granicus.if.org Git - imagemagick/blob - MagickCore/quantize.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %           QQQ   U   U   AAA   N   N  TTTTT  IIIII   ZZZZZ  EEEEE            %
   7 %          Q   Q  U   U  A   A  NN  N    T      I        ZZ  E                %
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   9 %          Q  QQ  U   U  A   A  N  NN    T      I     ZZ     E                %
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  11 %                                                                             %
  12 %                                                                             %
  13 %    MagickCore Methods to Reduce the Number of Unique Colors in an Image     %
  14 %                                                                             %
  15 %                           Software Design                                   %
  16 %                             John Cristy                                     %
  17 %                              July 1992                                      %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2011 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  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.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  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.
  43 %
  44 %  A reduction of colors in an image is also desirable for image
  45 %  transmission and real-time animation.
  46 %
  47 %  QuantizeImage() takes a standard RGB or monochrome images and quantizes
  48 %  them down to some fixed number of colors.
  49 %
  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).
  54 %
  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 =
  60 %  255.
  61 %
  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
  66 %  the origin.
  67 %
  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.
  73 %
  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).
  82 %
  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 +
  91 %  sum(i=1, k, 8k).
  92 %
  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)).
  98 %
  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
 103 %  such node:
 104 %
 105 %    n1: Number of pixels whose color is contained in the RGB cube which
 106 %    this node represents;
 107 %
 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.
 111 %
 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.
 116 %
 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.
 120 %
 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:
 127 %
 128 %    Ep = 0
 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
 132 %
 133 %  This has the effect of minimizing any quantization error when merging
 134 %  two nodes together.
 135 %
 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.
 141 %
 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.
 147 %
 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
 151 %  tree.
 152 %
 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.
 158 %
 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.
 164 %
 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.
 169 %
 170 %  This method is based on a similar algorithm written by Paul Raveling.
 171 %
 172 */
 173 \f
 174 /*
 175   Include declarations.
 176 */
 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"
 202 \f
 203 /*
 204   Define declarations.
 205 */
 206 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
 207 #define CacheShift  2
 208 #else
 209 #define CacheShift  3
 210 #endif
 211 #define ErrorQueueLength  16
 212 #define MaxNodes  266817
 213 #define MaxTreeDepth  8
 214 #define NodesInAList  1920
 215 \f
 216 /*
 217   Typdef declarations.
 218 */
 219 typedef struct _RealPixelPacket
 220 {
 221   MagickRealType
 222     red,
 223     green,
 224     blue,
 225     alpha;
 226 } RealPixelPacket;
 227
 228 typedef struct _NodeInfo
 229 {
 230   struct _NodeInfo
 231     *parent,
 232     *child[16];
 233
 234   MagickSizeType
 235     number_unique;
 236
 237   RealPixelPacket
 238     total_color;
 239
 240   MagickRealType
 241     quantize_error;
 242
 243   size_t
 244     color_number,
 245     id,
 246     level;
 247 } NodeInfo;
 248
 249 typedef struct _Nodes
 250 {
 251   NodeInfo
 252     *nodes;
 253
 254   struct _Nodes
 255     *next;
 256 } Nodes;
 257
 258 typedef struct _CubeInfo
 259 {
 260   NodeInfo
 261     *root;
 262
 263   size_t
 264     colors,
 265     maximum_colors;
 266
 267   ssize_t
 268     transparent_index;
 269
 270   MagickSizeType
 271     transparent_pixels;
 272
 273   RealPixelPacket
 274     target;
 275
 276   MagickRealType
 277     distance,
 278     pruning_threshold,
 279     next_threshold;
 280
 281   size_t
 282     nodes,
 283     free_nodes,
 284     color_number;
 285
 286   NodeInfo
 287     *next_node;
 288
 289   Nodes
 290     *node_queue;
 291
 292   ssize_t
 293     *cache;
 294
 295   RealPixelPacket
 296     error[ErrorQueueLength];
 297
 298   MagickRealType
 299     weights[ErrorQueueLength];
 300
 301   QuantizeInfo
 302     *quantize_info;
 303
 304   MagickBooleanType
 305     associate_alpha;
 306
 307   ssize_t
 308     x,
 309     y;
 310
 311   size_t
 312     depth;
 313
 314   MagickOffsetType
 315     offset;
 316
 317   MagickSizeType
 318     span;
 319 } CubeInfo;
 320 \f
 321 /*
 322   Method prototypes.
 323 */
 324 static CubeInfo
 325   *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
 326
 327 static NodeInfo
 328   *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
 329
 330 static MagickBooleanType
 331   AssignImageColors(Image *,CubeInfo *),
 332   ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
 333   DitherImage(Image *,CubeInfo *),
 334   SetGrayscaleImage(Image *);
 335
 336 static size_t
 337   DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
 338
 339 static void
 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 *);
 345 \f
 346 /*
 347 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 348 %                                                                             %
 349 %                                                                             %
 350 %                                                                             %
 351 %   A c q u i r e Q u a n t i z e I n f o                                     %
 352 %                                                                             %
 353 %                                                                             %
 354 %                                                                             %
 355 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 356 %
 357 %  AcquireQuantizeInfo() allocates the QuantizeInfo structure.
 358 %
 359 %  The format of the AcquireQuantizeInfo method is:
 360 %
 361 %      QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 362 %
 363 %  A description of each parameter follows:
 364 %
 365 %    o image_info: the image info.
 366 %
 367 */
 368 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 369 {
 370   QuantizeInfo
 371     *quantize_info;
 372
 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)
 378     {
 379       const char
 380         *option;
 381
 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;
 388     }
 389   return(quantize_info);
 390 }
 391 \f
 392 /*
 393 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 394 %                                                                             %
 395 %                                                                             %
 396 %                                                                             %
 397 +   A s s i g n I m a g e C o l o r s                                         %
 398 %                                                                             %
 399 %                                                                             %
 400 %                                                                             %
 401 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 402 %
 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.
 408 %
 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.
 414 %
 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.
 419 %
 420 %  The format of the AssignImageColors() method is:
 421 %
 422 %      MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
 423 %
 424 %  A description of each parameter follows.
 425 %
 426 %    o image: the image.
 427 %
 428 %    o cube_info: A pointer to the Cube structure.
 429 %
 430 */
 431
 432 static inline void AssociateAlphaPixel(const Image *image,
 433   const CubeInfo *cube_info,const Quantum *pixel,
 434   RealPixelPacket *alpha_pixel)
 435 {
 436   MagickRealType
 437     alpha;
 438
 439   if ((cube_info->associate_alpha == MagickFalse) ||
 440       (GetPixelAlpha(image,pixel)== OpaqueAlpha))
 441     {
 442       alpha_pixel->red=(MagickRealType) GetPixelRed(image,pixel);
 443       alpha_pixel->green=(MagickRealType) GetPixelGreen(image,pixel);
 444       alpha_pixel->blue=(MagickRealType) GetPixelBlue(image,pixel);
 445       alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
 446       return;
 447     }
 448   alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,pixel));
 449   alpha_pixel->red=alpha*GetPixelRed(image,pixel);
 450   alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
 451   alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
 452   alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
 453 }
 454
 455 static inline void AssociateAlphaPixelPacket(const Image *image,
 456   const CubeInfo *cube_info,const PixelPacket *pixel,
 457   RealPixelPacket *alpha_pixel)
 458 {
 459   MagickRealType
 460     alpha;
 461
 462   if ((cube_info->associate_alpha == MagickFalse) ||
 463       (pixel->alpha == OpaqueAlpha))
 464     {
 465       alpha_pixel->red=(MagickRealType) pixel->red;
 466       alpha_pixel->green=(MagickRealType) pixel->green;
 467       alpha_pixel->blue=(MagickRealType) pixel->blue;
 468       alpha_pixel->alpha=(MagickRealType) pixel->alpha;
 469       return;
 470     }
 471   alpha=(MagickRealType) (QuantumScale*pixel->alpha);
 472   alpha_pixel->red=alpha*pixel->red;
 473   alpha_pixel->green=alpha*pixel->green;
 474   alpha_pixel->blue=alpha*pixel->blue;
 475   alpha_pixel->alpha=(MagickRealType) pixel->alpha;
 476 }
 477
 478 static inline Quantum ClampToUnsignedQuantum(const MagickRealType value)
 479 {
 480   if (value <= 0.0)
 481     return((Quantum) 0);
 482   if (value >= QuantumRange)
 483     return((Quantum) QuantumRange);
 484   return((Quantum) (value+0.5));
 485 }
 486
 487 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
 488   const RealPixelPacket *pixel,size_t index)
 489 {
 490   size_t
 491     id;
 492
 493   id=(size_t) (((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red)) >> index) & 0x01) |
 494     ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green)) >> index) & 0x01) << 1 |
 495     ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue)) >> index) & 0x01) << 2);
 496   if (cube_info->associate_alpha != MagickFalse)
 497     id|=((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->alpha)) >> index) & 0x1) << 3;
 498   return(id);
 499 }
 500
 501 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
 502 {
 503 #define AssignImageTag  "Assign/Image"
 504
 505   ssize_t
 506     y;
 507
 508   /*
 509     Allocate image colormap.
 510   */
 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);
 515   else
 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) == MagickFalse)
 521     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
 522       image->filename);
 523   image->colors=0;
 524   cube_info->transparent_pixels=0;
 525   cube_info->transparent_index=(-1);
 526   (void) DefineImageColormap(image,cube_info,cube_info->root);
 527   /*
 528     Create a reduced color image.
 529   */
 530   if ((cube_info->quantize_info->dither != MagickFalse) &&
 531       (cube_info->quantize_info->dither_method != NoDitherMethod))
 532     (void) DitherImage(image,cube_info);
 533   else
 534     {
 535       CacheView
 536         *image_view;
 537
 538       ExceptionInfo
 539         *exception;
 540
 541       MagickBooleanType
 542         status;
 543
 544       status=MagickTrue;
 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)
 549 #endif
 550       for (y=0; y < (ssize_t) image->rows; y++)
 551       {
 552         CubeInfo
 553           cube;
 554
 555         register Quantum
 556           *restrict q;
 557
 558         register ssize_t
 559           x;
 560
 561         ssize_t
 562           count;
 563
 564         if (status == MagickFalse)
 565           continue;
 566         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
 567           exception);
 568         if (q == (const Quantum *) NULL)
 569           {
 570             status=MagickFalse;
 571             continue;
 572           }
 573         cube=(*cube_info);
 574         for (x=0; x < (ssize_t) image->columns; x+=count)
 575         {
 576           RealPixelPacket
 577             pixel;
 578
 579           register const NodeInfo
 580             *node_info;
 581
 582           register ssize_t
 583             i;
 584
 585           size_t
 586             id,
 587             index;
