2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6 % QQQ U U AAA N N TTTTT IIIII ZZZZZ EEEEE %
7 % Q Q U U A A NN N T I ZZ E %
8 % Q Q U U AAAAA N N N T I ZZZ EEEEE %
9 % Q QQ U U A A N NN T I ZZ E %
10 % QQQQ UUU A A N N T IIIII ZZZZZ EEEEE %
13 % MagickCore Methods to Reduce the Number of Unique Colors in an Image %
20 % Copyright 1999-2011 ImageMagick Studio LLC, a non-profit organization %
21 % dedicated to making software imaging solutions freely available. %
23 % You may not use this file except in compliance with the License. You may %
24 % obtain a copy of the License at %
26 % http://www.imagemagick.org/script/license.php %
28 % Unless required by applicable law or agreed to in writing, software %
29 % distributed under the License is distributed on an "AS IS" BASIS, %
30 % WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %
31 % See the License for the specific language governing permissions and %
32 % limitations under the License. %
34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
36 % Realism in computer graphics typically requires using 24 bits/pixel to
37 % generate an image. Yet many graphic display devices do not contain the
38 % amount of memory necessary to match the spatial and color resolution of
39 % the human eye. The Quantize methods takes a 24 bit image and reduces
40 % the number of colors so it can be displayed on raster device with less
41 % bits per pixel. In most instances, the quantized image closely
42 % resembles the original reference image.
44 % A reduction of colors in an image is also desirable for image
45 % transmission and real-time animation.
47 % QuantizeImage() takes a standard RGB or monochrome images and quantizes
48 % them down to some fixed number of colors.
50 % For purposes of color allocation, an image is a set of n pixels, where
51 % each pixel is a point in RGB space. RGB space is a 3-dimensional
52 % vector space, and each pixel, Pi, is defined by an ordered triple of
53 % red, green, and blue coordinates, (Ri, Gi, Bi).
55 % Each primary color component (red, green, or blue) represents an
56 % intensity which varies linearly from 0 to a maximum value, Cmax, which
57 % corresponds to full saturation of that color. Color allocation is
58 % defined over a domain consisting of the cube in RGB space with opposite
59 % vertices at (0,0,0) and (Cmax, Cmax, Cmax). QUANTIZE requires Cmax =
62 % The algorithm maps this domain onto a tree in which each node
63 % represents a cube within that domain. In the following discussion
64 % these cubes are defined by the coordinate of two opposite vertices:
65 % The vertex nearest the origin in RGB space and the vertex farthest from
68 % The tree's root node represents the entire domain, (0,0,0) through
69 % (Cmax,Cmax,Cmax). Each lower level in the tree is generated by
70 % subdividing one node's cube into eight smaller cubes of equal size.
71 % This corresponds to bisecting the parent cube with planes passing
72 % through the midpoints of each edge.
74 % The basic algorithm operates in three phases: Classification,
75 % Reduction, and Assignment. Classification builds a color description
76 % tree for the image. Reduction collapses the tree until the number it
77 % represents, at most, the number of colors desired in the output image.
78 % Assignment defines the output image's color map and sets each pixel's
79 % color by restorage_class in the reduced tree. Our goal is to minimize
80 % the numerical discrepancies between the original colors and quantized
81 % colors (quantization error).
83 % Classification begins by initializing a color description tree of
84 % sufficient depth to represent each possible input color in a leaf.
85 % However, it is impractical to generate a fully-formed color description
86 % tree in the storage_class phase for realistic values of Cmax. If
87 % colors components in the input image are quantized to k-bit precision,
88 % so that Cmax= 2k-1, the tree would need k levels below the root node to
89 % allow representing each possible input color in a leaf. This becomes
90 % prohibitive because the tree's total number of nodes is 1 +
93 % A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
94 % Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
95 % Initializes data structures for nodes only as they are needed; (2)
96 % Chooses a maximum depth for the tree as a function of the desired
97 % number of colors in the output image (currently log2(colormap size)).
99 % For each pixel in the input image, storage_class scans downward from
100 % the root of the color description tree. At each level of the tree it
101 % identifies the single node which represents a cube in RGB space
102 % containing the pixel's color. It updates the following data for each
105 % n1: Number of pixels whose color is contained in the RGB cube which
106 % this node represents;
108 % n2: Number of pixels whose color is not represented in a node at
109 % lower depth in the tree; initially, n2 = 0 for all nodes except
110 % leaves of the tree.
112 % Sr, Sg, Sb: Sums of the red, green, and blue component values for all
113 % pixels not classified at a lower depth. The combination of these sums
114 % and n2 will ultimately characterize the mean color of a set of
115 % pixels represented by this node.
117 % E: the distance squared in RGB space between each pixel contained
118 % within a node and the nodes' center. This represents the
119 % quantization error for a node.
121 % Reduction repeatedly prunes the tree until the number of nodes with n2
122 % > 0 is less than or equal to the maximum number of colors allowed in
123 % the output image. On any given iteration over the tree, it selects
124 % those nodes whose E count is minimal for pruning and merges their color
125 % statistics upward. It uses a pruning threshold, Ep, to govern node
126 % selection as follows:
129 % while number of nodes with (n2 > 0) > required maximum number of colors
130 % prune all nodes such that E <= Ep
131 % Set Ep to minimum E in remaining nodes
133 % This has the effect of minimizing any quantization error when merging
134 % two nodes together.
136 % When a node to be pruned has offspring, the pruning procedure invokes
137 % itself recursively in order to prune the tree from the leaves upward.
138 % n2, Sr, Sg, and Sb in a node being pruned are always added to the
139 % corresponding data in that node's parent. This retains the pruned
140 % node's color characteristics for later averaging.
142 % For each node, n2 pixels exist for which that node represents the
143 % smallest volume in RGB space containing those pixel's colors. When n2
144 % > 0 the node will uniquely define a color in the output image. At the
145 % beginning of reduction, n2 = 0 for all nodes except a the leaves of
146 % the tree which represent colors present in the input image.
148 % The other pixel count, n1, indicates the total number of colors within
149 % the cubic volume which the node represents. This includes n1 - n2
150 % pixels whose colors should be defined by nodes at a lower level in the
153 % Assignment generates the output image from the pruned tree. The output
154 % image consists of two parts: (1) A color map, which is an array of
155 % color descriptions (RGB triples) for each color present in the output
156 % image; (2) A pixel array, which represents each pixel as an index
157 % into the color map array.
159 % First, the assignment phase makes one pass over the pruned color
160 % description tree to establish the image's color map. For each node
161 % with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
162 % color of all pixels that classify no lower than this node. Each of
163 % these colors becomes an entry in the color map.
165 % Finally, the assignment phase reclassifies each pixel in the pruned
166 % tree to identify the deepest node containing the pixel's color. The
167 % pixel's value in the pixel array becomes the index of this node's mean
168 % color in the color map.
170 % This method is based on a similar algorithm written by Paul Raveling.
175 Include declarations.
177 #include "MagickCore/studio.h"
178 #include "MagickCore/attribute.h"
179 #include "MagickCore/cache-view.h"
180 #include "MagickCore/color.h"
181 #include "MagickCore/color-private.h"
182 #include "MagickCore/colormap.h"
183 #include "MagickCore/colorspace.h"
184 #include "MagickCore/colorspace-private.h"
185 #include "MagickCore/enhance.h"
186 #include "MagickCore/exception.h"
187 #include "MagickCore/exception-private.h"
188 #include "MagickCore/histogram.h"
189 #include "MagickCore/image.h"
190 #include "MagickCore/image-private.h"
191 #include "MagickCore/list.h"
192 #include "MagickCore/memory_.h"
193 #include "MagickCore/monitor.h"
194 #include "MagickCore/monitor-private.h"
195 #include "MagickCore/option.h"
196 #include "MagickCore/pixel-accessor.h"
197 #include "MagickCore/quantize.h"
198 #include "MagickCore/quantum.h"
199 #include "MagickCore/quantum-private.h"
200 #include "MagickCore/string_.h"
201 #include "MagickCore/thread-private.h"
206 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
211 #define ErrorQueueLength 16
212 #define MaxNodes 266817
213 #define MaxTreeDepth 8
214 #define NodesInAList 1920
219 typedef struct _RealPixelPacket
228 typedef struct _NodeInfo
249 typedef struct _Nodes
258 typedef struct _CubeInfo
296 error[ErrorQueueLength];
299 weights[ErrorQueueLength];
325 *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
328 *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
330 static MagickBooleanType
331 AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
332 ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
333 DitherImage(Image *,CubeInfo *),
334 SetGrayscaleImage(Image *,ExceptionInfo *);
337 DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
340 ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
341 DestroyCubeInfo(CubeInfo *),
342 PruneLevel(const Image *,CubeInfo *,const NodeInfo *),
343 PruneToCubeDepth(const Image *,CubeInfo *,const NodeInfo *),
344 ReduceImageColors(const Image *,CubeInfo *);
347 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
351 % A c q u i r e Q u a n t i z e I n f o %
355 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
357 % AcquireQuantizeInfo() allocates the QuantizeInfo structure.
359 % The format of the AcquireQuantizeInfo method is:
361 % QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
363 % A description of each parameter follows:
365 % o image_info: the image info.
