin: auto;">
4271 <h4><a name="pause_animate_" id="pause_animate_"></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 animation loops.</td><td style='text-align:right;'>[<a href="../www/animate.html">animate</a>]</td></tr></table>
4275
4276<p>Pause for the specified number of seconds before repeating the animation.</p>
4277
4278<div style="margin: auto;">
4279 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4280</div>
4281
4282<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>
4283
4284<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4285
4286<div style="margin: auto;">
4287 <h4><a name="ping" id="ping"></a>-ping</h4>
4288</div>
4289
4290<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>
4291
4292<div style="margin: auto;">
4293 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4294</div>
4295
4296<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>
4297
4298<div style="margin: auto;">
4299 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4300</div>
4301
4302<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>
4303
4304<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4305
4306<div style="margin: auto;">
4307 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4308</div>
4309
4310<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>
4311
4312<div style="margin: auto;">
4313 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4314</div>
4315
4316<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>
4317
4318<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>
4319
4320<pre class="text">
4321 Rotate
4322 Shear
4323 Roll
4324 Hue
4325 Saturation
4326 Brightness
4327 Gamma
4328 Spiff
4329 Dull
4330 Grayscale
4331 Quantize
4332 Despeckle
4333 ReduceNoise
4334 Add Noise
4335 Sharpen
4336 Blur
4337 Threshold
4338 EdgeDetect
4339 Spread
4340 Shade
4341 Raise
4342 Segment
4343 Solarize
4344 Swirl
4345 Implode
4346 Wave
4347 OilPaint
4348 CharcoalDrawing
4349 JPEG
4350</pre>
4351
4352<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4353
4354<p>The default preview is <kbd>JPEG</kbd>.</p>
4355
4356<div style="margin: auto;">
4357 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4358</div>
4359
4360<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>
4361
4362<div style="margin: auto;">
4363 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4364</div>
4365
4366<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>
4367
4368<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>
4369
4370<div style="margin: auto;">
4371 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4372 +profile <em class="arg">profile_name</em></h4>
4373</div>
4374
4375<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>
4376
4377<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>
4378
4379<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>
4380
4381<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>
4382
4383<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>
4384
4385<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4386
4387<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4388<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>
4389
4390<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>
4391<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4392CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4393</p>
4394
4395<div style="margin: auto;">
4396 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4397</div>
4398
4399<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>
4400
4401<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>
4402
4403<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>
4404
4405<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>
4406
4407<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>
4408
4409<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4410
4411<pre class="text">
4412 0: none
4413 1: sub
4414 2: up
4415 3: average
4416 4: Paeth
4417</pre>
4418
4419<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>
4420
4421<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4422
4423<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>
4424
4425<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>
4426
4427<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4428
4429<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>
4430
4431<div style="margin: auto;">
4432 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4433</div>
4434
4435<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>
4436
4437<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4438
4439
4440<div style="margin: auto;">
4441 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4442</div>
4443
4444<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>
4445
4446<div style="margin: auto;">
4447 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4448</div>
4449
4450<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>
4451
4452<p>Note that this is actually a rotational blur rather than a radial and as
4453such actually mis-named. </p>
4454
4455<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4456pixels which are outside the image proper are blurred into the final result.
4457</p>
4458
4459
4460<div style="margin: auto;">
4461 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4462</div>
4463
4464<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>
4465
4466<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>.
4467</p>
4468
4469<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4470
4471<div style="margin: auto;">
4472 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4473</div>
4474
4475<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>
4476
4477<div style="margin: auto;">
4478 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4479</div>
4480
4481<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>
4482
4483<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.