 588
 589           /*
 590             Identify the deepest node containing the pixel's color.
 591           */
 592           for (count=1; (x+count) < (ssize_t) image->columns; count++)
 593           {
 594             PixelPacket
 595               packet;
 596
 597             GetPixelPacket(image,q+count*GetPixelComponents(image),&packet);
 598             if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
 599               break;
 600           }
 601           AssociateAlphaPixel(image,&cube,q,&pixel);
 602           node_info=cube.root;
 603           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
 604           {
 605             id=ColorToNodeId(&cube,&pixel,index);
 606             if (node_info->child[id] == (NodeInfo *) NULL)
 607               break;
 608             node_info=node_info->child[id];
 609           }
 610           /*
 611             Find closest color among siblings and their children.
 612           */
 613           cube.target=pixel;
 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++)
 619           {
 620             if (image->storage_class == PseudoClass)
 621               SetPixelIndex(image,(Quantum) index,q);
 622             if (cube.quantize_info->measure_error == MagickFalse)
 623               {
 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);
 629               }
 630             q+=GetPixelComponents(image);
 631           }
 632         }
 633         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 634           status=MagickFalse;
 635         if (image->progress_monitor != (MagickProgressMonitor) NULL)
 636           {
 637             MagickBooleanType
 638               proceed;
 639
 640 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 641             #pragma omp critical (MagickCore_AssignImageColors)
 642 #endif
 643             proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
 644               image->rows);
 645             if (proceed == MagickFalse)
 646               status=MagickFalse;
 647           }
 648       }
 649       image_view=DestroyCacheView(image_view);
 650     }
 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))
 655     {
 656       Quantum
 657         intensity;
 658
 659       register PixelPacket
 660         *restrict q;
 661
 662       register ssize_t
 663         i;
 664
 665       /*
 666         Monochrome image.
 667       */
 668       q=image->colormap;
 669       for (i=0; i < (ssize_t) image->colors; i++)
 670       {
 671         intensity=(Quantum) ((MagickRealType) GetPixelPacketIntensity(q) <
 672           ((MagickRealType) QuantumRange/2.0) ? 0 : QuantumRange);
 673         q->red=intensity;
 674         q->green=intensity;
 675         q->blue=intensity;
 676         q++;
 677       }
 678     }
 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);
 683   return(MagickTrue);
 684 }
 685 \f
 686 /*
 687 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 688 %                                                                             %
 689 %                                                                             %
 690 %                                                                             %
 691 +   C l a s s i f y I m a g e C o l o r s                                     %
 692 %                                                                             %
 693 %                                                                             %
 694 %                                                                             %
 695 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 696 %
 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
 705 %  1 + sum(i=1,k,8k).
 706 %
 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)).
 712 %
 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:
 717 %
 718 %    n1 : Number of pixels whose color is contained in the RGB cube
 719 %    which this node represents;
 720 %
 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.
 724 %
 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.
 729 %
 730 %    E: the distance squared in RGB space between each pixel contained
 731 %    within a node and the nodes' center.  This represents the quantization
 732 %    error for a node.
 733 %
 734 %  The format of the ClassifyImageColors() method is:
 735 %
 736 %      MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 737 %        const Image *image,ExceptionInfo *exception)
 738 %
 739 %  A description of each parameter follows.
 740 %
 741 %    o cube_info: A pointer to the Cube structure.
 742 %
 743 %    o image: the image.
 744 %
 745 */
 746
 747 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
 748 {
 749   MagickBooleanType
 750     associate_alpha;
 751
 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;
 759 }
 760
 761 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 762   const Image *image,ExceptionInfo *exception)
 763 {
 764 #define ClassifyImageTag  "Classify/Image"
 765
 766   CacheView
 767     *image_view;
 768
 769   MagickBooleanType
 770     proceed;
 771
 772   MagickRealType
 773     bisect;
 774
 775   NodeInfo
 776     *node_info;
 777
 778   RealPixelPacket
 779     error,
 780     mid,
 781     midpoint,
 782     pixel;
 783
 784   size_t
 785     count,
 786     id,
 787     index,
 788     level;
 789
 790   ssize_t
 791     y;
 792
 793   /*
 794     Classify the first cube_info->maximum_colors colors to a tree depth of 8.
 795   */
 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);
 801   else
 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;
 810   error.alpha=0.0;
 811   image_view=AcquireCacheView(image);
 812   for (y=0; y < (ssize_t) image->rows; y++)
 813   {
 814     register const Quantum
 815       *restrict p;
 816
 817     register ssize_t
 818       x;
 819
 820     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 821     if (p == (const Quantum *) NULL)
 822       break;
 823     if (cube_info->nodes > MaxNodes)
 824       {
 825         /*
 826           Prune one level if the color tree is too large.
 827         */
 828         PruneLevel(image,cube_info,cube_info->root);
 829         cube_info->depth--;
 830       }
 831     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 832     {
 833       /*
 834         Start at the root and descend the color cube tree.
 835       */
 836       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 837       {
 838         PixelPacket
 839           packet;
 840
 841         GetPixelPacket(image,p+count*GetPixelComponents(image),&packet);
 842         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 843           break;
 844       }
 845       AssociateAlphaPixel(image,cube_info,p,&pixel);
 846       index=MaxTreeDepth-1;
 847       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 848       mid=midpoint;
 849       node_info=cube_info->root;
 850       for (level=1; level <= MaxTreeDepth; level++)
 851       {
 852         bisect*=0.5;
 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)
 859           {
 860             /*
 861               Set colors of new node to contain pixel.
 862             */
 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'",
 867                 image->filename);
 868             if (level == MaxTreeDepth)
 869               cube_info->colors++;
 870           }
 871         /*
 872           Approximate the quantization error represented by this node.
 873         */
 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;
 884         index--;
 885       }
 886       /*
 887         Sum RGB for this leaf for later derivation of the mean cube color.
 888       */
 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*GetPixelComponents(image);
 896     }
 897     if (cube_info->colors > cube_info->maximum_colors)
 898       {
 899         PruneToCubeDepth(image,cube_info,cube_info->root);
 900         break;
 901       }
 902     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 903       image->rows);
 904     if (proceed == MagickFalse)
 905       break;
 906   }
 907   for (y++; y < (ssize_t) image->rows; y++)
 908   {
 909     register const Quantum
 910       *restrict p;
 911
 912     register ssize_t
 913       x;
 914
 915     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 916     if (p == (const Quantum *) NULL)
 917       break;
 918     if (cube_info->nodes > MaxNodes)
 919       {
 920         /*
 921           Prune one level if the color tree is too large.
 922         */
 923         PruneLevel(image,cube_info,cube_info->root);
 924         cube_info->depth--;
 925       }
 926     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 927     {
 928       /*
 929         Start at the root and descend the color cube tree.
 930       */
 931       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 932       {
 933         PixelPacket
 934           packet;
 935
 936         GetPixelPacket(image,p+count*GetPixelComponents(image),&packet);
 937         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 938           break;
 939       }
 940       AssociateAlphaPixel(image,cube_info,p,&pixel);
 941       index=MaxTreeDepth-1;
 942       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 943       mid=midpoint;
 944       node_info=cube_info->root;
 945       for (level=1; level <= cube_info->depth; level++)
 946       {
 947         bisect*=0.5;
 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)
 954           {
 955             /*
 956               Set colors of new node to contain pixel.
 957             */
 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",
 962                 image->filename);
 963             if (level == cube_info->depth)
 964               cube_info->colors++;
 965           }
 966         /*
 967           Approximate the quantization error represented by this node.
 968         */
 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;
 979         index--;
 980       }
 981       /*
 982         Sum RGB for this leaf for later derivation of the mean cube color.
 983       */
 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*GetPixelComponents(image);
 991     }
 992     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 993       image->rows);
 994     if (proceed == MagickFalse)
 995       break;
 996   }
 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);
1001   return(MagickTrue);
1002 }
1003 \f
1004 /*
1005 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1006 %                                                                             %
1007 %                                                                             %
1008 %                                                                             %
1009 %   C l o n e Q u a n t i z e I n f o                                         %
1010 %                                                                             %
1011 %                                                                             %
1012 %                                                                             %
1013 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1014 %
1015 %  CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1016 %  or if quantize info is NULL, a new one.
1017 %
1018 %  The format of the CloneQuantizeInfo method is:
1019 %
1020 %      QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1021 %
1022 %  A description of each parameter follows:
1023 %
1024 %    o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1025 %      quantize info, or if image info is NULL a new one.
1026 %
1027 %    o quantize_info: a structure of type info.
1028 %
1029 */
1030 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1031 {
1032   QuantizeInfo
1033     *clone_info;
1034
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)
1040     return(clone_info);
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;
1047   return(clone_info);
1048 }
1049 \f
1050 /*
1051 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1052 %                                                                             %
1053 %                                                                             %
1054 %                                                                             %
1055 +   C l o s e s t C o l o r                                                   %
1056 %                                                                             %
1057 %                                                                             %
1058 %                                                                             %
1059 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1060 %
1061 %  ClosestColor() traverses the color cube tree at a particular node and
1062 %  determines which colormap entry best represents the input color.
1063 %
1064 %  The format of the ClosestColor method is:
1065 %
1066 %      void ClosestColor(const Image *image,CubeInfo *cube_info,
1067 %        const NodeInfo *node_info)
1068 %
1069 %  A description of each parameter follows.
1070 %
1071 %    o image: the image.
1072 %
1073 %    o cube_info: A pointer to the Cube structure.
1074 %
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.
1077 %
1078 */
1079 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1080   const NodeInfo *node_info)
1081 {
1082   register ssize_t
1083     i;
1084
1085   size_t
1086     number_children;
1087
1088   /*
1089     Traverse any children.
1090   */
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)
1096     {
1097       MagickRealType
1098         pixel;
1099
1100       register MagickRealType
1101         alpha,
1102         beta,
1103         distance;
1104
1105       register PixelPacket
1106         *restrict p;
1107
1108       register RealPixelPacket
1109         *restrict q;
1110
1111       /*
1112         Determine if this color is "closest".
1113       */
1114       p=image->colormap+node_info->color_number;
1115       q=(&cube_info->target);
1116       alpha=1.0;
1117       beta=1.0;
1118       if (cube_info->associate_alpha != MagickFalse)
1119         {
1120           alpha=(MagickRealType) (QuantumScale*p->alpha);
1121           beta=(MagickRealType) (QuantumScale*q->alpha);
1122         }
1123       pixel=alpha*p->red-beta*q->red;
1124       distance=pixel*pixel;
1125       if (distance <= cube_info->distance)
1126         {
1127           pixel=alpha*p->green-beta*q->green;
1128           distance+=pixel*pixel;
1129           if (distance <= cube_info->distance)
1130             {
1131               pixel=alpha*p->blue-beta*q->blue;
1132               distance+=pixel*pixel;
1133               if (distance <= cube_info->distance)
1134                 {
1135                   pixel=alpha-beta;
1136                   distance+=pixel*pixel;
1137                   if (distance <= cube_info->distance)
1138                     {
1139                       cube_info->distance=distance;
1140                       cube_info->color_number=node_info->color_number;
1141                     }
1142                 }
1143             }
1144         }
1145     }
1146 }
1147 \f
1148 /*
1149 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1150 %                                                                             %
1151 %                                                                             %
1152 %                                                                             %
1153 %   C o m p r e s s I m a g e C o l o r m a p                                 %
1154 %                                                                             %
1155 %                                                                             %
1156 %                                                                             %
1157 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1158 %
1159 %  CompressImageColormap() compresses an image colormap by removing any
1160 %  duplicate or unused color entries.
