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 1999-2012 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/resource_.h"
 201 #include "MagickCore/string_.h"
 202 #include "MagickCore/thread-private.h"
 203 \f
 204 /*
 205   Define declarations.
 206 */
 207 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
 208 #define CacheShift  2
 209 #else
 210 #define CacheShift  3
 211 #endif
 212 #define ErrorQueueLength  16
 213 #define MaxNodes  266817
 214 #define MaxTreeDepth  8
 215 #define NodesInAList  1920
 216 \f
 217 /*
 218   Typdef declarations.
 219 */
 220 typedef struct _RealPixelInfo
 221 {
 222   MagickRealType
 223     red,
 224     green,
 225     blue,
 226     alpha;
 227 } RealPixelInfo;
 228
 229 typedef struct _NodeInfo
 230 {
 231   struct _NodeInfo
 232     *parent,
 233     *child[16];
 234
 235   MagickSizeType
 236     number_unique;
 237
 238   RealPixelInfo
 239     total_color;
 240
 241   MagickRealType
 242     quantize_error;
 243
 244   size_t
 245     color_number,
 246     id,
 247     level;
 248 } NodeInfo;
 249
 250 typedef struct _Nodes
 251 {
 252   NodeInfo
 253     *nodes;
 254
 255   struct _Nodes
 256     *next;
 257 } Nodes;
 258
 259 typedef struct _CubeInfo
 260 {
 261   NodeInfo
 262     *root;
 263
 264   size_t
 265     colors,
 266     maximum_colors;
 267
 268   ssize_t
 269     transparent_index;
 270
 271   MagickSizeType
 272     transparent_pixels;
 273
 274   RealPixelInfo
 275     target;
 276
 277   MagickRealType
 278     distance,
 279     pruning_threshold,
 280     next_threshold;
 281
 282   size_t
 283     nodes,
 284     free_nodes,
 285     color_number;
 286
 287   NodeInfo
 288     *next_node;
 289
 290   Nodes
 291     *node_queue;
 292
 293   ssize_t
 294     *cache;
 295
 296   RealPixelInfo
 297     error[ErrorQueueLength];
 298
 299   MagickRealType
 300     weights[ErrorQueueLength];
 301
 302   QuantizeInfo
 303     *quantize_info;
 304
 305   MagickBooleanType
 306     associate_alpha;
 307
 308   ssize_t
 309     x,
 310     y;
 311
 312   size_t
 313     depth;
 314
 315   MagickOffsetType
 316     offset;
 317
 318   MagickSizeType
 319     span;
 320 } CubeInfo;
 321 \f
 322 /*
 323   Method prototypes.
 324 */
 325 static CubeInfo
 326   *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
 327
 328 static NodeInfo
 329   *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
 330
 331 static MagickBooleanType
 332   AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
 333   ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
 334   DitherImage(Image *,CubeInfo *,ExceptionInfo *),
 335   SetGrayscaleImage(Image *,ExceptionInfo *);
 336
 337 static size_t
 338   DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
 339
 340 static void
 341   ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
 342   DestroyCubeInfo(CubeInfo *),
 343   PruneLevel(const Image *,CubeInfo *,const NodeInfo *),
 344   PruneToCubeDepth(const Image *,CubeInfo *,const NodeInfo *),
 345   ReduceImageColors(const Image *,CubeInfo *);
 346 \f
 347 /*
 348 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 349 %                                                                             %
 350 %                                                                             %
 351 %                                                                             %
 352 %   A c q u i r e Q u a n t i z e I n f o                                     %
 353 %                                                                             %
 354 %                                                                             %
 355 %                                                                             %
 356 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 357 %
 358 %  AcquireQuantizeInfo() allocates the QuantizeInfo structure.
 359 %
 360 %  The format of the AcquireQuantizeInfo method is:
 361 %
 362 %      QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 363 %
 364 %  A description of each parameter follows:
 365 %
 366 %    o image_info: the image info.
 367 %
 368 */
 369 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 370 {
 371   QuantizeInfo
 372     *quantize_info;
 373
 374   quantize_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*quantize_info));
 375   if (quantize_info == (QuantizeInfo *) NULL)
 376     ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
 377   GetQuantizeInfo(quantize_info);
 378   if (image_info != (ImageInfo *) NULL)
 379     {
 380       const char
 381         *option;
 382
 383       quantize_info->dither=image_info->dither;
 384       option=GetImageOption(image_info,"dither");
 385       if (option != (const char *) NULL)
 386         quantize_info->dither_method=(DitherMethod) ParseCommandOption(
 387           MagickDitherOptions,MagickFalse,option);
 388       quantize_info->measure_error=image_info->verbose;
 389     }
 390   return(quantize_info);
 391 }
 392 \f
 393 /*
 394 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 395 %                                                                             %
 396 %                                                                             %
 397 %                                                                             %
 398 +   A s s i g n I m a g e C o l o r s                                         %
 399 %                                                                             %
 400 %                                                                             %
 401 %                                                                             %
 402 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 403 %
 404 %  AssignImageColors() generates the output image from the pruned tree.  The
 405 %  output image consists of two parts: (1)  A color map, which is an array
 406 %  of color descriptions (RGB triples) for each color present in the
 407 %  output image;  (2)  A pixel array, which represents each pixel as an
 408 %  index into the color map array.
 409 %
 410 %  First, the assignment phase makes one pass over the pruned color
 411 %  description tree to establish the image's color map.  For each node
 412 %  with n2  > 0, it divides Sr, Sg, and Sb by n2 .  This produces the mean
 413 %  color of all pixels that classify no lower than this node.  Each of
 414 %  these colors becomes an entry in the color map.
 415 %
 416 %  Finally,  the assignment phase reclassifies each pixel in the pruned
 417 %  tree to identify the deepest node containing the pixel's color.  The
 418 %  pixel's value in the pixel array becomes the index of this node's mean
 419 %  color in the color map.
 420 %
 421 %  The format of the AssignImageColors() method is:
 422 %
 423 %      MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
 424 %
 425 %  A description of each parameter follows.
 426 %
 427 %    o image: the image.
 428 %
 429 %    o cube_info: A pointer to the Cube structure.
 430 %
 431 */
 432
 433 static inline void AssociateAlphaPixel(const Image *image,
 434   const CubeInfo *cube_info,const Quantum *pixel,RealPixelInfo *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 AssociateAlphaPixelInfo(const Image *image,
 456   const CubeInfo *cube_info,const PixelInfo *pixel,
 457   RealPixelInfo *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 RealPixelInfo *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   ExceptionInfo *exception)
 503 {
 504 #define AssignImageTag  "Assign/Image"
 505
 506   ssize_t
 507     y;
 508
 509   /*
 510     Allocate image colormap.
 511   */
 512   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 513       (cube_info->quantize_info->colorspace != CMYKColorspace))
 514     (void) TransformImageColorspace((Image *) image,
 515       cube_info->quantize_info->colorspace,exception);
 516   else
 517     if ((image->colorspace != GRAYColorspace) &&
 518         (IssRGBColorspace(image->colorspace) == MagickFalse) &&
 519         (image->colorspace != CMYColorspace))
 520       (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 521   if (AcquireImageColormap(image,cube_info->colors,exception) == MagickFalse)
 522     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
 523       image->filename);
 524   image->colors=0;
 525   cube_info->transparent_pixels=0;
 526   cube_info->transparent_index=(-1);
 527   (void) DefineImageColormap(image,cube_info,cube_info->root);
 528   /*
 529     Create a reduced color image.
 530   */
 531   if ((cube_info->quantize_info->dither != MagickFalse) &&
 532       (cube_info->quantize_info->dither_method != NoDitherMethod))
 533     (void) DitherImage(image,cube_info,exception);
 534   else
 535     {
 536       CacheView
 537         *image_view;
 538
 539       MagickBooleanType
 540         status;
 541
 542       status=MagickTrue;
 543       image_view=AcquireAuthenticCacheView(image,exception);
 544 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 545       #pragma omp parallel for schedule(static,4) shared(status) \
 546         dynamic_number_threads(image->columns,image->rows,1)
 547 #endif
 548       for (y=0; y < (ssize_t) image->rows; y++)
 549       {
 550         CubeInfo
 551           cube;
 552
 553         register Quantum
 554           *restrict q;
 555
 556         register ssize_t
 557           x;
 558
 559         ssize_t
 560           count;
 561
 562         if (status == MagickFalse)
 563           continue;
 564         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
 565           exception);
 566         if (q == (Quantum *) NULL)
 567           {
 568             status=MagickFalse;
 569             continue;
 570           }
 571         cube=(*cube_info);
 572         for (x=0; x < (ssize_t) image->columns; x+=count)
 573         {
 574           RealPixelInfo
 575             pixel;
 576
 577           register const NodeInfo
 578             *node_info;
 579
 580           register ssize_t
 581             i;
 582
 583           size_t
 584             id,
 585             index;
 586
 587           /*
 588             Identify the deepest node containing the pixel's color.
 589           */
 590           for (count=1; (x+count) < (ssize_t) image->columns; count++)
 591           {
 592             PixelInfo
 593               packet;
 594
 595             GetPixelInfoPixel(image,q+count*GetPixelChannels(image),&packet);
 596             if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
 597               break;
 598           }
 599           AssociateAlphaPixel(image,&cube,q,&pixel);
 600           node_info=cube.root;
 601           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
 602           {
 603             id=ColorToNodeId(&cube,&pixel,index);
 604             if (node_info->child[id] == (NodeInfo *) NULL)
 605               break;
 606             node_info=node_info->child[id];
 607           }
 608           /*
 609             Find closest color among siblings and their children.
 610           */
 611           cube.target=pixel;
 612           cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*
 613             (QuantumRange+1.0)+1.0);
 614           ClosestColor(image,&cube,node_info->parent);
 615           index=cube.color_number;
 616           for (i=0; i < (ssize_t) count; i++)
 617           {
 618             if (image->storage_class == PseudoClass)
 619               SetPixelIndex(image,(Quantum) index,q);
 620             if (cube.quantize_info->measure_error == MagickFalse)
 621               {
 622                 SetPixelRed(image,ClampToQuantum(
 623                   image->colormap[index].red),q);
 624                 SetPixelGreen(image,ClampToQuantum(
 625                   image->colormap[index].green),q);
 626                 SetPixelBlue(image,ClampToQuantum(
 627                   image->colormap[index].blue),q);
 628                 if (cube.associate_alpha != MagickFalse)
 629                   SetPixelAlpha(image,ClampToQuantum(
 630                     image->colormap[index].alpha),q);
 631               }
 632             q+=GetPixelChannels(image);
 633           }
 634         }
 635         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 636           status=MagickFalse;
 637         if (image->progress_monitor != (MagickProgressMonitor) NULL)
 638           {
 639             MagickBooleanType
 640               proceed;
 641
 642 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 643             #pragma omp critical (MagickCore_AssignImageColors)
 644 #endif
 645             proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
 646               image->rows);
 647             if (proceed == MagickFalse)
 648               status=MagickFalse;
 649           }
 650       }
 651       image_view=DestroyCacheView(image_view);
 652     }
 653   if (cube_info->quantize_info->measure_error != MagickFalse)
 654     (void) GetImageQuantizeError(image,exception);
 655   if ((cube_info->quantize_info->number_colors == 2) &&
 656       (cube_info->quantize_info->colorspace == GRAYColorspace))
 657     {
 658       double
 659         intensity;
 660
 661       register PixelInfo
 662         *restrict q;
 663
 664       register ssize_t
 665         i;
 666
 667       /*
 668         Monochrome image.
 669       */
 670       q=image->colormap;
 671       for (i=0; i < (ssize_t) image->colors; i++)
 672       {
 673         intensity=(double) ((MagickRealType) GetPixelInfoIntensity(q) <
 674           ((MagickRealType) QuantumRange/2.0) ? 0 : QuantumRange);
 675         q->red=intensity;
 676         q->green=intensity;
 677         q->blue=intensity;
 678         q++;
 679       }
 680     }
 681   (void) SyncImage(image,exception);
 682   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 683       (cube_info->quantize_info->colorspace != CMYKColorspace))
 684     (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 685   return(MagickTrue);
 686 }
 687 \f
 688 /*
 689 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 690 %                                                                             %
 691 %                                                                             %
 692 %                                                                             %
 693 +   C l a s s i f y I m a g e C o l o r s                                     %
 694 %                                                                             %
 695 %                                                                             %
 696 %                                                                             %
 697 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 698 %
 699 %  ClassifyImageColors() begins by initializing a color description tree
 700 %  of sufficient depth to represent each possible input color in a leaf.