368 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
373 quantize_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*quantize_info));
374 if (quantize_info == (QuantizeInfo *) NULL)
375 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
376 GetQuantizeInfo(quantize_info);
377 if (image_info != (ImageInfo *) NULL)
382 quantize_info->dither=image_info->dither;
383 option=GetImageOption(image_info,"dither");
384 if (option != (const char *) NULL)
385 quantize_info->dither_method=(DitherMethod) ParseCommandOption(
386 MagickDitherOptions,MagickFalse,option);
387 quantize_info->measure_error=image_info->verbose;
389 return(quantize_info);
393 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
397 + A s s i g n I m a g e C o l o r s %
401 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
403 % AssignImageColors() generates the output image from the pruned tree. The
404 % output image consists of two parts: (1) A color map, which is an array
405 % of color descriptions (RGB triples) for each color present in the
406 % output image; (2) A pixel array, which represents each pixel as an
407 % index into the color map array.
409 % First, the assignment phase makes one pass over the pruned color
410 % description tree to establish the image's color map. For each node
411 % with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
412 % color of all pixels that classify no lower than this node. Each of
413 % these colors becomes an entry in the color map.
415 % Finally, the assignment phase reclassifies each pixel in the pruned
416 % tree to identify the deepest node containing the pixel's color. The
417 % pixel's value in the pixel array becomes the index of this node's mean
418 % color in the color map.
420 % The format of the AssignImageColors() method is:
422 % MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
424 % A description of each parameter follows.
426 % o image: the image.
428 % o cube_info: A pointer to the Cube structure.
432 static inline void AssociateAlphaPixel(const Image *image,
433 const CubeInfo *cube_info,const Quantum *pixel,RealPixelPacket *alpha_pixel)
438 if ((cube_info->associate_alpha == MagickFalse) ||
439 (GetPixelAlpha(image,pixel)== OpaqueAlpha))
441 alpha_pixel->red=(MagickRealType) GetPixelRed(image,pixel);
442 alpha_pixel->green=(MagickRealType) GetPixelGreen(image,pixel);
443 alpha_pixel->blue=(MagickRealType) GetPixelBlue(image,pixel);
444 alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
447 alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,pixel));
448 alpha_pixel->red=alpha*GetPixelRed(image,pixel);
449 alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
450 alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
451 alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
454 static inline void AssociateAlphaPixelPacket(const Image *image,
455 const CubeInfo *cube_info,const PixelPacket *pixel,
456 RealPixelPacket *alpha_pixel)
461 if ((cube_info->associate_alpha == MagickFalse) ||
462 (pixel->alpha == OpaqueAlpha))
464 alpha_pixel->red=(MagickRealType) pixel->red;
465 alpha_pixel->green=(MagickRealType) pixel->green;
466 alpha_pixel->blue=(MagickRealType) pixel->blue;
467 alpha_pixel->alpha=(MagickRealType) pixel->alpha;
470 alpha=(MagickRealType) (QuantumScale*pixel->alpha);
471 alpha_pixel->red=alpha*pixel->red;
472 alpha_pixel->green=alpha*pixel->green;
473 alpha_pixel->blue=alpha*pixel->blue;
474 alpha_pixel->alpha=(MagickRealType) pixel->alpha;
477 static inline Quantum ClampToUnsignedQuantum(const MagickRealType value)
481 if (value >= QuantumRange)
482 return((Quantum) QuantumRange);
483 return((Quantum) (value+0.5));
486 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
487 const RealPixelPacket *pixel,size_t index)
492 id=(size_t) (((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red)) >> index) & 0x01) |
493 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green)) >> index) & 0x01) << 1 |
494 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue)) >> index) & 0x01) << 2);
495 if (cube_info->associate_alpha != MagickFalse)
496 id|=((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->alpha)) >> index) & 0x1) << 3;
500 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info,
501 ExceptionInfo *exception)
503 #define AssignImageTag "Assign/Image"
509 Allocate image colormap.
511 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
512 (cube_info->quantize_info->colorspace != CMYKColorspace))
513 (void) TransformImageColorspace((Image *) image,
514 cube_info->quantize_info->colorspace);
516 if ((image->colorspace != GRAYColorspace) &&
517 (IsRGBColorspace(image->colorspace) == MagickFalse) &&
518 (image->colorspace != CMYColorspace))
519 (void) TransformImageColorspace((Image *) image,RGBColorspace);
520 if (AcquireImageColormap(image,cube_info->colors,exception) == MagickFalse)
521 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
524 cube_info->transparent_pixels=0;
525 cube_info->transparent_index=(-1);
526 (void) DefineImageColormap(image,cube_info,cube_info->root);
528 Create a reduced color image.
530 if ((cube_info->quantize_info->dither != MagickFalse) &&
531 (cube_info->quantize_info->dither_method != NoDitherMethod))
532 (void) DitherImage(image,cube_info);
545 exception=(&image->exception);
546 image_view=AcquireCacheView(image);
547 #if defined(MAGICKCORE_OPENMP_SUPPORT)
548 #pragma omp parallel for schedule(dynamic,4) shared(status)
550 for (y=0; y < (ssize_t) image->rows; y++)
564 if (status == MagickFalse)
566 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
568 if (q == (Quantum *) NULL)
574 for (x=0; x < (ssize_t) image->columns; x+=count)
579 register const NodeInfo
590 Identify the deepest node containing the pixel's color.
592 for (count=1; (x+count) < (ssize_t) image->columns; count++)
597 GetPixelPacket(image,q+count*GetPixelChannels(image),&packet);
598 if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
601 AssociateAlphaPixel(image,&cube,q,&pixel);
603 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
605 id=ColorToNodeId(&cube,&pixel,index);
606 if (node_info->child[id] == (NodeInfo *) NULL)
608 node_info=node_info->child[id];
611 Find closest color among siblings and their children.
614 cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*
615 (QuantumRange+1.0)+1.0);
616 ClosestColor(image,&cube,node_info->parent);
617 index=cube.color_number;
618 for (i=0; i < (ssize_t) count; i++)
620 if (image->storage_class == PseudoClass)
621 SetPixelIndex(image,(Quantum) index,q);
622 if (cube.quantize_info->measure_error == MagickFalse)
624 SetPixelRed(image,image->colormap[index].red,q);
625 SetPixelGreen(image,image->colormap[index].green,q);
626 SetPixelBlue(image,image->colormap[index].blue,q);
627 if (cube.associate_alpha != MagickFalse)
628 SetPixelAlpha(image,image->colormap[index].alpha,q);
630 q+=GetPixelChannels(image);
633 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
635 if (image->progress_monitor != (MagickProgressMonitor) NULL)
640 #if defined(MAGICKCORE_OPENMP_SUPPORT)
641 #pragma omp critical (MagickCore_AssignImageColors)
643 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
645 if (proceed == MagickFalse)
649 image_view=DestroyCacheView(image_view);
651 if (cube_info->quantize_info->measure_error != MagickFalse)
652 (void) GetImageQuantizeError(image);
653 if ((cube_info->quantize_info->number_colors == 2) &&
654 (cube_info->quantize_info->colorspace == GRAYColorspace))
669 for (i=0; i < (ssize_t) image->colors; i++)
671 intensity=(Quantum) ((MagickRealType) GetPixelPacketIntensity(q) <
672 ((MagickRealType) QuantumRange/2.0) ? 0 : QuantumRange);
679 (void) SyncImage(image);
680 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
681 (cube_info->quantize_info->colorspace != CMYKColorspace))
682 (void) TransformImageColorspace((Image *) image,RGBColorspace);
687 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
691 + C l a s s i f y I m a g e C o l o r s %
695 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
697 % ClassifyImageColors() begins by initializing a color description tree
698 % of sufficient depth to represent each possible input color in a leaf.
699 % However, it is impractical to generate a fully-formed color
700 % description tree in the storage_class phase for realistic values of
701 % Cmax. If colors components in the input image are quantized to k-bit
702 % precision, so that Cmax= 2k-1, the tree would need k levels below the
703 % root node to allow representing each possible input color in a leaf.
704 % This becomes prohibitive because the tree's total number of nodes is
707 % A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
708 % Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
709 % Initializes data structures for nodes only as they are needed; (2)
710 % Chooses a maximum depth for the tree as a function of the desired
711 % number of colors in the output image (currently log2(colormap size)).
713 % For each pixel in the input image, storage_class scans downward from
714 % the root of the color description tree. At each level of the tree it
715 % identifies the single node which represents a cube in RGB space
716 % containing It updates the following data for each such node:
718 % n1 : Number of pixels whose color is contained in the RGB cube
719 % which this node represents;
721 % n2 : Number of pixels whose color is not represented in a node at
722 % lower depth in the tree; initially, n2 = 0 for all nodes except
723 % leaves of the tree.
725 % Sr, Sg, Sb : Sums of the red, green, and blue component values for
726 % all pixels not classified at a lower depth. The combination of
727 % these sums and n2 will ultimately characterize the mean color of a
728 % set of pixels represented by this node.
730 % E: the distance squared in RGB space between each pixel contained
731 % within a node and the nodes' center. This represents the quantization
734 % The format of the ClassifyImageColors() method is:
736 % MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
737 % const Image *image,ExceptionInfo *exception)
739 % A description of each parameter follows.
