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Java Advanced Imaging Image I/O Tools API core, but without the classes
involved with javax.media.jai dependencies, JPEG2000 or
codecLibJIIO, meaning that this library can be distributed under the
modified BSD license and should be GPL compatible.
/*
* $RCSfile: PaletteBuilder.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistribution of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any
* kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
* WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
* EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
* NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
* USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
* ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
* CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
* REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
* INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for
* use in the design, construction, operation or maintenance of any
* nuclear facility.
*
* $Revision: 1.3 $
* $Date: 2007/08/31 00:06:00 $
* $State: Exp $
*/
package com.github.jaiimageio.impl.common;
import java.awt.Color;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import javax.imageio.ImageTypeSpecifier;
/**
* This class implements the octree quantization method
* as it is described in the "Graphics Gems"
* (ISBN 0-12-286166-3, Chapter 4, pages 297-293)
*/
public class PaletteBuilder {
/**
* maximum of tree depth
*/
protected static final int MAXLEVEL = 8;
protected RenderedImage src;
protected ColorModel srcColorModel;
protected Raster srcRaster;
protected int requiredSize;
protected ColorNode root;
protected int numNodes;
protected int maxNodes;
protected int currLevel;
protected int currSize;
protected ColorNode[] reduceList;
protected ColorNode[] palette;
protected int transparency;
protected ColorNode transColor;
/**
* Creates an image representing given image
* src using IndexColorModel.
*
* Lossless conversion is not always possible (e.g. if number
* of colors in the given image exceeds maximum palette size).
* Result image then is an approximation constructed by octree
* quantization method.
*
* @exception IllegalArgumentException if src is
* null.
*
* @exception UnsupportedOperationException if implemented method
* is unable to create approximation of src
* and canCreatePalette returns false.
*
* @see createIndexColorModel
*
* @see canCreatePalette
*
*/
public static RenderedImage createIndexedImage(RenderedImage src) {
PaletteBuilder pb = new PaletteBuilder(src);
pb.buildPalette();
return pb.getIndexedImage();
}
/**
* Creates an palette representing colors from given image
* img. If number of colors in the given image exceeds
* maximum palette size closest colors would be merged.
*
* @exception IllegalArgumentException if img is
* null.
*
* @exception UnsupportedOperationException if implemented method
* is unable to create approximation of img
* and canCreatePalette returns false.
*
* @see createIndexedImage
*
* @see canCreatePalette
*
*/
public static IndexColorModel createIndexColorModel(RenderedImage img) {
PaletteBuilder pb = new PaletteBuilder(img);
pb.buildPalette();
return pb.getIndexColorModel();
}
/**
* Returns true if PaletteBuilder is able to create
* palette for given image type.
*
* @param type an instance of ImageTypeSpecifier to be
* indexed.
*
* @return true if the PaletteBuilder
* is likely to be able to create palette for this image type.
*
* @exception IllegalArgumentException if type
* is null.
*/
public static boolean canCreatePalette(ImageTypeSpecifier type) {
if (type == null) {
throw new IllegalArgumentException("type == null");
}
return true;
}
/**
* Returns true if PaletteBuilder is able to create
* palette for given rendered image.
*
* @param image an instance of RenderedImage to be
* indexed.
*
* @return true if the PaletteBuilder
* is likely to be able to create palette for this image type.
*
* @exception IllegalArgumentException if image
* is null.