 701 %  However, it is impractical to generate a fully-formed color
 702 %  description tree in the storage_class phase for realistic values of
 703 %  Cmax.  If colors components in the input image are quantized to k-bit
 704 %  precision, so that Cmax= 2k-1, the tree would need k levels below the
 705 %  root node to allow representing each possible input color in a leaf.
 706 %  This becomes prohibitive because the tree's total number of nodes is
 707 %  1 + sum(i=1,k,8k).
 708 %
 709 %  A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
 710 %  Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
 711 %  Initializes data structures for nodes only as they are needed;  (2)
 712 %  Chooses a maximum depth for the tree as a function of the desired
 713 %  number of colors in the output image (currently log2(colormap size)).
 714 %
 715 %  For each pixel in the input image, storage_class scans downward from
 716 %  the root of the color description tree.  At each level of the tree it
 717 %  identifies the single node which represents a cube in RGB space
 718 %  containing It updates the following data for each such node:
 719 %
 720 %    n1 : Number of pixels whose color is contained in the RGB cube
 721 %    which this node represents;
 722 %
 723 %    n2 : Number of pixels whose color is not represented in a node at
 724 %    lower depth in the tree;  initially,  n2 = 0 for all nodes except
 725 %    leaves of the tree.
 726 %
 727 %    Sr, Sg, Sb : Sums of the red, green, and blue component values for
 728 %    all pixels not classified at a lower depth. The combination of
 729 %    these sums and n2  will ultimately characterize the mean color of a
 730 %    set of pixels represented by this node.
 731 %
 732 %    E: the distance squared in RGB space between each pixel contained
 733 %    within a node and the nodes' center.  This represents the quantization
 734 %    error for a node.
 735 %
 736 %  The format of the ClassifyImageColors() method is:
 737 %
 738 %      MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 739 %        const Image *image,ExceptionInfo *exception)
 740 %
 741 %  A description of each parameter follows.
 742 %
 743 %    o cube_info: A pointer to the Cube structure.
 744 %
 745 %    o image: the image.
 746 %
 747 */
 748
 749 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
 750 {
 751   MagickBooleanType
 752     associate_alpha;
 753
 754   associate_alpha=image->matte;
 755   if (cube_info->quantize_info->colorspace == TransparentColorspace)
 756     associate_alpha=MagickFalse;
 757   if ((cube_info->quantize_info->number_colors == 2) &&
 758       (cube_info->quantize_info->colorspace == GRAYColorspace))
 759     associate_alpha=MagickFalse;
 760   cube_info->associate_alpha=associate_alpha;
 761 }
 762
 763 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 764   const Image *image,ExceptionInfo *exception)
 765 {
 766 #define ClassifyImageTag  "Classify/Image"
 767
 768   CacheView
 769     *image_view;
 770
 771   MagickBooleanType
 772     proceed;
 773
 774   MagickRealType
 775     bisect;
 776
 777   NodeInfo
 778     *node_info;
 779
 780   RealPixelInfo
 781     error,
 782     mid,
 783     midpoint,
 784     pixel;
 785
 786   size_t
 787     count,
 788     id,
 789     index,
 790     level;
 791
 792   ssize_t
 793     y;
 794
 795   /*
 796     Classify the first cube_info->maximum_colors colors to a tree depth of 8.
 797   */
 798   SetAssociatedAlpha(image,cube_info);
 799   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 800       (cube_info->quantize_info->colorspace != CMYKColorspace))
 801     (void) TransformImageColorspace((Image *) image,
 802       cube_info->quantize_info->colorspace,exception);
 803   else
 804     if ((image->colorspace != GRAYColorspace) &&
 805         (image->colorspace != CMYColorspace) &&
 806         (IssRGBColorspace(image->colorspace) == MagickFalse))
 807       (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 808   midpoint.red=(MagickRealType) QuantumRange/2.0;
 809   midpoint.green=(MagickRealType) QuantumRange/2.0;
 810   midpoint.blue=(MagickRealType) QuantumRange/2.0;
 811   midpoint.alpha=(MagickRealType) QuantumRange/2.0;
 812   error.alpha=0.0;
 813   image_view=AcquireVirtualCacheView(image,exception);
 814   for (y=0; y < (ssize_t) image->rows; y++)
 815   {
 816     register const Quantum
 817       *restrict p;
 818
 819     register ssize_t
 820       x;
 821
 822     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 823     if (p == (const Quantum *) NULL)
 824       break;
 825     if (cube_info->nodes > MaxNodes)
 826       {
 827         /*
 828           Prune one level if the color tree is too large.
 829         */
 830         PruneLevel(image,cube_info,cube_info->root);
 831         cube_info->depth--;
 832       }
 833     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 834     {
 835       /*
 836         Start at the root and descend the color cube tree.
 837       */
 838       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 839       {
 840         PixelInfo
 841           packet;
 842
 843         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 844         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 845           break;
 846       }
 847       AssociateAlphaPixel(image,cube_info,p,&pixel);
 848       index=MaxTreeDepth-1;
 849       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 850       mid=midpoint;
 851       node_info=cube_info->root;
 852       for (level=1; level <= MaxTreeDepth; level++)
 853       {
 854         bisect*=0.5;
 855         id=ColorToNodeId(cube_info,&pixel,index);
 856         mid.red+=(id & 1) != 0 ? bisect : -bisect;
 857         mid.green+=(id & 2) != 0 ? bisect : -bisect;
 858         mid.blue+=(id & 4) != 0 ? bisect : -bisect;
 859         mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
 860         if (node_info->child[id] == (NodeInfo *) NULL)
 861           {
 862             /*
 863               Set colors of new node to contain pixel.
 864             */
 865             node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
 866             if (node_info->child[id] == (NodeInfo *) NULL)
 867               (void) ThrowMagickException(exception,GetMagickModule(),
 868                 ResourceLimitError,"MemoryAllocationFailed","'%s'",
 869                 image->filename);
 870             if (level == MaxTreeDepth)
 871               cube_info->colors++;
 872           }
 873         /*
 874           Approximate the quantization error represented by this node.
 875         */
 876         node_info=node_info->child[id];
 877         error.red=QuantumScale*(pixel.red-mid.red);
 878         error.green=QuantumScale*(pixel.green-mid.green);
 879         error.blue=QuantumScale*(pixel.blue-mid.blue);
 880         if (cube_info->associate_alpha != MagickFalse)
 881           error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
 882         node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
 883           count*error.green*error.green+count*error.blue*error.blue+
 884           count*error.alpha*error.alpha));
 885         cube_info->root->quantize_error+=node_info->quantize_error;
 886         index--;
 887       }
 888       /*
 889         Sum RGB for this leaf for later derivation of the mean cube color.
 890       */
 891       node_info->number_unique+=count;
 892       node_info->total_color.red+=count*QuantumScale*pixel.red;
 893       node_info->total_color.green+=count*QuantumScale*pixel.green;
 894       node_info->total_color.blue+=count*QuantumScale*pixel.blue;
 895       if (cube_info->associate_alpha != MagickFalse)
 896         node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
 897       p+=count*GetPixelChannels(image);
 898     }
 899     if (cube_info->colors > cube_info->maximum_colors)
 900       {
 901         PruneToCubeDepth(image,cube_info,cube_info->root);
 902         break;
 903       }
 904     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 905       image->rows);
 906     if (proceed == MagickFalse)
 907       break;
 908   }
 909   for (y++; y < (ssize_t) image->rows; y++)
 910   {
 911     register const Quantum
 912       *restrict p;
 913
 914     register ssize_t
 915       x;
 916
 917     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 918     if (p == (const Quantum *) NULL)
 919       break;
 920     if (cube_info->nodes > MaxNodes)
 921       {
 922         /*
 923           Prune one level if the color tree is too large.
 924         */
 925         PruneLevel(image,cube_info,cube_info->root);
 926         cube_info->depth--;
 927       }
 928     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 929     {
 930       /*
 931         Start at the root and descend the color cube tree.
 932       */
 933       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 934       {
 935         PixelInfo
 936           packet;
 937
 938         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 939         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 940           break;
 941       }
 942       AssociateAlphaPixel(image,cube_info,p,&pixel);
 943       index=MaxTreeDepth-1;
 944       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 945       mid=midpoint;
 946       node_info=cube_info->root;
 947       for (level=1; level <= cube_info->depth; level++)
 948       {
 949         bisect*=0.5;
 950         id=ColorToNodeId(cube_info,&pixel,index);
 951         mid.red+=(id & 1) != 0 ? bisect : -bisect;
 952         mid.green+=(id & 2) != 0 ? bisect : -bisect;
 953         mid.blue+=(id & 4) != 0 ? bisect : -bisect;
 954         mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
 955         if (node_info->child[id] == (NodeInfo *) NULL)
 956           {
 957             /*
 958               Set colors of new node to contain pixel.
 959             */
 960             node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
 961             if (node_info->child[id] == (NodeInfo *) NULL)
 962               (void) ThrowMagickException(exception,GetMagickModule(),
 963                 ResourceLimitError,"MemoryAllocationFailed","%s",
 964                 image->filename);
 965             if (level == cube_info->depth)
 966               cube_info->colors++;
 967           }
 968         /*
 969           Approximate the quantization error represented by this node.
 970         */
 971         node_info=node_info->child[id];
 972         error.red=QuantumScale*(pixel.red-mid.red);
 973         error.green=QuantumScale*(pixel.green-mid.green);
 974         error.blue=QuantumScale*(pixel.blue-mid.blue);
 975         if (cube_info->associate_alpha != MagickFalse)
 976           error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
 977         node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
 978           count*error.green*error.green+count*error.blue*error.blue+
 979           count*error.alpha*error.alpha));
 980         cube_info->root->quantize_error+=node_info->quantize_error;
 981         index--;
 982       }
 983       /*
 984         Sum RGB for this leaf for later derivation of the mean cube color.
 985       */
 986       node_info->number_unique+=count;
 987       node_info->total_color.red+=count*QuantumScale*pixel.red;
 988       node_info->total_color.green+=count*QuantumScale*pixel.green;
 989       node_info->total_color.blue+=count*QuantumScale*pixel.blue;
 990       if (cube_info->associate_alpha != MagickFalse)
 991         node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
 992       p+=count*GetPixelChannels(image);
 993     }
 994     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 995       image->rows);
 996     if (proceed == MagickFalse)
 997       break;
 998   }
 999   image_view=DestroyCacheView(image_view);
1000   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
1001       (cube_info->quantize_info->colorspace != CMYKColorspace))
1002     (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
1003   return(MagickTrue);
1004 }
1005 \f
1006 /*
1007 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1008 %                                                                             %
1009 %                                                                             %
1010 %                                                                             %
1011 %   C l o n e Q u a n t i z e I n f o                                         %
1012 %                                                                             %
1013 %                                                                             %
1014 %                                                                             %
1015 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1016 %
1017 %  CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1018 %  or if quantize info is NULL, a new one.
1019 %
1020 %  The format of the CloneQuantizeInfo method is:
1021 %
1022 %      QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1023 %
1024 %  A description of each parameter follows:
1025 %
1026 %    o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1027 %      quantize info, or if image info is NULL a new one.
1028 %
1029 %    o quantize_info: a structure of type info.