1161 %
1162 %  The format of the CompressImageColormap method is:
1163 %
1164 %      MagickBooleanType CompressImageColormap(Image *image)
1165 %
1166 %  A description of each parameter follows:
1167 %
1168 %    o image: the image.
1169 %
1170 */
1171 MagickExport MagickBooleanType CompressImageColormap(Image *image)
1172 {
1173   QuantizeInfo
1174     quantize_info;
1175
1176   assert(image != (Image *) NULL);
1177   assert(image->signature == MagickSignature);
1178   if (image->debug != MagickFalse)
1179     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1180   if (IsPaletteImage(image,&image->exception) == MagickFalse)
1181     return(MagickFalse);
1182   GetQuantizeInfo(&quantize_info);
1183   quantize_info.number_colors=image->colors;
1184   quantize_info.tree_depth=MaxTreeDepth;
1185   return(QuantizeImage(&quantize_info,image));
1186 }
1187 \f
1188 /*
1189 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1190 %                                                                             %
1191 %                                                                             %
1192 %                                                                             %
1193 +   D e f i n e I m a g e C o l o r m a p                                     %
1194 %                                                                             %
1195 %                                                                             %
1196 %                                                                             %
1197 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1198 %
1199 %  DefineImageColormap() traverses the color cube tree and notes each colormap
1200 %  entry.  A colormap entry is any node in the color cube tree where the
1201 %  of unique colors is not zero.  DefineImageColormap() returns the number of
1202 %  colors in the image colormap.
1203 %
1204 %  The format of the DefineImageColormap method is:
1205 %
1206 %      size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1207 %        NodeInfo *node_info)
1208 %
1209 %  A description of each parameter follows.
1210 %
1211 %    o image: the image.
1212 %
1213 %    o cube_info: A pointer to the Cube structure.
1214 %
1215 %    o node_info: the address of a structure of type NodeInfo which points to a
1216 %      node in the color cube tree that is to be pruned.
1217 %
1218 */
1219 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1220   NodeInfo *node_info)
1221 {
1222   register ssize_t
1223     i;
1224
1225   size_t
1226     number_children;
1227
1228   /*
1229     Traverse any children.
1230   */
1231   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1232   for (i=0; i < (ssize_t) number_children; i++)
1233     if (node_info->child[i] != (NodeInfo *) NULL)
1234       (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1235   if (node_info->number_unique != 0)
1236     {
1237       register MagickRealType
1238         alpha;
1239
1240       register PixelPacket
1241         *restrict q;
1242
1243       /*
1244         Colormap entry is defined by the mean color in this cube.
1245       */
1246       q=image->colormap+image->colors;
1247       alpha=(MagickRealType) ((MagickOffsetType) node_info->number_unique);
1248       alpha=1.0/(fabs(alpha) <= MagickEpsilon ? 1.0 : alpha);
1249       if (cube_info->associate_alpha == MagickFalse)
1250         {
1251           q->red=ClampToQuantum((MagickRealType)
1252             (alpha*QuantumRange*node_info->total_color.red));
1253           q->green=ClampToQuantum((MagickRealType)
1254             (alpha*QuantumRange*node_info->total_color.green));
1255           q->blue=ClampToQuantum((MagickRealType)
1256             (alpha*QuantumRange*node_info->total_color.blue));
1257           q->alpha=OpaqueAlpha;
1258         }
1259       else
1260         {
1261           MagickRealType
1262             opacity;
1263
1264           opacity=(MagickRealType) (alpha*QuantumRange*
1265             node_info->total_color.alpha);
1266           q->alpha=ClampToQuantum(opacity);
1267           if (q->alpha == OpaqueAlpha)
1268             {
1269               q->red=ClampToQuantum((MagickRealType)
1270                 (alpha*QuantumRange*node_info->total_color.red));
1271               q->green=ClampToQuantum((MagickRealType)
1272                 (alpha*QuantumRange*node_info->total_color.green));
1273               q->blue=ClampToQuantum((MagickRealType)
1274                 (alpha*QuantumRange*node_info->total_color.blue));
1275             }
1276           else
1277             {
1278               MagickRealType
1279                 gamma;
1280
1281               gamma=(MagickRealType) (QuantumScale*q->alpha);
1282               gamma=1.0/(fabs(gamma) <= MagickEpsilon ? 1.0 : gamma);
1283               q->red=ClampToQuantum((MagickRealType)
1284                 (alpha*gamma*QuantumRange*node_info->total_color.red));
1285               q->green=ClampToQuantum((MagickRealType)
1286                 (alpha*gamma*QuantumRange*node_info->total_color.green));
1287               q->blue=ClampToQuantum((MagickRealType)
1288                 (alpha*gamma*QuantumRange*node_info->total_color.blue));
1289               if (node_info->number_unique > cube_info->transparent_pixels)
1290                 {
1291                   cube_info->transparent_pixels=node_info->number_unique;
1292                   cube_info->transparent_index=(ssize_t) image->colors;
1293                 }
1294             }
1295         }
1296       node_info->color_number=image->colors++;
1297     }
1298   return(image->colors);
1299 }
1300 \f
1301 /*
1302 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1303 %                                                                             %
1304 %                                                                             %
1305 %                                                                             %
1306 +   D e s t r o y C u b e I n f o                                             %
1307 %                                                                             %
1308 %                                                                             %
1309 %                                                                             %
1310 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1311 %
1312 %  DestroyCubeInfo() deallocates memory associated with an image.
1313 %
1314 %  The format of the DestroyCubeInfo method is:
1315 %
1316 %      DestroyCubeInfo(CubeInfo *cube_info)
1317 %
1318 %  A description of each parameter follows:
1319 %
1320 %    o cube_info: the address of a structure of type CubeInfo.
1321 %
1322 */
1323 static void DestroyCubeInfo(CubeInfo *cube_info)
1324 {
1325   register Nodes
1326     *nodes;
1327
1328   /*
1329     Release color cube tree storage.
1330   */
1331   do
1332   {
1333     nodes=cube_info->node_queue->next;
1334     cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1335       cube_info->node_queue->nodes);
1336     cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1337       cube_info->node_queue);
1338     cube_info->node_queue=nodes;
1339   } while (cube_info->node_queue != (Nodes *) NULL);
1340   if (cube_info->cache != (ssize_t *) NULL)
1341     cube_info->cache=(ssize_t *) RelinquishMagickMemory(cube_info->cache);
1342   cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1343   cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1344 }
1345 \f
1346 /*
1347 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1348 %                                                                             %
1349 %                                                                             %
1350 %                                                                             %
1351 %   D e s t r o y Q u a n t i z e I n f o                                     %
1352 %                                                                             %
1353 %                                                                             %
1354 %                                                                             %
1355 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1356 %
1357 %  DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1358 %  structure.
1359 %
1360 %  The format of the DestroyQuantizeInfo method is:
1361 %
1362 %      QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1363 %
1364 %  A description of each parameter follows:
1365 %
1366 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1367 %
1368 */
1369 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1370 {
1371   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1372   assert(quantize_info != (QuantizeInfo *) NULL);
1373   assert(quantize_info->signature == MagickSignature);
1374   quantize_info->signature=(~MagickSignature);
1375   quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1376   return(quantize_info);
1377 }
1378 \f
1379 /*
1380 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1381 %                                                                             %
1382 %                                                                             %
1383 %                                                                             %
1384 +   D i t h e r I m a g e                                                     %
1385 %                                                                             %
1386 %                                                                             %
1387 %                                                                             %
1388 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1389 %
1390 %  DitherImage() distributes the difference between an original image and
1391 %  the corresponding color reduced algorithm to neighboring pixels using
1392 %  serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1393 %  MagickTrue if the image is dithered otherwise MagickFalse.
1394 %
1395 %  The format of the DitherImage method is:
1396 %
1397 %      MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1398 %
1399 %  A description of each parameter follows.
1400 %
1401 %    o image: the image.
1402 %
1403 %    o cube_info: A pointer to the Cube structure.
1404 %
1405 */
1406
1407 static RealPixelPacket **DestroyPixelThreadSet(RealPixelPacket **pixels)
1408 {
1409   register ssize_t
1410     i;
1411
1412   assert(pixels != (RealPixelPacket **) NULL);
1413   for (i=0; i < (ssize_t) GetOpenMPMaximumThreads(); i++)
1414     if (pixels[i] != (RealPixelPacket *) NULL)
1415       pixels[i]=(RealPixelPacket *) RelinquishMagickMemory(pixels[i]);
1416   pixels=(RealPixelPacket **) RelinquishMagickMemory(pixels);
1417   return(pixels);
1418 }
1419
1420 static RealPixelPacket **AcquirePixelThreadSet(const size_t count)
1421 {
1422   RealPixelPacket
1423     **pixels;
1424
1425   register ssize_t
1426     i;
1427
1428   size_t
1429     number_threads;
1430
1431   number_threads=GetOpenMPMaximumThreads();
1432   pixels=(RealPixelPacket **) AcquireQuantumMemory(number_threads,
1433     sizeof(*pixels));
1434   if (pixels == (RealPixelPacket **) NULL)
1435     return((RealPixelPacket **) NULL);
1436   (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1437   for (i=0; i < (ssize_t) number_threads; i++)
1438   {
1439     pixels[i]=(RealPixelPacket *) AcquireQuantumMemory(count,
1440       2*sizeof(**pixels));
1441     if (pixels[i] == (RealPixelPacket *) NULL)
1442       return(DestroyPixelThreadSet(pixels));
1443   }
1444   return(pixels);
1445 }
1446
1447 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1448   const RealPixelPacket *pixel)
1449 {
1450 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1451 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1452 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1453 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1454
1455   ssize_t
1456     offset;
1457
1458   offset=(ssize_t)
1459     (RedShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red))) |
1460     GreenShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green))) |
1461     BlueShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue))));
1462   if (cube_info->associate_alpha != MagickFalse)
1463     offset|=AlphaShift(ScaleQuantumToChar(ClampToUnsignedQuantum(
1464       pixel->alpha)));
1465   return(offset);
1466 }
1467
1468 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info)
1469 {
1470 #define DitherImageTag  "Dither/Image"
1471
1472   CacheView
1473     *image_view;
1474
1475   ExceptionInfo
1476     *exception;
1477
1478   MagickBooleanType
1479     status;
1480
1481   RealPixelPacket
1482     **pixels;
1483
1484   ssize_t
1485     y;
