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/*
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% %
% %
% %
% QQQ U U AAA N N TTTTT IIIII ZZZZZ EEEEE %
% Q Q U U A A NN N T I ZZ E %
% Q Q U U AAAAA N N N T I ZZZ EEEEE %
% Q QQ U U A A N NN T I ZZ E %
% QQQQ UUU A A N N T IIIII ZZZZZ EEEEE %
% %
% %
% MagickCore Methods to Reduce the Number of Unique Colors in an Image %
% %
% Software Design %
% Cristy %
% July 1992 %
% %
% %
% Copyright 1999-2020 ImageMagick Studio LLC, a non-profit organization %
% dedicated to making software imaging solutions freely available. %
% %
% You may not use this file except in compliance with the License. You may %
% obtain a copy of the License at %
% %
% https://imagemagick.org/script/license.php %
% %
% Unless required by applicable law or agreed to in writing, software %
% distributed under the License is distributed on an "AS IS" BASIS, %
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %
% See the License for the specific language governing permissions and %
% limitations under the License. %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Realism in computer graphics typically requires using 24 bits/pixel to
% generate an image. Yet many graphic display devices do not contain the
% amount of memory necessary to match the spatial and color resolution of
% the human eye. The Quantize methods takes a 24 bit image and reduces
% the number of colors so it can be displayed on raster device with less
% bits per pixel. In most instances, the quantized image closely
% resembles the original reference image.
%
% A reduction of colors in an image is also desirable for image
% transmission and real-time animation.
%
% QuantizeImage() takes a standard RGB or monochrome images and quantizes
% them down to some fixed number of colors.
%
% For purposes of color allocation, an image is a set of n pixels, where
% each pixel is a point in RGB space. RGB space is a 3-dimensional
% vector space, and each pixel, Pi, is defined by an ordered triple of
% red, green, and blue coordinates, (Ri, Gi, Bi).
%
% Each primary color component (red, green, or blue) represents an
% intensity which varies linearly from 0 to a maximum value, Cmax, which
% corresponds to full saturation of that color. Color allocation is
% defined over a domain consisting of the cube in RGB space with opposite
% vertices at (0,0,0) and (Cmax, Cmax, Cmax). QUANTIZE requires Cmax =
% 255.
%
% The algorithm maps this domain onto a tree in which each node
% represents a cube within that domain. In the following discussion
% these cubes are defined by the coordinate of two opposite vertices (vertex
% nearest the origin in RGB space and the vertex farthest from the origin).
%
% The tree's root node represents the entire domain, (0,0,0) through
% (Cmax,Cmax,Cmax). Each lower level in the tree is generated by
% subdividing one node's cube into eight smaller cubes of equal size.
% This corresponds to bisecting the parent cube with planes passing
% through the midpoints of each edge.
%
% The basic algorithm operates in three phases: Classification,
% Reduction, and Assignment. Classification builds a color description
% tree for the image. Reduction collapses the tree until the number it
% represents, at most, the number of colors desired in the output image.
% Assignment defines the output image's color map and sets each pixel's
% color by restorage_class in the reduced tree. Our goal is to minimize
% the numerical discrepancies between the original colors and quantized
% colors (quantization error).
%
% Classification begins by initializing a color description tree of
% sufficient depth to represent each possible input color in a leaf.
% However, it is impractical to generate a fully-formed color description
% tree in the storage_class phase for realistic values of Cmax. If
% colors components in the input image are quantized to k-bit precision,
% so that Cmax= 2k-1, the tree would need k levels below the root node to
% allow representing each possible input color in a leaf. This becomes
% prohibitive because the tree's total number of nodes is 1 +
% sum(i=1, k, 8k).
%
% A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
% Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
% Initializes data structures for nodes only as they are needed; (2)
% Chooses a maximum depth for the tree as a function of the desired
% number of colors in the output image (currently log2(colormap size)).
%
% For each pixel in the input image, storage_class scans downward from
% the root of the color description tree. At each level of the tree it
% identifies the single node which represents a cube in RGB space
% containing the pixel's color. It updates the following data for each
% such node:
%
% n1: Number of pixels whose color is contained in the RGB cube which
% this node represents;
%
% n2: Number of pixels whose color is not represented in a node at
% lower depth in the tree; initially, n2 = 0 for all nodes except
% leaves of the tree.
%
% Sr, Sg, Sb: Sums of the red, green, and blue component values for all
% pixels not classified at a lower depth. The combination of these sums
% and n2 will ultimately characterize the mean color of a set of pixels
% represented by this node.
%
% E: the distance squared in RGB space between each pixel contained
% within a node and the nodes' center. This represents the
% quantization error for a node.
%
% Reduction repeatedly prunes the tree until the number of nodes with n2
% > 0 is less than or equal to the maximum number of colors allowed in
% the output image. On any given iteration over the tree, it selects
% those nodes whose E count is minimal for pruning and merges their color
% statistics upward. It uses a pruning threshold, Ep, to govern node
% selection as follows:
%
% Ep = 0
% while number of nodes with (n2 > 0) > required maximum number of colors
% prune all nodes such that E <= Ep
% Set Ep to minimum E in remaining nodes
%
% This has the effect of minimizing any quantization error when merging
% two nodes together.
%
% When a node to be pruned has offspring, the pruning procedure invokes
% itself recursively in order to prune the tree from the leaves upward.
% n2, Sr, Sg, and Sb in a node being pruned are always added to the
% corresponding data in that node's parent. This retains the pruned
% node's color characteristics for later averaging.
%
% For each node, n2 pixels exist for which that node represents the
% smallest volume in RGB space containing those pixel's colors. When n2
% > 0 the node will uniquely define a color in the output image. At the
% beginning of reduction, n2 = 0 for all nodes except a the leaves of
% the tree which represent colors present in the input image.
%
% The other pixel count, n1, indicates the total number of colors within
% the cubic volume which the node represents. This includes n1 - n2
% pixels whose colors should be defined by nodes at a lower level in the
% tree.
%
% Assignment generates the output image from the pruned tree. The output
% image consists of two parts: (1) A color map, which is an array of
% color descriptions (RGB triples) for each color present in the output
% image; (2) A pixel array, which represents each pixel as an index
% into the color map array.
%
% First, the assignment phase makes one pass over the pruned color
% description tree to establish the image's color map. For each node
% with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
% color of all pixels that classify no lower than this node. Each of
% these colors becomes an entry in the color map.
%
% Finally, the assignment phase reclassifies each pixel in the pruned
% tree to identify the deepest node containing the pixel's color. The
% pixel's value in the pixel array becomes the index of this node's mean
% color in the color map.
%
% This method is based on a similar algorithm written by Paul Raveling.
%
*/
/*
Include declarations.
*/
#include "MagickCore/studio.h"
#include "MagickCore/artifact.h"
#include "MagickCore/attribute.h"
#include "MagickCore/cache-view.h"
#include "MagickCore/color.h"
#include "MagickCore/color-private.h"
#include "MagickCore/colormap.h"
#include "MagickCore/colorspace.h"
#include "MagickCore/colorspace-private.h"
#include "MagickCore/compare.h"
#include "MagickCore/enhance.h"
#include "MagickCore/exception.h"
#include "MagickCore/exception-private.h"
#include "MagickCore/histogram.h"
#include "MagickCore/image.h"
#include "MagickCore/image-private.h"
#include "MagickCore/list.h"
#include "MagickCore/memory_.h"
#include "MagickCore/memory-private.h"
#include "MagickCore/monitor.h"
#include "MagickCore/monitor-private.h"
#include "MagickCore/option.h"
#include "MagickCore/pixel-accessor.h"
#include "MagickCore/pixel-private.h"
#include "MagickCore/quantize.h"
#include "MagickCore/quantum.h"
#include "MagickCore/quantum-private.h"
#include "MagickCore/random_.h"
#include "MagickCore/resource_.h"
#include "MagickCore/string_.h"
#include "MagickCore/string-private.h"
#include "MagickCore/thread-private.h"
/*
Define declarations.
*/
#if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
#define CacheShift 2
#else
#define CacheShift 3
#endif
#define ErrorQueueLength 16
#define MaxNodes 266817
#define MaxTreeDepth 8
#define NodesInAList 1920
/*
Typdef declarations.