4484</p>
4485
4486<div style="margin: auto;">
4487 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4488</div>
4489
4490<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>
4491
4492<div style="margin: auto;">
4493 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4494</div>
4495
4496<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>
4497
4498<div style="margin: auto;">
4499 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4500</div>
4501
4502<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>
4503
4504<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4505the given colors are dithered over the image as necessary, otherwise the closest
4506color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4507
4508<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4509images in the current image sequence, all the images will have the same color
4510table. That means that when saved to a file format such as GIF, it will use
4511that color table as a single common or global color table, for all the images,
4512without requiring extra local color tables. </p>
4513
4514<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4515sequence to use a common color map over all the images. This equivalent to
4516appending all the images together (without extra background colors) and color
4517reducing those images using <a href="#colors">-colors</a> with a 256 color
4518limit, then <a href="#remap">-remap</a> those colors over the original list of
4519images. This ensures all the images follow a single color map. </p>
4520
4521<p>If the number of colors over all the images is less than 256, then <a
4522href="#remap">+remap</a> should not perform any color reduction or dithering, as
4523no color changes are needed. In that case, its only effect is to force the use
4524of a global color table. This recommended after using either <a
4525href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4526reduce the number of colors in an animated image sequence. </p>
4527
4528<div style="margin: auto;">
4529 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4530</div>
4531
4532<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>
4533
4534<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>
4535
4536<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>
4537
4538<div style="margin: auto;">
4539 <h4><a name="remote" id="remote"></a>-remote</h4>
4540</div>
4541
4542<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>
4543
4544<p>The only command recognized is the name of an image file to load.</p>
4545
4546<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>
4547
4548<div style="margin: auto;">
4549 <h4><a name="render" id="render"></a>-render</h4>
4550</div>
4551
4552<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>
4553
4554<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>
4555
4556<div style="margin: auto;">
4557<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4558</div>
4559
4560<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>
4561
4562<p>This option is like <a href="#page">-page</a> but acts as an image operator
4563rather than a setting. You can separately set the canvas size or the offset
4564of the image on that canvas by only providing those components. </p>
4565
4566<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>
4567
4568<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4569offset to move the image relative to its previous position. This useful for
4570animation sequences. </p>
4571
4572<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4573recalculate the canvas size so the image (at its current offset) will appear
4574completely on that canvas (unless it has a negative offset).</p>
4575
4576<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4577canvas meta-data from the images. </p>
4578
4579<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4580directly assign virtual canvas meta-data. </p>
4581
4582
4583<div style="margin: auto;">
4584 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4585</div>
4586
4587<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>
4588
4589<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>
4590
4591<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>
4592
4593<div style="margin: auto;">
4594 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4595</div>
4596
4597<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>
4598
4599<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>
4600
4601<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>
4602
4603<div style="margin: auto;">
4604 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4605</div>
4606
4607<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>
4608
4609<div style="margin: auto;">
4610 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4611</div>
4612
4613<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>
4614
4615
4616<div style="margin: auto;">
4617 <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>
4618</div>
4619
4620<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>
4621
4622<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>
4623
4624
4625<div style="margin: auto;">
4626 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4627</div>
4628
4629<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>
4630
4631<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>
4632
4633<p>Empty triangles in the corners, left over from rotating the image, are
4634filled with the <kbd>background</kbd> color. </p>
4635
4636<p>See also the <a href="#distort">-distort</a> operator and specifically the
4637'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4638
4639
4640<div style="margin: auto;">
4641 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4642</div>
4643
4644<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>
4645
4646<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>
4647
4648<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>
4649
4650
4651<div style="margin: auto;">
4652 <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>
4653</div>
4654
4655<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>
4656
4657<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>
4658
4659<div style="margin: auto;">
4660 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4661</div>
4662
4663<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>
4664
4665<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>
4666
4667<div style="margin: auto;">
4668 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4669</div>
4670
4671<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>
4672
4673<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4674
4675<div style="margin: auto;">
4676 <h4><a name="screen" id="screen"></a>-screen</h4>
4677</div>
4678
4679<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>
4680
4681<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>
4682
4683<div style="margin: auto;">
4684 <h4><a name="seed" id="seed"></a>-seed</h4>
4685</div>