1486
1487   /*
1488     Distribute quantization error using Floyd-Steinberg.
1489   */
1490   pixels=AcquirePixelThreadSet(image->columns);
1491   if (pixels == (RealPixelPacket **) NULL)
1492     return(MagickFalse);
1493   exception=(&image->exception);
1494   status=MagickTrue;
1495   image_view=AcquireCacheView(image);
1496   for (y=0; y < (ssize_t) image->rows; y++)
1497   {
1498     const int
1499       id = GetOpenMPThreadId();
1500
1501     CubeInfo
1502       cube;
1503
1504     RealPixelPacket
1505       *current,
1506       *previous;
1507
1508     register Quantum
1509       *restrict q;
1510
1511     register ssize_t
1512       x;
1513
1514     size_t
1515       index;
1516
1517     ssize_t
1518       v;
1519
1520     if (status == MagickFalse)
1521       continue;
1522     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1523     if (q == (const Quantum *) NULL)
1524       {
1525         status=MagickFalse;
1526         continue;
1527       }
1528     q+=(y & 0x01)*image->columns*GetPixelComponents(image);
1529     cube=(*cube_info);
1530     current=pixels[id]+(y & 0x01)*image->columns;
1531     previous=pixels[id]+((y+1) & 0x01)*image->columns;
1532     v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1533     for (x=0; x < (ssize_t) image->columns; x++)
1534     {
1535       RealPixelPacket
1536         color,
1537         pixel;
1538
1539       register ssize_t
1540         i;
1541
1542       ssize_t
1543         u;
1544
1545       q-=(y & 0x01)*GetPixelComponents(image);
1546       u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1547       AssociateAlphaPixel(image,&cube,q,&pixel);
1548       if (x > 0)
1549         {
1550           pixel.red+=7*current[u-v].red/16;
1551           pixel.green+=7*current[u-v].green/16;
1552           pixel.blue+=7*current[u-v].blue/16;
1553           if (cube.associate_alpha != MagickFalse)
1554             pixel.alpha+=7*current[u-v].alpha/16;
1555         }
1556       if (y > 0)
1557         {
1558           if (x < (ssize_t) (image->columns-1))
1559             {
1560               pixel.red+=previous[u+v].red/16;
1561               pixel.green+=previous[u+v].green/16;
1562               pixel.blue+=previous[u+v].blue/16;
1563               if (cube.associate_alpha != MagickFalse)
1564                 pixel.alpha+=previous[u+v].alpha/16;
1565             }
1566           pixel.red+=5*previous[u].red/16;
1567           pixel.green+=5*previous[u].green/16;
1568           pixel.blue+=5*previous[u].blue/16;
1569           if (cube.associate_alpha != MagickFalse)
1570             pixel.alpha+=5*previous[u].alpha/16;
1571           if (x > 0)
1572             {
1573               pixel.red+=3*previous[u-v].red/16;
1574               pixel.green+=3*previous[u-v].green/16;
1575               pixel.blue+=3*previous[u-v].blue/16;
1576               if (cube.associate_alpha != MagickFalse)
1577                 pixel.alpha+=3*previous[u-v].alpha/16;
1578             }
1579         }
1580       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1581       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1582       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1583       if (cube.associate_alpha != MagickFalse)
1584         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1585       i=CacheOffset(&cube,&pixel);
1586       if (cube.cache[i] < 0)
1587         {
1588           register NodeInfo
1589             *node_info;
1590
1591           register size_t
1592             id;
1593
1594           /*
1595             Identify the deepest node containing the pixel's color.
1596           */
1597           node_info=cube.root;
1598           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1599           {
1600             id=ColorToNodeId(&cube,&pixel,index);
1601             if (node_info->child[id] == (NodeInfo *) NULL)
1602               break;
1603             node_info=node_info->child[id];
1604           }
1605           /*
1606             Find closest color among siblings and their children.
1607           */
1608           cube.target=pixel;
1609           cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*(QuantumRange+
1610             1.0)+1.0);
1611           ClosestColor(image,&cube,node_info->parent);
1612           cube.cache[i]=(ssize_t) cube.color_number;
1613         }
1614       /*
1615         Assign pixel to closest colormap entry.
1616       */
1617       index=(size_t) cube.cache[i];
1618       if (image->storage_class == PseudoClass)
1619         SetPixelIndex(image,(Quantum) index,q);
1620       if (cube.quantize_info->measure_error == MagickFalse)
1621         {
1622           SetPixelRed(image,image->colormap[index].red,q);
1623           SetPixelGreen(image,image->colormap[index].green,q);
1624           SetPixelBlue(image,image->colormap[index].blue,q);
1625           if (cube.associate_alpha != MagickFalse)
1626             SetPixelAlpha(image,image->colormap[index].alpha,q);
1627         }
1628       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1629         status=MagickFalse;
1630       /*
1631         Store the error.
1632       */
1633       AssociateAlphaPixelPacket(image,&cube,image->colormap+index,&color);
1634       current[u].red=pixel.red-color.red;
1635       current[u].green=pixel.green-color.green;
1636       current[u].blue=pixel.blue-color.blue;
1637       if (cube.associate_alpha != MagickFalse)
1638         current[u].alpha=pixel.alpha-color.alpha;
1639       if (image->progress_monitor != (MagickProgressMonitor) NULL)
1640         {
1641           MagickBooleanType
1642             proceed;
1643
1644 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1645           #pragma omp critical (MagickCore_FloydSteinbergDither)
1646 #endif
1647           proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1648             image->rows);
1649           if (proceed == MagickFalse)
1650             status=MagickFalse;
1651         }
1652       q+=((y+1) & 0x01)*GetPixelComponents(image);
1653     }
1654   }
1655   image_view=DestroyCacheView(image_view);
1656   pixels=DestroyPixelThreadSet(pixels);
1657   return(MagickTrue);
1658 }
1659
1660 static MagickBooleanType
1661   RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int);
1662
1663 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1664   const size_t level,const unsigned int direction)
1665 {
1666   if (level == 1)
1667     switch (direction)
1668     {
1669       case WestGravity:
1670       {
1671         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1672         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1673         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1674         break;
1675       }
1676       case EastGravity:
1677       {
1678         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1679         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1680         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1681         break;
1682       }
1683       case NorthGravity:
1684       {
1685         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1686         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1687         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1688         break;
1689       }
1690       case SouthGravity:
1691       {
1692         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1693         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1694         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1695         break;
1696       }
1697       default:
1698         break;
1699     }
1700   else
1701     switch (direction)
1702     {
1703       case WestGravity:
1704       {
1705         Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1706         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1707         Riemersma(image,image_view,cube_info,level-1,WestGravity);
1708         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1709         Riemersma(image,image_view,cube_info,level-1,WestGravity);
1710         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1711         Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1712         break;
1713       }
1714       case EastGravity:
1715       {
1716         Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1717         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1718         Riemersma(image,image_view,cube_info,level-1,EastGravity);
1719         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1720         Riemersma(image,image_view,cube_info,level-1,EastGravity);
1721         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1722         Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1723         break;
1724       }
1725       case NorthGravity:
1726       {
1727         Riemersma(image,image_view,cube_info,level-1,WestGravity);
1728         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1729         Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1730         (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1731         Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1732         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1733         Riemersma(image,image_view,cube_info,level-1,EastGravity);
1734         break;
1735       }
1736       case SouthGravity:
1737       {
1738         Riemersma(image,image_view,cube_info,level-1,EastGravity);
1739         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1740         Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1741         (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1742         Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1743         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1744         Riemersma(image,image_view,cube_info,level-1,WestGravity);
1745         break;
1746       }
1747       default:
1748         break;
1749     }
1750 }
1751
1752 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1753   CubeInfo *cube_info,const unsigned int direction)
1754 {
1755 #define DitherImageTag  "Dither/Image"
1756
1757   MagickBooleanType
1758     proceed;
1759
1760   RealPixelPacket
1761     color,
1762     pixel;
1763
1764   register CubeInfo
1765     *p;
1766
1767   size_t
1768     index;
1769
1770   p=cube_info;
1771   if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1772       (p->y >= 0) && (p->y < (ssize_t) image->rows))
1773     {
1774       ExceptionInfo
1775         *exception;
1776
1777       register Quantum
1778         *restrict q;
1779
1780       register ssize_t
1781         i;
1782
1783       /*
1784         Distribute error.
1785       */
1786       exception=(&image->exception);
1787       q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1788       if (q == (const Quantum *) NULL)
1789         return(MagickFalse);
1790       AssociateAlphaPixel(image,cube_info,q,&pixel);
1791       for (i=0; i < ErrorQueueLength; i++)
1792       {
1793         pixel.red+=p->weights[i]*p->error[i].red;
1794         pixel.green+=p->weights[i]*p->error[i].green;
1795         pixel.blue+=p->weights[i]*p->error[i].blue;
1796         if (cube_info->associate_alpha != MagickFalse)
1797           pixel.alpha+=p->weights[i]*p->error[i].alpha;
1798       }
1799       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1800       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1801       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1802       if (cube_info->associate_alpha != MagickFalse)
1803         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1804       i=CacheOffset(cube_info,&pixel);
1805       if (p->cache[i] < 0)
1806         {
1807           register NodeInfo
1808             *node_info;
1809
1810           register size_t
1811             id;
1812
1813           /*
1814             Identify the deepest node containing the pixel's color.
1815           */
1816           node_info=p->root;
1817           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1818           {
1819             id=ColorToNodeId(cube_info,&pixel,index);
1820             if (node_info->child[id] == (NodeInfo *) NULL)
1821               break;
1822             node_info=node_info->child[id];
1823           }
1824           node_info=node_info->parent;
1825           /*
1826             Find closest color among siblings and their children.
1827           */
1828           p->target=pixel;
1829           p->distance=(MagickRealType) (4.0*(QuantumRange+1.0)*((MagickRealType)
1830             QuantumRange+1.0)+1.0);
1831           ClosestColor(image,p,node_info->parent);
1832           p->cache[i]=(ssize_t) p->color_number;
1833         }
1834       /*
1835         Assign pixel to closest colormap entry.
1836       */
1837       index=(size_t) p->cache[i];
1838       if (image->storage_class == PseudoClass)
1839         SetPixelIndex(image,(Quantum) index,q);
1840       if (cube_info->quantize_info->measure_error == MagickFalse)
1841         {
1842           SetPixelRed(image,image->colormap[index].red,q);
1843           SetPixelGreen(image,image->colormap[index].green,q);
1844           SetPixelBlue(image,image->colormap[index].blue,q);
1845           if (cube_info->associate_alpha != MagickFalse)
1846             SetPixelAlpha(image,image->colormap[index].alpha,q);
1847         }
1848       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1849         return(MagickFalse);