*/
typedef struct _DoublePixelPacket
{
double
red,
green,
blue,
alpha;
} DoublePixelPacket;
typedef struct _NodeInfo
{
struct _NodeInfo
*parent,
*child[16];
MagickSizeType
number_unique;
DoublePixelPacket
total_color;
double
quantize_error;
size_t
color_number,
id,
level;
} NodeInfo;
typedef struct _Nodes
{
NodeInfo
*nodes;
struct _Nodes
*next;
} Nodes;
typedef struct _CubeInfo
{
NodeInfo
*root;
size_t
colors,
maximum_colors;
ssize_t
transparent_index;
MagickSizeType
transparent_pixels;
DoublePixelPacket
target;
double
distance,
pruning_threshold,
next_threshold;
size_t
nodes,
free_nodes,
color_number;
NodeInfo
*next_node;
Nodes
*node_queue;
MemoryInfo
*memory_info;
ssize_t
*cache;
DoublePixelPacket
error[ErrorQueueLength];
double
weights[ErrorQueueLength];
QuantizeInfo
*quantize_info;
MagickBooleanType
associate_alpha;
ssize_t
x,
y;
size_t
depth;
MagickOffsetType
offset;
MagickSizeType
span;
} CubeInfo;
/*
Method prototypes.
*/
static CubeInfo
*GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
static NodeInfo
*GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
static MagickBooleanType
AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
DitherImage(Image *,CubeInfo *,ExceptionInfo *),
SetGrayscaleImage(Image *,ExceptionInfo *);
static size_t
DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
static void
ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
DestroyCubeInfo(CubeInfo *),
PruneLevel(CubeInfo *,const NodeInfo *),
PruneToCubeDepth(CubeInfo *,const NodeInfo *),
ReduceImageColors(const Image *,CubeInfo *);
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% A c q u i r e Q u a n t i z e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% AcquireQuantizeInfo() allocates the QuantizeInfo structure.
%
% The format of the AcquireQuantizeInfo method is:
%
% QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
%
% A description of each parameter follows:
%
% o image_info: the image info.
%
*/
MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
{
QuantizeInfo
*quantize_info;
quantize_info=(QuantizeInfo *) AcquireCriticalMemory(sizeof(*quantize_info));
GetQuantizeInfo(quantize_info);
if (image_info != (ImageInfo *) NULL)
{
const char
*option;
quantize_info->dither_method=image_info->dither == MagickFalse ?
NoDitherMethod : RiemersmaDitherMethod;
option=GetImageOption(image_info,"dither");
if (option != (const char *) NULL)
quantize_info->dither_method=(DitherMethod) ParseCommandOption(
MagickDitherOptions,MagickFalse,option);
quantize_info->measure_error=image_info->verbose;
}
return(quantize_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ A s s i g n I m a g e C o l o r s %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% AssignImageColors() generates the output image from the pruned tree. The
% output image consists of two parts: (1) A color map, which is an array
% of color descriptions (RGB triples) for each color present in the
% output image; (2) A pixel array, which represents each pixel as an
% index into the color map array.
%
% First, the assignment phase makes one pass over the pruned color
% description tree to establish the image's color map. For each node
% with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
% color of all pixels that classify no lower than this node. Each of
% these colors becomes an entry in the color map.
%
% Finally, the assignment phase reclassifies each pixel in the pruned
% tree to identify the deepest node containing the pixel's color. The
% pixel's value in the pixel array becomes the index of this node's mean
% color in the color map.
%
% The format of the AssignImageColors() method is:
%
% MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o cube_info: A pointer to the Cube structure.
%
*/
static inline void AssociateAlphaPixel(const Image *image,
const CubeInfo *cube_info,const Quantum *pixel,DoublePixelPacket *alpha_pixel)
{
double
alpha;
if ((cube_info->associate_alpha == MagickFalse) ||
(GetPixelAlpha(image,pixel) == OpaqueAlpha))
{
alpha_pixel->red=(double) GetPixelRed(image,pixel);
alpha_pixel->green=(double) GetPixelGreen(image,pixel);
alpha_pixel->blue=(double) GetPixelBlue(image,pixel);
alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
return;
}
alpha=(double) (QuantumScale*GetPixelAlpha(image,pixel));
alpha_pixel->red=alpha*GetPixelRed(image,pixel);
alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
}
static inline void AssociateAlphaPixelInfo(const CubeInfo *cube_info,
const PixelInfo *pixel,DoublePixelPacket *alpha_pixel)
{
double
alpha;
if ((cube_info->associate_alpha == MagickFalse) ||
(pixel->alpha == OpaqueAlpha))
{
alpha_pixel->red=(double) pixel->red;
alpha_pixel->green=(double) pixel->green;
alpha_pixel->blue=(double) pixel->blue;
alpha_pixel->alpha=(double) pixel->alpha;
return;
}
alpha=(double) (QuantumScale*pixel->alpha);
alpha_pixel->red=alpha*pixel->red;
alpha_pixel->green=alpha*pixel->green;
alpha_pixel->blue=alpha*pixel->blue;
alpha_pixel->alpha=(double) pixel->alpha;
}
static inline size_t ColorToNodeId(const CubeInfo *cube_info,
const DoublePixelPacket *pixel,size_t index)
{
size_t
id;
id=(size_t) (((ScaleQuantumToChar(ClampPixel(pixel->red)) >> index) & 0x01) |
((ScaleQuantumToChar(ClampPixel(pixel->green)) >> index) & 0x01) << 1 |
((ScaleQuantumToChar(ClampPixel(pixel->blue)) >> index) & 0x01) << 2);
if (cube_info->associate_alpha != MagickFalse)
id|=((ScaleQuantumToChar(ClampPixel(pixel->alpha)) >> index) & 0x1) << 3;
return(id);
}
static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info,
ExceptionInfo *exception)
{
#define AssignImageTag "Assign/Image"
ColorspaceType
colorspace;
ssize_t
y;
/*
Allocate image colormap.
*/
colorspace=image->colorspace;
if (cube_info->quantize_info->colorspace != UndefinedColorspace)
(void) TransformImageColorspace(image,cube_info->quantize_info->colorspace,
exception);
if (AcquireImageColormap(image,cube_info->colors,exception) == MagickFalse)
ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
image->filename);
image->colors=0;
cube_info->transparent_pixels=0;
cube_info->transparent_index=(-1);
(void) DefineImageColormap(image,cube_info,cube_info->root);
/*
Create a reduced color image.
*/
if (cube_info->quantize_info->dither_method != NoDitherMethod)
(void) DitherImage(image,cube_info,exception);
else
{
CacheView
*image_view;
MagickBooleanType
status;
status=MagickTrue;
image_view=AcquireAuthenticCacheView(image,exception);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,image,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
{
CubeInfo
cube;
register Quantum
*magick_restrict q;
register ssize_t
x;
ssize_t
count;
if (status == MagickFalse)
continue;
q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
exception);
if (q == (Quantum *) NULL)
{
status=MagickFalse;
continue;
}
cube=(*cube_info);
for (x=0; x < (ssize_t) image->columns; x+=count)
{
DoublePixelPacket
pixel;
register const NodeInfo
*node_info;
register ssize_t
i;
size_t
id,
index;
/*
Identify the deepest node containing the pixel's color.
*/
for (count=1; (x+count) < (ssize_t) image->columns; count++)
{
PixelInfo
packet;
GetPixelInfoPixel(image,q+count*GetPixelChannels(image),&packet);
if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
break;
}
AssociateAlphaPixel(image,&cube,q,&pixel);
node_info=cube.root;
for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
{
id=ColorToNodeId(&cube,&pixel,index);
if (node_info->child[id] == (NodeInfo *) NULL)
break;
node_info=node_info->child[id];
}
/*
Find closest color among siblings and their children.