1030 %
1031 */
1032 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1033 {
1034   QuantizeInfo
1035     *clone_info;
1036
1037   clone_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*clone_info));
1038   if (clone_info == (QuantizeInfo *) NULL)
1039     ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
1040   GetQuantizeInfo(clone_info);
1041   if (quantize_info == (QuantizeInfo *) NULL)
1042     return(clone_info);
1043   clone_info->number_colors=quantize_info->number_colors;
1044   clone_info->tree_depth=quantize_info->tree_depth;
1045   clone_info->dither=quantize_info->dither;
1046   clone_info->dither_method=quantize_info->dither_method;
1047   clone_info->colorspace=quantize_info->colorspace;
1048   clone_info->measure_error=quantize_info->measure_error;
1049   return(clone_info);
1050 }
1051 \f
1052 /*
1053 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1054 %                                                                             %
1055 %                                                                             %
1056 %                                                                             %
1057 +   C l o s e s t C o l o r                                                   %
1058 %                                                                             %
1059 %                                                                             %
1060 %                                                                             %
1061 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1062 %
1063 %  ClosestColor() traverses the color cube tree at a particular node and
1064 %  determines which colormap entry best represents the input color.
1065 %
1066 %  The format of the ClosestColor method is:
1067 %
1068 %      void ClosestColor(const Image *image,CubeInfo *cube_info,
1069 %        const NodeInfo *node_info)
1070 %
1071 %  A description of each parameter follows.
1072 %
1073 %    o image: the image.
1074 %
1075 %    o cube_info: A pointer to the Cube structure.
1076 %
1077 %    o node_info: the address of a structure of type NodeInfo which points to a
1078 %      node in the color cube tree that is to be pruned.
1079 %
1080 */
1081 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1082   const NodeInfo *node_info)
1083 {
1084   register ssize_t
1085     i;
1086
1087   size_t
1088     number_children;
1089
1090   /*
1091     Traverse any children.
1092   */
1093   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1094   for (i=0; i < (ssize_t) number_children; i++)
1095     if (node_info->child[i] != (NodeInfo *) NULL)
1096       ClosestColor(image,cube_info,node_info->child[i]);
1097   if (node_info->number_unique != 0)
1098     {
1099       MagickRealType
1100         pixel;
1101
1102       register MagickRealType
1103         alpha,
1104         beta,
1105         distance;
1106
1107       register PixelInfo
1108         *restrict p;
1109
1110       register RealPixelInfo
1111         *restrict q;
1112
1113       /*
1114         Determine if this color is "closest".
1115       */
1116       p=image->colormap+node_info->color_number;
1117       q=(&cube_info->target);
1118       alpha=1.0;
1119       beta=1.0;
1120       if (cube_info->associate_alpha != MagickFalse)
1121         {
1122           alpha=(MagickRealType) (QuantumScale*p->alpha);
1123           beta=(MagickRealType) (QuantumScale*q->alpha);
1124         }
1125       pixel=alpha*p->red-beta*q->red;
1126       distance=pixel*pixel;
1127       if (distance <= cube_info->distance)
1128         {
1129           pixel=alpha*p->green-beta*q->green;
1130           distance+=pixel*pixel;
1131           if (distance <= cube_info->distance)
1132             {
1133               pixel=alpha*p->blue-beta*q->blue;
1134               distance+=pixel*pixel;
1135               if (distance <= cube_info->distance)
1136                 {
1137                   pixel=alpha-beta;
1138                   distance+=pixel*pixel;
1139                   if (distance <= cube_info->distance)
1140                     {
1141                       cube_info->distance=distance;
1142                       cube_info->color_number=node_info->color_number;
1143                     }
1144                 }
1145             }
1146         }
1147     }
1148 }
1149 \f
1150 /*
1151 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1152 %                                                                             %
1153 %                                                                             %
1154 %                                                                             %
1155 %   C o m p r e s s I m a g e C o l o r m a p                                 %
1156 %                                                                             %
1157 %                                                                             %
1158 %                                                                             %
1159 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1160 %
1161 %  CompressImageColormap() compresses an image colormap by removing any
1162 %  duplicate or unused color entries.
1163 %
1164 %  The format of the CompressImageColormap method is:
1165 %
1166 %      MagickBooleanType CompressImageColormap(Image *image,
1167 %        ExceptionInfo *exception)
1168 %
1169 %  A description of each parameter follows:
1170 %
1171 %    o image: the image.
1172 %
1173 %    o exception: return any errors or warnings in this structure.
1174 %
1175 */
1176 MagickExport MagickBooleanType CompressImageColormap(Image *image,
1177   ExceptionInfo *exception)
1178 {
1179   QuantizeInfo
1180     quantize_info;
1181
1182   assert(image != (Image *) NULL);
1183   assert(image->signature == MagickSignature);
1184   if (image->debug != MagickFalse)
1185     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1186   if (IsPaletteImage(image,exception) == MagickFalse)
1187     return(MagickFalse);
1188   GetQuantizeInfo(&quantize_info);
1189   quantize_info.number_colors=image->colors;
1190   quantize_info.tree_depth=MaxTreeDepth;
1191   return(QuantizeImage(&quantize_info,image,exception));
1192 }
1193 \f
1194 /*
1195 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1196 %                                                                             %
1197 %                                                                             %
1198 %                                                                             %
1199 +   D e f i n e I m a g e C o l o r m a p                                     %
1200 %                                                                             %
1201 %                                                                             %
1202 %                                                                             %
1203 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1204 %
1205 %  DefineImageColormap() traverses the color cube tree and notes each colormap
1206 %  entry.  A colormap entry is any node in the color cube tree where the
1207 %  of unique colors is not zero.  DefineImageColormap() returns the number of
1208 %  colors in the image colormap.
1209 %
1210 %  The format of the DefineImageColormap method is:
1211 %
1212 %      size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1213 %        NodeInfo *node_info)
1214 %
1215 %  A description of each parameter follows.
1216 %
1217 %    o image: the image.
1218 %
1219 %    o cube_info: A pointer to the Cube structure.
1220 %
1221 %    o node_info: the address of a structure of type NodeInfo which points to a
1222 %      node in the color cube tree that is to be pruned.
1223 %
1224 */
1225 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1226   NodeInfo *node_info)
1227 {
1228   register ssize_t
1229     i;
1230
1231   size_t
1232     number_children;
1233
1234   /*
1235     Traverse any children.
1236   */
1237   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1238   for (i=0; i < (ssize_t) number_children; i++)
1239     if (node_info->child[i] != (NodeInfo *) NULL)
1240       (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1241   if (node_info->number_unique != 0)
1242     {
1243       register MagickRealType
1244         alpha;
1245
1246       register PixelInfo
1247         *restrict q;
1248
1249       /*
1250         Colormap entry is defined by the mean color in this cube.
1251       */
1252       q=image->colormap+image->colors;
1253       alpha=(MagickRealType) ((MagickOffsetType) node_info->number_unique);
1254       alpha=1.0/(fabs(alpha) <= MagickEpsilon ? 1.0 : alpha);
1255       if (cube_info->associate_alpha == MagickFalse)
1256         {
1257           q->red=(double) ClampToQuantum((MagickRealType)
1258             (alpha*QuantumRange*node_info->total_color.red));
1259           q->green=(double) ClampToQuantum((MagickRealType)
1260             (alpha*QuantumRange*node_info->total_color.green));
1261           q->blue=(double) ClampToQuantum((MagickRealType)
1262             (alpha*(double) QuantumRange*node_info->total_color.blue));
1263           q->alpha=OpaqueAlpha;
1264         }
1265       else
1266         {
1267           MagickRealType
1268             opacity;
1269
1270           opacity=(MagickRealType) (alpha*QuantumRange*
1271             node_info->total_color.alpha);
1272           q->alpha=(double) ClampToQuantum(opacity);
1273           if (q->alpha == OpaqueAlpha)
1274             {
1275               q->red=(double) ClampToQuantum((MagickRealType)
1276                 (alpha*QuantumRange*node_info->total_color.red));
1277               q->green=(double) ClampToQuantum((MagickRealType)
1278                 (alpha*QuantumRange*node_info->total_color.green));
1279               q->blue=(double) ClampToQuantum((MagickRealType)
1280                 (alpha*QuantumRange*node_info->total_color.blue));
1281             }
1282           else
1283             {
1284               MagickRealType
1285                 gamma;
1286
1287               gamma=(MagickRealType) (QuantumScale*q->alpha);
1288               gamma=1.0/(fabs(gamma) <= MagickEpsilon ? 1.0 : gamma);
1289               q->red=(double) ClampToQuantum((MagickRealType)
1290                 (alpha*gamma*QuantumRange*node_info->total_color.red));
1291               q->green=(double) ClampToQuantum((MagickRealType)
1292                 (alpha*gamma*QuantumRange*node_info->total_color.green));
1293               q->blue=(double) ClampToQuantum((MagickRealType)
1294                 (alpha*gamma*QuantumRange*node_info->total_color.blue));
1295               if (node_info->number_unique > cube_info->transparent_pixels)
1296                 {
1297                   cube_info->transparent_pixels=node_info->number_unique;
1298                   cube_info->transparent_index=(ssize_t) image->colors;
1299                 }
1300             }
1301         }
1302       node_info->color_number=image->colors++;
1303     }
1304   return(image->colors);
1305 }
1306 \f
1307 /*
1308 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1309 %                                                                             %
1310 %                                                                             %
1311 %                                                                             %
1312 +   D e s t r o y C u b e I n f o                                             %
1313 %                                                                             %
1314 %                                                                             %
1315 %                                                                             %
1316 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1317 %
1318 %  DestroyCubeInfo() deallocates memory associated with an image.
1319 %
1320 %  The format of the DestroyCubeInfo method is:
1321 %
1322 %      DestroyCubeInfo(CubeInfo *cube_info)
1323 %
1324 %  A description of each parameter follows:
1325 %
1326 %    o cube_info: the address of a structure of type CubeInfo.
1327 %
1328 */
1329 static void DestroyCubeInfo(CubeInfo *cube_info)
1330 {
1331   register Nodes
1332     *nodes;
1333
1334   /*
1335     Release color cube tree storage.
1336   */
1337   do
1338   {
1339     nodes=cube_info->node_queue->next;
1340     cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1341       cube_info->node_queue->nodes);
1342     cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1343       cube_info->node_queue);
1344     cube_info->node_queue=nodes;
1345   } while (cube_info->node_queue != (Nodes *) NULL);
1346   if (cube_info->cache != (ssize_t *) NULL)
1347     cube_info->cache=(ssize_t *) RelinquishMagickMemory(cube_info->cache);
1348   cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1349   cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1350 }
1351 \f
1352 /*
1353 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1354 %                                                                             %
1355 %                                                                             %
1356 %                                                                             %
1357 %   D e s t r o y Q u a n t i z e I n f o                                     %
1358 %                                                                             %
1359 %                                                                             %
1360 %                                                                             %
1361 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1362 %
1363 %  DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1364 %  structure.
1365 %
1366 %  The format of the DestroyQuantizeInfo method is:
1367 %
1368 %      QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1369 %
1370 %  A description of each parameter follows:
1371 %
1372 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1373 %
1374 */
1375 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1376 {
1377   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1378   assert(quantize_info != (QuantizeInfo *) NULL);
1379   assert(quantize_info->signature == MagickSignature);
1380   quantize_info->signature=(~MagickSignature);
1381   quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1382   return(quantize_info);
1383 }
1384 \f
1385 /*
1386 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1387 %                                                                             %
1388 %                                                                             %
1389 %                                                                             %
1390 +   D i t h e r I m a g e                                                     %
1391 %                                                                             %
1392 %                                                                             %
1393 %                                                                             %
1394 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1395 %
1396 %  DitherImage() distributes the difference between an original image and
1397 %  the corresponding color reduced algorithm to neighboring pixels using
1398 %  serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1399 %  MagickTrue if the image is dithered otherwise MagickFalse.