1850       /*
1851         Propagate the error as the last entry of the error queue.
1852       */
1853       (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1854         sizeof(p->error[0]));
1855       AssociateAlphaPixelPacket(image,cube_info,image->colormap+index,&color);
1856       p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1857       p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1858       p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1859       if (cube_info->associate_alpha != MagickFalse)
1860         p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1861       proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1862       if (proceed == MagickFalse)
1863         return(MagickFalse);
1864       p->offset++;
1865     }
1866   switch (direction)
1867   {
1868     case WestGravity: p->x--; break;
1869     case EastGravity: p->x++; break;
1870     case NorthGravity: p->y--; break;
1871     case SouthGravity: p->y++; break;
1872   }
1873   return(MagickTrue);
1874 }
1875
1876 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1877 {
1878   if (x > y)
1879     return(x);
1880   return(y);
1881 }
1882
1883 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1884 {
1885   if (x < y)
1886     return(x);
1887   return(y);
1888 }
1889
1890 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1891 {
1892   CacheView
1893     *image_view;
1894
1895   MagickBooleanType
1896     status;
1897
1898   register ssize_t
1899     i;
1900
1901   size_t
1902     depth;
1903
1904   if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1905     return(FloydSteinbergDither(image,cube_info));
1906   /*
1907     Distribute quantization error along a Hilbert curve.
1908   */
1909   (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1910     sizeof(*cube_info->error));
1911   cube_info->x=0;
1912   cube_info->y=0;
1913   i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1914   for (depth=1; i != 0; depth++)
1915     i>>=1;
1916   if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1917     depth++;
1918   cube_info->offset=0;
1919   cube_info->span=(MagickSizeType) image->columns*image->rows;
1920   image_view=AcquireCacheView(image);
1921   if (depth > 1)
1922     Riemersma(image,image_view,cube_info,depth-1,NorthGravity);
1923   status=RiemersmaDither(image,image_view,cube_info,ForgetGravity);
1924   image_view=DestroyCacheView(image_view);
1925   return(status);
1926 }
1927 \f
1928 /*
1929 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1930 %                                                                             %
1931 %                                                                             %
1932 %                                                                             %
1933 +   G e t C u b e I n f o                                                     %
1934 %                                                                             %
1935 %                                                                             %
1936 %                                                                             %
1937 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1938 %
1939 %  GetCubeInfo() initialize the Cube data structure.
1940 %
1941 %  The format of the GetCubeInfo method is:
1942 %
1943 %      CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1944 %        const size_t depth,const size_t maximum_colors)
1945 %
1946 %  A description of each parameter follows.
1947 %
1948 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1949 %
1950 %    o depth: Normally, this integer value is zero or one.  A zero or
1951 %      one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1952 %      A tree of this depth generally allows the best representation of the
1953 %      reference image with the least amount of memory and the fastest
1954 %      computational speed.  In some cases, such as an image with low color
1955 %      dispersion (a few number of colors), a value other than
1956 %      Log4(number_colors) is required.  To expand the color tree completely,
1957 %      use a value of 8.
1958 %
1959 %    o maximum_colors: maximum colors.
1960 %
1961 */
1962 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
1963   const size_t depth,const size_t maximum_colors)
1964 {
1965   CubeInfo
1966     *cube_info;
1967
1968   MagickRealType
1969     sum,
1970     weight;
1971
1972   register ssize_t
1973     i;
1974
1975   size_t
1976     length;
1977
1978   /*
1979     Initialize tree to describe color cube_info.
1980   */
1981   cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
1982   if (cube_info == (CubeInfo *) NULL)
1983     return((CubeInfo *) NULL);
1984   (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
1985   cube_info->depth=depth;
1986   if (cube_info->depth > MaxTreeDepth)
1987     cube_info->depth=MaxTreeDepth;
1988   if (cube_info->depth < 2)
1989     cube_info->depth=2;
1990   cube_info->maximum_colors=maximum_colors;
1991   /*
1992     Initialize root node.
1993   */
1994   cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
1995   if (cube_info->root == (NodeInfo *) NULL)
1996     return((CubeInfo *) NULL);
1997   cube_info->root->parent=cube_info->root;
1998   cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
1999   if (cube_info->quantize_info->dither == MagickFalse)
2000     return(cube_info);
2001   /*
2002     Initialize dither resources.
2003   */
2004   length=(size_t) (1UL << (4*(8-CacheShift)));
2005   cube_info->cache=(ssize_t *) AcquireQuantumMemory(length,
2006     sizeof(*cube_info->cache));
2007   if (cube_info->cache == (ssize_t *) NULL)
2008     return((CubeInfo *) NULL);
2009   /*
2010     Initialize color cache.
2011   */
2012   for (i=0; i < (ssize_t) length; i++)
2013     cube_info->cache[i]=(-1);
2014   /*
2015     Distribute weights along a curve of exponential decay.
2016   */
2017   weight=1.0;
2018   for (i=0; i < ErrorQueueLength; i++)
2019   {
2020     cube_info->weights[ErrorQueueLength-i-1]=1.0/weight;
2021     weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2022   }
2023   /*
2024     Normalize the weighting factors.
2025   */
2026   weight=0.0;
2027   for (i=0; i < ErrorQueueLength; i++)
2028     weight+=cube_info->weights[i];
2029   sum=0.0;
2030   for (i=0; i < ErrorQueueLength; i++)
2031   {
2032     cube_info->weights[i]/=weight;
2033     sum+=cube_info->weights[i];
2034   }
2035   cube_info->weights[0]+=1.0-sum;
2036   return(cube_info);
2037 }
2038 \f
2039 /*
2040 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2041 %                                                                             %
2042 %                                                                             %
2043 %                                                                             %
2044 +   G e t N o d e I n f o                                                     %
2045 %                                                                             %
2046 %                                                                             %
2047 %                                                                             %
2048 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2049 %
2050 %  GetNodeInfo() allocates memory for a new node in the color cube tree and
2051 %  presets all fields to zero.
2052 %
2053 %  The format of the GetNodeInfo method is:
2054 %
2055 %      NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2056 %        const size_t level,NodeInfo *parent)
2057 %
2058 %  A description of each parameter follows.
2059 %
2060 %    o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2061 %
2062 %    o id: Specifies the child number of the node.
2063 %
2064 %    o level: Specifies the level in the storage_class the node resides.
2065 %
2066 */
2067 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2068   const size_t level,NodeInfo *parent)
2069 {
2070   NodeInfo
2071     *node_info;
2072
2073   if (cube_info->free_nodes == 0)
2074     {
2075       Nodes
2076         *nodes;
2077
2078       /*
2079         Allocate a new queue of nodes.
2080       */
2081       nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2082       if (nodes == (Nodes *) NULL)
2083         return((NodeInfo *) NULL);
2084       nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2085         sizeof(*nodes->nodes));
2086       if (nodes->nodes == (NodeInfo *) NULL)
2087         return((NodeInfo *) NULL);
2088       nodes->next=cube_info->node_queue;
2089       cube_info->node_queue=nodes;
2090       cube_info->next_node=nodes->nodes;
2091       cube_info->free_nodes=NodesInAList;
2092     }
2093   cube_info->nodes++;
2094   cube_info->free_nodes--;
2095   node_info=cube_info->next_node++;
2096   (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2097   node_info->parent=parent;
2098   node_info->id=id;
2099   node_info->level=level;
2100   return(node_info);
2101 }
2102 \f
2103 /*
2104 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2105 %                                                                             %
2106 %                                                                             %
2107 %                                                                             %
2108 %  G e t I m a g e Q u a n t i z e E r r o r                                  %
2109 %                                                                             %
2110 %                                                                             %
2111 %                                                                             %
2112 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2113 %
2114 %  GetImageQuantizeError() measures the difference between the original
2115 %  and quantized images.  This difference is the total quantization error.
2116 %  The error is computed by summing over all pixels in an image the distance
2117 %  squared in RGB space between each reference pixel value and its quantized
2118 %  value.  These values are computed:
2119 %
2120 %    o mean_error_per_pixel:  This value is the mean error for any single
2121 %      pixel in the image.
2122 %
2123 %    o normalized_mean_square_error:  This value is the normalized mean
2124 %      quantization error for any single pixel in the image.  This distance
2125 %      measure is normalized to a range between 0 and 1.  It is independent
2126 %      of the range of red, green, and blue values in the image.
2127 %
2128 %    o normalized_maximum_square_error:  Thsi value is the normalized
2129 %      maximum quantization error for any single pixel in the image.  This
2130 %      distance measure is normalized to a range between 0 and 1.  It is
2131 %      independent of the range of red, green, and blue values in your image.
2132 %
2133 %  The format of the GetImageQuantizeError method is:
2134 %
2135 %      MagickBooleanType GetImageQuantizeError(Image *image)
2136 %
2137 %  A description of each parameter follows.
2138 %
2139 %    o image: the image.
2140 %
2141 */
2142 MagickExport MagickBooleanType GetImageQuantizeError(Image *image)
2143 {
2144   CacheView
2145     *image_view;
2146
2147   ExceptionInfo
2148     *exception;
2149
2150   MagickRealType
2151     alpha,
2152     area,
2153     beta,
2154     distance,
2155     maximum_error,
2156     mean_error,
2157     mean_error_per_pixel;
2158
2159   size_t
2160     index;
2161
2162   ssize_t
2163     y;
2164
2165   assert(image != (Image *) NULL);
2166   assert(image->signature == MagickSignature);
2167   if (image->debug != MagickFalse)
2168     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2169   image->total_colors=GetNumberColors(image,(FILE *) NULL,&image->exception);
2170   (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2171   if (image->storage_class == DirectClass)
2172     return(MagickTrue);
2173   alpha=1.0;
2174   beta=1.0;
2175   area=3.0*image->columns*image->rows;
2176   maximum_error=0.0;
2177   mean_error_per_pixel=0.0;
2178   mean_error=0.0;
2179   exception=(&image->exception);
2180   image_view=AcquireCacheView(image);
2181   for (y=0; y < (ssize_t) image->rows; y++)
2182   {
2183     register const Quantum
2184       *restrict p;
2185
2186     register ssize_t
2187       x;
2188
2189     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2190     if (p == (const Quantum *) NULL)
2191       break;
2192     for (x=0; x < (ssize_t) image->columns; x++)
2193     {
2194       index=1UL*GetPixelIndex(image,p);
2195       if (image->matte != MagickFalse)
2196         {
2197           alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,p));
2198           beta=(MagickRealType) (QuantumScale*image->colormap[index].alpha);
2199         }
2200       distance=fabs(alpha*GetPixelRed(image,p)-beta*
2201         image->colormap[index].red);
2202       mean_error_per_pixel+=distance;
2203       mean_error+=distance*distance;
2204       if (distance > maximum_error)
2205         maximum_error=distance;
2206       distance=fabs(alpha*GetPixelGreen(image,p)-beta*
2207         image->colormap[index].green);
2208       mean_error_per_pixel+=distance;
2209       mean_error+=distance*distance;
2210       if (distance > maximum_error)
2211         maximum_error=distance;
2212       distance=fabs(alpha*GetPixelBlue(image,p)-beta*
2213         image->colormap[index].blue);
2214       mean_error_per_pixel+=distance;
2215       mean_error+=distance*distance;
2216       if (distance > maximum_error)
2217         maximum_error=distance;
2218       p+=GetPixelComponents(image);
2219     }
2220   }
2221   image_view=DestroyCacheView(image_view);
2222   image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2223   image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2224     mean_error/area;
2225   image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2226   return(MagickTrue);
2227 }
2228 \f
2229 /*
2230 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2231 %                                                                             %
2232 %                                                                             %
2233 %                                                                             %
2234 %   G e t Q u a n t i z e I n f o                                             %
2235 %                                                                             %
2236 %                                                                             %
2237 %                                                                             %
2238 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2239 %
2240 %  GetQuantizeInfo() initializes the QuantizeInfo structure.