*/
cube.target=pixel;
cube.distance=(double) (4.0*(QuantumRange+1.0)*(QuantumRange+1.0)+
1.0);
ClosestColor(image,&cube,node_info->parent);
index=cube.color_number;
for (i=0; i < (ssize_t) count; i++)
{
if (image->storage_class == PseudoClass)
SetPixelIndex(image,(Quantum) index,q);
if (cube.quantize_info->measure_error == MagickFalse)
{
SetPixelRed(image,ClampToQuantum(
image->colormap[index].red),q);
SetPixelGreen(image,ClampToQuantum(
image->colormap[index].green),q);
SetPixelBlue(image,ClampToQuantum(
image->colormap[index].blue),q);
if (cube.associate_alpha != MagickFalse)
SetPixelAlpha(image,ClampToQuantum(
image->colormap[index].alpha),q);
}
q+=GetPixelChannels(image);
}
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
status=MagickFalse;
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
image_view=DestroyCacheView(image_view);
}
if (cube_info->quantize_info->measure_error != MagickFalse)
(void) GetImageQuantizeError(image,exception);
if ((cube_info->quantize_info->number_colors == 2) &&
((cube_info->quantize_info->colorspace == LinearGRAYColorspace) ||
(cube_info->quantize_info->colorspace == GRAYColorspace)))
{
double
intensity;
/*
Monochrome image.
*/
intensity=GetPixelInfoLuma(image->colormap+0) < QuantumRange/2.0 ? 0.0 :
QuantumRange;
if (image->colors > 1)
{
intensity=0.0;
if (GetPixelInfoLuma(image->colormap+0) >
GetPixelInfoLuma(image->colormap+1))
intensity=(double) QuantumRange;
}
image->colormap[0].red=intensity;
image->colormap[0].green=intensity;
image->colormap[0].blue=intensity;
if (image->colors > 1)
{
image->colormap[1].red=(double) QuantumRange-intensity;
image->colormap[1].green=(double) QuantumRange-intensity;
image->colormap[1].blue=(double) QuantumRange-intensity;
}
}
(void) SyncImage(image,exception);
if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
(IssRGBCompatibleColorspace(colorspace) == MagickFalse))
(void) TransformImageColorspace(image,colorspace,exception);
return(MagickTrue);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ C l a s s i f y I m a g e C o l o r s %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ClassifyImageColors() begins by initializing a color description tree
% of sufficient depth to represent each possible input color in a leaf.
% However, it is impractical to generate a fully-formed color
% description tree in the storage_class phase for realistic values of
% Cmax. If colors components in the input image are quantized to k-bit
% precision, so that Cmax= 2k-1, the tree would need k levels below the
% root node to allow representing each possible input color in a leaf.
% This becomes prohibitive because the tree's total number of nodes is
% 1 + sum(i=1,k,8k).
%
% A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
% Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
% Initializes data structures for nodes only as they are needed; (2)
% Chooses a maximum depth for the tree as a function of the desired
% number of colors in the output image (currently log2(colormap size)).
%
% For each pixel in the input image, storage_class scans downward from
% the root of the color description tree. At each level of the tree it
% identifies the single node which represents a cube in RGB space
% containing It updates the following data for each such node:
%
% n1 : Number of pixels whose color is contained in the RGB cube
% which this node represents;
%
% n2 : Number of pixels whose color is not represented in a node at
% lower depth in the tree; initially, n2 = 0 for all nodes except
% leaves of the tree.
%
% Sr, Sg, Sb : Sums of the red, green, and blue component values for
% all pixels not classified at a lower depth. The combination of
% these sums and n2 will ultimately characterize the mean color of a
% set of pixels represented by this node.
%
% E: the distance squared in RGB space between each pixel contained
% within a node and the nodes' center. This represents the quantization
% error for a node.
%
% The format of the ClassifyImageColors() method is:
%
% MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
% const Image *image,ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o cube_info: A pointer to the Cube structure.
%
% o image: the image.
%
*/
static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
{
MagickBooleanType
associate_alpha;
associate_alpha=image->alpha_trait == BlendPixelTrait ? MagickTrue :
MagickFalse;
if ((cube_info->quantize_info->number_colors == 2) &&
((cube_info->quantize_info->colorspace == LinearGRAYColorspace) ||
(cube_info->quantize_info->colorspace == GRAYColorspace)))
associate_alpha=MagickFalse;
cube_info->associate_alpha=associate_alpha;
}
static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
const Image *image,ExceptionInfo *exception)
{
#define ClassifyImageTag "Classify/Image"
CacheView
*image_view;
DoublePixelPacket
error,
mid,
midpoint,
pixel;
MagickBooleanType
proceed;
double
bisect;
NodeInfo
*node_info;
size_t
count,
id,
index,
level;
ssize_t
y;
/*
Classify the first cube_info->maximum_colors colors to a tree depth of 8.
*/
SetAssociatedAlpha(image,cube_info);
if (cube_info->quantize_info->colorspace != image->colorspace)
{
if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
(cube_info->quantize_info->colorspace != CMYKColorspace))
(void) TransformImageColorspace((Image *) image,
cube_info->quantize_info->colorspace,exception);
else
if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
(void) TransformImageColorspace((Image *) image,sRGBColorspace,
exception);
}
midpoint.red=(double) QuantumRange/2.0;
midpoint.green=(double) QuantumRange/2.0;
midpoint.blue=(double) QuantumRange/2.0;
midpoint.alpha=(double) QuantumRange/2.0;
error.alpha=0.0;
image_view=AcquireVirtualCacheView(image,exception);
for (y=0; y < (ssize_t) image->rows; y++)
{
register const Quantum
*magick_restrict p;
register ssize_t
x;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const Quantum *) NULL)
break;
if (cube_info->nodes > MaxNodes)
{
/*
Prune one level if the color tree is too large.
*/
PruneLevel(cube_info,cube_info->root);
cube_info->depth--;
}
for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
{
/*
Start at the root and descend the color cube tree.
*/
for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
{
PixelInfo
packet;
GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
break;
}
AssociateAlphaPixel(image,cube_info,p,&pixel);
index=MaxTreeDepth-1;
bisect=((double) QuantumRange+1.0)/2.0;
mid=midpoint;
node_info=cube_info->root;
for (level=1; level <= MaxTreeDepth; level++)
{
double
distance;
bisect*=0.5;
id=ColorToNodeId(cube_info,&pixel,index);
mid.red+=(id & 1) != 0 ? bisect : -bisect;
mid.green+=(id & 2) != 0 ? bisect : -bisect;
mid.blue+=(id & 4) != 0 ? bisect : -bisect;
mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
if (node_info->child[id] == (NodeInfo *) NULL)
{
/*
Set colors of new node to contain pixel.
*/
node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
if (node_info->child[id] == (NodeInfo *) NULL)
{
(void) ThrowMagickException(exception,GetMagickModule(),
ResourceLimitError,"MemoryAllocationFailed","`%s'",
image->filename);
continue;
}
if (level == MaxTreeDepth)
cube_info->colors++;
}
/*
Approximate the quantization error represented by this node.
*/
node_info=node_info->child[id];
error.red=QuantumScale*(pixel.red-mid.red);
error.green=QuantumScale*(pixel.green-mid.green);
error.blue=QuantumScale*(pixel.blue-mid.blue);
if (cube_info->associate_alpha != MagickFalse)
error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
distance=(double) (error.red*error.red+error.green*error.green+
error.blue*error.blue+error.alpha*error.alpha);
if (IsNaN(distance))
distance=0.0;
node_info->quantize_error+=count*sqrt(distance);
cube_info->root->quantize_error+=node_info->quantize_error;
index--;
}
/*
Sum RGB for this leaf for later derivation of the mean cube color.
*/
node_info->number_unique+=count;
node_info->total_color.red+=count*QuantumScale*ClampPixel(pixel.red);
node_info->total_color.green+=count*QuantumScale*ClampPixel(pixel.green);
node_info->total_color.blue+=count*QuantumScale*ClampPixel(pixel.blue);
if (cube_info->associate_alpha != MagickFalse)
node_info->total_color.alpha+=count*QuantumScale*
ClampPixel(pixel.alpha);
else
node_info->total_color.alpha+=count*QuantumScale*
ClampPixel((MagickRealType) OpaqueAlpha);
p+=count*GetPixelChannels(image);
}
if (cube_info->colors > cube_info->maximum_colors)
{
PruneToCubeDepth(cube_info,cube_info->root);
break;
}
proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
image->rows);
if (proceed == MagickFalse)
break;
}
for (y++; y < (ssize_t) image->rows; y++)
{
register const Quantum
*magick_restrict p;
register ssize_t
x;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const Quantum *) NULL)
break;
if (cube_info->nodes > MaxNodes)
{
/*
Prune one level if the color tree is too large.
*/
PruneLevel(cube_info,cube_info->root);
cube_info->depth--;
}
for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
{
/*
Start at the root and descend the color cube tree.
