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170
171<div class="main">
172
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]173<p class="navigation-index">[<a href="#AcquirePixelCacheNexus">AcquirePixelCacheNexus</a> &bull; <a href="#GetAuthenticIndexQueue">GetAuthenticIndexQueue</a> &bull; <a href="#GetAuthenticPixelQueue">GetAuthenticPixelQueue</a> &bull; <a href="#GetAuthenticPixels">GetAuthenticPixels</a> &bull; <a href="#GetOneAuthenticPixel">GetOneAuthenticPixel</a> &bull; <a href="#GetOneVirtualMagickPixel">GetOneVirtualMagickPixel</a> &bull; <a href="#GetOneVirtualMethodPixel">GetOneVirtualMethodPixel</a> &bull; <a href="#GetOneVirtualPixel">GetOneVirtualPixel</a> &bull; <a href="#GetVirtualIndexQueue">GetVirtualIndexQueue</a> &bull; <a href="#VirtualPixelModulo">VirtualPixelModulo</a> &bull; <a href="#GetVirtualPixelQueue">GetVirtualPixelQueue</a> &bull; <a href="#GetVirtualPixels">GetVirtualPixels</a> &bull; <a href="#QueueAuthenticPixels">QueueAuthenticPixels</a> &bull; <a href="#SetPixelCacheVirtualMethod">SetPixelCacheVirtualMethod</a> &bull; <a href="#SyncAuthenticPixels">SyncAuthenticPixels</a>]</p>
174
175<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
176_8c.html" target="source" name="AcquirePixelCacheNexus">AcquirePixelCacheNexus</a></h2>
177<div class="doc-section">
178
179<p>AcquirePixelCacheNexus() allocates the NexusInfo structure.</p></ol>
180
181<p>The format of the AcquirePixelCacheNexus method is:</p>
182
183<pre class="code">
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]184 NexusInfo **AcquirePixelCacheNexus(const size_t number_threads)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]185</pre>
186
187<p>A description of each parameter follows:</p></ol>
188
189<h5>number_threads</h5>
190<ol><p>the number of nexus threads.</p></ol>
191
192 </div>
193<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
194_8c.html" target="source" name="GetAuthenticIndexQueue">GetAuthenticIndexQueue</a></h2>
195<div class="doc-section">
196
197<p>GetAuthenticIndexQueue() returns the authentic black channel or the colormap indexes associated with the last call to QueueAuthenticPixels() or GetVirtualPixels(). NULL is returned if the black channel or colormap indexes are not available.</p></ol>
198
199<p>The format of the GetAuthenticIndexQueue() method is:</p>
200
201<pre class="code">
202 IndexPacket *GetAuthenticIndexQueue(const Image *image)
203</pre>
204
205<p>A description of each parameter follows:</p></ol>
206
207<h5>image</h5>
208<ol><p>the image.</p></ol>
209
210 </div>
211<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
212_8c.html" target="source" name="GetAuthenticPixelQueue">GetAuthenticPixelQueue</a></h2>
213<div class="doc-section">
214
215<p>GetAuthenticPixelQueue() returns the authentic pixels associated with the last call to QueueAuthenticPixels() or GetAuthenticPixels().</p></ol>
216
217<p>The format of the GetAuthenticPixelQueue() method is:</p>
218
219<pre class="code">
220 PixelPacket *GetAuthenticPixelQueue(const Image image)
221</pre>
222
223<p>A description of each parameter follows:</p></ol>
224
225<h5>image</h5>
226<ol><p>the image.</p></ol>
227
228 </div>
229<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
230_8c.html" target="source" name="GetAuthenticPixels">GetAuthenticPixels</a></h2>
231<div class="doc-section">
232
233<p>GetAuthenticPixels() obtains a pixel region for read/write access. If the region is successfully accessed, a pointer to a PixelPacket array representing the region is returned, otherwise NULL is returned.</p></ol>
234
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]235<p>The returned pointer may point to a temporary working copy of the pixels or it may point to the original pixels in memory. Performance is maximized if the selected region is part of one row, or one or more full rows, since then there is opportunity to access the pixels in-place (without a copy) if the image is in memory, or in a memory-mapped file. The returned pointer must *never* be deallocated by the user.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]236
237<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or if the storage class is PseduoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to obtain the black color component or colormap indexes (of type IndexPacket) corresponding to the region. Once the PixelPacket (and/or IndexPacket) array has been updated, the changes must be saved back to the underlying image using SyncAuthenticPixels() or they may be lost.</p></ol>
238