2241 %
2242 %  The format of the GetQuantizeInfo method is:
2243 %
2244 %      GetQuantizeInfo(QuantizeInfo *quantize_info)
2245 %
2246 %  A description of each parameter follows:
2247 %
2248 %    o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2249 %
2250 */
2251 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2252 {
2253   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2254   assert(quantize_info != (QuantizeInfo *) NULL);
2255   (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2256   quantize_info->number_colors=256;
2257   quantize_info->dither=MagickTrue;
2258   quantize_info->dither_method=RiemersmaDitherMethod;
2259   quantize_info->colorspace=UndefinedColorspace;
2260   quantize_info->measure_error=MagickFalse;
2261   quantize_info->signature=MagickSignature;
2262 }
2263 \f
2264 /*
2265 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2266 %                                                                             %
2267 %                                                                             %
2268 %                                                                             %
2269 %     P o s t e r i z e I m a g e C h a n n e l                               %
2270 %                                                                             %
2271 %                                                                             %
2272 %                                                                             %
2273 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2274 %
2275 %  PosterizeImage() reduces the image to a limited number of colors for a
2276 %  "poster" effect.
2277 %
2278 %  The format of the PosterizeImage method is:
2279 %
2280 %      MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2281 %        const MagickBooleanType dither)
2282 %
2283 %  A description of each parameter follows:
2284 %
2285 %    o image: Specifies a pointer to an Image structure.
2286 %
2287 %    o levels: Number of color levels allowed in each channel.  Very low values
2288 %      (2, 3, or 4) have the most visible effect.
2289 %
2290 %    o dither: Set this integer value to something other than zero to dither
2291 %      the mapped image.
2292 %
2293 */
2294
2295 static inline ssize_t MagickRound(MagickRealType x)
2296 {
2297   /*
2298     Round the fraction to nearest integer.
2299   */
2300   if (x >= 0.0)
2301     return((ssize_t) (x+0.5));
2302   return((ssize_t) (x-0.5));
2303 }
2304
2305 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2306   const MagickBooleanType dither)
2307 {
2308 #define PosterizeImageTag  "Posterize/Image"
2309 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2310   QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2311
2312   CacheView
2313     *image_view;
2314
2315   ExceptionInfo
2316     *exception;
2317
2318   MagickBooleanType
2319     status;
2320
2321   MagickOffsetType
2322     progress;
2323
2324   QuantizeInfo
2325     *quantize_info;
2326
2327   register ssize_t
2328     i;
2329
2330   ssize_t
2331     y;
2332
2333   assert(image != (Image *) NULL);
2334   assert(image->signature == MagickSignature);
2335   if (image->debug != MagickFalse)
2336     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2337   if (image->storage_class == PseudoClass)
2338 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2339     #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2340 #endif
2341     for (i=0; i < (ssize_t) image->colors; i++)
2342     {
2343       /*
2344         Posterize colormap.
2345       */
2346       if ((GetPixelRedTraits(image) & ActivePixelTrait) != 0)
2347         image->colormap[i].red=PosterizePixel(image->colormap[i].red);
2348       if ((GetPixelGreenTraits(image) & ActivePixelTrait) != 0)
2349         image->colormap[i].green=PosterizePixel(image->colormap[i].green);
2350       if ((GetPixelBlueTraits(image) & ActivePixelTrait) != 0)
2351         image->colormap[i].blue=PosterizePixel(image->colormap[i].blue);
2352       if ((GetPixelAlphaTraits(image) & ActivePixelTrait) != 0)
2353         image->colormap[i].alpha=PosterizePixel(image->colormap[i].alpha);
2354     }
2355   /*
2356     Posterize image.
2357   */
2358   status=MagickTrue;
2359   progress=0;
2360   exception=(&image->exception);
2361   image_view=AcquireCacheView(image);
2362 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2363   #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2364 #endif
2365   for (y=0; y < (ssize_t) image->rows; y++)
2366   {
2367     register Quantum
2368       *restrict q;
2369
2370     register ssize_t
2371       x;
2372
2373     if (status == MagickFalse)
2374       continue;
2375     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2376     if (q == (const Quantum *) NULL)
2377       {
2378         status=MagickFalse;
2379         continue;
2380       }
2381     for (x=0; x < (ssize_t) image->columns; x++)
2382     {
2383       if ((GetPixelRedTraits(image) & ActivePixelTrait) != 0)
2384         SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2385       if ((GetPixelGreenTraits(image) & ActivePixelTrait) != 0)
2386         SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2387       if ((GetPixelBlueTraits(image) & ActivePixelTrait) != 0)
2388         SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2389       if (((GetPixelBlackTraits(image) & ActivePixelTrait) != 0) &&
2390           (image->colorspace == CMYKColorspace))
2391         SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2392       if (((GetPixelAlphaTraits(image) & ActivePixelTrait) != 0) &&
2393           (image->matte == MagickTrue))
2394         SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2395       q+=GetPixelComponents(image);
2396     }
2397     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2398       status=MagickFalse;
2399     if (image->progress_monitor != (MagickProgressMonitor) NULL)
2400       {
2401         MagickBooleanType
2402           proceed;
2403
2404 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2405         #pragma omp critical (MagickCore_PosterizeImage)
2406 #endif
2407         proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2408           image->rows);
2409         if (proceed == MagickFalse)
2410           status=MagickFalse;
2411       }
2412   }
2413   image_view=DestroyCacheView(image_view);
2414   quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2415   quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2416     levels,MaxColormapSize+1);
2417   quantize_info->dither=dither;
2418   quantize_info->tree_depth=MaxTreeDepth;
2419   status=QuantizeImage(quantize_info,image);
2420   quantize_info=DestroyQuantizeInfo(quantize_info);
2421   return(status);
2422 }
2423 \f
2424 /*
2425 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2426 %                                                                             %
2427 %                                                                             %
2428 %                                                                             %
2429 +   P r u n e C h i l d                                                       %
2430 %                                                                             %
2431 %                                                                             %
2432 %                                                                             %
2433 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2434 %
2435 %  PruneChild() deletes the given node and merges its statistics into its
2436 %  parent.
2437 %
2438 %  The format of the PruneSubtree method is:
2439 %
2440 %      PruneChild(const Image *image,CubeInfo *cube_info,
2441 %        const NodeInfo *node_info)
2442 %
2443 %  A description of each parameter follows.
2444 %
2445 %    o image: the image.
2446 %
2447 %    o cube_info: A pointer to the Cube structure.
2448 %
2449 %    o node_info: pointer to node in color cube tree that is to be pruned.
2450 %
2451 */
2452 static void PruneChild(const Image *image,CubeInfo *cube_info,
2453   const NodeInfo *node_info)
2454 {
2455   NodeInfo
2456     *parent;
2457
2458   register ssize_t
2459     i;
2460
2461   size_t
2462     number_children;
2463
2464   /*
2465     Traverse any children.
2466   */
2467   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2468   for (i=0; i < (ssize_t) number_children; i++)
2469     if (node_info->child[i] != (NodeInfo *) NULL)
2470       PruneChild(image,cube_info,node_info->child[i]);
2471   /*
2472     Merge color statistics into parent.
2473   */
2474   parent=node_info->parent;
2475   parent->number_unique+=node_info->number_unique;
2476   parent->total_color.red+=node_info->total_color.red;
2477   parent->total_color.green+=node_info->total_color.green;
2478   parent->total_color.blue+=node_info->total_color.blue;
2479   parent->total_color.alpha+=node_info->total_color.alpha;
2480   parent->child[node_info->id]=(NodeInfo *) NULL;
2481   cube_info->nodes--;
2482 }
2483 \f
2484 /*
2485 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2486 %                                                                             %
2487 %                                                                             %
2488 %                                                                             %
2489 +  P r u n e L e v e l                                                        %
2490 %                                                                             %
2491 %                                                                             %
2492 %                                                                             %
2493 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2494 %
2495 %  PruneLevel() deletes all nodes at the bottom level of the color tree merging
2496 %  their color statistics into their parent node.
2497 %
2498 %  The format of the PruneLevel method is:
2499 %
2500 %      PruneLevel(const Image *image,CubeInfo *cube_info,
2501 %        const NodeInfo *node_info)
2502 %
2503 %  A description of each parameter follows.
2504 %
2505 %    o image: the image.
2506 %
2507 %    o cube_info: A pointer to the Cube structure.
2508 %
2509 %    o node_info: pointer to node in color cube tree that is to be pruned.
2510 %
2511 */
2512 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2513   const NodeInfo *node_info)
2514 {
2515   register ssize_t
2516     i;
2517
2518   size_t
2519     number_children;
2520
2521   /*
2522     Traverse any children.
2523   */
2524   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2525   for (i=0; i < (ssize_t) number_children; i++)
2526     if (node_info->child[i] != (NodeInfo *) NULL)
2527       PruneLevel(image,cube_info,node_info->child[i]);
2528   if (node_info->level == cube_info->depth)
2529     PruneChild(image,cube_info,node_info);
2530 }
2531 \f
2532 /*
2533 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2534 %                                                                             %
2535 %                                                                             %
2536 %                                                                             %
2537 +  P r u n e T o C u b e D e p t h                                            %
2538 %                                                                             %
2539 %                                                                             %
2540 %                                                                             %
2541 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2542 %
2543 %  PruneToCubeDepth() deletes any nodes at a depth greater than
2544 %  cube_info->depth while merging their color statistics into their parent
2545 %  node.
2546 %
2547 %  The format of the PruneToCubeDepth method is:
2548 %
2549 %      PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2550 %        const NodeInfo *node_info)
2551 %
2552 %  A description of each parameter follows.
2553 %
2554 %    o cube_info: A pointer to the Cube structure.
2555 %
2556 %    o node_info: pointer to node in color cube tree that is to be pruned.