4686
4687<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>
4688
4689<div style="margin: auto;">
4690 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4691</div>
4692
4693<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>
4694
4695<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>
4696
4697<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>
4698
4699<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4700of the color clusters is returned.</p>
4701
4702
4703<div style="margin: auto;">
4704 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4705</div>
4706
4707<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>
4708
4709<div style="margin: auto;">
4710 <h4><a name="separate" id="separate"></a>-separate</h4>
4711</div>
4712
4713<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>
4714
4715<div style="margin: auto;">
4716 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4717</div>
4718
4719<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>
4720
4721<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4722
4723<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>
4724
4725<div style="margin: auto;">
4726 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4727</div>
4728
4729<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>
4730
4731<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>
4732
4733<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>
4734<p>The <a href="#repage">-repage</a> operator will also set the
4735'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4736separately set the virtual canvas's size and offset components, and also allows
4737relative offset changes, and automatic canvas size re-calculating. The above
4738<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4739virtual canvas (page) meta-data. </p>
4740
4741<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>
4742
4743<div style="margin: auto;">
4744 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4745</div>
4746
4747<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>
4748
4749<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>
4750
4751<div style="margin: auto;">
4752 <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>
4753</div>
4754
4755<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>
4756
4757<div style="margin: auto;">
4758 <h4><a name="shared-memory"
4759id="shared-memory"></a>-shared-memory</h4>
4760</div>
4761
4762<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>
4763
4764<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>
4765
4766<div style="margin: auto;">
4767 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4768</div>
4769
4770<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>
4771
4772<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4773
4774<div style="margin: auto;">
4775 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4776</div>
4777
4778<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>
4779
4780<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>
4781
4782<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>
4783
4784<div style="margin: auto;">
4785 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4786</div>
4787
4788<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>
4789
4790<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>
4791
4792<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>
4793
4794<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>
4795
4796<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>
4797
4798<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>
4799<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>
4800
4801<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4802<div style="margin: auto;">
4803 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4804</div>
4805
4806<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>
4807
4808<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>
4809
4810<div style="margin: auto;">
4811 <h4><a name="silent" id="silent"></a>-silent</h4>
4812</div>
4813
4814<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>
4815
4816<div style="margin: auto;">
4817 <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>
4818</div>
4819
4820<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>
4821
4822<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>
4823
4824<p>For Photo CD images, choose from these sizes:</p>
4825
4826<pre class="text">
4827 192x128
4828 384x256
4829 768x512
4830 1536x1024
4831 3072x2048
4832</pre>
4833
cristy3ed852e2009-09-05 21:47:34 +00004834<div style="margin: auto;">
4835 <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>
4836</div>
4837
4838<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>
4839
4840<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>
4841
4842<div style="margin: auto;">
4843 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
4844</div>
4845
4846<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>
4847
4848<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
4849
4850<div style="margin: auto;">
4851 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
4852</div>
4853
4854<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>
4855
4856<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4857
4858<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
4859
4860<div style="margin: auto;">
4861 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
4862 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
4863</div>
4864
4865<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>
4866
4867
4868<table class="doc">
4869 <tbody>
4870 <tr valign="top">
4871 <th align="left" style="width: 8%">Method</th>
4872 <th align="left">Description</th>
4873 </tr>
4874
4875 <tr valign="top">
4876 <td valign="top">voronoi</td>
4877 <td valign="top">Simply map each pixel to the to nearest color point
4878 given. The result are polygonal 'cells' of solid color. </td>
4879 </tr>
4880
4881 <tr valign="top">
4882 <td valign="top">shepards</td>
4883 <td valign="top">Colors points basied on the ratio of inverse distance
4884 squared. Generating spots of color in a sea of the average of
4885 colors. </td>
4886 </tr>
4887
4888 <tr valign="top">
4889 <td valign="top">barycentric</td>
4890 <td valign="top">three point triangle of color given 3 points.
4891 Giving only 2 points will form a linear gradient between those points.
4892 Gradient is however not restricted to just the triangle or line. </td>
4893 </tr>
4894
4895 <tr valign="top">
4896 <td valign="top">bilinear</td>
4897 <td valign="top">Like barycentric but for 4 points. Less than 4 points
4898 fall back to barycentric. </td>
4899 </tr>
4900
4901 </tbody>
4902</table>
4903
4904<p>The points are placed according to the images location on the virtual
4905canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
4906offset), and do not actually have to exist on the given image, but may be
4907some point beyond the edge of the image. All points are floating point values.