741 % o cube_info: A pointer to the Cube structure.
743 % o image: the image.
747 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
752 associate_alpha=image->matte;
753 if (cube_info->quantize_info->colorspace == TransparentColorspace)
754 associate_alpha=MagickFalse;
755 if ((cube_info->quantize_info->number_colors == 2) &&
756 (cube_info->quantize_info->colorspace == GRAYColorspace))
757 associate_alpha=MagickFalse;
758 cube_info->associate_alpha=associate_alpha;
761 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
762 const Image *image,ExceptionInfo *exception)
764 #define ClassifyImageTag "Classify/Image"
794 Classify the first cube_info->maximum_colors colors to a tree depth of 8.
796 SetAssociatedAlpha(image,cube_info);
797 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
798 (cube_info->quantize_info->colorspace != CMYKColorspace))
799 (void) TransformImageColorspace((Image *) image,
800 cube_info->quantize_info->colorspace);
802 if ((image->colorspace != GRAYColorspace) &&
803 (image->colorspace != CMYColorspace) &&
804 (IsRGBColorspace(image->colorspace) == MagickFalse))
805 (void) TransformImageColorspace((Image *) image,RGBColorspace);
806 midpoint.red=(MagickRealType) QuantumRange/2.0;
807 midpoint.green=(MagickRealType) QuantumRange/2.0;
808 midpoint.blue=(MagickRealType) QuantumRange/2.0;
809 midpoint.alpha=(MagickRealType) QuantumRange/2.0;
811 image_view=AcquireCacheView(image);
812 for (y=0; y < (ssize_t) image->rows; y++)
814 register const Quantum
820 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
821 if (p == (const Quantum *) NULL)
823 if (cube_info->nodes > MaxNodes)
826 Prune one level if the color tree is too large.
828 PruneLevel(image,cube_info,cube_info->root);
831 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
834 Start at the root and descend the color cube tree.
836 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
841 GetPixelPacket(image,p+count*GetPixelChannels(image),&packet);
842 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
845 AssociateAlphaPixel(image,cube_info,p,&pixel);
846 index=MaxTreeDepth-1;
847 bisect=((MagickRealType) QuantumRange+1.0)/2.0;
849 node_info=cube_info->root;
850 for (level=1; level <= MaxTreeDepth; level++)
853 id=ColorToNodeId(cube_info,&pixel,index);
854 mid.red+=(id & 1) != 0 ? bisect : -bisect;
855 mid.green+=(id & 2) != 0 ? bisect : -bisect;
856 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
857 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
858 if (node_info->child[id] == (NodeInfo *) NULL)
861 Set colors of new node to contain pixel.
863 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
864 if (node_info->child[id] == (NodeInfo *) NULL)
865 (void) ThrowMagickException(exception,GetMagickModule(),
866 ResourceLimitError,"MemoryAllocationFailed","`%s'",
868 if (level == MaxTreeDepth)
872 Approximate the quantization error represented by this node.
874 node_info=node_info->child[id];
875 error.red=QuantumScale*(pixel.red-mid.red);
876 error.green=QuantumScale*(pixel.green-mid.green);
877 error.blue=QuantumScale*(pixel.blue-mid.blue);
878 if (cube_info->associate_alpha != MagickFalse)
879 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
880 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
881 count*error.green*error.green+count*error.blue*error.blue+
882 count*error.alpha*error.alpha));
883 cube_info->root->quantize_error+=node_info->quantize_error;
887 Sum RGB for this leaf for later derivation of the mean cube color.
889 node_info->number_unique+=count;
890 node_info->total_color.red+=count*QuantumScale*pixel.red;
891 node_info->total_color.green+=count*QuantumScale*pixel.green;
892 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
893 if (cube_info->associate_alpha != MagickFalse)
894 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
895 p+=count*GetPixelChannels(image);
897 if (cube_info->colors > cube_info->maximum_colors)
899 PruneToCubeDepth(image,cube_info,cube_info->root);
902 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
904 if (proceed == MagickFalse)
907 for (y++; y < (ssize_t) image->rows; y++)
909 register const Quantum
915 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
916 if (p == (const Quantum *) NULL)
918 if (cube_info->nodes > MaxNodes)
921 Prune one level if the color tree is too large.
923 PruneLevel(image,cube_info,cube_info->root);
926 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
929 Start at the root and descend the color cube tree.
931 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
936 GetPixelPacket(image,p+count*GetPixelChannels(image),&packet);
937 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
940 AssociateAlphaPixel(image,cube_info,p,&pixel);
941 index=MaxTreeDepth-1;
942 bisect=((MagickRealType) QuantumRange+1.0)/2.0;
944 node_info=cube_info->root;
945 for (level=1; level <= cube_info->depth; level++)
948 id=ColorToNodeId(cube_info,&pixel,index);
949 mid.red+=(id & 1) != 0 ? bisect : -bisect;
950 mid.green+=(id & 2) != 0 ? bisect : -bisect;
951 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
952 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
953 if (node_info->child[id] == (NodeInfo *) NULL)
956 Set colors of new node to contain pixel.
958 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
959 if (node_info->child[id] == (NodeInfo *) NULL)
960 (void) ThrowMagickException(exception,GetMagickModule(),
961 ResourceLimitError,"MemoryAllocationFailed","%s",
963 if (level == cube_info->depth)
967 Approximate the quantization error represented by this node.
969 node_info=node_info->child[id];
970 error.red=QuantumScale*(pixel.red-mid.red);
971 error.green=QuantumScale*(pixel.green-mid.green);
972 error.blue=QuantumScale*(pixel.blue-mid.blue);
973 if (cube_info->associate_alpha != MagickFalse)
974 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
975 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
976 count*error.green*error.green+count*error.blue*error.blue+
977 count*error.alpha*error.alpha));
978 cube_info->root->quantize_error+=node_info->quantize_error;
982 Sum RGB for this leaf for later derivation of the mean cube color.
984 node_info->number_unique+=count;
985 node_info->total_color.red+=count*QuantumScale*pixel.red;
986 node_info->total_color.green+=count*QuantumScale*pixel.green;
987 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
988 if (cube_info->associate_alpha != MagickFalse)
989 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
990 p+=count*GetPixelChannels(image);
992 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
994 if (proceed == MagickFalse)
997 image_view=DestroyCacheView(image_view);
998 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
999 (cube_info->quantize_info->colorspace != CMYKColorspace))
1000 (void) TransformImageColorspace((Image *) image,RGBColorspace);
1005 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1009 % C l o n e Q u a n t i z e I n f o %
1013 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1015 % CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1016 % or if quantize info is NULL, a new one.
1018 % The format of the CloneQuantizeInfo method is:
1020 % QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1022 % A description of each parameter follows:
1024 % o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1025 % quantize info, or if image info is NULL a new one.
1027 % o quantize_info: a structure of type info.
1030 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1035 clone_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*clone_info));
1036 if (clone_info == (QuantizeInfo *) NULL)
1037 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
1038 GetQuantizeInfo(clone_info);
1039 if (quantize_info == (QuantizeInfo *) NULL)
1041 clone_info->number_colors=quantize_info->number_colors;
1042 clone_info->tree_depth=quantize_info->tree_depth;
1043 clone_info->dither=quantize_info->dither;
1044 clone_info->dither_method=quantize_info->dither_method;
1045 clone_info->colorspace=quantize_info->colorspace;
1046 clone_info->measure_error=quantize_info->measure_error;
1051 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1055 + C l o s e s t C o l o r %
1059 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1061 % ClosestColor() traverses the color cube tree at a particular node and
1062 % determines which colormap entry best represents the input color.
1064 % The format of the ClosestColor method is:
1066 % void ClosestColor(const Image *image,CubeInfo *cube_info,
1067 % const NodeInfo *node_info)
1069 % A description of each parameter follows.
1071 % o image: the image.
1073 % o cube_info: A pointer to the Cube structure.
1075 % o node_info: the address of a structure of type NodeInfo which points to a
1076 % node in the color cube tree that is to be pruned.
1079 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1080 const NodeInfo *node_info)
1089 Traverse any children.
1091 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1092 for (i=0; i < (ssize_t) number_children; i++)
1093 if (node_info->child[i] != (NodeInfo *) NULL)
1094 ClosestColor(image,cube_info,node_info->child[i]);
1095 if (node_info->number_unique != 0)
1100 register MagickRealType
1105 register PixelPacket
1108 register RealPixelPacket
1112 Determine if this color is "closest".
1114 p=image->colormap+node_info->color_number;
1115 q=(&cube_info->target);
1118 if (cube_info->associate_alpha != MagickFalse)
1120 alpha=(MagickRealType) (QuantumScale*p->alpha);
1121 beta=(MagickRealType) (QuantumScale*q->alpha);
1123 pixel=alpha*p->red-beta*q->red;
1124 distance=pixel*pixel;
1125 if (distance <= cube_info->distance)
1127 pixel=alpha*p->green-beta*q->green;
1128 distance+=pixel*pixel;
1129 if (distance <= cube_info->distance)
1131 pixel=alpha*p->blue-beta*q->blue;
1132 distance+=pixel*pixel;
1133 if (distance <= cube_info->distance)
1136 distance+=pixel*pixel;
1137 if (distance <= cube_info->distance)
1139 cube_info->distance=distance;
1140 cube_info->color_number=node_info->color_number;
1149 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1153 % C o m p r e s s I m a g e C o l o r m a p %
1157 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1159 % CompressImageColormap() compresses an image colormap by removing any
1160 % duplicate or unused color entries.