2557 %
2558 */
2559 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2560   const NodeInfo *node_info)
2561 {
2562   register ssize_t
2563     i;
2564
2565   size_t
2566     number_children;
2567
2568   /*
2569     Traverse any children.
2570   */
2571   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2572   for (i=0; i < (ssize_t) number_children; i++)
2573     if (node_info->child[i] != (NodeInfo *) NULL)
2574       PruneToCubeDepth(image,cube_info,node_info->child[i]);
2575   if (node_info->level > cube_info->depth)
2576     PruneChild(image,cube_info,node_info);
2577 }
2578 \f
2579 /*
2580 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2581 %                                                                             %
2582 %                                                                             %
2583 %                                                                             %
2584 %  Q u a n t i z e I m a g e                                                  %
2585 %                                                                             %
2586 %                                                                             %
2587 %                                                                             %
2588 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2589 %
2590 %  QuantizeImage() analyzes the colors within a reference image and chooses a
2591 %  fixed number of colors to represent the image.  The goal of the algorithm
2592 %  is to minimize the color difference between the input and output image while
2593 %  minimizing the processing time.
2594 %
2595 %  The format of the QuantizeImage method is:
2596 %
2597 %      MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2598 %        Image *image)
2599 %
2600 %  A description of each parameter follows:
2601 %
2602 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2603 %
2604 %    o image: the image.
2605 %
2606 */
2607 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2608   Image *image)
2609 {
2610   CubeInfo
2611     *cube_info;
2612
2613   MagickBooleanType
2614     status;
2615
2616   size_t
2617     depth,
2618     maximum_colors;
2619
2620   assert(quantize_info != (const QuantizeInfo *) NULL);
2621   assert(quantize_info->signature == MagickSignature);
2622   assert(image != (Image *) NULL);
2623   assert(image->signature == MagickSignature);
2624   if (image->debug != MagickFalse)
2625     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2626   maximum_colors=quantize_info->number_colors;
2627   if (maximum_colors == 0)
2628     maximum_colors=MaxColormapSize;
2629   if (maximum_colors > MaxColormapSize)
2630     maximum_colors=MaxColormapSize;
2631   if ((IsImageGray(image,&image->exception) != MagickFalse) &&
2632       (image->matte == MagickFalse))
2633     (void) SetGrayscaleImage(image);
2634   if ((image->storage_class == PseudoClass) &&
2635       (image->colors <= maximum_colors))
2636     return(MagickTrue);
2637   depth=quantize_info->tree_depth;
2638   if (depth == 0)
2639     {
2640       size_t
2641         colors;
2642
2643       /*
2644         Depth of color tree is: Log4(colormap size)+2.
2645       */
2646       colors=maximum_colors;
2647       for (depth=1; colors != 0; depth++)
2648         colors>>=2;
2649       if ((quantize_info->dither != MagickFalse) && (depth > 2))
2650         depth--;
2651       if ((image->matte != MagickFalse) && (depth > 5))
2652         depth--;
2653     }
2654   /*
2655     Initialize color cube.
2656   */
2657   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2658   if (cube_info == (CubeInfo *) NULL)
2659     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2660       image->filename);
2661   status=ClassifyImageColors(cube_info,image,&image->exception);
2662   if (status != MagickFalse)
2663     {
2664       /*
2665         Reduce the number of colors in the image.
2666       */
2667       ReduceImageColors(image,cube_info);
2668       status=AssignImageColors(image,cube_info);
2669     }
2670   DestroyCubeInfo(cube_info);
2671   return(status);
2672 }
2673 \f
2674 /*
2675 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2676 %                                                                             %
2677 %                                                                             %
2678 %                                                                             %
2679 %   Q u a n t i z e I m a g e s                                               %
2680 %                                                                             %
2681 %                                                                             %
2682 %                                                                             %
2683 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2684 %
2685 %  QuantizeImages() analyzes the colors within a set of reference images and
2686 %  chooses a fixed number of colors to represent the set.  The goal of the
2687 %  algorithm is to minimize the color difference between the input and output
2688 %  images while minimizing the processing time.
2689 %
2690 %  The format of the QuantizeImages method is:
2691 %
2692 %      MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2693 %        Image *images)
2694 %
2695 %  A description of each parameter follows:
2696 %
2697 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2698 %
2699 %    o images: Specifies a pointer to a list of Image structures.
2700 %
2701 */
2702 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2703   Image *images)
2704 {
2705   CubeInfo
2706     *cube_info;
2707
2708   Image
2709     *image;
2710
2711   MagickBooleanType
2712     proceed,
2713     status;
2714
2715   MagickProgressMonitor
2716     progress_monitor;
2717
2718   register ssize_t
2719     i;
2720
2721   size_t
2722     depth,
2723     maximum_colors,
2724     number_images;
2725
2726   assert(quantize_info != (const QuantizeInfo *) NULL);
2727   assert(quantize_info->signature == MagickSignature);
2728   assert(images != (Image *) NULL);
2729   assert(images->signature == MagickSignature);
2730   if (images->debug != MagickFalse)
2731     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2732   if (GetNextImageInList(images) == (Image *) NULL)
2733     {
2734       /*
2735         Handle a single image with QuantizeImage.
2736       */
2737       status=QuantizeImage(quantize_info,images);
2738       return(status);
2739     }
2740   status=MagickFalse;
2741   maximum_colors=quantize_info->number_colors;
2742   if (maximum_colors == 0)
2743     maximum_colors=MaxColormapSize;
2744   if (maximum_colors > MaxColormapSize)
2745     maximum_colors=MaxColormapSize;
2746   depth=quantize_info->tree_depth;
2747   if (depth == 0)
2748     {
2749       size_t
2750         colors;
2751
2752       /*
2753         Depth of color tree is: Log4(colormap size)+2.
2754       */
2755       colors=maximum_colors;
2756       for (depth=1; colors != 0; depth++)
2757         colors>>=2;
2758       if (quantize_info->dither != MagickFalse)
2759         depth--;
2760     }
2761   /*
2762     Initialize color cube.
2763   */
2764   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2765   if (cube_info == (CubeInfo *) NULL)
2766     {
2767       (void) ThrowMagickException(&images->exception,GetMagickModule(),
2768         ResourceLimitError,"MemoryAllocationFailed","`%s'",images->filename);
2769       return(MagickFalse);
2770     }
2771   number_images=GetImageListLength(images);
2772   image=images;
2773   for (i=0; image != (Image *) NULL; i++)
2774   {
2775     progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2776       image->client_data);
2777     status=ClassifyImageColors(cube_info,image,&image->exception);
2778     if (status == MagickFalse)
2779       break;
2780     (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2781     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2782       number_images);
2783     if (proceed == MagickFalse)
2784       break;
2785     image=GetNextImageInList(image);
2786   }
2787   if (status != MagickFalse)
2788     {
2789       /*
2790         Reduce the number of colors in an image sequence.
2791       */
2792       ReduceImageColors(images,cube_info);
2793       image=images;
2794       for (i=0; image != (Image *) NULL; i++)
2795       {
2796         progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2797           NULL,image->client_data);
2798         status=AssignImageColors(image,cube_info);
2799         if (status == MagickFalse)
2800           break;
2801         (void) SetImageProgressMonitor(image,progress_monitor,
2802           image->client_data);
2803         proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2804           number_images);
2805         if (proceed == MagickFalse)
2806           break;
2807         image=GetNextImageInList(image);
2808       }
2809     }
2810   DestroyCubeInfo(cube_info);
2811   return(status);
2812 }
2813 \f
2814 /*
2815 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2816 %                                                                             %
2817 %                                                                             %
2818 %                                                                             %
2819 +   R e d u c e                                                               %
2820 %                                                                             %
2821 %                                                                             %
2822 %                                                                             %
2823 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2824 %
2825 %  Reduce() traverses the color cube tree and prunes any node whose
2826 %  quantization error falls below a particular threshold.
2827 %
2828 %  The format of the Reduce method is:
2829 %
2830 %      Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2831 %
2832 %  A description of each parameter follows.
2833 %
2834 %    o image: the image.
2835 %
2836 %    o cube_info: A pointer to the Cube structure.
2837 %
2838 %    o node_info: pointer to node in color cube tree that is to be pruned.
2839 %
2840 */
2841 static void Reduce(const Image *image,CubeInfo *cube_info,
2842   const NodeInfo *node_info)
2843 {
2844   register ssize_t
2845     i;
2846
2847   size_t
2848     number_children;
2849
2850   /*
2851     Traverse any children.
2852   */
2853   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2854   for (i=0; i < (ssize_t) number_children; i++)
2855     if (node_info->child[i] != (NodeInfo *) NULL)
2856       Reduce(image,cube_info,node_info->child[i]);
2857   if (node_info->quantize_error <= cube_info->pruning_threshold)
2858     PruneChild(image,cube_info,node_info);
2859   else
2860     {
2861       /*
2862         Find minimum pruning threshold.
2863       */
2864       if (node_info->number_unique > 0)
2865         cube_info->colors++;
2866       if (node_info->quantize_error < cube_info->next_threshold)
2867         cube_info->next_threshold=node_info->quantize_error;
2868     }
2869 }
2870 \f
2871 /*
2872 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2873 %                                                                             %
2874 %                                                                             %
2875 %                                                                             %
2876 +   R e d u c e I m a g e C o l o r s                                         %
2877 %                                                                             %
2878 %                                                                             %
2879 %                                                                             %
2880 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2881 %
2882 %  ReduceImageColors() repeatedly prunes the tree until the number of nodes
2883 %  with n2 > 0 is less than or equal to the maximum number of colors allowed
2884 %  in the output image.  On any given iteration over the tree, it selects
2885 %  those nodes whose E value is minimal for pruning and merges their
2886 %  color statistics upward. It uses a pruning threshold, Ep, to govern
2887 %  node selection as follows:
2888 %
2889 %    Ep = 0
2890 %    while number of nodes with (n2 > 0) > required maximum number of colors
2891 %      prune all nodes such that E <= Ep
2892 %      Set Ep to minimum E in remaining nodes
2893 %
2894 %  This has the effect of minimizing any quantization error when merging
2895 %  two nodes together.
2896 %
2897 %  When a node to be pruned has offspring, the pruning procedure invokes
2898 %  itself recursively in order to prune the tree from the leaves upward.
2899 %  n2,  Sr, Sg,  and  Sb in a node being pruned are always added to the
2900 %  corresponding data in that node's parent.  This retains the pruned
2901 %  node's color characteristics for later averaging.
2902 %
2903 %  For each node, n2 pixels exist for which that node represents the
2904 %  smallest volume in RGB space containing those pixel's colors.  When n2
2905 %  > 0 the node will uniquely define a color in the output image. At the
2906 %  beginning of reduction,  n2 = 0  for all nodes except a the leaves of
2907 %  the tree which represent colors present in the input image.
2908 %
2909 %  The other pixel count, n1, indicates the total number of colors
2910 %  within the cubic volume which the node represents.  This includes n1 -
2911 %  n2  pixels whose colors should be defined by nodes at a lower level in
2912 %  the tree.