*/
public static boolean canCreatePalette(RenderedImage image) {
if (image == null) {
throw new IllegalArgumentException("image == null");
}
ImageTypeSpecifier type = new ImageTypeSpecifier(image);
return canCreatePalette(type);
}
protected RenderedImage getIndexedImage() {
IndexColorModel icm = getIndexColorModel();
BufferedImage dst =
new BufferedImage(src.getWidth(), src.getHeight(),
BufferedImage.TYPE_BYTE_INDEXED, icm);
WritableRaster wr = dst.getRaster();
int minX = src.getMinX();
int minY = src.getMinY();
for (int y =0; y < dst.getHeight(); y++) {
for (int x = 0; x < dst.getWidth(); x++) {
Color aColor = getSrcColor(x + minX, y + minY);
wr.setSample(x, y, 0, findColorIndex(root, aColor));
}
}
return dst;
}
protected PaletteBuilder(RenderedImage src) {
this(src, 256);
}
protected PaletteBuilder(RenderedImage src, int size) {
this.src = src;
this.srcColorModel = src.getColorModel();
this.srcRaster = src.getData();
this.transparency =
srcColorModel.getTransparency();
if (transparency != Transparency.OPAQUE) {
this.requiredSize = size - 1;
transColor = new ColorNode();
transColor.isLeaf = true;
} else {
this.requiredSize = size;
}
}
private Color getSrcColor(int x, int y) {
int argb = srcColorModel.getRGB(srcRaster.getDataElements(x, y, null));
return new Color(argb, transparency != Transparency.OPAQUE);
}
protected int findColorIndex(ColorNode aNode, Color aColor) {
if (transparency != Transparency.OPAQUE &&
aColor.getAlpha() != 0xff)
{
return 0; // default transparnt pixel
}
if (aNode.isLeaf) {
return aNode.paletteIndex;
} else {
int childIndex = getBranchIndex(aColor, aNode.level);
return findColorIndex(aNode.children[childIndex], aColor);
}
}
protected void buildPalette() {
reduceList = new ColorNode[MAXLEVEL + 1];
for (int i = 0; i < reduceList.length; i++) {
reduceList[i] = null;
}
numNodes = 0;
maxNodes = 0;
root = null;
currSize = 0;
currLevel = MAXLEVEL;
/*
from the book
*/
int w = src.getWidth();
int h = src.getHeight();
int minX = src.getMinX();
int minY = src.getMinY();
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
Color aColor = getSrcColor(w - x + minX - 1, h - y + minY - 1);
/*
* If transparency of given image is not opaque we assume all
* colors with alpha less than 1.0 as fully transparent.
*/
if (transparency != Transparency.OPAQUE &&
aColor.getAlpha() != 0xff)
{
transColor = insertNode(transColor, aColor, 0);
} else {
root = insertNode(root, aColor, 0);
}
if (currSize > requiredSize) {
reduceTree();
}
}
}
}
protected ColorNode insertNode(ColorNode aNode, Color aColor, int aLevel) {
if (aNode == null) {
aNode = new ColorNode();
numNodes++;
if (numNodes > maxNodes) {
maxNodes = numNodes;
}
aNode.level = aLevel;
aNode.isLeaf = (aLevel > MAXLEVEL);
if (aNode.isLeaf) {
currSize++;
}
}
aNode.colorCount++;
aNode.red += aColor.getRed();
aNode.green += aColor.getGreen();
aNode.blue += aColor.getBlue();
if (!aNode.isLeaf) {
int branchIndex = getBranchIndex(aColor, aLevel);
if (aNode.children[branchIndex] == null) {
aNode.childCount++;
if (aNode.childCount == 2) {
aNode.nextReducible = reduceList[aLevel];
reduceList[aLevel] = aNode;
}
}
aNode.children[branchIndex] =
insertNode(aNode.children[branchIndex], aColor, aLevel + 1);
}
return aNode;
}
protected IndexColorModel getIndexColorModel() {
int size = currSize;
if (transparency != Transparency.OPAQUE) {
size ++; // we need place for transparent color;
}
byte[] red = new byte[size];
byte[] green = new byte[size];
byte[] blue = new byte[size];
int index = 0;
palette = new ColorNode[size];
if (transparency != Transparency.OPAQUE) {