1400 %
1401 %  The format of the DitherImage method is:
1402 %
1403 %      MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1404 %        ExceptionInfo *exception)
1405 %
1406 %  A description of each parameter follows.
1407 %
1408 %    o image: the image.
1409 %
1410 %    o cube_info: A pointer to the Cube structure.
1411 %
1412 %    o exception: return any errors or warnings in this structure.
1413 %
1414 */
1415
1416 static RealPixelInfo **DestroyPixelThreadSet(RealPixelInfo **pixels)
1417 {
1418   register ssize_t
1419     i;
1420
1421   assert(pixels != (RealPixelInfo **) NULL);
1422   for (i=0; i < (ssize_t) GetMagickResourceLimit(ThreadResource); i++)
1423     if (pixels[i] != (RealPixelInfo *) NULL)
1424       pixels[i]=(RealPixelInfo *) RelinquishMagickMemory(pixels[i]);
1425   pixels=(RealPixelInfo **) RelinquishMagickMemory(pixels);
1426   return(pixels);
1427 }
1428
1429 static RealPixelInfo **AcquirePixelThreadSet(const size_t count)
1430 {
1431   RealPixelInfo
1432     **pixels;
1433
1434   register ssize_t
1435     i;
1436
1437   size_t
1438     number_threads;
1439
1440   number_threads=GetOpenMPMaximumThreads();
1441   pixels=(RealPixelInfo **) AcquireQuantumMemory(number_threads,
1442     sizeof(*pixels));
1443   if (pixels == (RealPixelInfo **) NULL)
1444     return((RealPixelInfo **) NULL);
1445   (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1446   for (i=0; i < (ssize_t) number_threads; i++)
1447   {
1448     pixels[i]=(RealPixelInfo *) AcquireQuantumMemory(count,
1449       2*sizeof(**pixels));
1450     if (pixels[i] == (RealPixelInfo *) NULL)
1451       return(DestroyPixelThreadSet(pixels));
1452   }
1453   return(pixels);
1454 }
1455
1456 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1457   const RealPixelInfo *pixel)
1458 {
1459 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1460 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1461 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1462 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1463
1464   ssize_t
1465     offset;
1466
1467   offset=(ssize_t)
1468     (RedShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red))) |
1469     GreenShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green))) |
1470     BlueShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue))));
1471   if (cube_info->associate_alpha != MagickFalse)
1472     offset|=AlphaShift(ScaleQuantumToChar(ClampToUnsignedQuantum(
1473       pixel->alpha)));
1474   return(offset);
1475 }
1476
1477 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info,
1478   ExceptionInfo *exception)
1479 {
1480 #define DitherImageTag  "Dither/Image"
1481
1482   CacheView
1483     *image_view;
1484
1485   MagickBooleanType
1486     status;
1487
1488   RealPixelInfo
1489     **pixels;
1490
1491   ssize_t
1492     y;
1493
1494   /*
1495     Distribute quantization error using Floyd-Steinberg.
1496   */
1497   pixels=AcquirePixelThreadSet(image->columns);
1498   if (pixels == (RealPixelInfo **) NULL)
1499     return(MagickFalse);
1500   status=MagickTrue;
1501   image_view=AcquireAuthenticCacheView(image,exception);
1502   for (y=0; y < (ssize_t) image->rows; y++)
1503   {
1504     const int
1505       id = GetOpenMPThreadId();
1506
1507     CubeInfo
1508       cube;
1509
1510     RealPixelInfo
1511       *current,
1512       *previous;
1513
1514     register Quantum
1515       *restrict q;
1516
1517     register ssize_t
1518       x;
1519
1520     size_t
1521       index;
1522
1523     ssize_t
1524       v;
1525
1526     if (status == MagickFalse)
1527       continue;
1528     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1529     if (q == (Quantum *) NULL)
1530       {
1531         status=MagickFalse;
1532         continue;
1533       }
1534     q+=(y & 0x01)*image->columns*GetPixelChannels(image);
1535     cube=(*cube_info);
1536     current=pixels[id]+(y & 0x01)*image->columns;
1537     previous=pixels[id]+((y+1) & 0x01)*image->columns;
1538     v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1539     for (x=0; x < (ssize_t) image->columns; x++)
1540     {
1541       RealPixelInfo
1542         color,
1543         pixel;
1544
1545       register ssize_t
1546         i;
1547
1548       ssize_t
1549         u;
1550
1551       q-=(y & 0x01)*GetPixelChannels(image);
1552       u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1553       AssociateAlphaPixel(image,&cube,q,&pixel);
1554       if (x > 0)
1555         {
1556           pixel.red+=7*current[u-v].red/16;
1557           pixel.green+=7*current[u-v].green/16;
1558           pixel.blue+=7*current[u-v].blue/16;
1559           if (cube.associate_alpha != MagickFalse)
1560             pixel.alpha+=7*current[u-v].alpha/16;
1561         }
1562       if (y > 0)
1563         {
1564           if (x < (ssize_t) (image->columns-1))
1565             {
1566               pixel.red+=previous[u+v].red/16;
1567               pixel.green+=previous[u+v].green/16;
1568               pixel.blue+=previous[u+v].blue/16;
1569               if (cube.associate_alpha != MagickFalse)
1570                 pixel.alpha+=previous[u+v].alpha/16;
1571             }
1572           pixel.red+=5*previous[u].red/16;
1573           pixel.green+=5*previous[u].green/16;
1574           pixel.blue+=5*previous[u].blue/16;
1575           if (cube.associate_alpha != MagickFalse)
1576             pixel.alpha+=5*previous[u].alpha/16;
1577           if (x > 0)
1578             {
1579               pixel.red+=3*previous[u-v].red/16;
1580               pixel.green+=3*previous[u-v].green/16;
1581               pixel.blue+=3*previous[u-v].blue/16;
1582               if (cube.associate_alpha != MagickFalse)
1583                 pixel.alpha+=3*previous[u-v].alpha/16;
1584             }
1585         }
1586       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1587       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1588       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1589       if (cube.associate_alpha != MagickFalse)
1590         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1591       i=CacheOffset(&cube,&pixel);
1592       if (cube.cache[i] < 0)
1593         {
1594           register NodeInfo
1595             *node_info;
1596
1597           register size_t
1598             id;
1599
1600           /*
1601             Identify the deepest node containing the pixel's color.
1602           */
1603           node_info=cube.root;
1604           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1605           {
1606             id=ColorToNodeId(&cube,&pixel,index);
1607             if (node_info->child[id] == (NodeInfo *) NULL)
1608               break;
1609             node_info=node_info->child[id];
1610           }
1611           /*
1612             Find closest color among siblings and their children.
1613           */
1614           cube.target=pixel;
1615           cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*(QuantumRange+
1616             1.0)+1.0);
1617           ClosestColor(image,&cube,node_info->parent);
1618           cube.cache[i]=(ssize_t) cube.color_number;
1619         }
1620       /*
1621         Assign pixel to closest colormap entry.
1622       */
1623       index=(size_t) cube.cache[i];
1624       if (image->storage_class == PseudoClass)
1625         SetPixelIndex(image,(Quantum) index,q);
1626       if (cube.quantize_info->measure_error == MagickFalse)
1627         {
1628           SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
1629           SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
1630           SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
1631           if (cube.associate_alpha != MagickFalse)
1632             SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
1633         }
1634       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1635         status=MagickFalse;
1636       /*
1637         Store the error.
1638       */
1639       AssociateAlphaPixelInfo(image,&cube,image->colormap+index,&color);
1640       current[u].red=pixel.red-color.red;
1641       current[u].green=pixel.green-color.green;
1642       current[u].blue=pixel.blue-color.blue;
1643       if (cube.associate_alpha != MagickFalse)
1644         current[u].alpha=pixel.alpha-color.alpha;
1645       if (image->progress_monitor != (MagickProgressMonitor) NULL)
1646         {
1647           MagickBooleanType
1648             proceed;
1649
1650 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1651           #pragma omp critical (MagickCore_FloydSteinbergDither)
1652 #endif
1653           proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1654             image->rows);
1655           if (proceed == MagickFalse)
1656             status=MagickFalse;
1657         }
1658       q+=((y+1) & 0x01)*GetPixelChannels(image);
1659     }
1660   }
1661   image_view=DestroyCacheView(image_view);
1662   pixels=DestroyPixelThreadSet(pixels);
1663   return(MagickTrue);
1664 }
1665
1666 static MagickBooleanType
1667   RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int,
1668     ExceptionInfo *exception);
1669
1670 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1671   const size_t level,const unsigned int direction,ExceptionInfo *exception)
1672 {
1673   if (level == 1)
1674     switch (direction)
1675     {
1676       case WestGravity:
1677       {
1678         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1679           exception);
1680         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1681           exception);
1682         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1683           exception);
1684         break;
1685       }
1686       case EastGravity:
1687       {
1688         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1689           exception);
1690         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1691           exception);
1692         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1693           exception);
1694         break;
1695       }
1696       case NorthGravity:
1697       {
1698         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1699           exception);
1700         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1701           exception);
1702         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1703           exception);
1704         break;
1705       }
1706       case SouthGravity:
1707       {
1708         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1709           exception);
1710         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1711           exception);
1712         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1713           exception);
1714         break;
1715       }
1716       default:
1717         break;
1718     }
1719   else
1720     switch (direction)
1721     {
1722       case WestGravity:
1723       {
1724         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1725           exception);
1726         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1727           exception);
1728         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1729           exception);
1730         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1731           exception);
1732         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1733           exception);
1734         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1735           exception);
1736         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1737           exception);
1738         break;
1739       }
1740       case EastGravity:
1741       {
1742         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1743           exception);
1744         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1745           exception);
1746         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1747           exception);
1748         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1749           exception);
1750         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1751           exception);
1752         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1753           exception);
1754         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1755           exception);
1756         break;
1757       }
1758       case NorthGravity:
1759       {
1760         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1761           exception);
1762         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1763           exception);
1764         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1765           exception);
1766         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1767           exception);
1768         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1769           exception);
1770         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1771           exception);
1772         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1773           exception);
1774         break;
1775       }
1776       case SouthGravity:
1777       {
1778         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1779           exception);
1780         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1781           exception);
1782         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1783           exception);
1784         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1785           exception);
1786         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1787           exception);
1788         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1789           exception);
1790         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1791           exception);
1792         break;
1793       }
1794       default:
1795         break;
1796     }
1797 }
1798
1799 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1800   CubeInfo *cube_info,const unsigned int direction,ExceptionInfo *exception)
1801 {
1802 #define DitherImageTag  "Dither/Image"
1803
1804   MagickBooleanType
1805     proceed;
1806
1807   RealPixelInfo
1808     color,
1809     pixel;
1810
1811   register CubeInfo
1812     *p;
1813
1814   size_t
1815     index;
1816
1817   p=cube_info;
1818   if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1819       (p->y >= 0) && (p->y < (ssize_t) image->rows))
1820     {
1821       register Quantum
1822         *restrict q;
1823
1824       register ssize_t
1825         i;
1826
1827       /*
1828         Distribute error.
1829       */
1830       q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1831       if (q == (Quantum *) NULL)
1832         return(MagickFalse);
1833       AssociateAlphaPixel(image,cube_info,q,&pixel);
1834       for (i=0; i < ErrorQueueLength; i++)
1835       {
1836         pixel.red+=p->weights[i]*p->error[i].red;
1837         pixel.green+=p->weights[i]*p->error[i].green;
1838         pixel.blue+=p->weights[i]*p->error[i].blue;
1839         if (cube_info->associate_alpha != MagickFalse)
1840           pixel.alpha+=p->weights[i]*p->error[i].alpha;
1841       }
1842       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1843       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1844       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1845       if (cube_info->associate_alpha != MagickFalse)
1846         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1847       i=CacheOffset(cube_info,&pixel);
1848       if (p->cache[i] < 0)
1849         {
1850           register NodeInfo
1851             *node_info;
1852
1853           register size_t
1854             id;