239<p>The format of the GetAuthenticPixels() method is:</p>
240
241<pre class="code">
cristyeaedf062010-05-29 22:36:02 +0000[diff] [blame]242 PixelPacket *GetAuthenticPixels(Image *image,const ssize_t x,
243 const ssize_t y,const size_t columns,const size_t rows,
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]244 ExceptionInfo *exception)
245</pre>
246
247<p>A description of each parameter follows:</p></ol>
248
249<h5>image</h5>
250<ol><p>the image.</p></ol>
251
252<h5>x,y,columns,rows</h5>
253<ol><p>These values define the perimeter of a region of pixels.</p></ol>
254
255<h5>exception</h5>
256<ol><p>return any errors or warnings in this structure.</p></ol>
257
258 </div>
259<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
260_8c.html" target="source" name="GetOneAuthenticPixel">GetOneAuthenticPixel</a></h2>
261<div class="doc-section">
262
263<p>GetOneAuthenticPixel() returns a single pixel at the specified (x,y) location. The image background color is returned if an error occurs.</p></ol>
264
265<p>The format of the GetOneAuthenticPixel() method is:</p>
266
267<pre class="code">
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]268 MagickBooleanType GetOneAuthenticPixel(const Image image,const ssize_t x,
269 const ssize_t y,PixelPacket *pixel,ExceptionInfo *exception)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]270</pre>
271
272<p>A description of each parameter follows:</p></ol>
273
274<h5>image</h5>
275<ol><p>the image.</p></ol>
276
277<h5>x,y</h5>
278<ol><p>These values define the location of the pixel to return.</p></ol>
279
280<h5>pixel</h5>
281<ol><p>return a pixel at the specified (x,y) location.</p></ol>
282
283<h5>exception</h5>
284<ol><p>return any errors or warnings in this structure.</p></ol>
285
286 </div>
287<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
288_8c.html" target="source" name="GetOneVirtualMagickPixel">GetOneVirtualMagickPixel</a></h2>
289<div class="doc-section">
290
291<p>GetOneVirtualMagickPixel() returns a single pixel at the specified (x,y) location. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
292
293<p>The format of the GetOneVirtualMagickPixel() method is:</p>
294
295<pre class="code">
296 MagickBooleanType GetOneVirtualMagickPixel(const Image image,
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]297 const ssize_t x,const ssize_t y,MagickPixelPacket *pixel,
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]298 ExceptionInfo exception)
299</pre>
300
301<p>A description of each parameter follows:</p></ol>
302
303<h5>image</h5>
304<ol><p>the image.</p></ol>
305
306<h5>x,y</h5>
307<ol><p>these values define the location of the pixel to return.</p></ol>
308
309<h5>pixel</h5>
310<ol><p>return a pixel at the specified (x,y) location.</p></ol>
311
312<h5>exception</h5>
313<ol><p>return any errors or warnings in this structure.</p></ol>
314
315 </div>
316<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
317_8c.html" target="source" name="GetOneVirtualMethodPixel">GetOneVirtualMethodPixel</a></h2>
318<div class="doc-section">
319
320<p>GetOneVirtualMethodPixel() returns a single pixel at the specified (x,y) location as defined by specified pixel method. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
321
322<p>The format of the GetOneVirtualMethodPixel() method is:</p>
323
324<pre class="code">
325 MagickBooleanType GetOneVirtualMethodPixel(const Image image,
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]326 const VirtualPixelMethod virtual_pixel_method,const ssize_t x,
327 const ssize_t y,Pixelpacket *pixel,ExceptionInfo exception)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]328</pre>
329
330<p>A description of each parameter follows:</p></ol>
331
332<h5>image</h5>
333<ol><p>the image.</p></ol>
334
335<h5>virtual_pixel_method</h5>
336<ol><p>the virtual pixel method.</p></ol>
337
338<h5>x,y</h5>
339<ol><p>These values define the location of the pixel to return.</p></ol>
340
341<h5>pixel</h5>
342<ol><p>return a pixel at the specified (x,y) location.</p></ol>
343
344<h5>exception</h5>
345<ol><p>return any errors or warnings in this structure.</p></ol>
346
347 </div>
348<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
349_8c.html" target="source" name="GetOneVirtualPixel">GetOneVirtualPixel</a></h2>
350<div class="doc-section">
351
352<p>GetOneVirtualPixel() returns a single virtual pixel at the specified (x,y) location. The image background color is returned if an error occurs. If you plan to modify the pixel, use GetOneAuthenticPixel() instead.</p></ol>
353
