/*
* Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.imageio.plugins.common;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.awt.Color;
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
* <code>src</code> using <code>IndexColorModel</code>.
*
* 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 <code>src</code> is
* <code>null</code>.
*
* @exception UnsupportedOperationException if implemented method
* is unable to create approximation of <code>src</code>
* and <code>canCreatePalette</code> returns <code>false</code>.
*
* @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
* <code>img</code>. If number of colors in the given image exceeds
* maximum palette size closest colors would be merged.
*
* @exception IllegalArgumentException if <code>img</code> is
* <code>null</code>.
*
* @exception UnsupportedOperationException if implemented method
* is unable to create approximation of <code>img</code>
* and <code>canCreatePalette</code> returns <code>false</code>.
*
* @see createIndexedImage
*
* @see canCreatePalette
*
*/
public static IndexColorModel createIndexColorModel(RenderedImage img) {
PaletteBuilder pb = new PaletteBuilder(img);
pb.buildPalette();
return pb.getIndexColorModel();
}
/**
* Returns <code>true</code> if PaletteBuilder is able to create
* palette for given image type.
*
* @param type an instance of <code>ImageTypeSpecifier</code> to be
* indexed.
*
* @return <code>true</code> if the <code>PaletteBuilder</code>
* is likely to be able to create palette for this image type.
*
* @exception IllegalArgumentException if <code>type</code>
* is <code>null</code>.
*/
public static boolean canCreatePalette(ImageTypeSpecifier type) {
if (type == null) {
throw new IllegalArgumentException("type == null");
}
return true;
}
/**
* Returns <code>true</code> if PaletteBuilder is able to create
* palette for given rendered image.
*
* @param image an instance of <code>RenderedImage</code> to be
* indexed.
*
* @return <code>true</code> if the <code>PaletteBuilder</code>
* is likely to be able to create palette for this image type.
*
* @exception IllegalArgumentException if <code>image</code>
* is <code>null</code>.
*/
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();
for (int y =0; y < dst.getHeight(); y++) {
for (int x = 0; x < dst.getWidth(); x++) {
Color aColor = getSrcColor(x,y);
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();
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();
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
Color aColor = getSrcColor(w - x - 1, h - y - 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)
{
if (transColor == null) {
this.requiredSize --; // one slot for transparent color
transColor = new ColorNode();
transColor.isLeaf = true;
}
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 (transColor != null) {
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 (transColor != null) {
index ++;
}
if (root != null) {
findPaletteEntry(root, index, red, green, blue);
}
IndexColorModel icm = null;
if (transColor != null) {
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;
}
}
}