1855
1856           /*
1857             Identify the deepest node containing the pixel's color.
1858           */
1859           node_info=p->root;
1860           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1861           {
1862             id=ColorToNodeId(cube_info,&pixel,index);
1863             if (node_info->child[id] == (NodeInfo *) NULL)
1864               break;
1865             node_info=node_info->child[id];
1866           }
1867           node_info=node_info->parent;
1868           /*
1869             Find closest color among siblings and their children.
1870           */
1871           p->target=pixel;
1872           p->distance=(MagickRealType) (4.0*(QuantumRange+1.0)*((MagickRealType)
1873             QuantumRange+1.0)+1.0);
1874           ClosestColor(image,p,node_info->parent);
1875           p->cache[i]=(ssize_t) p->color_number;
1876         }
1877       /*
1878         Assign pixel to closest colormap entry.
1879       */
1880       index=(size_t) p->cache[i];
1881       if (image->storage_class == PseudoClass)
1882         SetPixelIndex(image,(Quantum) index,q);
1883       if (cube_info->quantize_info->measure_error == MagickFalse)
1884         {
1885           SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
1886           SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
1887           SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
1888           if (cube_info->associate_alpha != MagickFalse)
1889             SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
1890         }
1891       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1892         return(MagickFalse);
1893       /*
1894         Propagate the error as the last entry of the error queue.
1895       */
1896       (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1897         sizeof(p->error[0]));
1898       AssociateAlphaPixelInfo(image,cube_info,image->colormap+index,&color);
1899       p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1900       p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1901       p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1902       if (cube_info->associate_alpha != MagickFalse)
1903         p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1904       proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1905       if (proceed == MagickFalse)
1906         return(MagickFalse);
1907       p->offset++;
1908     }
1909   switch (direction)
1910   {
1911     case WestGravity: p->x--; break;
1912     case EastGravity: p->x++; break;
1913     case NorthGravity: p->y--; break;
1914     case SouthGravity: p->y++; break;
1915   }
1916   return(MagickTrue);
1917 }
1918
1919 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1920 {
1921   if (x > y)
1922     return(x);
1923   return(y);
1924 }
1925
1926 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1927 {
1928   if (x < y)
1929     return(x);
1930   return(y);
1931 }
1932
1933 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1934   ExceptionInfo *exception)
1935 {
1936   CacheView
1937     *image_view;
1938
1939   MagickBooleanType
1940     status;
1941
1942   register ssize_t
1943     i;
1944
1945   size_t
1946     depth;
1947
1948   if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1949     return(FloydSteinbergDither(image,cube_info,exception));
1950   /*
1951     Distribute quantization error along a Hilbert curve.
1952   */
1953   (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1954     sizeof(*cube_info->error));
1955   cube_info->x=0;
1956   cube_info->y=0;
1957   i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1958   for (depth=1; i != 0; depth++)
1959     i>>=1;
1960   if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1961     depth++;
1962   cube_info->offset=0;
1963   cube_info->span=(MagickSizeType) image->columns*image->rows;
1964   image_view=AcquireAuthenticCacheView(image,exception);
1965   if (depth > 1)
1966     Riemersma(image,image_view,cube_info,depth-1,NorthGravity,exception);
1967   status=RiemersmaDither(image,image_view,cube_info,ForgetGravity,exception);
1968   image_view=DestroyCacheView(image_view);
1969   return(status);
1970 }
1971 \f
1972 /*
1973 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1974 %                                                                             %
1975 %                                                                             %
1976 %                                                                             %
1977 +   G e t C u b e I n f o                                                     %
1978 %                                                                             %
1979 %                                                                             %
1980 %                                                                             %
1981 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1982 %
1983 %  GetCubeInfo() initialize the Cube data structure.
1984 %
1985 %  The format of the GetCubeInfo method is:
1986 %
1987 %      CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1988 %        const size_t depth,const size_t maximum_colors)
1989 %
1990 %  A description of each parameter follows.
1991 %
1992 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1993 %
1994 %    o depth: Normally, this integer value is zero or one.  A zero or
1995 %      one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1996 %      A tree of this depth generally allows the best representation of the
1997 %      reference image with the least amount of memory and the fastest
1998 %      computational speed.  In some cases, such as an image with low color
1999 %      dispersion (a few number of colors), a value other than
2000 %      Log4(number_colors) is required.  To expand the color tree completely,
2001 %      use a value of 8.
2002 %
2003 %    o maximum_colors: maximum colors.
2004 %
2005 */
2006 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
2007   const size_t depth,const size_t maximum_colors)
2008 {
2009   CubeInfo
2010     *cube_info;
2011
2012   MagickRealType
2013     sum,
2014     weight;
2015
2016   register ssize_t
2017     i;
2018
2019   size_t
2020     length;
2021
2022   /*
2023     Initialize tree to describe color cube_info.
2024   */
2025   cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
2026   if (cube_info == (CubeInfo *) NULL)
2027     return((CubeInfo *) NULL);
2028   (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
2029   cube_info->depth=depth;
2030   if (cube_info->depth > MaxTreeDepth)
2031     cube_info->depth=MaxTreeDepth;
2032   if (cube_info->depth < 2)
2033     cube_info->depth=2;
2034   cube_info->maximum_colors=maximum_colors;
2035   /*
2036     Initialize root node.
2037   */
2038   cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
2039   if (cube_info->root == (NodeInfo *) NULL)
2040     return((CubeInfo *) NULL);
2041   cube_info->root->parent=cube_info->root;
2042   cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
2043   if (cube_info->quantize_info->dither == MagickFalse)
2044     return(cube_info);
2045   /*
2046     Initialize dither resources.
2047   */
2048   length=(size_t) (1UL << (4*(8-CacheShift)));
2049   cube_info->cache=(ssize_t *) AcquireQuantumMemory(length,
2050     sizeof(*cube_info->cache));
2051   if (cube_info->cache == (ssize_t *) NULL)
2052     return((CubeInfo *) NULL);
2053   /*
2054     Initialize color cache.
2055   */
2056   for (i=0; i < (ssize_t) length; i++)
2057     cube_info->cache[i]=(-1);
2058   /*
2059     Distribute weights along a curve of exponential decay.
2060   */
2061   weight=1.0;
2062   for (i=0; i < ErrorQueueLength; i++)
2063   {
2064     cube_info->weights[ErrorQueueLength-i-1]=1.0/weight;
2065     weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2066   }
2067   /*
2068     Normalize the weighting factors.
2069   */
2070   weight=0.0;
2071   for (i=0; i < ErrorQueueLength; i++)
2072     weight+=cube_info->weights[i];
2073   sum=0.0;
2074   for (i=0; i < ErrorQueueLength; i++)
2075   {
2076     cube_info->weights[i]/=weight;
2077     sum+=cube_info->weights[i];
2078   }
2079   cube_info->weights[0]+=1.0-sum;
2080   return(cube_info);
2081 }
2082 \f
2083 /*
2084 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2085 %                                                                             %
2086 %                                                                             %
2087 %                                                                             %
2088 +   G e t N o d e I n f o                                                     %
2089 %                                                                             %
2090 %                                                                             %
2091 %                                                                             %
2092 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2093 %
2094 %  GetNodeInfo() allocates memory for a new node in the color cube tree and
2095 %  presets all fields to zero.
2096 %
2097 %  The format of the GetNodeInfo method is:
2098 %
2099 %      NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2100 %        const size_t level,NodeInfo *parent)
2101 %
2102 %  A description of each parameter follows.
2103 %
2104 %    o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2105 %
2106 %    o id: Specifies the child number of the node.
2107 %
2108 %    o level: Specifies the level in the storage_class the node resides.
2109 %
2110 */
2111 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2112   const size_t level,NodeInfo *parent)
2113 {
2114   NodeInfo
2115     *node_info;
2116
2117   if (cube_info->free_nodes == 0)
2118     {
2119       Nodes
2120         *nodes;
2121
2122       /*
2123         Allocate a new queue of nodes.
2124       */
2125       nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2126       if (nodes == (Nodes *) NULL)
2127         return((NodeInfo *) NULL);
2128       nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2129         sizeof(*nodes->nodes));
2130       if (nodes->nodes == (NodeInfo *) NULL)
2131         return((NodeInfo *) NULL);
2132       nodes->next=cube_info->node_queue;
2133       cube_info->node_queue=nodes;
2134       cube_info->next_node=nodes->nodes;
2135       cube_info->free_nodes=NodesInAList;
2136     }
2137   cube_info->nodes++;
2138   cube_info->free_nodes--;
2139   node_info=cube_info->next_node++;
2140   (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2141   node_info->parent=parent;
2142   node_info->id=id;
2143   node_info->level=level;
2144   return(node_info);
2145 }
2146 \f
2147 /*
2148 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2149 %                                                                             %
2150 %                                                                             %
2151 %                                                                             %
2152 %  G e t I m a g e Q u a n t i z e E r r o r                                  %
2153 %                                                                             %
2154 %                                                                             %
2155 %                                                                             %
2156 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2157 %
2158 %  GetImageQuantizeError() measures the difference between the original
2159 %  and quantized images.  This difference is the total quantization error.
2160 %  The error is computed by summing over all pixels in an image the distance
2161 %  squared in RGB space between each reference pixel value and its quantized
2162 %  value.  These values are computed:
2163 %
2164 %    o mean_error_per_pixel:  This value is the mean error for any single
2165 %      pixel in the image.
2166 %
2167 %    o normalized_mean_square_error:  This value is the normalized mean
2168 %      quantization error for any single pixel in the image.  This distance
2169 %      measure is normalized to a range between 0 and 1.  It is independent
2170 %      of the range of red, green, and blue values in the image.
2171 %
2172 %    o normalized_maximum_square_error:  Thsi value is the normalized
2173 %      maximum quantization error for any single pixel in the image.  This
2174 %      distance measure is normalized to a range between 0 and 1.  It is
2175 %      independent of the range of red, green, and blue values in your image.
2176 %
2177 %  The format of the GetImageQuantizeError method is:
2178 %
2179 %      MagickBooleanType GetImageQuantizeError(Image *image,
2180 %        ExceptionInfo *exception)
2181 %
2182 %  A description of each parameter follows.
2183 %
2184 %    o image: the image.
2185 %
2186 %    o exception: return any errors or warnings in this structure.