4908</p>
4909
4910<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
4911modified, whcih means the matte/alpha transparency channel is not effected by
4912default. If enabled, the image also needs a the matte/alpha channel to be
4913enabled for this operator to effect an images transparency. This is typical
4914transparency handling for images. </p>
4915
4916<p>All the above methods when given a single point of color will replace all
4917the colors in the image with the color given, regardless of the point. This is
4918logical, and provides an alternative technique to recolor a image to some
4919default value. </p>
4920
4921
4922<div style="margin: auto;">
4923 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
4924</div>
4925
4926<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>
4927
4928<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>
4929
4930<div style="margin: auto;">
4931 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
4932</div>
4933
4934<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>
4935
4936<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>
4937
4938<div style="margin: auto;">
4939 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
4940</div>
4941
4942<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>
4943
4944<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>
4945
4946<div style="margin: auto;">
4947 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
4948</div>
4949
4950<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>
4951
4952<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>
4953
4954<div style="margin: auto;">
4955 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
4956</div>
4957
4958<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>
4959
4960<pre class="text">
4961 char store pixels as unsigned characters
4962 double store pixels as doubles
4963 float store pixels as floats
4964 integer store pixels as integers
4965 long store pixels as longs
4966 quantum store pixels in the native depth of your ImageMagick distribution
4967 short store pixels as unsigned shorts
4968</pre>
4969
4970<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
4971values range from 0 to the maximum value the storage type can support.</p>
4972
4973<div style="margin: auto;">
4974 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
4975</div>
4976
4977<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>
4978
4979<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>
4980
4981<pre class="text">
4982 Any
4983 Condensed
4984 Expanded
4985 ExtraCondensed
4986 ExtraExpanded
4987 Normal
4988 SemiCondensed
4989 SemiExpanded
4990 UltraCondensed
4991 UltraExpanded
4992</pre>
4993
4994<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
4995
4996<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>
4997
4998<div style="margin: auto;">
4999 <h4><a name="strip" id="strip"></a>-strip</h4>
5000</div>
5001
5002<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>
5003
5004<div style="margin: auto;">
5005 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
5006</div>
5007
5008<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>
5009
5010<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5011
5012<p>See <a href="#draw">-draw</a> for further details.</p>
5013
5014<div style="margin: auto;">
5015 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</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 the stroke width.</td><td style='text-align:right;'></td></tr></table>
5019
5020<p>See <a href="#draw">-draw</a> for further details.</p>
5021
5022<div style="margin: auto;">
5023 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5024</div>
5025
5026<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font style for text.</td><td style='text-align:right;'></td></tr></table>
5027
5028<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>
5029
5030<pre class="text">
5031 Any
5032 Italic
5033 Normal
5034 Oblique
5035</pre>
5036
5037<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>
5038
5039<div style="margin: auto;">
5040 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5041</div>
5042
5043<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>
5044
5045<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>
5046
5047<div style="margin: auto;">
5048 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5049</div>
5050
5051<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>
5052
5053<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5054
5055<div style="margin: auto;">
5056 <h4><a name="taint" id="taint"></a>-taint</h4>
5057</div>
5058
5059<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>
5060
5061<div style="margin: auto;">
5062 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5063</div>
5064
5065<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>
5066
5067<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>
5068
5069<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>
5070
5071<div style="margin: auto;">
5072 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5073</div>
5074
5075<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>
5076
5077<div style="margin: auto;">
5078 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5079</div>
5080
5081<!-- {<em class="arg">green,blue,opacity</em>}
5082<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>
5083-->
5084
5085<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>
5086
5087<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>
5088
5089<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.
5090</p>
5091
5092<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>
5093
5094<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5095<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>
5096
5097
5098<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>
5099<p>Note that the values of the transparency channel is treated as 'matte'
5100values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5101
5102<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>.