1162 % The format of the CompressImageColormap method is:
1164 % MagickBooleanType CompressImageColormap(Image *image,
1165 % ExceptionInfo *exception)
1167 % A description of each parameter follows:
1169 % o image: the image.
1171 % o exception: return any errors or warnings in this structure.
1174 MagickExport MagickBooleanType CompressImageColormap(Image *image,
1175 ExceptionInfo *exception)
1180 assert(image != (Image *) NULL);
1181 assert(image->signature == MagickSignature);
1182 if (image->debug != MagickFalse)
1183 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1184 if (IsPaletteImage(image,&image->exception) == MagickFalse)
1185 return(MagickFalse);
1186 GetQuantizeInfo(&quantize_info);
1187 quantize_info.number_colors=image->colors;
1188 quantize_info.tree_depth=MaxTreeDepth;
1189 return(QuantizeImage(&quantize_info,image,exception));
1193 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1197 + D e f i n e I m a g e C o l o r m a p %
1201 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1203 % DefineImageColormap() traverses the color cube tree and notes each colormap
1204 % entry. A colormap entry is any node in the color cube tree where the
1205 % of unique colors is not zero. DefineImageColormap() returns the number of
1206 % colors in the image colormap.
1208 % The format of the DefineImageColormap method is:
1210 % size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1211 % NodeInfo *node_info)
1213 % A description of each parameter follows.
1215 % o image: the image.
1217 % o cube_info: A pointer to the Cube structure.
1219 % o node_info: the address of a structure of type NodeInfo which points to a
1220 % node in the color cube tree that is to be pruned.
1223 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1224 NodeInfo *node_info)
1233 Traverse any children.
1235 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1236 for (i=0; i < (ssize_t) number_children; i++)
1237 if (node_info->child[i] != (NodeInfo *) NULL)
1238 (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1239 if (node_info->number_unique != 0)
1241 register MagickRealType
1244 register PixelPacket
1248 Colormap entry is defined by the mean color in this cube.
1250 q=image->colormap+image->colors;
1251 alpha=(MagickRealType) ((MagickOffsetType) node_info->number_unique);
1252 alpha=1.0/(fabs(alpha) <= MagickEpsilon ? 1.0 : alpha);
1253 if (cube_info->associate_alpha == MagickFalse)
1255 q->red=ClampToQuantum((MagickRealType)
1256 (alpha*QuantumRange*node_info->total_color.red));
1257 q->green=ClampToQuantum((MagickRealType)
1258 (alpha*QuantumRange*node_info->total_color.green));
1259 q->blue=ClampToQuantum((MagickRealType)
1260 (alpha*QuantumRange*node_info->total_color.blue));
1261 q->alpha=OpaqueAlpha;
1268 opacity=(MagickRealType) (alpha*QuantumRange*
1269 node_info->total_color.alpha);
1270 q->alpha=ClampToQuantum(opacity);
1271 if (q->alpha == OpaqueAlpha)
1273 q->red=ClampToQuantum((MagickRealType)
1274 (alpha*QuantumRange*node_info->total_color.red));
1275 q->green=ClampToQuantum((MagickRealType)
1276 (alpha*QuantumRange*node_info->total_color.green));
1277 q->blue=ClampToQuantum((MagickRealType)
1278 (alpha*QuantumRange*node_info->total_color.blue));
1285 gamma=(MagickRealType) (QuantumScale*q->alpha);
1286 gamma=1.0/(fabs(gamma) <= MagickEpsilon ? 1.0 : gamma);
1287 q->red=ClampToQuantum((MagickRealType)
1288 (alpha*gamma*QuantumRange*node_info->total_color.red));
1289 q->green=ClampToQuantum((MagickRealType)
1290 (alpha*gamma*QuantumRange*node_info->total_color.green));
1291 q->blue=ClampToQuantum((MagickRealType)
1292 (alpha*gamma*QuantumRange*node_info->total_color.blue));
1293 if (node_info->number_unique > cube_info->transparent_pixels)
1295 cube_info->transparent_pixels=node_info->number_unique;
1296 cube_info->transparent_index=(ssize_t) image->colors;
1300 node_info->color_number=image->colors++;
1302 return(image->colors);
1306 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1310 + D e s t r o y C u b e I n f o %
1314 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1316 % DestroyCubeInfo() deallocates memory associated with an image.
1318 % The format of the DestroyCubeInfo method is:
1320 % DestroyCubeInfo(CubeInfo *cube_info)
1322 % A description of each parameter follows:
1324 % o cube_info: the address of a structure of type CubeInfo.
1327 static void DestroyCubeInfo(CubeInfo *cube_info)
1333 Release color cube tree storage.
1337 nodes=cube_info->node_queue->next;
1338 cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1339 cube_info->node_queue->nodes);
1340 cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1341 cube_info->node_queue);
1342 cube_info->node_queue=nodes;
1343 } while (cube_info->node_queue != (Nodes *) NULL);
1344 if (cube_info->cache != (ssize_t *) NULL)
1345 cube_info->cache=(ssize_t *) RelinquishMagickMemory(cube_info->cache);
1346 cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1347 cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1351 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1355 % D e s t r o y Q u a n t i z e I n f o %
1359 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1361 % DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1364 % The format of the DestroyQuantizeInfo method is:
1366 % QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1368 % A description of each parameter follows:
1370 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1373 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1375 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1376 assert(quantize_info != (QuantizeInfo *) NULL);
1377 assert(quantize_info->signature == MagickSignature);
1378 quantize_info->signature=(~MagickSignature);
1379 quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1380 return(quantize_info);
1384 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1388 + D i t h e r I m a g e %
1392 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1394 % DitherImage() distributes the difference between an original image and
1395 % the corresponding color reduced algorithm to neighboring pixels using
1396 % serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1397 % MagickTrue if the image is dithered otherwise MagickFalse.
1399 % The format of the DitherImage method is:
1401 % MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1403 % A description of each parameter follows.
1405 % o image: the image.
1407 % o cube_info: A pointer to the Cube structure.
1411 static RealPixelPacket **DestroyPixelThreadSet(RealPixelPacket **pixels)
1416 assert(pixels != (RealPixelPacket **) NULL);
1417 for (i=0; i < (ssize_t) GetOpenMPMaximumThreads(); i++)
1418 if (pixels[i] != (RealPixelPacket *) NULL)
1419 pixels[i]=(RealPixelPacket *) RelinquishMagickMemory(pixels[i]);
1420 pixels=(RealPixelPacket **) RelinquishMagickMemory(pixels);
1424 static RealPixelPacket **AcquirePixelThreadSet(const size_t count)
1435 number_threads=GetOpenMPMaximumThreads();
1436 pixels=(RealPixelPacket **) AcquireQuantumMemory(number_threads,
1438 if (pixels == (RealPixelPacket **) NULL)
1439 return((RealPixelPacket **) NULL);
1440 (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1441 for (i=0; i < (ssize_t) number_threads; i++)
1443 pixels[i]=(RealPixelPacket *) AcquireQuantumMemory(count,
1444 2*sizeof(**pixels));
1445 if (pixels[i] == (RealPixelPacket *) NULL)
1446 return(DestroyPixelThreadSet(pixels));
1451 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1452 const RealPixelPacket *pixel)
1454 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1455 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1456 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1457 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1463 (RedShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red))) |
1464 GreenShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green))) |
1465 BlueShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue))));
1466 if (cube_info->associate_alpha != MagickFalse)
1467 offset|=AlphaShift(ScaleQuantumToChar(ClampToUnsignedQuantum(
1472 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info)
1474 #define DitherImageTag "Dither/Image"
1492 Distribute quantization error using Floyd-Steinberg.
1494 pixels=AcquirePixelThreadSet(image->columns);
1495 if (pixels == (RealPixelPacket **) NULL)
1496 return(MagickFalse);
1497 exception=(&image->exception);
1499 image_view=AcquireCacheView(image);
1500 for (y=0; y < (ssize_t) image->rows; y++)
1503 id = GetOpenMPThreadId();
1524 if (status == MagickFalse)
1526 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1527 if (q == (Quantum *) NULL)
1532 q+=(y & 0x01)*image->columns*GetPixelChannels(image);
1534 current=pixels[id]+(y & 0x01)*image->columns;
1535 previous=pixels[id]+((y+1) & 0x01)*image->columns;
1536 v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1537 for (x=0; x < (ssize_t) image->columns; x++)
1549 q-=(y & 0x01)*GetPixelChannels(image);
1550 u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1551 AssociateAlphaPixel(image,&cube,q,&pixel);
1554 pixel.red+=7*current[u-v].red/16;
1555 pixel.green+=7*current[u-v].green/16;
1556 pixel.blue+=7*current[u-v].blue/16;
1557 if (cube.associate_alpha != MagickFalse)
1558 pixel.alpha+=7*current[u-v].alpha/16;
1562 if (x < (ssize_t) (image->columns-1))
1564 pixel.red+=previous[u+v].red/16;
1565 pixel.green+=previous[u+v].green/16;
1566 pixel.blue+=previous[u+v].blue/16;
1567 if (cube.associate_alpha != MagickFalse)
1568 pixel.alpha+=previous[u+v].alpha/16;
1570 pixel.red+=5*previous[u].red/16;
1571 pixel.green+=5*previous[u].green/16;
1572 pixel.blue+=5*previous[u].blue/16;
1573 if (cube.associate_alpha != MagickFalse)
1574 pixel.alpha+=5*previous[u].alpha/16;
1577 pixel.red+=3*previous[u-v].red/16;
1578 pixel.green+=3*previous[u-v].green/16;
1579 pixel.blue+=3*previous[u-v].blue/16;
1580 if (cube.associate_alpha != MagickFalse)
1581 pixel.alpha+=3*previous[u-v].alpha/16;
1584 pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1585 pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1586 pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1587 if (cube.associate_alpha != MagickFalse)
1588 pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1589 i=CacheOffset(&cube,&pixel);
1590 if (cube.cache[i] < 0)