354<p>The format of the GetOneVirtualPixel() method is:</p>
355
356<pre class="code">
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]357 MagickBooleanType GetOneVirtualPixel(const Image image,const ssize_t x,
358 const ssize_t y,PixelPacket *pixel,ExceptionInfo exception)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]359</pre>
360
361<p>A description of each parameter follows:</p></ol>
362
363<h5>image</h5>
364<ol><p>the image.</p></ol>
365
366<h5>x,y</h5>
367<ol><p>These values define the location of the pixel to return.</p></ol>
368
369<h5>pixel</h5>
370<ol><p>return a pixel at the specified (x,y) location.</p></ol>
371
372<h5>exception</h5>
373<ol><p>return any errors or warnings in this structure.</p></ol>
374
375 </div>
376<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
377_8c.html" target="source" name="GetVirtualIndexQueue">GetVirtualIndexQueue</a></h2>
378<div class="doc-section">
379
380<p>GetVirtualIndexQueue() returns the virtual black channel or the colormap indexes associated with the last call to QueueAuthenticPixels() or GetVirtualPixels(). NULL is returned if the black channel or colormap indexes are not available.</p></ol>
381
382<p>The format of the GetVirtualIndexQueue() method is:</p>
383
384<pre class="code">
385 const IndexPacket *GetVirtualIndexQueue(const Image *image)
386</pre>
387
388<p>A description of each parameter follows:</p></ol>
389
390<h5>image</h5>
391<ol><p>the image.</p></ol>
392
393 </div>
394<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
395_8c.html" target="source" name="VirtualPixelModulo">VirtualPixelModulo</a></h2>
396<div class="doc-section">
397
398<p>VirtualPixelModulo() computes the remainder of dividing offset by extent. It returns not only the quotient (tile the offset falls in) but also the positive remainer within that tile such that 0 <= remainder < extent. This method is essentially a ldiv() using a floored modulo division rather than the normal default truncated modulo division. </p>
399 </div>
400<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
401_8c.html" target="source" name="GetVirtualPixelQueue">GetVirtualPixelQueue</a></h2>
402<div class="doc-section">
403
404<p>GetVirtualPixelQueue() returns the virtual pixels associated with the last call to QueueAuthenticPixels() or GetVirtualPixels().</p></ol>
405
406<p>The format of the GetVirtualPixelQueue() method is:</p>
407
408<pre class="code">
409 const PixelPacket *GetVirtualPixelQueue(const Image image)
410</pre>
411
412<p>A description of each parameter follows:</p></ol>
413
414<h5>image</h5>
415<ol><p>the image.</p></ol>
416
417 </div>
418<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
419_8c.html" target="source" name="GetVirtualPixels">GetVirtualPixels</a></h2>
420<div class="doc-section">
421
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]422<p>GetVirtualPixels() returns an immutable pixel region. If the region is successfully accessed, a pointer to it is returned, otherwise NULL is returned. The returned pointer may point to a temporary working copy of the pixels or it may point to the original pixels in memory. Performance is maximized if the selected region is part of one row, or one or more full rows, since there is opportunity to access the pixels in-place (without a copy) if the image is in memory, or in a memory-mapped file. The returned pointer must *never* be deallocated by the user.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]423
424<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or the storage class is PseudoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to access the black color component or to obtain the colormap indexes (of type IndexPacket) corresponding to the region.</p></ol>
425
426<p>If you plan to modify the pixels, use GetAuthenticPixels() instead.</p></ol>
427
428<p>Note, the GetVirtualPixels() and GetAuthenticPixels() methods are not thread- safe. In a threaded environment, use GetCacheViewVirtualPixels() or GetCacheViewAuthenticPixels() instead.</p></ol>
429
430<p>The format of the GetVirtualPixels() method is:</p>
431
432<pre class="code">
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]433 const PixelPacket *GetVirtualPixels(const Image *image,const ssize_t x,
434 const ssize_t y,const size_t columns,const size_t rows,
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]435 ExceptionInfo *exception)
436</pre>
437
438<p>A description of each parameter follows:</p></ol>
439
440<h5>image</h5>
441<ol><p>the image.</p></ol>
442
443<h5>x,y,columns,rows</h5>
444<ol><p>These values define the perimeter of a region of pixels.</p></ol>