*/
for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
{
PixelInfo
packet;
GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
break;
}
AssociateAlphaPixel(image,cube_info,p,&pixel);
index=MaxTreeDepth-1;
bisect=((double) QuantumRange+1.0)/2.0;
mid=midpoint;
node_info=cube_info->root;
for (level=1; level <= cube_info->depth; level++)
{
double
distance;
bisect*=0.5;
id=ColorToNodeId(cube_info,&pixel,index);
mid.red+=(id & 1) != 0 ? bisect : -bisect;
mid.green+=(id & 2) != 0 ? bisect : -bisect;
mid.blue+=(id & 4) != 0 ? bisect : -bisect;
mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
if (node_info->child[id] == (NodeInfo *) NULL)
{
/*
Set colors of new node to contain pixel.
*/
node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
if (node_info->child[id] == (NodeInfo *) NULL)
{
(void) ThrowMagickException(exception,GetMagickModule(),
ResourceLimitError,"MemoryAllocationFailed","%s",
image->filename);
continue;
}
if (level == cube_info->depth)
cube_info->colors++;
}
/*
Approximate the quantization error represented by this node.
*/
node_info=node_info->child[id];
error.red=QuantumScale*(pixel.red-mid.red);
error.green=QuantumScale*(pixel.green-mid.green);
error.blue=QuantumScale*(pixel.blue-mid.blue);
if (cube_info->associate_alpha != MagickFalse)
error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
distance=(double) (error.red*error.red+error.green*error.green+
error.blue*error.blue+error.alpha*error.alpha);
if (IsNaN(distance) != MagickFalse)
distance=0.0;
node_info->quantize_error+=count*sqrt(distance);
cube_info->root->quantize_error+=node_info->quantize_error;
index--;
}
/*
Sum RGB for this leaf for later derivation of the mean cube color.
*/
node_info->number_unique+=count;
node_info->total_color.red+=count*QuantumScale*ClampPixel(pixel.red);
node_info->total_color.green+=count*QuantumScale*ClampPixel(pixel.green);
node_info->total_color.blue+=count*QuantumScale*ClampPixel(pixel.blue);
if (cube_info->associate_alpha != MagickFalse)
node_info->total_color.alpha+=count*QuantumScale*
ClampPixel(pixel.alpha);
else
node_info->total_color.alpha+=count*QuantumScale*
ClampPixel((MagickRealType) OpaqueAlpha);
p+=count*GetPixelChannels(image);
}
proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
image->rows);
if (proceed == MagickFalse)
break;
}
image_view=DestroyCacheView(image_view);
if (cube_info->quantize_info->colorspace != image->colorspace)
if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
(cube_info->quantize_info->colorspace != CMYKColorspace))
(void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
return(y < (ssize_t) image->rows ? MagickFalse : MagickTrue);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% C l o n e Q u a n t i z e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
% or if quantize info is NULL, a new one.
%
% The format of the CloneQuantizeInfo method is:
%
% QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
%
% A description of each parameter follows:
%
% o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
% quantize info, or if image info is NULL a new one.
%
% o quantize_info: a structure of type info.
%
*/
MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
{
QuantizeInfo
*clone_info;
clone_info=(QuantizeInfo *) AcquireCriticalMemory(sizeof(*clone_info));
GetQuantizeInfo(clone_info);
if (quantize_info == (QuantizeInfo *) NULL)
return(clone_info);
clone_info->number_colors=quantize_info->number_colors;
clone_info->tree_depth=quantize_info->tree_depth;
clone_info->dither_method=quantize_info->dither_method;
clone_info->colorspace=quantize_info->colorspace;
clone_info->measure_error=quantize_info->measure_error;
return(clone_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ C l o s e s t C o l o r %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ClosestColor() traverses the color cube tree at a particular node and
% determines which colormap entry best represents the input color.
%
% The format of the ClosestColor method is:
%
% void ClosestColor(const Image *image,CubeInfo *cube_info,
% const NodeInfo *node_info)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o cube_info: A pointer to the Cube structure.
%
% o node_info: the address of a structure of type NodeInfo which points to a
% node in the color cube tree that is to be pruned.
%
*/
static void ClosestColor(const Image *image,CubeInfo *cube_info,
const NodeInfo *node_info)
{
register ssize_t
i;
size_t
number_children;
/*
Traverse any children.
*/
number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
for (i=0; i < (ssize_t) number_children; i++)
if (node_info->child[i] != (NodeInfo *) NULL)
ClosestColor(image,cube_info,node_info->child[i]);
if (node_info->number_unique != 0)
{
double
pixel;
register double
alpha,
beta,
distance;
register DoublePixelPacket
*magick_restrict q;
register PixelInfo
*magick_restrict p;
/*
Determine if this color is "closest".
*/
p=image->colormap+node_info->color_number;
q=(&cube_info->target);
alpha=1.0;
beta=1.0;
if (cube_info->associate_alpha != MagickFalse)
{
alpha=(double) (QuantumScale*p->alpha);
beta=(double) (QuantumScale*q->alpha);
}
pixel=alpha*p->red-beta*q->red;
distance=pixel*pixel;
if (distance <= cube_info->distance)
{
pixel=alpha*p->green-beta*q->green;
distance+=pixel*pixel;
if (distance <= cube_info->distance)
{
pixel=alpha*p->blue-beta*q->blue;
distance+=pixel*pixel;
if (distance <= cube_info->distance)
{
if (cube_info->associate_alpha != MagickFalse)
{
pixel=p->alpha-q->alpha;
distance+=pixel*pixel;
}
if (distance <= cube_info->distance)
{
cube_info->distance=distance;
cube_info->color_number=node_info->color_number;
}
}
}
}
}
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% C o m p r e s s I m a g e C o l o r m a p %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% CompressImageColormap() compresses an image colormap by removing any
% duplicate or unused color entries.
%
% The format of the CompressImageColormap method is:
%
% MagickBooleanType CompressImageColormap(Image *image,
% ExceptionInfo *exception)
%
% A description of each parameter follows:
%
% o image: the image.
%
% o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType CompressImageColormap(Image *image,
ExceptionInfo *exception)
{
QuantizeInfo
quantize_info;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
if (IsPaletteImage(image) == MagickFalse)
return(MagickFalse);
GetQuantizeInfo(&quantize_info);
quantize_info.number_colors=image->colors;
quantize_info.tree_depth=MaxTreeDepth;
return(QuantizeImage(&quantize_info,image,exception));
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ D e f i n e I m a g e C o l o r m a p %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DefineImageColormap() traverses the color cube tree and notes each colormap
% entry. A colormap entry is any node in the color cube tree where the
% of unique colors is not zero. DefineImageColormap() returns the number of
% colors in the image colormap.
%
% The format of the DefineImageColormap method is:
%
% size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
% NodeInfo *node_info)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o cube_info: A pointer to the Cube structure.
%
% o node_info: the address of a structure of type NodeInfo which points to a
% node in the color cube tree that is to be pruned.
%
*/
static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
NodeInfo *node_info)
{
register ssize_t
i;
size_t
number_children;
/*
Traverse any children.
*/
number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
for (i=0; i < (ssize_t) number_children; i++)
if (node_info->child[i] != (NodeInfo *) NULL)
(void) DefineImageColormap(image,cube_info,node_info->child[i]);
if (node_info->number_unique != 0)
{
register double
alpha;
register PixelInfo
*magick_restrict q;
/*
Colormap entry is defined by the mean color in this cube.
*/
q=image->colormap+image->colors;
alpha=(double) ((MagickOffsetType) node_info->number_unique);
alpha=PerceptibleReciprocal(alpha);
if (cube_info->associate_alpha == MagickFalse)
{
q->red=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.red);
q->green=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.green);
q->blue=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.blue);
q->alpha=(double) OpaqueAlpha;
}
else
{
double
opacity;
opacity=(double) (alpha*QuantumRange*node_info->total_color.alpha);
q->alpha=(double) ClampToQuantum(opacity);
if (q->alpha == OpaqueAlpha)
{
q->red=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.red);
q->green=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.green);
q->blue=(double) ClampToQuantum(alpha*QuantumRange*
node_info->total_color.blue);
}
else
{
double
gamma;
gamma=(double) (QuantumScale*q->alpha);
gamma=PerceptibleReciprocal(gamma);
q->red=(double) ClampToQuantum(alpha*gamma*QuantumRange*
node_info->total_color.red);
q->green=(double) ClampToQuantum(alpha*gamma*QuantumRange*
node_info->total_color.green);
q->blue=(double) ClampToQuantum(alpha*gamma*QuantumRange*
node_info->total_color.blue);
if (node_info->number_unique > cube_info->transparent_pixels)
{
cube_info->transparent_pixels=node_info->number_unique;
cube_info->transparent_index=(ssize_t) image->colors;
}
}
}
node_info->color_number=image->colors++;
}
return(image->colors);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ D e s t r o y C u b e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DestroyCubeInfo() deallocates memory associated with an image.