5103</p>
5104
5105<div style="margin: auto;">
5106 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5107</div>
5108
5109<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>
5110
5111<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>
5112
5113<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>
5114
5115<div style="margin: auto;">
5116 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5117</div>
5118
5119<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>
5120
5121<div style="margin: auto;">
5122 <h4>-tile <em class="arg">geometry</em></h4>
5123</div>
5124
5125<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>
5126
5127<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>
5128
5129<div style="margin: auto;">
5130 <h4>-tile</h4>
5131</div>
5132
5133<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>
5134
5135<div style="margin: auto;">
5136 <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>
5137</div>
5138
5139<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>
5140
5141<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>
5142
5143<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>
5144
5145<div style="margin: auto;">
5146 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5147</div>
5148
5149<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>
5150
5151<p>Tint the image with the fill color.</p>
5152
5153<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>
5154
5155<div style="margin: auto;">
5156 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5157</div>
5158
5159<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>
5160
5161<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>
5162
5163<p>For example,</p>
5164
5165<p class="crtsnip">
5166 -title "%m:%f %wx%h"
5167</p>
5168
5169<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>
5170
5171
5172<div style="margin: auto;">
5173 <h4><a name="transform" id="transform"></a>-transform</h4>
5174</div>
5175
5176<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>
5177
5178<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5179
5180<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>
5181<div style="margin: auto;">
5182 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5183</div>
5184
5185<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>
5186
5187<p>The <em class="arg">color</em> argument is defined using the format
5188described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5189>-fuzz</a> setting can be used to match and replace colors similar to the one
5190given. </p>
5191
5192<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5193href="#transparent" >-transparent</a> but replaces the matching color same as
5194the current <a href="#fill">-fill</a> color setting. </p>
5195
5196<p>This does not define the 'transparency color' used for color-mapped image
5197formats, such as GIF. For that use <a href="#transparent-color"
5198>-transparent-color</a> </p>
5199
5200<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5201paint any pixel that does not match the target color, with the fill color.</p>
5202
5203
5204<div style="margin: auto;">
5205 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5206</div>
5207
5208<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>
5209
5210<p>Sometimes this is used for saving to image formats such as
5211GIF and PNG8 which uses this color to represent boolean transparency. This
5212does not make a color transparent, it only defines what color the transparent
5213color is in the color palette of the saved image. Use <a
5214href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5215
5216<p>This option allows you to have both an opaque visible color, as well as a
5217transparent color of the same color value without conflict. That is, you can
5218use the same color for both the transparent and opaque color areas within an
5219image. This, in turn, frees to you to select a transparent color that is
5220appropriate when an image is displayed by an application that does not handle a
5221transparent color index, while allowing ImageMagick to correctly handle images of this
5222type. </p>
5223
5224<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5225
5226<div style="margin: auto;">
5227 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5228</div>
5229
5230<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>
5231
5232<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5233</p>
5234
5235<div style="margin: auto;">
5236 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5237</div>
5238
5239<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>
5240
5241
5242<div style="margin: auto;">
5243 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5244</div>
5245
5246<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>
5247
5248<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>
5249
5250<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>
5251
5252<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>
5253
5254<div style="margin: auto;">
5255 <h4><a name="trim" id="trim"></a>-trim</h4>
5256</div>
5257
5258<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>
5259
5260<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>
5261
5262<p>The page or virtual canvas information of the image is preserved allowing
5263you to extract the result of the <a href="#trim">-trim</a> operation from the
5264image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5265information if it is unwanted.</p>
5266
5267<p>If the trimmed image 'disappears' an warning is produced, and a special
5268single pixel transparent 'missed' image is returned, in the same way as when a
5269<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5270
5271
5272<div style="margin: auto;">
5273 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5274</div>
5275
5276<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>
5277 <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>
5278
5279<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>
5280
5281<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5282<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>
5283
5284<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5285
5286<div style="margin: auto;">
5287 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5288</div>
5289
5290<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>
5291
5292<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5293
5294<p>See <a href="#draw">-draw</a> for further details.</p>
5295
5296
5297<div style="margin: auto;">
5298 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5299</div>
5300
5301<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>
5302
5303<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>
5304
5305
5306<div style="margin: auto;">
5307 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5308</div>
5309
5310<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>
5311
5312
5313<div style="margin: auto;">
5314 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5315</div>
5316
5317<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>
5318
5319<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>
5320
5321
5322<div style="margin: auto;">
5323 <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>
5324</div>
5325
5326<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>
5327
5328<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>
5329
5330<p>The parameters are:</p>
5331
5332<pre class="text">
5333 radius: The radius of the Gaussian, in pixels, not counting the center
5334 pixel (default 0).
5335 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5336 amount: The fraction of the difference between the original and the blur
5337 image that is added back into the original (default 1.0).
5338 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5339 difference amount (default 0.05).