445
446<h5>exception</h5>
447<ol><p>return any errors or warnings in this structure.</p></ol>
448
449 </div>
450<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
451_8c.html" target="source" name="QueueAuthenticPixels">QueueAuthenticPixels</a></h2>
452<div class="doc-section">
453
454<p>QueueAuthenticPixels() queues a mutable pixel region. If the region is successfully intialized a pointer to a PixelPacket array representing the region is returned, otherwise NULL is returned. The returned pointer may point to a temporary working buffer for the pixels or it may point to the final location of the pixels in memory.</p></ol>
455
456<p>Write-only access means that any existing pixel values corresponding to the region are ignored. This is useful if the initial image is being created from scratch, or if the existing pixel values are to be completely replaced without need to refer to their pre-existing values. The application is free to read and write the pixel buffer returned by QueueAuthenticPixels() any way it pleases. QueueAuthenticPixels() does not initialize the pixel array values. Initializing pixel array values is the application's responsibility.</p></ol>
457
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]458<p>Performance is maximized if the selected region is part of one row, or one or more full rows, since then there is opportunity to access the pixels in-place (without a copy) if the image is in memory, or in a memory-mapped file. The returned pointer must *never* be deallocated by the user.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]459
460<p>Pixels accessed via the returned pointer represent a simple array of type PixelPacket. If the image type is CMYK or the storage class is PseudoClass, call GetAuthenticIndexQueue() after invoking GetAuthenticPixels() to obtain the black color component or the colormap indexes (of type IndexPacket) corresponding to the region. Once the PixelPacket (and/or IndexPacket) array has been updated, the changes must be saved back to the underlying image using SyncAuthenticPixels() or they may be lost.</p></ol>
461
462<p>The format of the QueueAuthenticPixels() method is:</p>
463
464<pre class="code">
cristyeaedf062010-05-29 22:36:02 +0000[diff] [blame]465 PixelPacket *QueueAuthenticPixels(Image *image,const ssize_t x,
466 const ssize_t y,const size_t columns,const size_t rows,
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]467 ExceptionInfo *exception)
468</pre>
469
470<p>A description of each parameter follows:</p></ol>
471
472<h5>image</h5>
473<ol><p>the image.</p></ol>
474
475<h5>x,y,columns,rows</h5>
476<ol><p>These values define the perimeter of a region of pixels.</p></ol>
477
478<h5>exception</h5>
479<ol><p>return any errors or warnings in this structure.</p></ol>
480
481 </div>
482<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
483_8c.html" target="source" name="SetPixelCacheVirtualMethod">SetPixelCacheVirtualMethod</a></h2>
484<div class="doc-section">
485
486<p>SetPixelCacheVirtualMethod() sets the "virtual pixels" method for the pixel cache and returns the previous setting. A virtual pixel is any pixel access that is outside the boundaries of the image cache.</p></ol>
487
488<p>The format of the SetPixelCacheVirtualMethod() method is:</p>
489
490<pre class="code">
491 VirtualPixelMethod SetPixelCacheVirtualMethod(const Image *image,
492 const VirtualPixelMethod virtual_pixel_method)
493</pre>
494
495<p>A description of each parameter follows:</p></ol>
496
497<h5>image</h5>
498<ol><p>the image.</p></ol>
499
500<h5>virtual_pixel_method</h5>
501<ol><p>choose the type of virtual pixel.</p></ol>
502
503 </div>
504<h2><a href="http://www.imagemagick.org/api/MagickCore/cache
505_8c.html" target="source" name="SyncAuthenticPixels">SyncAuthenticPixels</a></h2>
506<div class="doc-section">
507
508<p>SyncAuthenticPixels() saves the image pixels to the in-memory or disk cache. The method returns MagickTrue if the pixel region is flushed, otherwise MagickFalse.</p></ol>
509
510<p>The format of the SyncAuthenticPixels() method is:</p>
511
512<pre class="code">
513 MagickBooleanType SyncAuthenticPixels(Image *image,
514 ExceptionInfo *exception)
515</pre>
516
517<p>A description of each parameter follows:</p></ol>
518
519<h5>image</h5>
520<ol><p>the image.</p></ol>
521
522<h5>exception</h5>
523<ol><p>return any errors or warnings in this structure.</p></ol>
524
525 </div>
cristy3eaa0ef2010-03-06 20:35:26 +0000[diff] [blame]526
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