%
% The format of the DestroyCubeInfo method is:
%
% DestroyCubeInfo(CubeInfo *cube_info)
%
% A description of each parameter follows:
%
% o cube_info: the address of a structure of type CubeInfo.
%
*/
static void DestroyCubeInfo(CubeInfo *cube_info)
{
register Nodes
*nodes;
/*
Release color cube tree storage.
*/
do
{
nodes=cube_info->node_queue->next;
cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
cube_info->node_queue->nodes);
cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
cube_info->node_queue);
cube_info->node_queue=nodes;
} while (cube_info->node_queue != (Nodes *) NULL);
if (cube_info->memory_info != (MemoryInfo *) NULL)
cube_info->memory_info=RelinquishVirtualMemory(cube_info->memory_info);
cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% D e s t r o y Q u a n t i z e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
% structure.
%
% The format of the DestroyQuantizeInfo method is:
%
% QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
%
% A description of each parameter follows:
%
% o quantize_info: Specifies a pointer to an QuantizeInfo structure.
%
*/
MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
{
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
assert(quantize_info != (QuantizeInfo *) NULL);
assert(quantize_info->signature == MagickCoreSignature);
quantize_info->signature=(~MagickCoreSignature);
quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
return(quantize_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ D i t h e r I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DitherImage() distributes the difference between an original image and
% the corresponding color reduced algorithm to neighboring pixels using
% serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
% MagickTrue if the image is dithered otherwise MagickFalse.
%
% The format of the DitherImage method is:
%
% MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
% ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o cube_info: A pointer to the Cube structure.
%
% o exception: return any errors or warnings in this structure.
%
*/
static DoublePixelPacket **DestroyPixelThreadSet(DoublePixelPacket **pixels)
{
register ssize_t
i;
assert(pixels != (DoublePixelPacket **) NULL);
for (i=0; i < (ssize_t) GetMagickResourceLimit(ThreadResource); i++)
if (pixels[i] != (DoublePixelPacket *) NULL)
pixels[i]=(DoublePixelPacket *) RelinquishMagickMemory(pixels[i]);
pixels=(DoublePixelPacket **) RelinquishMagickMemory(pixels);
return(pixels);
}
static DoublePixelPacket **AcquirePixelThreadSet(const size_t count)
{
DoublePixelPacket
**pixels;
register ssize_t
i;
size_t
number_threads;
number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
pixels=(DoublePixelPacket **) AcquireQuantumMemory(number_threads,
sizeof(*pixels));
if (pixels == (DoublePixelPacket **) NULL)
return((DoublePixelPacket **) NULL);
(void) memset(pixels,0,number_threads*sizeof(*pixels));
for (i=0; i < (ssize_t) number_threads; i++)
{
pixels[i]=(DoublePixelPacket *) AcquireQuantumMemory(count,2*
sizeof(**pixels));
if (pixels[i] == (DoublePixelPacket *) NULL)
return(DestroyPixelThreadSet(pixels));
}
return(pixels);
}
static inline ssize_t CacheOffset(CubeInfo *cube_info,
const DoublePixelPacket *pixel)
{
#define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
#define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
#define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
#define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
ssize_t
offset;
offset=(ssize_t) (RedShift(ScaleQuantumToChar(ClampPixel(pixel->red))) |
GreenShift(ScaleQuantumToChar(ClampPixel(pixel->green))) |
BlueShift(ScaleQuantumToChar(ClampPixel(pixel->blue))));
if (cube_info->associate_alpha != MagickFalse)
offset|=AlphaShift(ScaleQuantumToChar(ClampPixel(pixel->alpha)));
return(offset);
}
static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info,
ExceptionInfo *exception)
{
#define DitherImageTag "Dither/Image"
CacheView
*image_view;
const char
*artifact;
double
amount;
DoublePixelPacket
**pixels;
MagickBooleanType
status;
ssize_t
y;
/*
Distribute quantization error using Floyd-Steinberg.
*/
pixels=AcquirePixelThreadSet(image->columns);
if (pixels == (DoublePixelPacket **) NULL)
return(MagickFalse);
status=MagickTrue;
amount=1.0;
artifact=GetImageArtifact(image,"dither:diffusion-amount");
if (artifact != (const char *) NULL)
amount=StringToDoubleInterval(artifact,1.0);
image_view=AcquireAuthenticCacheView(image,exception);
for (y=0; y < (ssize_t) image->rows; y++)
{
const int
id = GetOpenMPThreadId();
CubeInfo
cube;
DoublePixelPacket
*current,
*previous;
register Quantum
*magick_restrict q;
register ssize_t
x;
size_t
index;
ssize_t
v;
if (status == MagickFalse)
continue;
q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
if (q == (Quantum *) NULL)
{
status=MagickFalse;
continue;
}
cube=(*cube_info);
current=pixels[id]+(y & 0x01)*image->columns;
previous=pixels[id]+((y+1) & 0x01)*image->columns;
v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
for (x=0; x < (ssize_t) image->columns; x++)
{
DoublePixelPacket
color,
pixel;
register ssize_t
i;
ssize_t
u;
u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
AssociateAlphaPixel(image,&cube,q+u*GetPixelChannels(image),&pixel);
if (x > 0)
{
pixel.red+=7.0*amount*current[u-v].red/16;
pixel.green+=7.0*amount*current[u-v].green/16;
pixel.blue+=7.0*amount*current[u-v].blue/16;
if (cube.associate_alpha != MagickFalse)
pixel.alpha+=7.0*amount*current[u-v].alpha/16;
}
if (y > 0)
{
if (x < (ssize_t) (image->columns-1))
{
pixel.red+=previous[u+v].red/16;
pixel.green+=previous[u+v].green/16;
pixel.blue+=previous[u+v].blue/16;
if (cube.associate_alpha != MagickFalse)
pixel.alpha+=previous[u+v].alpha/16;
}
pixel.red+=5.0*amount*previous[u].red/16;
pixel.green+=5.0*amount*previous[u].green/16;
pixel.blue+=5.0*amount*previous[u].blue/16;
if (cube.associate_alpha != MagickFalse)
pixel.alpha+=5.0*amount*previous[u].alpha/16;
if (x > 0)
{
pixel.red+=3.0*amount*previous[u-v].red/16;
pixel.green+=3.0*amount*previous[u-v].green/16;
pixel.blue+=3.0*amount*previous[u-v].blue/16;
if (cube.associate_alpha != MagickFalse)
pixel.alpha+=3.0*amount*previous[u-v].alpha/16;
}
}
pixel.red=(double) ClampPixel(pixel.red);
pixel.green=(double) ClampPixel(pixel.green);
pixel.blue=(double) ClampPixel(pixel.blue);
if (cube.associate_alpha != MagickFalse)
pixel.alpha=(double) ClampPixel(pixel.alpha);
i=CacheOffset(&cube,&pixel);
if (cube.cache[i] < 0)
{
register NodeInfo
*node_info;
register size_t
node_id;
/*
Identify the deepest node containing the pixel's color.
*/
node_info=cube.root;
for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
{
node_id=ColorToNodeId(&cube,&pixel,index);
if (node_info->child[node_id] == (NodeInfo *) NULL)
break;
node_info=node_info->child[node_id];
}
/*
Find closest color among siblings and their children.
*/
cube.target=pixel;
cube.distance=(double) (4.0*(QuantumRange+1.0)*(QuantumRange+1.0)+
1.0);
ClosestColor(image,&cube,node_info->parent);
cube.cache[i]=(ssize_t) cube.color_number;
}
/*
Assign pixel to closest colormap entry.