1599 Identify the deepest node containing the pixel's color.
1601 node_info=cube.root;
1602 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1604 id=ColorToNodeId(&cube,&pixel,index);
1605 if (node_info->child[id] == (NodeInfo *) NULL)
1607 node_info=node_info->child[id];
1610 Find closest color among siblings and their children.
1613 cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*(QuantumRange+
1615 ClosestColor(image,&cube,node_info->parent);
1616 cube.cache[i]=(ssize_t) cube.color_number;
1619 Assign pixel to closest colormap entry.
1621 index=(size_t) cube.cache[i];
1622 if (image->storage_class == PseudoClass)
1623 SetPixelIndex(image,(Quantum) index,q);
1624 if (cube.quantize_info->measure_error == MagickFalse)
1626 SetPixelRed(image,image->colormap[index].red,q);
1627 SetPixelGreen(image,image->colormap[index].green,q);
1628 SetPixelBlue(image,image->colormap[index].blue,q);
1629 if (cube.associate_alpha != MagickFalse)
1630 SetPixelAlpha(image,image->colormap[index].alpha,q);
1632 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1637 AssociateAlphaPixelPacket(image,&cube,image->colormap+index,&color);
1638 current[u].red=pixel.red-color.red;
1639 current[u].green=pixel.green-color.green;
1640 current[u].blue=pixel.blue-color.blue;
1641 if (cube.associate_alpha != MagickFalse)
1642 current[u].alpha=pixel.alpha-color.alpha;
1643 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1648 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1649 #pragma omp critical (MagickCore_FloydSteinbergDither)
1651 proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1653 if (proceed == MagickFalse)
1656 q+=((y+1) & 0x01)*GetPixelChannels(image);
1659 image_view=DestroyCacheView(image_view);
1660 pixels=DestroyPixelThreadSet(pixels);
1664 static MagickBooleanType
1665 RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int);
1667 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1668 const size_t level,const unsigned int direction)
1675 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1676 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1677 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1682 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1683 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1684 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1689 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1690 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1691 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1696 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1697 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1698 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1709 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1710 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1711 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1712 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1713 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1714 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1715 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1720 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1721 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1722 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1723 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1724 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1725 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1726 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1731 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1732 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1733 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1734 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1735 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1736 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1737 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1742 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1743 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1744 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1745 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1746 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1747 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1748 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1756 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1757 CubeInfo *cube_info,const unsigned int direction)
1759 #define DitherImageTag "Dither/Image"
1775 if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1776 (p->y >= 0) && (p->y < (ssize_t) image->rows))
1790 exception=(&image->exception);
1791 q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1792 if (q == (Quantum *) NULL)
1793 return(MagickFalse);
1794 AssociateAlphaPixel(image,cube_info,q,&pixel);
1795 for (i=0; i < ErrorQueueLength; i++)
1797 pixel.red+=p->weights[i]*p->error[i].red;
1798 pixel.green+=p->weights[i]*p->error[i].green;
1799 pixel.blue+=p->weights[i]*p->error[i].blue;
1800 if (cube_info->associate_alpha != MagickFalse)
1801 pixel.alpha+=p->weights[i]*p->error[i].alpha;
1803 pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1804 pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1805 pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1806 if (cube_info->associate_alpha != MagickFalse)
1807 pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1808 i=CacheOffset(cube_info,&pixel);
1809 if (p->cache[i] < 0)
1818 Identify the deepest node containing the pixel's color.
1821 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1823 id=ColorToNodeId(cube_info,&pixel,index);
1824 if (node_info->child[id] == (NodeInfo *) NULL)
1826 node_info=node_info->child[id];
1828 node_info=node_info->parent;
1830 Find closest color among siblings and their children.
1833 p->distance=(MagickRealType) (4.0*(QuantumRange+1.0)*((MagickRealType)
1834 QuantumRange+1.0)+1.0);
1835 ClosestColor(image,p,node_info->parent);
1836 p->cache[i]=(ssize_t) p->color_number;
1839 Assign pixel to closest colormap entry.
1841 index=(size_t) p->cache[i];
1842 if (image->storage_class == PseudoClass)
1843 SetPixelIndex(image,(Quantum) index,q);
1844 if (cube_info->quantize_info->measure_error == MagickFalse)
1846 SetPixelRed(image,image->colormap[index].red,q);
1847 SetPixelGreen(image,image->colormap[index].green,q);
1848 SetPixelBlue(image,image->colormap[index].blue,q);
1849 if (cube_info->associate_alpha != MagickFalse)
1850 SetPixelAlpha(image,image->colormap[index].alpha,q);
1852 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1853 return(MagickFalse);
1855 Propagate the error as the last entry of the error queue.
1857 (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1858 sizeof(p->error[0]));
1859 AssociateAlphaPixelPacket(image,cube_info,image->colormap+index,&color);
1860 p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1861 p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1862 p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1863 if (cube_info->associate_alpha != MagickFalse)
1864 p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1865 proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1866 if (proceed == MagickFalse)
1867 return(MagickFalse);
1872 case WestGravity: p->x--; break;
1873 case EastGravity: p->x++; break;
1874 case NorthGravity: p->y--; break;
1875 case SouthGravity: p->y++; break;
1880 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1887 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1894 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1908 if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1909 return(FloydSteinbergDither(image,cube_info));
1911 Distribute quantization error along a Hilbert curve.
1913 (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1914 sizeof(*cube_info->error));
1917 i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1918 for (depth=1; i != 0; depth++)
1920 if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1922 cube_info->offset=0;
1923 cube_info->span=(MagickSizeType) image->columns*image->rows;
1924 image_view=AcquireCacheView(image);
1926 Riemersma(image,image_view,cube_info,depth-1,NorthGravity);
1927 status=RiemersmaDither(image,image_view,cube_info,ForgetGravity);
1928 image_view=DestroyCacheView(image_view);
1933 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1937 + G e t C u b e I n f o %
1941 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1943 % GetCubeInfo() initialize the Cube data structure.
1945 % The format of the GetCubeInfo method is:
1947 % CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1948 % const size_t depth,const size_t maximum_colors)
1950 % A description of each parameter follows.
1952 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1954 % o depth: Normally, this integer value is zero or one. A zero or
1955 % one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1956 % A tree of this depth generally allows the best representation of the
1957 % reference image with the least amount of memory and the fastest
1958 % computational speed. In some cases, such as an image with low color
1959 % dispersion (a few number of colors), a value other than
1960 % Log4(number_colors) is required. To expand the color tree completely,
1963 % o maximum_colors: maximum colors.
1966 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
1967 const size_t depth,const size_t maximum_colors)
1983 Initialize tree to describe color cube_info.
1985 cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
1986 if (cube_info == (CubeInfo *) NULL)
1987 return((CubeInfo *) NULL);
1988 (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
1989 cube_info->depth=depth;
1990 if (cube_info->depth > MaxTreeDepth)
1991 cube_info->depth=MaxTreeDepth;
1992 if (cube_info->depth < 2)
1994 cube_info->maximum_colors=maximum_colors;
1996 Initialize root node.
1998 cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
1999 if (cube_info->root == (NodeInfo *) NULL)
2000 return((CubeInfo *) NULL);
2001 cube_info->root->parent=cube_info->root;
2002 cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
2003 if (cube_info->quantize_info->dither == MagickFalse)
2006 Initialize dither resources.
2008 length=(size_t) (1UL << (4*(8-CacheShift)));
2009 cube_info->cache=(ssize_t *) AcquireQuantumMemory(length,
2010 sizeof(*cube_info->cache));
2011 if (cube_info->cache == (ssize_t *) NULL)
2012 return((CubeInfo *) NULL);
2014 Initialize color cache.
2016 for (i=0; i < (ssize_t) length; i++)
2017 cube_info->cache[i]=(-1);
2019 Distribute weights along a curve of exponential decay.
2022 for (i=0; i < ErrorQueueLength; i++)
2024 cube_info->weights[ErrorQueueLength-i-1]=1.0/weight;
2025 weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2028 Normalize the weighting factors.