2187 %
2188 */
2189 MagickExport MagickBooleanType GetImageQuantizeError(Image *image,
2190   ExceptionInfo *exception)
2191 {
2192   CacheView
2193     *image_view;
2194
2195   MagickRealType
2196     alpha,
2197     area,
2198     beta,
2199     distance,
2200     maximum_error,
2201     mean_error,
2202     mean_error_per_pixel;
2203
2204   size_t
2205     index;
2206
2207   ssize_t
2208     y;
2209
2210   assert(image != (Image *) NULL);
2211   assert(image->signature == MagickSignature);
2212   if (image->debug != MagickFalse)
2213     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2214   image->total_colors=GetNumberColors(image,(FILE *) NULL,exception);
2215   (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2216   if (image->storage_class == DirectClass)
2217     return(MagickTrue);
2218   alpha=1.0;
2219   beta=1.0;
2220   area=3.0*image->columns*image->rows;
2221   maximum_error=0.0;
2222   mean_error_per_pixel=0.0;
2223   mean_error=0.0;
2224   image_view=AcquireVirtualCacheView(image,exception);
2225   for (y=0; y < (ssize_t) image->rows; y++)
2226   {
2227     register const Quantum
2228       *restrict p;
2229
2230     register ssize_t
2231       x;
2232
2233     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2234     if (p == (const Quantum *) NULL)
2235       break;
2236     for (x=0; x < (ssize_t) image->columns; x++)
2237     {
2238       index=1UL*GetPixelIndex(image,p);
2239       if (image->matte != MagickFalse)
2240         {
2241           alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,p));
2242           beta=(MagickRealType) (QuantumScale*image->colormap[index].alpha);
2243         }
2244       distance=fabs(alpha*GetPixelRed(image,p)-beta*
2245         image->colormap[index].red);
2246       mean_error_per_pixel+=distance;
2247       mean_error+=distance*distance;
2248       if (distance > maximum_error)
2249         maximum_error=distance;
2250       distance=fabs(alpha*GetPixelGreen(image,p)-beta*
2251         image->colormap[index].green);
2252       mean_error_per_pixel+=distance;
2253       mean_error+=distance*distance;
2254       if (distance > maximum_error)
2255         maximum_error=distance;
2256       distance=fabs(alpha*GetPixelBlue(image,p)-beta*
2257         image->colormap[index].blue);
2258       mean_error_per_pixel+=distance;
2259       mean_error+=distance*distance;
2260       if (distance > maximum_error)
2261         maximum_error=distance;
2262       p+=GetPixelChannels(image);
2263     }
2264   }
2265   image_view=DestroyCacheView(image_view);
2266   image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2267   image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2268     mean_error/area;
2269   image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2270   return(MagickTrue);
2271 }
2272 \f
2273 /*
2274 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2275 %                                                                             %
2276 %                                                                             %
2277 %                                                                             %
2278 %   G e t Q u a n t i z e I n f o                                             %
2279 %                                                                             %
2280 %                                                                             %
2281 %                                                                             %
2282 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2283 %
2284 %  GetQuantizeInfo() initializes the QuantizeInfo structure.
2285 %
2286 %  The format of the GetQuantizeInfo method is:
2287 %
2288 %      GetQuantizeInfo(QuantizeInfo *quantize_info)
2289 %
2290 %  A description of each parameter follows:
2291 %
2292 %    o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2293 %
2294 */
2295 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2296 {
2297   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2298   assert(quantize_info != (QuantizeInfo *) NULL);
2299   (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2300   quantize_info->number_colors=256;
2301   quantize_info->dither=MagickTrue;
2302   quantize_info->dither_method=RiemersmaDitherMethod;
2303   quantize_info->colorspace=UndefinedColorspace;
2304   quantize_info->measure_error=MagickFalse;
2305   quantize_info->signature=MagickSignature;
2306 }
2307 \f
2308 /*
2309 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2310 %                                                                             %
2311 %                                                                             %
2312 %                                                                             %
2313 %     P o s t e r i z e I m a g e                                             %
2314 %                                                                             %
2315 %                                                                             %
2316 %                                                                             %
2317 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2318 %
2319 %  PosterizeImage() reduces the image to a limited number of colors for a
2320 %  "poster" effect.
2321 %
2322 %  The format of the PosterizeImage method is:
2323 %
2324 %      MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2325 %        const MagickBooleanType dither,ExceptionInfo *exception)
2326 %
2327 %  A description of each parameter follows:
2328 %
2329 %    o image: Specifies a pointer to an Image structure.
2330 %
2331 %    o levels: Number of color levels allowed in each channel.  Very low values
2332 %      (2, 3, or 4) have the most visible effect.
2333 %
2334 %    o dither: Set this integer value to something other than zero to dither
2335 %      the mapped image.
2336 %
2337 %    o exception: return any errors or warnings in this structure.
2338 %
2339 */
2340
2341 static inline ssize_t MagickRound(MagickRealType x)
2342 {
2343   /*
2344     Round the fraction to nearest integer.
2345   */
2346   if (x >= 0.0)
2347     return((ssize_t) (x+0.5));
2348   return((ssize_t) (x-0.5));
2349 }
2350
2351 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2352   const MagickBooleanType dither,ExceptionInfo *exception)
2353 {
2354 #define PosterizeImageTag  "Posterize/Image"
2355 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2356   QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2357
2358   CacheView
2359     *image_view;
2360
2361   MagickBooleanType
2362     status;
2363
2364   MagickOffsetType
2365     progress;
2366
2367   QuantizeInfo
2368     *quantize_info;
2369
2370   register ssize_t
2371     i;
2372
2373   ssize_t
2374     y;
2375
2376   assert(image != (Image *) NULL);
2377   assert(image->signature == MagickSignature);
2378   if (image->debug != MagickFalse)
2379     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2380   if (image->storage_class == PseudoClass)
2381 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2382     #pragma omp parallel for schedule(static,4) shared(progress,status) \
2383       dynamic_number_threads(image->columns,1,1)
2384 #endif
2385     for (i=0; i < (ssize_t) image->colors; i++)
2386     {
2387       /*
2388         Posterize colormap.
2389       */
2390       if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2391         image->colormap[i].red=(double)
2392           PosterizePixel(image->colormap[i].red);
2393       if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2394         image->colormap[i].green=(double)
2395           PosterizePixel(image->colormap[i].green);
2396       if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2397         image->colormap[i].blue=(double)
2398           PosterizePixel(image->colormap[i].blue);
2399       if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
2400         image->colormap[i].alpha=(double)
2401           PosterizePixel(image->colormap[i].alpha);
2402     }
2403   /*
2404     Posterize image.
2405   */
2406   status=MagickTrue;
2407   progress=0;
2408   image_view=AcquireAuthenticCacheView(image,exception);
2409 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2410   #pragma omp parallel for schedule(static,4) shared(progress,status) \
2411     dynamic_number_threads(image->columns,image->rows,1)
2412 #endif
2413   for (y=0; y < (ssize_t) image->rows; y++)
2414   {
2415     register Quantum
2416       *restrict q;
2417
2418     register ssize_t
2419       x;
2420
2421     if (status == MagickFalse)
2422       continue;
2423     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2424     if (q == (Quantum *) NULL)
2425       {
2426         status=MagickFalse;
2427         continue;
2428       }
2429     for (x=0; x < (ssize_t) image->columns; x++)
2430     {
2431       if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2432         SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2433       if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2434         SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2435       if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2436         SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2437       if (((GetPixelBlackTraits(image) & UpdatePixelTrait) != 0) &&
2438           (image->colorspace == CMYKColorspace))
2439         SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2440       if (((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0) &&
2441           (image->matte == MagickTrue))
2442         SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2443       q+=GetPixelChannels(image);
2444     }
2445     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2446       status=MagickFalse;
2447     if (image->progress_monitor != (MagickProgressMonitor) NULL)
2448       {
2449         MagickBooleanType
2450           proceed;
2451
2452 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2453         #pragma omp critical (MagickCore_PosterizeImage)
2454 #endif
2455         proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2456           image->rows);
2457         if (proceed == MagickFalse)
2458           status=MagickFalse;
2459       }
2460   }
2461   image_view=DestroyCacheView(image_view);
2462   quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2463   quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2464     levels,MaxColormapSize+1);
2465   quantize_info->dither=dither;
2466   quantize_info->tree_depth=MaxTreeDepth;
2467   status=QuantizeImage(quantize_info,image,exception);
2468   quantize_info=DestroyQuantizeInfo(quantize_info);
2469   return(status);
2470 }
2471 \f
2472 /*
2473 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2474 %                                                                             %
2475 %                                                                             %
2476 %                                                                             %
2477 +   P r u n e C h i l d                                                       %
2478 %                                                                             %
2479 %                                                                             %
2480 %                                                                             %
2481 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2482 %
2483 %  PruneChild() deletes the given node and merges its statistics into its
2484 %  parent.
2485 %
2486 %  The format of the PruneSubtree method is:
2487 %
2488 %      PruneChild(const Image *image,CubeInfo *cube_info,
2489 %        const NodeInfo *node_info)
2490 %
2491 %  A description of each parameter follows.
2492 %
2493 %    o image: the image.
2494 %
2495 %    o cube_info: A pointer to the Cube structure.
2496 %
2497 %    o node_info: pointer to node in color cube tree that is to be pruned.
2498 %
2499 */
2500 static void PruneChild(const Image *image,CubeInfo *cube_info,
2501   const NodeInfo *node_info)
2502 {
2503   NodeInfo
2504     *parent;
2505
2506   register ssize_t
2507     i;
2508
2509   size_t
2510     number_children;
2511
2512   /*
2513     Traverse any children.
2514   */
2515   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2516   for (i=0; i < (ssize_t) number_children; i++)
2517     if (node_info->child[i] != (NodeInfo *) NULL)
2518       PruneChild(image,cube_info,node_info->child[i]);
2519   /*
2520     Merge color statistics into parent.
2521   */
2522   parent=node_info->parent;
2523   parent->number_unique+=node_info->number_unique;
2524   parent->total_color.red+=node_info->total_color.red;
2525   parent->total_color.green+=node_info->total_color.green;
2526   parent->total_color.blue+=node_info->total_color.blue;
2527   parent->total_color.alpha+=node_info->total_color.alpha;
2528   parent->child[node_info->id]=(NodeInfo *) NULL;
2529   cube_info->nodes--;
2530 }
2531 \f
2532 /*
2533 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2534 %                                                                             %
2535 %                                                                             %
2536 %                                                                             %
2537 +  P r u n e L e v e l                                                        %
2538 %                                                                             %
2539 %                                                                             %
2540 %                                                                             %
2541 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2542 %
2543 %  PruneLevel() deletes all nodes at the bottom level of the color tree merging
2544 %  their color statistics into their parent node.
2545 %
2546 %  The format of the PruneLevel method is:
2547 %
2548 %      PruneLevel(const Image *image,CubeInfo *cube_info,
2549 %        const NodeInfo *node_info)
2550 %
2551 %  A description of each parameter follows.
2552 %
2553 %    o image: the image.
2554 %
2555 %    o cube_info: A pointer to the Cube structure.
2556 %
2557 %    o node_info: pointer to node in color cube tree that is to be pruned.
2558 %
2559 */
2560 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2561   const NodeInfo *node_info)
2562 {
2563   register ssize_t
2564     i;
2565
2566   size_t
2567     number_children;
2568
2569   /*
2570     Traverse any children.
2571   */
2572   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2573   for (i=0; i < (ssize_t) number_children; i++)
2574     if (node_info->child[i] != (NodeInfo *) NULL)
2575       PruneLevel(image,cube_info,node_info->child[i]);
2576   if (node_info->level == cube_info->depth)
2577     PruneChild(image,cube_info,node_info);
2578 }
2579 \f
2580 /*
2581 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2582 %                                                                             %
2583 %                                                                             %
2584 %                                                                             %
2585 +  P r u n e T o C u b e D e p t h                                            %
2586 %                                                                             %
2587 %                                                                             %
2588 %                                                                             %
2589 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2590 %
2591 %  PruneToCubeDepth() deletes any nodes at a depth greater than
2592 %  cube_info->depth while merging their color statistics into their parent
2593 %  node.
2594 %
2595 %  The format of the PruneToCubeDepth method is:
2596 %
2597 %      PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2598 %        const NodeInfo *node_info)
2599 %
2600 %  A description of each parameter follows.
2601 %
2602 %    o cube_info: A pointer to the Cube structure.
2603 %
2604 %    o node_info: pointer to node in color cube tree that is to be pruned.
2605 %
2606 */
2607 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2608   const NodeInfo *node_info)
2609 {
2610   register ssize_t
2611     i;
2612
2613   size_t
2614     number_children;
2615
2616   /*
2617     Traverse any children.
2618   */
2619   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2620   for (i=0; i < (ssize_t) number_children; i++)
2621     if (node_info->child[i] != (NodeInfo *) NULL)
2622       PruneToCubeDepth(image,cube_info,node_info->child[i]);
2623   if (node_info->level > cube_info->depth)
2624     PruneChild(image,cube_info,node_info);
2625 }
2626 \f
2627 /*
2628 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2629 %                                                                             %
2630 %                                                                             %
2631 %                                                                             %
2632 %  Q u a n t i z e I m a g e                                                  %
2633 %                                                                             %
2634 %                                                                             %
2635 %                                                                             %
2636 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2637 %
2638 %  QuantizeImage() analyzes the colors within a reference image and chooses a
2639 %  fixed number of colors to represent the image.  The goal of the algorithm
2640 %  is to minimize the color difference between the input and output image while
2641 %  minimizing the processing time.