*/
index=(size_t) cube.cache[i];
if (image->storage_class == PseudoClass)
SetPixelIndex(image,(Quantum) index,q+u*GetPixelChannels(image));
if (cube.quantize_info->measure_error == MagickFalse)
{
SetPixelRed(image,ClampToQuantum(image->colormap[index].red),
q+u*GetPixelChannels(image));
SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),
q+u*GetPixelChannels(image));
SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),
q+u*GetPixelChannels(image));
if (cube.associate_alpha != MagickFalse)
SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),
q+u*GetPixelChannels(image));
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
status=MagickFalse;
/*
Store the error.
*/
AssociateAlphaPixelInfo(&cube,image->colormap+index,&color);
current[u].red=pixel.red-color.red;
current[u].green=pixel.green-color.green;
current[u].blue=pixel.blue-color.blue;
if (cube.associate_alpha != MagickFalse)
current[u].alpha=pixel.alpha-color.alpha;
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
}
image_view=DestroyCacheView(image_view);
pixels=DestroyPixelThreadSet(pixels);
return(MagickTrue);
}
static MagickBooleanType
RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int,
ExceptionInfo *);
static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
const size_t level,const unsigned int direction,ExceptionInfo *exception)
{
if (level == 1)
switch (direction)
{
case WestGravity:
{
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
break;
}
case EastGravity:
{
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
break;
}
case NorthGravity:
{
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
break;
}
case SouthGravity:
{
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
break;
}
default:
break;
}
else
switch (direction)
{
case WestGravity:
{
Riemersma(image,image_view,cube_info,level-1,NorthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,WestGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,WestGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,SouthGravity,
exception);
break;
}
case EastGravity:
{
Riemersma(image,image_view,cube_info,level-1,SouthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,EastGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,EastGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,NorthGravity,
exception);
break;
}
case NorthGravity:
{
Riemersma(image,image_view,cube_info,level-1,WestGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,NorthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,EastGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,NorthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,EastGravity,
exception);
break;
}
case SouthGravity:
{
Riemersma(image,image_view,cube_info,level-1,EastGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,SouthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,WestGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,SouthGravity,
exception);
(void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
exception);
Riemersma(image,image_view,cube_info,level-1,WestGravity,
exception);
break;
}
default:
break;
}
}
static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
CubeInfo *cube_info,const unsigned int direction,ExceptionInfo *exception)
{
#define DitherImageTag "Dither/Image"
DoublePixelPacket
color,
pixel;
MagickBooleanType
proceed;
register CubeInfo
*p;
size_t
index;
p=cube_info;
if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
(p->y >= 0) && (p->y < (ssize_t) image->rows))
{
register Quantum
*magick_restrict q;
register ssize_t
i;
/*
Distribute error.
*/
q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
if (q == (Quantum *) NULL)
return(MagickFalse);
AssociateAlphaPixel(image,cube_info,q,&pixel);
for (i=0; i < ErrorQueueLength; i++)
{
pixel.red+=p->weights[i]*p->error[i].red;
pixel.green+=p->weights[i]*p->error[i].green;
pixel.blue+=p->weights[i]*p->error[i].blue;
if (cube_info->associate_alpha != MagickFalse)
pixel.alpha+=p->weights[i]*p->error[i].alpha;
}
pixel.red=(double) ClampPixel(pixel.red);
pixel.green=(double) ClampPixel(pixel.green);
pixel.blue=(double) ClampPixel(pixel.blue);
if (cube_info->associate_alpha != MagickFalse)
pixel.alpha=(double) ClampPixel(pixel.alpha);
i=CacheOffset(cube_info,&pixel);
if (p->cache[i] < 0)
{
register NodeInfo
*node_info;
register size_t
id;
/*
Identify the deepest node containing the pixel's color.
*/
node_info=p->root;
for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
{
id=ColorToNodeId(cube_info,&pixel,index);
if (node_info->child[id] == (NodeInfo *) NULL)
break;
node_info=node_info->child[id];
}
/*
Find closest color among siblings and their children.
*/
p->target=pixel;
p->distance=(double) (4.0*(QuantumRange+1.0)*((double)
QuantumRange+1.0)+1.0);
ClosestColor(image,p,node_info->parent);
p->cache[i]=(ssize_t) p->color_number;
}
/*
Assign pixel to closest colormap entry.
*/
index=(size_t) p->cache[i];
if (image->storage_class == PseudoClass)
SetPixelIndex(image,(Quantum) index,q);
if (cube_info->quantize_info->measure_error == MagickFalse)
{
SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
if (cube_info->associate_alpha != MagickFalse)
SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
return(MagickFalse);
/*
Propagate the error as the last entry of the error queue.
*/
(void) memmove(p->error,p->error+1,(ErrorQueueLength-1)*
sizeof(p->error[0]));
AssociateAlphaPixelInfo(cube_info,image->colormap+index,&color);
p->error[ErrorQueueLength-1].red=pixel.red-color.red;
p->error[ErrorQueueLength-1].green=pixel.green-color.green;
p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
if (cube_info->associate_alpha != MagickFalse)
p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
if (proceed == MagickFalse)
return(MagickFalse);
p->offset++;
}
switch (direction)
{
case WestGravity: p->x--; break;
case EastGravity: p->x++; break;
case NorthGravity: p->y--; break;
case SouthGravity: p->y++; break;
}
return(MagickTrue);
}
static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
ExceptionInfo *exception)
{
CacheView
*image_view;
MagickBooleanType
status;
register ssize_t
i;
size_t
depth;
if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
return(FloydSteinbergDither(image,cube_info,exception));
/*
Distribute quantization error along a Hilbert curve.
*/
(void) memset(cube_info->error,0,ErrorQueueLength*sizeof(*cube_info->error));
cube_info->x=0;
cube_info->y=0;
i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
for (depth=1; i != 0; depth++)
i>>=1;
if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
depth++;
cube_info->offset=0;
cube_info->span=(MagickSizeType) image->columns*image->rows;
image_view=AcquireAuthenticCacheView(image,exception);
if (depth > 1)
Riemersma(image,image_view,cube_info,depth-1,NorthGravity,exception);
status=RiemersmaDither(image,image_view,cube_info,ForgetGravity,exception);
image_view=DestroyCacheView(image_view);
return(status);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ G e t C u b e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% GetCubeInfo() initialize the Cube data structure.
%
% The format of the GetCubeInfo method is:
%
% CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
% const size_t depth,const size_t maximum_colors)
%
% A description of each parameter follows.
%
% o quantize_info: Specifies a pointer to an QuantizeInfo structure.
%
% o depth: Normally, this integer value is zero or one. A zero or
% one tells Quantize to choose a optimal tree depth of Log4(number_colors).
% A tree of this depth generally allows the best representation of the
% reference image with the least amount of memory and the fastest
% computational speed. In some cases, such as an image with low color
% dispersion (a few number of colors), a value other than
% Log4(number_colors) is required. To expand the color tree completely,
% use a value of 8.
%
% o maximum_colors: maximum colors.
%
*/
static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
const size_t depth,const size_t maximum_colors)
{
CubeInfo
*cube_info;
double
sum,
weight;
register ssize_t
i;
size_t
length;
/*
Initialize tree to describe color cube_info.
*/
cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
if (cube_info == (CubeInfo *) NULL)
return((CubeInfo *) NULL);
(void) memset(cube_info,0,sizeof(*cube_info));
cube_info->depth=depth;
if (cube_info->depth > MaxTreeDepth)
cube_info->depth=MaxTreeDepth;
if (cube_info->depth < 2)
cube_info->depth=2;
cube_info->maximum_colors=maximum_colors;
/*
Initialize root node.
*/
cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
if (cube_info->root == (NodeInfo *) NULL)
return((CubeInfo *) NULL);
cube_info->root->parent=cube_info->root;
cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
if (cube_info->quantize_info->dither_method == NoDitherMethod)
return(cube_info);
/*
Initialize dither resources.
*/
length=(size_t) (1UL << (4*(8-CacheShift)));
cube_info->memory_info=AcquireVirtualMemory(length,sizeof(*cube_info->cache));
if (cube_info->memory_info == (MemoryInfo *) NULL)
return((CubeInfo *) NULL);
cube_info->cache=(ssize_t *) GetVirtualMemoryBlob(cube_info->memory_info);
/*
Initialize color cache.