index ++;
}
int lastIndex = findPaletteEntry(root, index, red, green, blue);
IndexColorModel icm = null;
if (transparency != Transparency.OPAQUE) {
icm = new IndexColorModel(8, size, red, green, blue, 0);
} else {
icm = new IndexColorModel(8, currSize, red, green, blue);
}
return icm;
}
protected int findPaletteEntry(ColorNode aNode, int index,
byte[] red, byte[] green, byte[] blue)
{
if (aNode.isLeaf) {
red[index] = (byte)(aNode.red/aNode.colorCount);
green[index] = (byte)(aNode.green/aNode.colorCount);
blue[index] = (byte)(aNode.blue/aNode.colorCount);
aNode.paletteIndex = index;
palette[index] = aNode;
index++;
} else {
for (int i = 0; i < 8; i++) {
if (aNode.children[i] != null) {
index = findPaletteEntry(aNode.children[i], index,
red, green, blue);
}
}
}
return index;
}
protected int getBranchIndex(Color aColor, int aLevel) {
if (aLevel > MAXLEVEL || aLevel < 0) {
throw new IllegalArgumentException("Invalid octree node depth: " +
aLevel);
}
int shift = MAXLEVEL - aLevel;
int red_index = 0x1 & ((0xff & aColor.getRed()) >> shift);
int green_index = 0x1 & ((0xff & aColor.getGreen()) >> shift);
int blue_index = 0x1 & ((0xff & aColor.getBlue()) >> shift);
int index = (red_index << 2) | (green_index << 1) | blue_index;
return index;
}
protected void reduceTree() {
int level = reduceList.length - 1;
while (reduceList[level] == null && level >= 0) {
level--;
}
ColorNode thisNode = reduceList[level];
if (thisNode == null) {
// nothing to reduce
return;
}
// look for element with lower color count
ColorNode pList = thisNode;
int minColorCount = pList.colorCount;
int cnt = 1;
while (pList.nextReducible != null) {
if (minColorCount > pList.nextReducible.colorCount) {
thisNode = pList;
minColorCount = pList.colorCount;
}
pList = pList.nextReducible;
cnt++;
}
// save pointer to first reducible node
// NB: current color count for node could be changed in future
if (thisNode == reduceList[level]) {
reduceList[level] = thisNode.nextReducible;
} else {
pList = thisNode.nextReducible; // we need to process it
thisNode.nextReducible = pList.nextReducible;
thisNode = pList;
}
if (thisNode.isLeaf) {
return;
}
// reduce node
int leafChildCount = thisNode.getLeafChildCount();
thisNode.isLeaf = true;
currSize -= (leafChildCount - 1);
int aDepth = thisNode.level;
for (int i = 0; i < 8; i++) {
thisNode.children[i] = freeTree(thisNode.children[i]);
}
thisNode.childCount = 0;
}
protected ColorNode freeTree(ColorNode aNode) {
if (aNode == null) {
return null;
}
for (int i = 0; i < 8; i++) {
aNode.children[i] = freeTree(aNode.children[i]);
}
numNodes--;
return null;
}
/**
* The node of color tree.
*/
protected class ColorNode {
public boolean isLeaf;
public int childCount;
ColorNode[] children;
public int colorCount;
public long red;
public long blue;
public long green;
public int paletteIndex;
public int level;
ColorNode nextReducible;
public ColorNode() {
isLeaf = false;
level = 0;
childCount = 0;
children = new ColorNode[8];
for (int i = 0; i < 8; i++) {
children[i] = null;
}
colorCount = 0;
red = green = blue = 0;
paletteIndex = 0;
}
public int getLeafChildCount() {
if (isLeaf) {
return 0;
}
int cnt = 0;
for (int i = 0; i < children.length; i++) {
if (children[i] != null) {
if (children[i].isLeaf) {
cnt ++;
} else {
cnt += children[i].getLeafChildCount();
}
}
}
return cnt;
}
public int getRGB() {
int r = (int)red/colorCount;
int g = (int)green/colorCount;
int b = (int)blue/colorCount;
int c = 0xff << 24 | (0xff&r) << 16 | (0xff&g) << 8 | (0xff&b);
return c;
}
}
}
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