2642 %
2643 %  The format of the QuantizeImage method is:
2644 %
2645 %      MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2646 %        Image *image,ExceptionInfo *exception)
2647 %
2648 %  A description of each parameter follows:
2649 %
2650 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2651 %
2652 %    o image: the image.
2653 %
2654 %    o exception: return any errors or warnings in this structure.
2655 %
2656 */
2657
2658 static MagickBooleanType DirectToColormapImage(Image *image,
2659   ExceptionInfo *exception)
2660 {
2661   CacheView
2662     *image_view;
2663
2664   MagickBooleanType
2665     status;
2666
2667   register ssize_t
2668     i;
2669
2670   size_t
2671     number_colors;
2672
2673   ssize_t
2674     y;
2675
2676   status=MagickTrue;
2677   number_colors=(size_t) (image->columns*image->rows);
2678   if (AcquireImageColormap(image,number_colors,exception) == MagickFalse)
2679     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2680       image->filename);
2681   if (image->colors != number_colors)
2682     return(MagickFalse);
2683   i=0;
2684   image_view=AcquireAuthenticCacheView(image,exception);
2685   for (y=0; y < (ssize_t) image->rows; y++)
2686   {
2687     MagickBooleanType
2688       proceed;
2689
2690     register Quantum
2691       *restrict q;
2692
2693     register ssize_t
2694       x;
2695
2696     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2697     if (q == (Quantum *) NULL)
2698       break;
2699     for (x=0; x < (ssize_t) image->columns; x++)
2700     {
2701       image->colormap[i].red=(double) GetPixelRed(image,q);
2702       image->colormap[i].green=(double) GetPixelGreen(image,q);
2703       image->colormap[i].blue=(double) GetPixelBlue(image,q);
2704       image->colormap[i].alpha=(double) GetPixelAlpha(image,q);
2705       SetPixelIndex(image,(Quantum) i,q);
2706       i++;
2707       q+=GetPixelChannels(image);
2708     }
2709     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2710       break;
2711     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
2712       image->rows);
2713     if (proceed == MagickFalse)
2714       status=MagickFalse;
2715   }
2716   image_view=DestroyCacheView(image_view);
2717   return(status);
2718 }
2719
2720 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2721   Image *image,ExceptionInfo *exception)
2722 {
2723   CubeInfo
2724     *cube_info;
2725
2726   MagickBooleanType
2727     status;
2728
2729   size_t
2730     depth,
2731     maximum_colors;
2732
2733   assert(quantize_info != (const QuantizeInfo *) NULL);
2734   assert(quantize_info->signature == MagickSignature);
2735   assert(image != (Image *) NULL);
2736   assert(image->signature == MagickSignature);
2737   if (image->debug != MagickFalse)
2738     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2739   maximum_colors=quantize_info->number_colors;
2740   if (maximum_colors == 0)
2741     maximum_colors=MaxColormapSize;
2742   if (maximum_colors > MaxColormapSize)
2743     maximum_colors=MaxColormapSize;
2744   if ((image->columns*image->rows) <= maximum_colors)
2745     (void) DirectToColormapImage(image,exception);
2746   if ((IsImageGray(image,exception) != MagickFalse) &&
2747       (image->matte == MagickFalse))
2748     (void) SetGrayscaleImage(image,exception);
2749   if ((image->storage_class == PseudoClass) &&
2750       (image->colors <= maximum_colors))
2751     return(MagickTrue);
2752   depth=quantize_info->tree_depth;
2753   if (depth == 0)
2754     {
2755       size_t
2756         colors;
2757
2758       /*
2759         Depth of color tree is: Log4(colormap size)+2.
2760       */
2761       colors=maximum_colors;
2762       for (depth=1; colors != 0; depth++)
2763         colors>>=2;
2764       if ((quantize_info->dither != MagickFalse) && (depth > 2))
2765         depth--;
2766       if ((image->matte != MagickFalse) && (depth > 5))
2767         depth--;
2768     }
2769   /*
2770     Initialize color cube.
2771   */
2772   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2773   if (cube_info == (CubeInfo *) NULL)
2774     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2775       image->filename);
2776   status=ClassifyImageColors(cube_info,image,exception);
2777   if (status != MagickFalse)
2778     {
2779       /*
2780         Reduce the number of colors in the image.
2781       */
2782       ReduceImageColors(image,cube_info);
2783       status=AssignImageColors(image,cube_info,exception);
2784     }
2785   DestroyCubeInfo(cube_info);
2786   return(status);
2787 }
2788 \f
2789 /*
2790 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2791 %                                                                             %
2792 %                                                                             %
2793 %                                                                             %
2794 %   Q u a n t i z e I m a g e s                                               %
2795 %                                                                             %
2796 %                                                                             %
2797 %                                                                             %
2798 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2799 %
2800 %  QuantizeImages() analyzes the colors within a set of reference images and
2801 %  chooses a fixed number of colors to represent the set.  The goal of the
2802 %  algorithm is to minimize the color difference between the input and output
2803 %  images while minimizing the processing time.
2804 %
2805 %  The format of the QuantizeImages method is:
2806 %
2807 %      MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2808 %        Image *images,ExceptionInfo *exception)
2809 %
2810 %  A description of each parameter follows:
2811 %
2812 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2813 %
2814 %    o images: Specifies a pointer to a list of Image structures.
2815 %
2816 %    o exception: return any errors or warnings in this structure.
2817 %
2818 */
2819 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2820   Image *images,ExceptionInfo *exception)
2821 {
2822   CubeInfo
2823     *cube_info;
2824
2825   Image
2826     *image;
2827
2828   MagickBooleanType
2829     proceed,
2830     status;
2831
2832   MagickProgressMonitor
2833     progress_monitor;
2834
2835   register ssize_t
2836     i;
2837
2838   size_t
2839     depth,
2840     maximum_colors,
2841     number_images;
2842
2843   assert(quantize_info != (const QuantizeInfo *) NULL);
2844   assert(quantize_info->signature == MagickSignature);
2845   assert(images != (Image *) NULL);
2846   assert(images->signature == MagickSignature);
2847   if (images->debug != MagickFalse)
2848     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2849   if (GetNextImageInList(images) == (Image *) NULL)
2850     {
2851       /*
2852         Handle a single image with QuantizeImage.
2853       */
2854       status=QuantizeImage(quantize_info,images,exception);
2855       return(status);
2856     }
2857   status=MagickFalse;
2858   maximum_colors=quantize_info->number_colors;
2859   if (maximum_colors == 0)
2860     maximum_colors=MaxColormapSize;
2861   if (maximum_colors > MaxColormapSize)
2862     maximum_colors=MaxColormapSize;
2863   depth=quantize_info->tree_depth;
2864   if (depth == 0)
2865     {
2866       size_t
2867         colors;
2868
2869       /*
2870         Depth of color tree is: Log4(colormap size)+2.
2871       */
2872       colors=maximum_colors;
2873       for (depth=1; colors != 0; depth++)
2874         colors>>=2;
2875       if (quantize_info->dither != MagickFalse)
2876         depth--;
2877     }
2878   /*
2879     Initialize color cube.
2880   */
2881   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2882   if (cube_info == (CubeInfo *) NULL)
2883     {
2884       (void) ThrowMagickException(exception,GetMagickModule(),
2885         ResourceLimitError,"MemoryAllocationFailed","'%s'",images->filename);
2886       return(MagickFalse);
2887     }
2888   number_images=GetImageListLength(images);
2889   image=images;
2890   for (i=0; image != (Image *) NULL; i++)
2891   {
2892     progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2893       image->client_data);
2894     status=ClassifyImageColors(cube_info,image,exception);
2895     if (status == MagickFalse)
2896       break;
2897     (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2898     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2899       number_images);
2900     if (proceed == MagickFalse)
2901       break;
2902     image=GetNextImageInList(image);
2903   }
2904   if (status != MagickFalse)
2905     {
2906       /*
2907         Reduce the number of colors in an image sequence.
2908       */
2909       ReduceImageColors(images,cube_info);
2910       image=images;
2911       for (i=0; image != (Image *) NULL; i++)
2912       {
2913         progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2914           NULL,image->client_data);
2915         status=AssignImageColors(image,cube_info,exception);
2916         if (status == MagickFalse)
2917           break;
2918         (void) SetImageProgressMonitor(image,progress_monitor,
2919           image->client_data);
2920         proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2921           number_images);
2922         if (proceed == MagickFalse)
2923           break;
2924         image=GetNextImageInList(image);
2925       }
2926     }
2927   DestroyCubeInfo(cube_info);
2928   return(status);
2929 }
2930 \f
2931 /*
2932 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2933 %                                                                             %
2934 %                                                                             %
2935 %                                                                             %
2936 +   R e d u c e                                                               %
2937 %                                                                             %
2938 %                                                                             %
2939 %                                                                             %
2940 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2941 %
2942 %  Reduce() traverses the color cube tree and prunes any node whose
2943 %  quantization error falls below a particular threshold.
2944 %
2945 %  The format of the Reduce method is:
2946 %
2947 %      Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2948 %
2949 %  A description of each parameter follows.
2950 %
2951 %    o image: the image.
2952 %
2953 %    o cube_info: A pointer to the Cube structure.
2954 %
2955 %    o node_info: pointer to node in color cube tree that is to be pruned.
2956 %
2957 */
2958 static void Reduce(const Image *image,CubeInfo *cube_info,
2959   const NodeInfo *node_info)
2960 {
2961   register ssize_t
2962     i;
2963
2964   size_t
2965     number_children;
2966
2967   /*
2968     Traverse any children.
2969   */
2970   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2971   for (i=0; i < (ssize_t) number_children; i++)
2972     if (node_info->child[i] != (NodeInfo *) NULL)
2973       Reduce(image,cube_info,node_info->child[i]);
2974   if (node_info->quantize_error <= cube_info->pruning_threshold)
2975     PruneChild(image,cube_info,node_info);
2976   else
2977     {
2978       /*
2979         Find minimum pruning threshold.
2980       */
2981       if (node_info->number_unique > 0)
2982         cube_info->colors++;
2983       if (node_info->quantize_error < cube_info->next_threshold)
2984         cube_info->next_threshold=node_info->quantize_error;
2985     }
2986 }
2987 \f
2988 /*
2989 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2990 %                                                                             %
2991 %                                                                             %
2992 %                                                                             %
2993 +   R e d u c e I m a g e C o l o r s                                         %
2994 %                                                                             %
2995 %                                                                             %
2996 %                                                                             %
2997 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2998 %
2999 %  ReduceImageColors() repeatedly prunes the tree until the number of nodes
3000 %  with n2 > 0 is less than or equal to the maximum number of colors allowed
3001 %  in the output image.  On any given iteration over the tree, it selects
3002 %  those nodes whose E value is minimal for pruning and merges their
3003 %  color statistics upward. It uses a pruning threshold, Ep, to govern
3004 %  node selection as follows:
3005 %
3006 %    Ep = 0
3007 %    while number of nodes with (n2 > 0) > required maximum number of colors
3008 %      prune all nodes such that E <= Ep
3009 %      Set Ep to minimum E in remaining nodes
3010 %
3011 %  This has the effect of minimizing any quantization error when merging
3012 %  two nodes together.
3013 %
3014 %  When a node to be pruned has offspring, the pruning procedure invokes
3015 %  itself recursively in order to prune the tree from the leaves upward.
3016 %  n2,  Sr, Sg,  and  Sb in a node being pruned are always added to the
3017 %  corresponding data in that node's parent.  This retains the pruned
3018 %  node's color characteristics for later averaging.