*/
(void) memset(cube_info->cache,(-1),sizeof(*cube_info->cache)*length);
/*
Distribute weights along a curve of exponential decay.
*/
weight=1.0;
for (i=0; i < ErrorQueueLength; i++)
{
cube_info->weights[ErrorQueueLength-i-1]=PerceptibleReciprocal(weight);
weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
}
/*
Normalize the weighting factors.
*/
weight=0.0;
for (i=0; i < ErrorQueueLength; i++)
weight+=cube_info->weights[i];
sum=0.0;
for (i=0; i < ErrorQueueLength; i++)
{
cube_info->weights[i]/=weight;
sum+=cube_info->weights[i];
}
cube_info->weights[0]+=1.0-sum;
return(cube_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ G e t N o d e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% GetNodeInfo() allocates memory for a new node in the color cube tree and
% presets all fields to zero.
%
% The format of the GetNodeInfo method is:
%
% NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
% const size_t level,NodeInfo *parent)
%
% A description of each parameter follows.
%
% o node: The GetNodeInfo method returns a pointer to a queue of nodes.
%
% o id: Specifies the child number of the node.
%
% o level: Specifies the level in the storage_class the node resides.
%
*/
static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
const size_t level,NodeInfo *parent)
{
NodeInfo
*node_info;
if (cube_info->free_nodes == 0)
{
Nodes
*nodes;
/*
Allocate a new queue of nodes.
*/
nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
if (nodes == (Nodes *) NULL)
return((NodeInfo *) NULL);
nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
sizeof(*nodes->nodes));
if (nodes->nodes == (NodeInfo *) NULL)
return((NodeInfo *) NULL);
nodes->next=cube_info->node_queue;
cube_info->node_queue=nodes;
cube_info->next_node=nodes->nodes;
cube_info->free_nodes=NodesInAList;
}
cube_info->nodes++;
cube_info->free_nodes--;
node_info=cube_info->next_node++;
(void) memset(node_info,0,sizeof(*node_info));
node_info->parent=parent;
node_info->id=id;
node_info->level=level;
return(node_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% G e t I m a g e Q u a n t i z e E r r o r %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% GetImageQuantizeError() measures the difference between the original
% and quantized images. This difference is the total quantization error.
% The error is computed by summing over all pixels in an image the distance
% squared in RGB space between each reference pixel value and its quantized
% value. These values are computed:
%
% o mean_error_per_pixel: This value is the mean error for any single
% pixel in the image.
%
% o normalized_mean_square_error: This value is the normalized mean
% quantization error for any single pixel in the image. This distance
% measure is normalized to a range between 0 and 1. It is independent
% of the range of red, green, and blue values in the image.
%
% o normalized_maximum_square_error: Thsi value is the normalized
% maximum quantization error for any single pixel in the image. This
% distance measure is normalized to a range between 0 and 1. It is
% independent of the range of red, green, and blue values in your image.
%
% The format of the GetImageQuantizeError method is:
%
% MagickBooleanType GetImageQuantizeError(Image *image,
% ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType GetImageQuantizeError(Image *image,
ExceptionInfo *exception)
{
CacheView
*image_view;
double
alpha,
area,
beta,
distance,
maximum_error,
mean_error,
mean_error_per_pixel;
ssize_t
index,
y;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
image->total_colors=GetNumberColors(image,(FILE *) NULL,exception);
(void) memset(&image->error,0,sizeof(image->error));
if (image->storage_class == DirectClass)
return(MagickTrue);
alpha=1.0;
beta=1.0;
area=3.0*image->columns*image->rows;
maximum_error=0.0;
mean_error_per_pixel=0.0;
mean_error=0.0;
image_view=AcquireVirtualCacheView(image,exception);
for (y=0; y < (ssize_t) image->rows; y++)
{
register const Quantum
*magick_restrict p;
register ssize_t
x;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const Quantum *) NULL)
break;
for (x=0; x < (ssize_t) image->columns; x++)
{
index=(ssize_t) GetPixelIndex(image,p);
if (image->alpha_trait == BlendPixelTrait)
{
alpha=(double) (QuantumScale*GetPixelAlpha(image,p));
beta=(double) (QuantumScale*image->colormap[index].alpha);
}
distance=fabs((double) (alpha*GetPixelRed(image,p)-beta*
image->colormap[index].red));
mean_error_per_pixel+=distance;
mean_error+=distance*distance;
if (distance > maximum_error)
maximum_error=distance;
distance=fabs((double) (alpha*GetPixelGreen(image,p)-beta*
image->colormap[index].green));
mean_error_per_pixel+=distance;
mean_error+=distance*distance;
if (distance > maximum_error)
maximum_error=distance;
distance=fabs((double) (alpha*GetPixelBlue(image,p)-beta*
image->colormap[index].blue));
mean_error_per_pixel+=distance;
mean_error+=distance*distance;
if (distance > maximum_error)
maximum_error=distance;
p+=GetPixelChannels(image);
}
}
image_view=DestroyCacheView(image_view);
image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
mean_error/area;
image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
return(MagickTrue);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% G e t Q u a n t i z e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% GetQuantizeInfo() initializes the QuantizeInfo structure.
%
% The format of the GetQuantizeInfo method is:
%
% GetQuantizeInfo(QuantizeInfo *quantize_info)
%
% A description of each parameter follows:
%
% o quantize_info: Specifies a pointer to a QuantizeInfo structure.
%
*/
MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
{
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
assert(quantize_info != (QuantizeInfo *) NULL);
(void) memset(quantize_info,0,sizeof(*quantize_info));
quantize_info->number_colors=256;
quantize_info->dither_method=RiemersmaDitherMethod;
quantize_info->colorspace=UndefinedColorspace;
quantize_info->measure_error=MagickFalse;
quantize_info->signature=MagickCoreSignature;
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% K m e a n s I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% KmeansImage() applies k-means color reduction to an image. This is a
% colorspace clustering or segmentation technique.
%
% The format of the KmeansImage method is:
%
% MagickBooleanType KmeansImage(Image *image,const size_t number_colors,
% const size_t max_iterations,const double tolerance,
% ExceptionInfo *exception)
%
% A description of each parameter follows:
%
% o image: the image.
%
% o number_colors: number of colors to use as seeds.
%
% o max_iterations: maximum number of iterations while converging.
%
% o tolerance: the maximum tolerance.
%
% o exception: return any errors or warnings in this structure.
%
*/
typedef struct _KmeansInfo
{
double
red,
green,
blue,
alpha,
black,
count,
distortion;
} KmeansInfo;
static KmeansInfo **DestroyKmeansThreadSet(KmeansInfo **kmeans_info)
{
register ssize_t
i;
assert(kmeans_info != (KmeansInfo **) NULL);
for (i=0; i < (ssize_t) GetMagickResourceLimit(ThreadResource); i++)
if (kmeans_info[i] != (KmeansInfo *) NULL)
kmeans_info[i]=(KmeansInfo *) RelinquishMagickMemory(kmeans_info[i]);
kmeans_info=(KmeansInfo **) RelinquishMagickMemory(kmeans_info);
return(kmeans_info);
}
static KmeansInfo **AcquireKmeansThreadSet(const size_t number_colors)
{
KmeansInfo
**kmeans_info;
register ssize_t
i;
size_t
number_threads;
number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
kmeans_info=(KmeansInfo **) AcquireQuantumMemory(number_threads,
sizeof(*kmeans_info));
if (kmeans_info == (KmeansInfo **) NULL)
return((KmeansInfo **) NULL);
(void) memset(kmeans_info,0,number_threads*sizeof(*kmeans_info));
for (i=0; i < (ssize_t) number_threads; i++)
{
kmeans_info[i]=(KmeansInfo *) AcquireQuantumMemory(number_colors,
sizeof(**kmeans_info));
if (kmeans_info[i] == (KmeansInfo *) NULL)
return(DestroyKmeansThreadSet(kmeans_info));
}
return(kmeans_info);
}
static inline double KmeansMetric(const Image *magick_restrict image,
const Quantum *magick_restrict p,const PixelInfo *magick_restrict q)
{
register double
gamma,
metric,
pixel;
gamma=1.0;
metric=0.0;
if ((image->alpha_trait != UndefinedPixelTrait) ||
(q->alpha_trait != UndefinedPixelTrait))
{
pixel=GetPixelAlpha(image,p)-(q->alpha_trait != UndefinedPixelTrait ?