5340</pre>
5341
5342
5343<div style="margin: auto;">
5344 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5345</div>
5346
5347<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>
5348
5349
5350<div style="margin: auto;">
5351 <h4><a name="version" id="version"></a>-version</h4>
5352</div>
5353
5354<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>
5355
5356
5357<div style="margin: auto;">
5358 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5359</div>
5360
5361<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>
5362
5363
5364<div style="margin: auto;">
5365 <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>
5366</div>
5367
5368<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>
5369
5370
5371<div style="margin: auto;">
5372 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5373</div>
5374
5375<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>
5376
5377<p>This option defines what color source should be used if and when a color
5378lookup completely 'misses' the source image. The color(s) that appear to
5379surround the source image. Generally this color is derived from the source
5380image, but could also be set to a specify background color. </p>
5381
5382<p>Choose from these methods:</p>
5383
5384<pre class="text">
5385 background: the area surrounding the image is the background color
5386 black: the area surrounding the image is black
5387 checker-tile: alternate squares with image and background color
5388 dither: non-random 32x32 dithered pattern
5389 edge: extend the edge pixel toward infinity
5390 gray: the area surrounding the image is gray
5391 horizontal-tile: horizontally tile the image, background color above/below
5392 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5393 mirror: mirror tile the image
5394 random: choose a random pixel from the image
5395 tile: tile the image (default)
5396 transparent: the area surrounding the image is transparent blackness
5397 vertical-tile: vertically tile the image, sides are background color
5398 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5399 white: the area surrounding the image is white
5400</pre>
5401
5402<p>The default value is "edge".</p>
5403
5404<p>This most important for distortion operators such as <a href="#distort"
5405>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5406However it also effects operations that may access pixels just outside the
5407image proper, such as <a href="#convolve">-convolve</a>, <a
5408href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5409
5410<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5411
5412
5413<div style="margin: auto;">
5414 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5415</div>
5416
5417<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>
5418
5419<p>Choose from these visual classes:</p>
5420
5421<pre class="text">
5422 StaticGray
5423 GrayScale
5424 StaticColor
5425 PseudoColor
5426 TrueColor
5427 DirectColor
5428 default
5429 visual id
5430</pre>
5431
5432<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>
5433
5434
5435<div style="margin: auto;">
5436 <h4><a name="watermark" id="watermark"></a>-watermark <em
5437 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5438</div>
5439
5440<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
5441saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5442
5443<p>Take a grayscale image (with alpha mask) and modify the destination image's
5444brightness according to watermark image's grayscale value and the <em
5445class="arg">brightness</em> percentage. The destinations color saturation
5446attribute is just direct modified by the <em class="arg">saturation</em>
5447percentage, which defaults to 100 percent (no color change). </p>
5448
5449
5450<div style="margin: auto;">
5451 <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>
5452</div>
5453
5454<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>
5455
5456<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5457
5458<div style="margin: auto;">
5459 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5460</div>
5461
5462<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>
5463
5464<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>
5465
5466<table class="doc">
5467 <col width="25%" />
5468 <col width="75%" />
5469 <thead>
5470 <tr>
5471 <th><em class="arg">fontWeight</em></th>
5472 <th>Description</th>
5473 </tr>
5474 </thead>
5475 <tbody>
5476 <tr><td>All </td> <td>No effect. </td></tr>
5477 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5478 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5479 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5480 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5481 </tbody>
5482 </table>
5483
5484<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5485
5486<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>
5487
5488<div style="margin: auto;">
5489 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5490</div>
5491
5492<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>
5493
5494<div style="margin: auto;">
cristy5cadd612009-09-21 19:33:41 +00005495 <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 +00005496</div>
5497
cristy5cadd612009-09-21 19:33:41 +00005498<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>
5499
5500<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.
5501</p>
cristy3ed852e2009-09-05 21:47:34 +00005502
5503<div style="margin: auto;">
5504 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5505</div>
5506
5507<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>
5508
5509<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>
5510
5511<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>
5512
5513<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>
5514
5515<div style="margin: auto;">
5516 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5517</div>
5518
5519<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>
5520
5521<div style="margin: auto;">
5522 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5523</div>
5524
5525<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>
5526 <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>
5527
5528<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5529
cristyf3bb4782009-09-08 13:10:04 +00005530
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cristyf3bb4782009-09-08 13:10:04 +00005539 </span>
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