2031 for (i=0; i < ErrorQueueLength; i++)
2032 weight+=cube_info->weights[i];
2034 for (i=0; i < ErrorQueueLength; i++)
2036 cube_info->weights[i]/=weight;
2037 sum+=cube_info->weights[i];
2039 cube_info->weights[0]+=1.0-sum;
2044 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2048 + G e t N o d e I n f o %
2052 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2054 % GetNodeInfo() allocates memory for a new node in the color cube tree and
2055 % presets all fields to zero.
2057 % The format of the GetNodeInfo method is:
2059 % NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2060 % const size_t level,NodeInfo *parent)
2062 % A description of each parameter follows.
2064 % o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2066 % o id: Specifies the child number of the node.
2068 % o level: Specifies the level in the storage_class the node resides.
2071 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2072 const size_t level,NodeInfo *parent)
2077 if (cube_info->free_nodes == 0)
2083 Allocate a new queue of nodes.
2085 nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2086 if (nodes == (Nodes *) NULL)
2087 return((NodeInfo *) NULL);
2088 nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2089 sizeof(*nodes->nodes));
2090 if (nodes->nodes == (NodeInfo *) NULL)
2091 return((NodeInfo *) NULL);
2092 nodes->next=cube_info->node_queue;
2093 cube_info->node_queue=nodes;
2094 cube_info->next_node=nodes->nodes;
2095 cube_info->free_nodes=NodesInAList;
2098 cube_info->free_nodes--;
2099 node_info=cube_info->next_node++;
2100 (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2101 node_info->parent=parent;
2103 node_info->level=level;
2108 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2112 % G e t I m a g e Q u a n t i z e E r r o r %
2116 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2118 % GetImageQuantizeError() measures the difference between the original
2119 % and quantized images. This difference is the total quantization error.
2120 % The error is computed by summing over all pixels in an image the distance
2121 % squared in RGB space between each reference pixel value and its quantized
2122 % value. These values are computed:
2124 % o mean_error_per_pixel: This value is the mean error for any single
2125 % pixel in the image.
2127 % o normalized_mean_square_error: This value is the normalized mean
2128 % quantization error for any single pixel in the image. This distance
2129 % measure is normalized to a range between 0 and 1. It is independent
2130 % of the range of red, green, and blue values in the image.
2132 % o normalized_maximum_square_error: Thsi value is the normalized
2133 % maximum quantization error for any single pixel in the image. This
2134 % distance measure is normalized to a range between 0 and 1. It is
2135 % independent of the range of red, green, and blue values in your image.
2137 % The format of the GetImageQuantizeError method is:
2139 % MagickBooleanType GetImageQuantizeError(Image *image)
2141 % A description of each parameter follows.
2143 % o image: the image.
2146 MagickExport MagickBooleanType GetImageQuantizeError(Image *image)
2161 mean_error_per_pixel;
2169 assert(image != (Image *) NULL);
2170 assert(image->signature == MagickSignature);
2171 if (image->debug != MagickFalse)
2172 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2173 image->total_colors=GetNumberColors(image,(FILE *) NULL,&image->exception);
2174 (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2175 if (image->storage_class == DirectClass)
2179 area=3.0*image->columns*image->rows;
2181 mean_error_per_pixel=0.0;
2183 exception=(&image->exception);
2184 image_view=AcquireCacheView(image);
2185 for (y=0; y < (ssize_t) image->rows; y++)
2187 register const Quantum
2193 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2194 if (p == (const Quantum *) NULL)
2196 for (x=0; x < (ssize_t) image->columns; x++)
2198 index=1UL*GetPixelIndex(image,p);
2199 if (image->matte != MagickFalse)
2201 alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,p));
2202 beta=(MagickRealType) (QuantumScale*image->colormap[index].alpha);
2204 distance=fabs(alpha*GetPixelRed(image,p)-beta*
2205 image->colormap[index].red);
2206 mean_error_per_pixel+=distance;
2207 mean_error+=distance*distance;
2208 if (distance > maximum_error)
2209 maximum_error=distance;
2210 distance=fabs(alpha*GetPixelGreen(image,p)-beta*
2211 image->colormap[index].green);
2212 mean_error_per_pixel+=distance;
2213 mean_error+=distance*distance;
2214 if (distance > maximum_error)
2215 maximum_error=distance;
2216 distance=fabs(alpha*GetPixelBlue(image,p)-beta*
2217 image->colormap[index].blue);
2218 mean_error_per_pixel+=distance;
2219 mean_error+=distance*distance;
2220 if (distance > maximum_error)
2221 maximum_error=distance;
2222 p+=GetPixelChannels(image);
2225 image_view=DestroyCacheView(image_view);
2226 image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2227 image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2229 image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2234 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2238 % G e t Q u a n t i z e I n f o %
2242 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2244 % GetQuantizeInfo() initializes the QuantizeInfo structure.
2246 % The format of the GetQuantizeInfo method is:
2248 % GetQuantizeInfo(QuantizeInfo *quantize_info)
2250 % A description of each parameter follows:
2252 % o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2255 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2257 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2258 assert(quantize_info != (QuantizeInfo *) NULL);
2259 (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2260 quantize_info->number_colors=256;
2261 quantize_info->dither=MagickTrue;
2262 quantize_info->dither_method=RiemersmaDitherMethod;
2263 quantize_info->colorspace=UndefinedColorspace;
2264 quantize_info->measure_error=MagickFalse;
2265 quantize_info->signature=MagickSignature;
2269 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2273 % P o s t e r i z e I m a g e %
2277 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2279 % PosterizeImage() reduces the image to a limited number of colors for a
2282 % The format of the PosterizeImage method is:
2284 % MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2285 % const MagickBooleanType dither,ExceptionInfo *exception)
2287 % A description of each parameter follows:
2289 % o image: Specifies a pointer to an Image structure.
2291 % o levels: Number of color levels allowed in each channel. Very low values
2292 % (2, 3, or 4) have the most visible effect.
2294 % o dither: Set this integer value to something other than zero to dither
2297 % o exception: return any errors or warnings in this structure.
2301 static inline ssize_t MagickRound(MagickRealType x)
2304 Round the fraction to nearest integer.
2307 return((ssize_t) (x+0.5));
2308 return((ssize_t) (x-0.5));
2311 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2312 const MagickBooleanType dither,ExceptionInfo *exception)
2314 #define PosterizeImageTag "Posterize/Image"
2315 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2316 QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2336 assert(image != (Image *) NULL);
2337 assert(image->signature == MagickSignature);
2338 if (image->debug != MagickFalse)
2339 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2340 if (image->storage_class == PseudoClass)
2341 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2342 #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2344 for (i=0; i < (ssize_t) image->colors; i++)
2349 if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2350 image->colormap[i].red=PosterizePixel(image->colormap[i].red);
2351 if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2352 image->colormap[i].green=PosterizePixel(image->colormap[i].green);
2353 if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2354 image->colormap[i].blue=PosterizePixel(image->colormap[i].blue);
2355 if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
2356 image->colormap[i].alpha=PosterizePixel(image->colormap[i].alpha);
2363 image_view=AcquireCacheView(image);
2364 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2365 #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2367 for (y=0; y < (ssize_t) image->rows; y++)
2375 if (status == MagickFalse)
2377 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2378 if (q == (Quantum *) NULL)
2383 for (x=0; x < (ssize_t) image->columns; x++)
2385 if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2386 SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2387 if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2388 SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2389 if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2390 SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2391 if (((GetPixelBlackTraits(image) & UpdatePixelTrait) != 0) &&
2392 (image->colorspace == CMYKColorspace))
2393 SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2394 if (((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0) &&
2395 (image->matte == MagickTrue))
2396 SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2397 q+=GetPixelChannels(image);
2399 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2401 if (image->progress_monitor != (MagickProgressMonitor) NULL)
2406 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2407 #pragma omp critical (MagickCore_PosterizeImage)
2409 proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2411 if (proceed == MagickFalse)
2415 image_view=DestroyCacheView(image_view);
2416 quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2417 quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2418 levels,MaxColormapSize+1);
2419 quantize_info->dither=dither;
2420 quantize_info->tree_depth=MaxTreeDepth;
2421 status=QuantizeImage(quantize_info,image,exception);
2422 quantize_info=DestroyQuantizeInfo(quantize_info);
2427 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2431 + P r u n e C h i l d %
2435 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2437 % PruneChild() deletes the given node and merges its statistics into its
2440 % The format of the PruneSubtree method is:
2442 % PruneChild(const Image *image,CubeInfo *cube_info,
2443 % const NodeInfo *node_info)
2445 % A description of each parameter follows.
2447 % o image: the image.
2449 % o cube_info: A pointer to the Cube structure.
2451 % o node_info: pointer to node in color cube tree that is to be pruned.
2454 static void PruneChild(const Image *image,CubeInfo *cube_info,
2455 const NodeInfo *node_info)
2467 Traverse any children.
2469 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2470 for (i=0; i < (ssize_t) number_children; i++)
2471 if (node_info->child[i] != (NodeInfo *) NULL)
2472 PruneChild(image,cube_info,node_info->child[i]);
2474 Merge color statistics into parent.
2476 parent=node_info->parent;
2477 parent->number_unique+=node_info->number_unique;
2478 parent->total_color.red+=node_info->total_color.red;
2479 parent->total_color.green+=node_info->total_color.green;
2480 parent->total_color.blue+=node_info->total_color.blue;
2481 parent->total_color.alpha+=node_info->total_color.alpha;
2482 parent->child[node_info->id]=(NodeInfo *) NULL;
2487 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2491 + P r u n e L e v e l %
2495 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2497 % PruneLevel() deletes all nodes at the bottom level of the color tree merging
2498 % their color statistics into their parent node.