q->alpha : OpaqueAlpha);
metric+=pixel*pixel;
if (image->alpha_trait != UndefinedPixelTrait)
gamma*=QuantumScale*GetPixelAlpha(image,p);
if (q->alpha_trait != UndefinedPixelTrait)
gamma*=QuantumScale*q->alpha;
}
if (image->colorspace == CMYKColorspace)
{
pixel=QuantumScale*(GetPixelBlack(image,p)-q->black);
metric+=gamma*pixel*pixel;
gamma*=QuantumScale*(QuantumRange-GetPixelBlack(image,p));
gamma*=QuantumScale*(QuantumRange-q->black);
}
metric*=3.0;
pixel=QuantumScale*(GetPixelRed(image,p)-q->red);
if (IsHueCompatibleColorspace(image->colorspace) != MagickFalse)
{
if (fabs((double) pixel) > 0.5)
pixel-=0.5;
pixel*=2.0;
}
metric+=gamma*pixel*pixel;
pixel=QuantumScale*(GetPixelGreen(image,p)-q->green);
metric+=gamma*pixel*pixel;
pixel=QuantumScale*(GetPixelBlue(image,p)-q->blue);
metric+=gamma*pixel*pixel;
return(metric);
}
MagickExport MagickBooleanType KmeansImage(Image *image,
const size_t number_colors,const size_t max_iterations,const double tolerance,
ExceptionInfo *exception)
{
#define KmeansImageTag "Kmeans/Image"
#define RandomColorComponent(info) (QuantumRange*GetPseudoRandomValue(info))
CacheView
*image_view;
const char
*colors;
double
previous_tolerance;
KmeansInfo
**kmeans_pixels;
MagickBooleanType
verbose,
status;
register ssize_t
n;
size_t
number_threads;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
assert(exception != (ExceptionInfo *) NULL);
assert(exception->signature == MagickCoreSignature);
colors=GetImageArtifact(image,"kmeans:seed-colors");
if (colors == (const char *) NULL)
{
CubeInfo
*cube_info;
QuantizeInfo
*quantize_info;
size_t
colors,
depth;
/*
Seed clusters from color quantization.
*/
quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
quantize_info->colorspace=image->colorspace;
quantize_info->number_colors=number_colors;
quantize_info->dither_method=NoDitherMethod;
colors=number_colors;
for (depth=1; colors != 0; depth++)
colors>>=2;
cube_info=GetCubeInfo(quantize_info,depth,number_colors);
if (cube_info == (CubeInfo *) NULL)
{
quantize_info=DestroyQuantizeInfo(quantize_info);
ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
image->filename);
}
status=ClassifyImageColors(cube_info,image,exception);
if (status != MagickFalse)
{
if (cube_info->colors > cube_info->maximum_colors)
ReduceImageColors(image,cube_info);
status=AcquireImageColormap(image,number_colors,exception);
if (status != MagickFalse)
{
image->colors=0;
(void) DefineImageColormap(image,cube_info,cube_info->root);
}
}
DestroyCubeInfo(cube_info);
quantize_info=DestroyQuantizeInfo(quantize_info);
if (status == MagickFalse)
return(status);
}
else
{
char
color[MagickPathExtent];
register const char
*p;
/*
Seed clusters from color list (e.g. red;green;blue).
*/
status=AcquireImageColormap(image,number_colors,exception);
if (status == MagickFalse)
return(status);
for (n=0, p=colors; n < (ssize_t) image->colors; n++)
{
register const char
*q;
for (q=p; *q != '\0'; q++)
if (*q == ';')
break;
(void) CopyMagickString(color,p,(size_t) MagickMin(q-p+1,
MagickPathExtent));
(void) QueryColorCompliance(color,AllCompliance,image->colormap+n,
exception);
if (*q == '\0')
{
n++;
break;
}
p=q+1;
}
if (n < (ssize_t) image->colors)
{
RandomInfo
*random_info;
/*
Seed clusters from random values.
*/
random_info=AcquireRandomInfo();
for ( ; n < (ssize_t) image->colors; n++)
{
(void) QueryColorCompliance("#000",AllCompliance,image->colormap+n,
exception);
image->colormap[n].red=RandomColorComponent(random_info);
image->colormap[n].green=RandomColorComponent(random_info);
image->colormap[n].blue=RandomColorComponent(random_info);
if (image->alpha_trait != BlendPixelTrait)
image->colormap[n].alpha=RandomColorComponent(random_info);
if (image->colorspace == CMYKColorspace)
image->colormap[n].black=RandomColorComponent(random_info);
}
random_info=DestroyRandomInfo(random_info);
}
}
/*
Iterative refinement.
*/
kmeans_pixels=AcquireKmeansThreadSet(number_colors);
if (kmeans_pixels == (KmeansInfo **) NULL)
ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
image->filename);
previous_tolerance=0.0;
verbose=IsStringTrue(GetImageArtifact(image,"debug"));
number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
image_view=AcquireAuthenticCacheView(image,exception);
for (n=0; n < (ssize_t) max_iterations; n++)
{
double
distortion;
register ssize_t
i;
ssize_t
y;
for (i=0; i < (ssize_t) number_threads; i++)
(void) memset(kmeans_pixels[i],0,image->colors*sizeof(*kmeans_pixels[i]));
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(dynamic) shared(status) \
magick_number_threads(image,image,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
{
const int
id = GetOpenMPThreadId();
register Quantum
*magick_restrict q;
register ssize_t
x;
if (status == MagickFalse)
continue;
q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
if (q == (Quantum *) NULL)
{
status=MagickFalse;
continue;
}
for (x=0; x < (ssize_t) image->columns; x++)
{
double
min_distance;
register ssize_t
i;
ssize_t
j;
/*
Assign each pixel whose mean has the least squared color distance.
*/
j=0;
min_distance=KmeansMetric(image,q,image->colormap+0);
for (i=1; i < (ssize_t) image->colors; i++)
{
double
distance;
if (min_distance <= MagickEpsilon)
break;
distance=KmeansMetric(image,q,image->colormap+i);
if (distance < min_distance)
{
min_distance=distance;
j=i;
}
}
kmeans_pixels[id][j].red+=QuantumScale*GetPixelRed(image,q);
kmeans_pixels[id][j].green+=QuantumScale*GetPixelGreen(image,q);
kmeans_pixels[id][j].blue+=QuantumScale*GetPixelBlue(image,q);
if (image->alpha_trait != BlendPixelTrait)
kmeans_pixels[id][j].alpha+=QuantumScale*GetPixelAlpha(image,q);
if (image->colorspace == CMYKColorspace)
kmeans_pixels[id][j].black+=QuantumScale*GetPixelBlack(image,q);
kmeans_pixels[id][j].count++;
kmeans_pixels[id][j].distortion+=min_distance;
SetPixelIndex(image,(Quantum) j,q);
q+=GetPixelChannels(image);
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
status=MagickFalse;
}
if (status == MagickFalse)
break;
/*
Reduce sums to [0] entry.
*/
for (i=1; i < (ssize_t) number_threads; i++)
{
register ssize_t
j;
for (j=0; j < (ssize_t) image->colors; j++)
{
kmeans_pixels[0][j].red+=kmeans_pixels[i][j].red;
kmeans_pixels[0][j].green+=kmeans_pixels[i][j].green;
kmeans_pixels[0][j].blue+=kmeans_pixels[i][j].blue;
if (image->alpha_trait != BlendPixelTrait)
kmeans_pixels[0][j].alpha+=kmeans_pixels[i][j].alpha;
if (image->colorspace == CMYKColorspace)
kmeans_pixels[0][j].black+=kmeans_pixels[i][j].black;
kmeans_pixels[0][j].count+=kmeans_pixels[i][j].count;
kmeans_pixels[0][j].distortion+=kmeans_pixels[i][j].distortion;
}
}
/*
Calculate the new means (centroids) of the pixels in the new clusters.
*/
distortion=0.0;
for (i=0; i < (ssize_t) image->colors; i++)
{
double
gamma;
gamma=PerceptibleReciprocal((double) kmeans_pixels[0][i].count);
image->colormap[i].red=gamma*QuantumRange*kmeans_pixels[0][i].red;
image->colormap[i].green=gamma*QuantumRange<