2913 %
2914 %  The format of the ReduceImageColors method is:
2915 %
2916 %      ReduceImageColors(const Image *image,CubeInfo *cube_info)
2917 %
2918 %  A description of each parameter follows.
2919 %
2920 %    o image: the image.
2921 %
2922 %    o cube_info: A pointer to the Cube structure.
2923 %
2924 */
2925 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
2926 {
2927 #define ReduceImageTag  "Reduce/Image"
2928
2929   MagickBooleanType
2930     proceed;
2931
2932   MagickOffsetType
2933     offset;
2934
2935   size_t
2936     span;
2937
2938   cube_info->next_threshold=0.0;
2939   for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
2940   {
2941     cube_info->pruning_threshold=cube_info->next_threshold;
2942     cube_info->next_threshold=cube_info->root->quantize_error-1;
2943     cube_info->colors=0;
2944     Reduce(image,cube_info,cube_info->root);
2945     offset=(MagickOffsetType) span-cube_info->colors;
2946     proceed=SetImageProgress(image,ReduceImageTag,offset,span-
2947       cube_info->maximum_colors+1);
2948     if (proceed == MagickFalse)
2949       break;
2950   }
2951 }
2952 \f
2953 /*
2954 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2955 %                                                                             %
2956 %                                                                             %
2957 %                                                                             %
2958 %   R e m a p I m a g e                                                       %
2959 %                                                                             %
2960 %                                                                             %
2961 %                                                                             %
2962 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2963 %
2964 %  RemapImage() replaces the colors of an image with the closest color from
2965 %  a reference image.
2966 %
2967 %  The format of the RemapImage method is:
2968 %
2969 %      MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
2970 %        Image *image,const Image *remap_image)
2971 %
2972 %  A description of each parameter follows:
2973 %
2974 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2975 %
2976 %    o image: the image.
2977 %
2978 %    o remap_image: the reference image.
2979 %
2980 */
2981 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
2982   Image *image,const Image *remap_image)
2983 {
2984   CubeInfo
2985     *cube_info;
2986
2987   MagickBooleanType
2988     status;
2989
2990   /*
2991     Initialize color cube.
2992   */
2993   assert(image != (Image *) NULL);
2994   assert(image->signature == MagickSignature);
2995   if (image->debug != MagickFalse)
2996     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2997   assert(remap_image != (Image *) NULL);
2998   assert(remap_image->signature == MagickSignature);
2999   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3000     quantize_info->number_colors);
3001   if (cube_info == (CubeInfo *) NULL)
3002     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3003       image->filename);
3004   status=ClassifyImageColors(cube_info,remap_image,&image->exception);
3005   if (status != MagickFalse)
3006     {
3007       /*
3008         Classify image colors from the reference image.
3009       */
3010       cube_info->quantize_info->number_colors=cube_info->colors;
3011       status=AssignImageColors(image,cube_info);
3012     }
3013   DestroyCubeInfo(cube_info);
3014   return(status);
3015 }
3016 \f
3017 /*
3018 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3019 %                                                                             %
3020 %                                                                             %
3021 %                                                                             %
3022 %   R e m a p I m a g e s                                                     %
3023 %                                                                             %
3024 %                                                                             %
3025 %                                                                             %
3026 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3027 %
3028 %  RemapImages() replaces the colors of a sequence of images with the
3029 %  closest color from a reference image.
3030 %
3031 %  The format of the RemapImage method is:
3032 %
3033 %      MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3034 %        Image *images,Image *remap_image)
3035 %
3036 %  A description of each parameter follows:
3037 %
3038 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3039 %
3040 %    o images: the image sequence.
3041 %
3042 %    o remap_image: the reference image.
3043 %
3044 */
3045 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3046   Image *images,const Image *remap_image)
3047 {
3048   CubeInfo
3049     *cube_info;
3050
3051   Image
3052     *image;
3053
3054   MagickBooleanType
3055     status;
3056
3057   assert(images != (Image *) NULL);
3058   assert(images->signature == MagickSignature);
3059   if (images->debug != MagickFalse)
3060     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3061   image=images;
3062   if (remap_image == (Image *) NULL)
3063     {
3064       /*
3065         Create a global colormap for an image sequence.
3066       */
3067       status=QuantizeImages(quantize_info,images);
3068       return(status);
3069     }
3070   /*
3071     Classify image colors from the reference image.
3072   */
3073   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3074     quantize_info->number_colors);
3075   if (cube_info == (CubeInfo *) NULL)
3076     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3077       image->filename);
3078   status=ClassifyImageColors(cube_info,remap_image,&image->exception);
3079   if (status != MagickFalse)
3080     {
3081       /*
3082         Classify image colors from the reference image.
3083       */
3084       cube_info->quantize_info->number_colors=cube_info->colors;
3085       image=images;
3086       for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3087       {
3088         status=AssignImageColors(image,cube_info);
3089         if (status == MagickFalse)
3090           break;
3091       }
3092     }
3093   DestroyCubeInfo(cube_info);
3094   return(status);
3095 }
3096 \f
3097 /*
3098 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3099 %                                                                             %
3100 %                                                                             %
3101 %                                                                             %
3102 %   S e t G r a y s c a l e I m a g e                                         %
3103 %                                                                             %
3104 %                                                                             %
3105 %                                                                             %
3106 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3107 %
3108 %  SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3109 %
3110 %  The format of the SetGrayscaleImage method is:
3111 %
3112 %      MagickBooleanType SetGrayscaleImage(Image *image)
3113 %
3114 %  A description of each parameter follows:
3115 %
3116 %    o image: The image.
3117 %
3118 */
3119
3120 #if defined(__cplusplus) || defined(c_plusplus)
3121 extern "C" {
3122 #endif
3123
3124 static int IntensityCompare(const void *x,const void *y)
3125 {
3126   PixelPacket
3127     *color_1,
3128     *color_2;
3129
3130   ssize_t
3131     intensity;
3132
3133   color_1=(PixelPacket *) x;
3134   color_2=(PixelPacket *) y;
3135   intensity=GetPixelPacketIntensity(color_1)-(ssize_t)
3136     GetPixelPacketIntensity(color_2);
3137   return((int) intensity);
3138 }
3139
3140 #if defined(__cplusplus) || defined(c_plusplus)
3141 }
3142 #endif
3143
3144 static MagickBooleanType SetGrayscaleImage(Image *image)
3145 {
3146   CacheView
3147     *image_view;
3148
3149   ExceptionInfo
3150     *exception;
3151
3152   MagickBooleanType
3153     status;
3154
3155   PixelPacket
3156     *colormap;
3157
3158   register ssize_t
3159     i;
3160
3161   ssize_t
3162     *colormap_index,
3163     j,
3164     y;
3165
3166   assert(image != (Image *) NULL);
3167   assert(image->signature == MagickSignature);
3168   if (image->type != GrayscaleType)
3169     (void) TransformImageColorspace(image,GRAYColorspace);
3170   colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3171     sizeof(*colormap_index));
3172   if (colormap_index == (ssize_t *) NULL)
3173     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3174       image->filename);
3175   if (image->storage_class != PseudoClass)
3176     {
3177       ExceptionInfo
3178         *exception;
3179
3180       for (i=0; i <= (ssize_t) MaxMap; i++)
3181         colormap_index[i]=(-1);
3182       if (AcquireImageColormap(image,MaxMap+1) == MagickFalse)
3183         ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3184           image->filename);
3185       image->colors=0;
3186       status=MagickTrue;
3187       exception=(&image->exception);
3188       image_view=AcquireCacheView(image);
3189 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3190       #pragma omp parallel for schedule(dynamic,4) shared(status)
3191 #endif
3192       for (y=0; y < (ssize_t) image->rows; y++)
3193       {
3194         register Quantum
3195           *restrict q;
3196
3197         register ssize_t
3198           x;
3199
3200         if (status == MagickFalse)
3201           continue;
3202         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3203           exception);
3204         if (q == (const Quantum *) NULL)
3205           {
3206             status=MagickFalse;
3207             continue;
3208           }
3209         for (x=0; x < (ssize_t) image->columns; x++)
3210         {
3211           register size_t
3212             intensity;
3213
3214           intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3215           if (colormap_index[intensity] < 0)
3216             {
3217 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3218     #pragma omp critical (MagickCore_SetGrayscaleImage)
3219 #endif
3220               if (colormap_index[intensity] < 0)
3221                 {
3222                   colormap_index[intensity]=(ssize_t) image->colors;
3223                   image->colormap[image->colors].red=GetPixelRed(image,q);
3224                   image->colormap[image->colors].green=GetPixelGreen(image,q);
3225                   image->colormap[image->colors].blue=GetPixelBlue(image,q);
3226                   image->colors++;
3227                }
3228             }
3229           SetPixelIndex(image,(Quantum)
3230             colormap_index[intensity],q);
3231           q+=GetPixelComponents(image);
3232         }
3233         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3234           status=MagickFalse;
3235       }
3236       image_view=DestroyCacheView(image_view);
3237     }
3238   for (i=0; i < (ssize_t) image->colors; i++)
3239     image->colormap[i].alpha=(unsigned short) i;
3240   qsort((void *) image->colormap,image->colors,sizeof(PixelPacket),
3241     IntensityCompare);
3242   colormap=(PixelPacket *) AcquireQuantumMemory(image->colors,
3243     sizeof(*colormap));
3244   if (colormap == (PixelPacket *) NULL)
3245     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3246       image->filename);
3247   j=0;
3248   colormap[j]=image->colormap[0];
3249   for (i=0; i < (ssize_t) image->colors; i++)
3250   {
3251     if (IsPixelPacketEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3252       {
3253         j++;
3254         colormap[j]=image->colormap[i];
3255       }
3256     colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3257   }
3258   image->colors=(size_t) (j+1);
3259   image->colormap=(PixelPacket *) RelinquishMagickMemory(image->colormap);
3260   image->colormap=colormap;
3261   status=MagickTrue;
3262   exception=(&image->exception);
3263   image_view=AcquireCacheView(image);
3264 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3265   #pragma omp parallel for schedule(dynamic,4) shared(status)
3266 #endif
3267   for (y=0; y < (ssize_t) image->rows; y++)
3268   {
3269     register Quantum
3270       *restrict q;
3271
3272     register ssize_t
3273       x;
3274
3275     if (status == MagickFalse)
3276       continue;
3277     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3278     if (q == (const Quantum *) NULL)
3279       {
3280         status=MagickFalse;
3281         continue;
3282       }
3283     for (x=0; x < (ssize_t) image->columns; x++)
3284     {
3285       SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3286         GetPixelIndex(image,q))],q);
3287       q+=GetPixelComponents(image);
3288     }
3289     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3290       status=MagickFalse;
3291   }
3292   image_view=DestroyCacheView(image_view);
3293   colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3294   image->type=GrayscaleType;
3295   if (IsImageMonochrome(image,&image->exception) != MagickFalse)
3296     image->type=BilevelType;
3297   return(status);
3298 }