2500 % The format of the PruneLevel method is:
2502 % PruneLevel(const Image *image,CubeInfo *cube_info,
2503 % const NodeInfo *node_info)
2505 % A description of each parameter follows.
2507 % o image: the image.
2509 % o cube_info: A pointer to the Cube structure.
2511 % o node_info: pointer to node in color cube tree that is to be pruned.
2514 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2515 const NodeInfo *node_info)
2524 Traverse any children.
2526 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2527 for (i=0; i < (ssize_t) number_children; i++)
2528 if (node_info->child[i] != (NodeInfo *) NULL)
2529 PruneLevel(image,cube_info,node_info->child[i]);
2530 if (node_info->level == cube_info->depth)
2531 PruneChild(image,cube_info,node_info);
2535 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2539 + P r u n e T o C u b e D e p t h %
2543 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2545 % PruneToCubeDepth() deletes any nodes at a depth greater than
2546 % cube_info->depth while merging their color statistics into their parent
2549 % The format of the PruneToCubeDepth method is:
2551 % PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2552 % const NodeInfo *node_info)
2554 % A description of each parameter follows.
2556 % o cube_info: A pointer to the Cube structure.
2558 % o node_info: pointer to node in color cube tree that is to be pruned.
2561 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2562 const NodeInfo *node_info)
2571 Traverse any children.
2573 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2574 for (i=0; i < (ssize_t) number_children; i++)
2575 if (node_info->child[i] != (NodeInfo *) NULL)
2576 PruneToCubeDepth(image,cube_info,node_info->child[i]);
2577 if (node_info->level > cube_info->depth)
2578 PruneChild(image,cube_info,node_info);
2582 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2586 % Q u a n t i z e I m a g e %
2590 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2592 % QuantizeImage() analyzes the colors within a reference image and chooses a
2593 % fixed number of colors to represent the image. The goal of the algorithm
2594 % is to minimize the color difference between the input and output image while
2595 % minimizing the processing time.
2597 % The format of the QuantizeImage method is:
2599 % MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2600 % Image *image,ExceptionInfo *exception)
2602 % A description of each parameter follows:
2604 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2606 % o image: the image.
2608 % o exception: return any errors or warnings in this structure.
2612 static MagickBooleanType DirectToColormapImage(Image *image,
2613 ExceptionInfo *exception)
2631 number_colors=(size_t) (image->columns*image->rows);
2632 if (AcquireImageColormap(image,number_colors,exception) == MagickFalse)
2633 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2635 if (image->colors != number_colors)
2636 return(MagickFalse);
2638 image_view=AcquireCacheView(image);
2639 for (y=0; y < (ssize_t) image->rows; y++)
2650 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2651 if (q == (Quantum *) NULL)
2653 for (x=0; x < (ssize_t) image->columns; x++)
2655 image->colormap[i].red=GetPixelRed(image,q);
2656 image->colormap[i].green=GetPixelGreen(image,q);
2657 image->colormap[i].blue=GetPixelBlue(image,q);
2658 image->colormap[i].alpha=GetPixelAlpha(image,q);
2659 SetPixelIndex(image,(Quantum) i,q);
2661 q+=GetPixelChannels(image);
2663 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2665 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
2667 if (proceed == MagickFalse)
2670 image_view=DestroyCacheView(image_view);
2674 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2675 Image *image,ExceptionInfo *exception)
2687 assert(quantize_info != (const QuantizeInfo *) NULL);
2688 assert(quantize_info->signature == MagickSignature);
2689 assert(image != (Image *) NULL);
2690 assert(image->signature == MagickSignature);
2691 if (image->debug != MagickFalse)
2692 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2693 maximum_colors=quantize_info->number_colors;
2694 if (maximum_colors == 0)
2695 maximum_colors=MaxColormapSize;
2696 if (maximum_colors > MaxColormapSize)
2697 maximum_colors=MaxColormapSize;
2698 if ((image->columns*image->rows) <= maximum_colors)
2699 (void) DirectToColormapImage(image,&image->exception);
2700 if ((IsImageGray(image,&image->exception) != MagickFalse) &&
2701 (image->matte == MagickFalse))
2702 (void) SetGrayscaleImage(image,exception);
2703 if ((image->storage_class == PseudoClass) &&
2704 (image->colors <= maximum_colors))
2706 depth=quantize_info->tree_depth;
2713 Depth of color tree is: Log4(colormap size)+2.
2715 colors=maximum_colors;
2716 for (depth=1; colors != 0; depth++)
2718 if ((quantize_info->dither != MagickFalse) && (depth > 2))
2720 if ((image->matte != MagickFalse) && (depth > 5))
2724 Initialize color cube.
2726 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2727 if (cube_info == (CubeInfo *) NULL)
2728 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2730 status=ClassifyImageColors(cube_info,image,&image->exception);
2731 if (status != MagickFalse)
2734 Reduce the number of colors in the image.
2736 ReduceImageColors(image,cube_info);
2737 status=AssignImageColors(image,cube_info,exception);
2739 DestroyCubeInfo(cube_info);
2744 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2748 % Q u a n t i z e I m a g e s %
2752 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2754 % QuantizeImages() analyzes the colors within a set of reference images and
2755 % chooses a fixed number of colors to represent the set. The goal of the
2756 % algorithm is to minimize the color difference between the input and output
2757 % images while minimizing the processing time.
2759 % The format of the QuantizeImages method is:
2761 % MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2762 % Image *images,ExceptionInfo *exception)
2764 % A description of each parameter follows:
2766 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2768 % o images: Specifies a pointer to a list of Image structures.
2770 % o exception: return any errors or warnings in this structure.
2773 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2774 Image *images,ExceptionInfo *exception)
2786 MagickProgressMonitor
2797 assert(quantize_info != (const QuantizeInfo *) NULL);
2798 assert(quantize_info->signature == MagickSignature);
2799 assert(images != (Image *) NULL);
2800 assert(images->signature == MagickSignature);
2801 if (images->debug != MagickFalse)
2802 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2803 if (GetNextImageInList(images) == (Image *) NULL)
2806 Handle a single image with QuantizeImage.
2808 status=QuantizeImage(quantize_info,images,exception);
2812 maximum_colors=quantize_info->number_colors;
2813 if (maximum_colors == 0)
2814 maximum_colors=MaxColormapSize;
2815 if (maximum_colors > MaxColormapSize)
2816 maximum_colors=MaxColormapSize;
2817 depth=quantize_info->tree_depth;
2824 Depth of color tree is: Log4(colormap size)+2.
2826 colors=maximum_colors;
2827 for (depth=1; colors != 0; depth++)
2829 if (quantize_info->dither != MagickFalse)
2833 Initialize color cube.
2835 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2836 if (cube_info == (CubeInfo *) NULL)
2838 (void) ThrowMagickException(&images->exception,GetMagickModule(),
2839 ResourceLimitError,"MemoryAllocationFailed","`%s'",images->filename);
2840 return(MagickFalse);
2842 number_images=GetImageListLength(images);
2844 for (i=0; image != (Image *) NULL; i++)
2846 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2847 image->client_data);
2848 status=ClassifyImageColors(cube_info,image,&image->exception);
2849 if (status == MagickFalse)
2851 (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2852 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2854 if (proceed == MagickFalse)
2856 image=GetNextImageInList(image);
2858 if (status != MagickFalse)
2861 Reduce the number of colors in an image sequence.
2863 ReduceImageColors(images,cube_info);
2865 for (i=0; image != (Image *) NULL; i++)
2867 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2868 NULL,image->client_data);
2869 status=AssignImageColors(image,cube_info,exception);
2870 if (status == MagickFalse)
2872 (void) SetImageProgressMonitor(image,progress_monitor,
2873 image->client_data);
2874 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2876 if (proceed == MagickFalse)
2878 image=GetNextImageInList(image);
2881 DestroyCubeInfo(cube_info);
2886 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2894 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2896 % Reduce() traverses the color cube tree and prunes any node whose
2897 % quantization error falls below a particular threshold.
2899 % The format of the Reduce method is:
2901 % Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2903 % A description of each parameter follows.
2905 % o image: the image.
2907 % o cube_info: A pointer to the Cube structure.
2909 % o node_info: pointer to node in color cube tree that is to be pruned.