3019 %
3020 %  For each node, n2 pixels exist for which that node represents the
3021 %  smallest volume in RGB space containing those pixel's colors.  When n2
3022 %  > 0 the node will uniquely define a color in the output image. At the
3023 %  beginning of reduction,  n2 = 0  for all nodes except a the leaves of
3024 %  the tree which represent colors present in the input image.
3025 %
3026 %  The other pixel count, n1, indicates the total number of colors
3027 %  within the cubic volume which the node represents.  This includes n1 -
3028 %  n2  pixels whose colors should be defined by nodes at a lower level in
3029 %  the tree.
3030 %
3031 %  The format of the ReduceImageColors method is:
3032 %
3033 %      ReduceImageColors(const Image *image,CubeInfo *cube_info)
3034 %
3035 %  A description of each parameter follows.
3036 %
3037 %    o image: the image.
3038 %
3039 %    o cube_info: A pointer to the Cube structure.
3040 %
3041 */
3042 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
3043 {
3044 #define ReduceImageTag  "Reduce/Image"
3045
3046   MagickBooleanType
3047     proceed;
3048
3049   MagickOffsetType
3050     offset;
3051
3052   size_t
3053     span;
3054
3055   cube_info->next_threshold=0.0;
3056   for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
3057   {
3058     cube_info->pruning_threshold=cube_info->next_threshold;
3059     cube_info->next_threshold=cube_info->root->quantize_error-1;
3060     cube_info->colors=0;
3061     Reduce(image,cube_info,cube_info->root);
3062     offset=(MagickOffsetType) span-cube_info->colors;
3063     proceed=SetImageProgress(image,ReduceImageTag,offset,span-
3064       cube_info->maximum_colors+1);
3065     if (proceed == MagickFalse)
3066       break;
3067   }
3068 }
3069 \f
3070 /*
3071 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3072 %                                                                             %
3073 %                                                                             %
3074 %                                                                             %
3075 %   R e m a p I m a g e                                                       %
3076 %                                                                             %
3077 %                                                                             %
3078 %                                                                             %
3079 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3080 %
3081 %  RemapImage() replaces the colors of an image with a dither of the colors
3082 %  provided.
3083 %
3084 %  The format of the RemapImage method is:
3085 %
3086 %      MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3087 %        Image *image,const Image *remap_image,ExceptionInfo *exception)
3088 %
3089 %  A description of each parameter follows:
3090 %
3091 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3092 %
3093 %    o image: the image.
3094 %
3095 %    o remap_image: the reference image.
3096 %
3097 %    o exception: return any errors or warnings in this structure.
3098 %
3099 */
3100 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3101   Image *image,const Image *remap_image,ExceptionInfo *exception)
3102 {
3103   CubeInfo
3104     *cube_info;
3105
3106   MagickBooleanType
3107     status;
3108
3109   /*
3110     Initialize color cube.
3111   */
3112   assert(image != (Image *) NULL);
3113   assert(image->signature == MagickSignature);
3114   if (image->debug != MagickFalse)
3115     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3116   assert(remap_image != (Image *) NULL);
3117   assert(remap_image->signature == MagickSignature);
3118   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3119     quantize_info->number_colors);
3120   if (cube_info == (CubeInfo *) NULL)
3121     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3122       image->filename);
3123   status=ClassifyImageColors(cube_info,remap_image,exception);
3124   if (status != MagickFalse)
3125     {
3126       /*
3127         Classify image colors from the reference image.
3128       */
3129       cube_info->quantize_info->number_colors=cube_info->colors;
3130       status=AssignImageColors(image,cube_info,exception);
3131     }
3132   DestroyCubeInfo(cube_info);
3133   return(status);
3134 }
3135 \f
3136 /*
3137 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3138 %                                                                             %
3139 %                                                                             %
3140 %                                                                             %
3141 %   R e m a p I m a g e s                                                     %
3142 %                                                                             %
3143 %                                                                             %
3144 %                                                                             %
3145 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3146 %
3147 %  RemapImages() replaces the colors of a sequence of images with the
3148 %  closest color from a reference image.
3149 %
3150 %  The format of the RemapImage method is:
3151 %
3152 %      MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3153 %        Image *images,Image *remap_image,ExceptionInfo *exception)
3154 %
3155 %  A description of each parameter follows:
3156 %
3157 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3158 %
3159 %    o images: the image sequence.
3160 %
3161 %    o remap_image: the reference image.
3162 %
3163 %    o exception: return any errors or warnings in this structure.
3164 %
3165 */
3166 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3167   Image *images,const Image *remap_image,ExceptionInfo *exception)
3168 {
3169   CubeInfo
3170     *cube_info;
3171
3172   Image
3173     *image;
3174
3175   MagickBooleanType
3176     status;
3177
3178   assert(images != (Image *) NULL);
3179   assert(images->signature == MagickSignature);
3180   if (images->debug != MagickFalse)
3181     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3182   image=images;
3183   if (remap_image == (Image *) NULL)
3184     {
3185       /*
3186         Create a global colormap for an image sequence.
3187       */
3188       status=QuantizeImages(quantize_info,images,exception);
3189       return(status);
3190     }
3191   /*
3192     Classify image colors from the reference image.
3193   */
3194   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3195     quantize_info->number_colors);
3196   if (cube_info == (CubeInfo *) NULL)
3197     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3198       image->filename);
3199   status=ClassifyImageColors(cube_info,remap_image,exception);
3200   if (status != MagickFalse)
3201     {
3202       /*
3203         Classify image colors from the reference image.
3204       */
3205       cube_info->quantize_info->number_colors=cube_info->colors;
3206       image=images;
3207       for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3208       {
3209         status=AssignImageColors(image,cube_info,exception);
3210         if (status == MagickFalse)
3211           break;
3212       }
3213     }
3214   DestroyCubeInfo(cube_info);
3215   return(status);
3216 }
3217 \f
3218 /*
3219 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3220 %                                                                             %
3221 %                                                                             %
3222 %                                                                             %
3223 %   S e t G r a y s c a l e I m a g e                                         %
3224 %                                                                             %
3225 %                                                                             %
3226 %                                                                             %
3227 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3228 %
3229 %  SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3230 %
3231 %  The format of the SetGrayscaleImage method is:
3232 %
3233 %      MagickBooleanType SetGrayscaleImage(Image *image,ExceptionInfo *exeption)
3234 %
3235 %  A description of each parameter follows:
3236 %
3237 %    o image: The image.
3238 %
3239 %    o exception: return any errors or warnings in this structure.
3240 %
3241 */
3242
3243 #if defined(__cplusplus) || defined(c_plusplus)
3244 extern "C" {
3245 #endif
3246
3247 static int IntensityCompare(const void *x,const void *y)
3248 {
3249   PixelInfo
3250     *color_1,
3251     *color_2;
3252
3253   ssize_t
3254     intensity;
3255
3256   color_1=(PixelInfo *) x;
3257   color_2=(PixelInfo *) y;
3258   intensity=GetPixelInfoIntensity(color_1)-(ssize_t)
3259     GetPixelInfoIntensity(color_2);
3260   return((int) intensity);
3261 }
3262
3263 #if defined(__cplusplus) || defined(c_plusplus)
3264 }
3265 #endif
3266
3267 static MagickBooleanType SetGrayscaleImage(Image *image,
3268   ExceptionInfo *exception)
3269 {
3270   CacheView
3271     *image_view;
3272
3273   MagickBooleanType
3274     status;
3275
3276   PixelInfo
3277     *colormap;
3278
3279   register ssize_t
3280     i;
3281
3282   ssize_t
3283     *colormap_index,
3284     j,
3285     y;
3286
3287   assert(image != (Image *) NULL);
3288   assert(image->signature == MagickSignature);
3289   if (image->type != GrayscaleType)
3290     (void) TransformImageColorspace(image,GRAYColorspace,exception);
3291   colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3292     sizeof(*colormap_index));
3293   if (colormap_index == (ssize_t *) NULL)
3294     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3295       image->filename);
3296   if (image->storage_class != PseudoClass)
3297     {
3298       for (i=0; i <= (ssize_t) MaxMap; i++)
3299         colormap_index[i]=(-1);
3300       if (AcquireImageColormap(image,MaxMap+1,exception) == MagickFalse)
3301         ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3302           image->filename);
3303       image->colors=0;
3304       status=MagickTrue;
3305       image_view=AcquireAuthenticCacheView(image,exception);
3306 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3307       #pragma omp parallel for schedule(static,4) shared(status) \
3308         dynamic_number_threads(image->columns,image->rows,1)
3309 #endif
3310       for (y=0; y < (ssize_t) image->rows; y++)
3311       {
3312         register Quantum
3313           *restrict q;
3314
3315         register ssize_t
3316           x;
3317
3318         if (status == MagickFalse)
3319           continue;
3320         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3321           exception);
3322         if (q == (Quantum *) NULL)
3323           {
3324             status=MagickFalse;
3325             continue;
3326           }
3327         for (x=0; x < (ssize_t) image->columns; x++)
3328         {
3329           register size_t
3330             intensity;
3331
3332           intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3333           if (colormap_index[intensity] < 0)
3334             {
3335 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3336               #pragma omp critical (MagickCore_SetGrayscaleImage)
3337 #endif
3338               if (colormap_index[intensity] < 0)
3339                 {
3340                   colormap_index[intensity]=(ssize_t) image->colors;
3341                   image->colormap[image->colors].red=(double)
3342                     GetPixelRed(image,q);
3343                   image->colormap[image->colors].green=(double)
3344                     GetPixelGreen(image,q);
3345                   image->colormap[image->colors].blue=(double)
3346                     GetPixelBlue(image,q);
3347                   image->colors++;
3348                }
3349             }
3350           SetPixelIndex(image,(Quantum)
3351             colormap_index[intensity],q);
3352           q+=GetPixelChannels(image);
3353         }
3354         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3355           status=MagickFalse;
3356       }
3357       image_view=DestroyCacheView(image_view);
3358     }
3359   for (i=0; i < (ssize_t) image->colors; i++)
3360     image->colormap[i].alpha=(double) i;
3361   qsort((void *) image->colormap,image->colors,sizeof(PixelInfo),
3362     IntensityCompare);
3363   colormap=(PixelInfo *) AcquireQuantumMemory(image->colors,
3364     sizeof(*colormap));
3365   if (colormap == (PixelInfo *) NULL)
3366     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3367       image->filename);
3368   j=0;
3369   colormap[j]=image->colormap[0];
3370   for (i=0; i < (ssize_t) image->colors; i++)
3371   {
3372     if (IsPixelInfoEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3373       {
3374         j++;
3375         colormap[j]=image->colormap[i];
3376       }
3377     colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3378   }
3379   image->colors=(size_t) (j+1);
3380   image->colormap=(PixelInfo *) RelinquishMagickMemory(image->colormap);
3381   image->colormap=colormap;
3382   status=MagickTrue;
3383   image_view=AcquireAuthenticCacheView(image,exception);
3384 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3385   #pragma omp parallel for schedule(static,4) shared(status) \
3386     dynamic_number_threads(image->columns,image->rows,1)
3387 #endif
3388   for (y=0; y < (ssize_t) image->rows; y++)
3389   {
3390     register Quantum
3391       *restrict q;
3392
3393     register ssize_t
3394       x;
3395
3396     if (status == MagickFalse)
3397       continue;
3398     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3399     if (q == (Quantum *) NULL)
3400       {
3401         status=MagickFalse;
3402         continue;
3403       }
3404     for (x=0; x < (ssize_t) image->columns; x++)
3405     {
3406       SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3407         GetPixelIndex(image,q))],q);
3408       q+=GetPixelChannels(image);
3409     }
3410     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3411       status=MagickFalse;
3412   }
3413   image_view=DestroyCacheView(image_view);
3414   colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3415   image->type=GrayscaleType;
3416   if (IsImageMonochrome(image,exception) != MagickFalse)
3417     image->type=BilevelType;
3418   return(status);
3419 }