2912 static void Reduce(const Image *image,CubeInfo *cube_info,
2913 const NodeInfo *node_info)
2922 Traverse any children.
2924 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2925 for (i=0; i < (ssize_t) number_children; i++)
2926 if (node_info->child[i] != (NodeInfo *) NULL)
2927 Reduce(image,cube_info,node_info->child[i]);
2928 if (node_info->quantize_error <= cube_info->pruning_threshold)
2929 PruneChild(image,cube_info,node_info);
2933 Find minimum pruning threshold.
2935 if (node_info->number_unique > 0)
2936 cube_info->colors++;
2937 if (node_info->quantize_error < cube_info->next_threshold)
2938 cube_info->next_threshold=node_info->quantize_error;
2943 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2947 + R e d u c e I m a g e C o l o r s %
2951 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2953 % ReduceImageColors() repeatedly prunes the tree until the number of nodes
2954 % with n2 > 0 is less than or equal to the maximum number of colors allowed
2955 % in the output image. On any given iteration over the tree, it selects
2956 % those nodes whose E value is minimal for pruning and merges their
2957 % color statistics upward. It uses a pruning threshold, Ep, to govern
2958 % node selection as follows:
2961 % while number of nodes with (n2 > 0) > required maximum number of colors
2962 % prune all nodes such that E <= Ep
2963 % Set Ep to minimum E in remaining nodes
2965 % This has the effect of minimizing any quantization error when merging
2966 % two nodes together.
2968 % When a node to be pruned has offspring, the pruning procedure invokes
2969 % itself recursively in order to prune the tree from the leaves upward.
2970 % n2, Sr, Sg, and Sb in a node being pruned are always added to the
2971 % corresponding data in that node's parent. This retains the pruned
2972 % node's color characteristics for later averaging.
2974 % For each node, n2 pixels exist for which that node represents the
2975 % smallest volume in RGB space containing those pixel's colors. When n2
2976 % > 0 the node will uniquely define a color in the output image. At the
2977 % beginning of reduction, n2 = 0 for all nodes except a the leaves of
2978 % the tree which represent colors present in the input image.
2980 % The other pixel count, n1, indicates the total number of colors
2981 % within the cubic volume which the node represents. This includes n1 -
2982 % n2 pixels whose colors should be defined by nodes at a lower level in
2985 % The format of the ReduceImageColors method is:
2987 % ReduceImageColors(const Image *image,CubeInfo *cube_info)
2989 % A description of each parameter follows.
2991 % o image: the image.
2993 % o cube_info: A pointer to the Cube structure.
2996 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
2998 #define ReduceImageTag "Reduce/Image"
3009 cube_info->next_threshold=0.0;
3010 for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
3012 cube_info->pruning_threshold=cube_info->next_threshold;
3013 cube_info->next_threshold=cube_info->root->quantize_error-1;
3014 cube_info->colors=0;
3015 Reduce(image,cube_info,cube_info->root);
3016 offset=(MagickOffsetType) span-cube_info->colors;
3017 proceed=SetImageProgress(image,ReduceImageTag,offset,span-
3018 cube_info->maximum_colors+1);
3019 if (proceed == MagickFalse)
3025 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3029 % R e m a p I m a g e %
3033 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3035 % RemapImage() replaces the colors of an image with the closest color from
3036 % a reference image.
3038 % The format of the RemapImage method is:
3040 % MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3041 % Image *image,const Image *remap_image,ExceptionInfo *exception)
3043 % A description of each parameter follows:
3045 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3047 % o image: the image.
3049 % o remap_image: the reference image.
3051 % o exception: return any errors or warnings in this structure.
3054 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3055 Image *image,const Image *remap_image,ExceptionInfo *exception)
3064 Initialize color cube.
3066 assert(image != (Image *) NULL);
3067 assert(image->signature == MagickSignature);
3068 if (image->debug != MagickFalse)
3069 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3070 assert(remap_image != (Image *) NULL);
3071 assert(remap_image->signature == MagickSignature);
3072 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3073 quantize_info->number_colors);
3074 if (cube_info == (CubeInfo *) NULL)
3075 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3077 status=ClassifyImageColors(cube_info,remap_image,&image->exception);
3078 if (status != MagickFalse)
3081 Classify image colors from the reference image.
3083 cube_info->quantize_info->number_colors=cube_info->colors;
3084 status=AssignImageColors(image,cube_info,exception);
3086 DestroyCubeInfo(cube_info);
3091 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3095 % R e m a p I m a g e s %
3099 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3101 % RemapImages() replaces the colors of a sequence of images with the
3102 % closest color from a reference image.
3104 % The format of the RemapImage method is:
3106 % MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3107 % Image *images,Image *remap_image,ExceptionInfo *exception)
3109 % A description of each parameter follows:
3111 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3113 % o images: the image sequence.
3115 % o remap_image: the reference image.
3117 % o exception: return any errors or warnings in this structure.
3120 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3121 Image *images,const Image *remap_image,ExceptionInfo *exception)
3132 assert(images != (Image *) NULL);
3133 assert(images->signature == MagickSignature);
3134 if (images->debug != MagickFalse)
3135 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3137 if (remap_image == (Image *) NULL)
3140 Create a global colormap for an image sequence.
3142 status=QuantizeImages(quantize_info,images,exception);
3146 Classify image colors from the reference image.
3148 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3149 quantize_info->number_colors);
3150 if (cube_info == (CubeInfo *) NULL)
3151 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3153 status=ClassifyImageColors(cube_info,remap_image,exception);
3154 if (status != MagickFalse)
3157 Classify image colors from the reference image.
3159 cube_info->quantize_info->number_colors=cube_info->colors;
3161 for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3163 status=AssignImageColors(image,cube_info,exception);
3164 if (status == MagickFalse)
3168 DestroyCubeInfo(cube_info);
3173 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3177 % S e t G r a y s c a l e I m a g e %
3181 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3183 % SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3185 % The format of the SetGrayscaleImage method is:
3187 % MagickBooleanType SetGrayscaleImage(Image *image,ExceptionInfo *exeption)
3189 % A description of each parameter follows:
3191 % o image: The image.
3193 % o exception: return any errors or warnings in this structure.
3197 #if defined(__cplusplus) || defined(c_plusplus)
3201 static int IntensityCompare(const void *x,const void *y)
3210 color_1=(PixelPacket *) x;
3211 color_2=(PixelPacket *) y;
3212 intensity=GetPixelPacketIntensity(color_1)-(ssize_t)
3213 GetPixelPacketIntensity(color_2);
3214 return((int) intensity);
3217 #if defined(__cplusplus) || defined(c_plusplus)
3221 static MagickBooleanType SetGrayscaleImage(Image *image,
3222 ExceptionInfo *exception)
3241 assert(image != (Image *) NULL);
3242 assert(image->signature == MagickSignature);
3243 if (image->type != GrayscaleType)
3244 (void) TransformImageColorspace(image,GRAYColorspace);
3245 colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3246 sizeof(*colormap_index));
3247 if (colormap_index == (ssize_t *) NULL)
3248 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3250 if (image->storage_class != PseudoClass)
3252 for (i=0; i <= (ssize_t) MaxMap; i++)
3253 colormap_index[i]=(-1);
3254 if (AcquireImageColormap(image,MaxMap+1,exception) == MagickFalse)
3255 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3259 image_view=AcquireCacheView(image);
3260 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3261 #pragma omp parallel for schedule(dynamic,4) shared(status)
3263 for (y=0; y < (ssize_t) image->rows; y++)
3271 if (status == MagickFalse)
3273 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3275 if (q == (Quantum *) NULL)
3280 for (x=0; x < (ssize_t) image->columns; x++)
3285 intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3286 if (colormap_index[intensity] < 0)
3288 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3289 #pragma omp critical (MagickCore_SetGrayscaleImage)
3291 if (colormap_index[intensity] < 0)
3293 colormap_index[intensity]=(ssize_t) image->colors;
3294 image->colormap[image->colors].red=GetPixelRed(image,q);
3295 image->colormap[image->colors].green=GetPixelGreen(image,q);
3296 image->colormap[image->colors].blue=GetPixelBlue(image,q);
3300 SetPixelIndex(image,(Quantum)
3301 colormap_index[intensity],q);
3302 q+=GetPixelChannels(image);
3304 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3307 image_view=DestroyCacheView(image_view);
3309 for (i=0; i < (ssize_t) image->colors; i++)
3310 image->colormap[i].alpha=(unsigned short) i;
3311 qsort((void *) image->colormap,image->colors,sizeof(PixelPacket),
3313 colormap=(PixelPacket *) AcquireQuantumMemory(image->colors,
3315 if (colormap == (PixelPacket *) NULL)
3316 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3319 colormap[j]=image->colormap[0];
3320 for (i=0; i < (ssize_t) image->colors; i++)
3322 if (IsPixelPacketEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3325 colormap[j]=image->colormap[i];
3327 colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3329 image->colors=(size_t) (j+1);
3330 image->colormap=(PixelPacket *) RelinquishMagickMemory(image->colormap);
3331 image->colormap=colormap;
3333 image_view=AcquireCacheView(image);
3334 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3335 #pragma omp parallel for schedule(dynamic,4) shared(status)
3337 for (y=0; y < (ssize_t) image->rows; y++)
3345 if (status == MagickFalse)
3347 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3348 if (q == (Quantum *) NULL)
3353 for (x=0; x < (ssize_t) image->columns; x++)
3355 SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3356 GetPixelIndex(image,q))],q);
3357 q+=GetPixelChannels(image);
3359 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3362 image_view=DestroyCacheView(image_view);
3363 colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3364 image->type=GrayscaleType;
3365 if (IsImageMonochrome(image,&image->exception) != MagickFalse)
3366 image->type=BilevelType;