001/* BandCombineOp.java - perform a combination on the bands of a raster 002 Copyright (C) 2004, 2006 Free Software Foundation 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package java.awt.image; 039 040import java.awt.RenderingHints; 041import java.awt.geom.Point2D; 042import java.awt.geom.Rectangle2D; 043import java.util.Arrays; 044 045/** 046 * Filter Raster pixels by applying a matrix. 047 * 048 * BandCombineOp applies a matrix to each pixel to produce new pixel values. 049 * The width of the matrix must be the same or one more than the number of 050 * bands in the source Raster. If one more, the pixels in the source are 051 * assumed to contain an implicit 1.0 at the end. 052 * 053 * The rows of the matrix are multiplied by the pixel to produce the values 054 * for the destination. Therefore the destination Raster must contain the 055 * same number of bands as the number of rows in the filter matrix. 056 * 057 * This Op assumes that samples are integers; floating point sample types will 058 * be rounded to their nearest integer value during filtering. 059 * 060 * @author Jerry Quinn (jlquinn@optonline.net) 061 */ 062public class BandCombineOp implements RasterOp 063{ 064 private RenderingHints hints; 065 private float[][] matrix; 066 067 /** 068 * Construct a BandCombineOp. 069 * 070 * @param matrix The matrix to filter pixels with. 071 * @param hints Rendering hints to apply. Ignored. 072 * @throws ArrayIndexOutOfBoundsException if the matrix is invalid 073 */ 074 public BandCombineOp(float[][] matrix, RenderingHints hints) 075 { 076 this.matrix = new float[matrix.length][]; 077 int width = matrix[0].length; 078 for (int i = 0; i < matrix.length; i++) 079 { 080 this.matrix[i] = new float[width + 1]; 081 for (int j = 0; j < width; j++) 082 this.matrix[i][j] = matrix[i][j]; 083 084 // The reference implementation pads the array with a trailing zero... 085 this.matrix[i][width] = 0; 086 } 087 088 this.hints = hints; 089 } 090 091 /** 092 * Filter Raster pixels through a matrix. Applies the Op matrix to source 093 * pixes to produce dest pixels. Each row of the matrix is multiplied by the 094 * src pixel components to produce the dest pixel. If matrix is one more than 095 * the number of bands in the src, the last element is implicitly multiplied 096 * by 1, i.e. added to the sum for that dest component. If dest is null, a 097 * suitable Raster is created. This implementation uses 098 * createCompatibleDestRaster. 099 * 100 * @param src The source Raster. 101 * @param dest The destination Raster, or null. 102 * @throws IllegalArgumentException if the destination raster is incompatible 103 * with the source raster. 104 * @return The filtered Raster. 105 * @see java.awt.image.RasterOp#filter(java.awt.image.Raster, 106 * java.awt.image.WritableRaster) 107 */ 108 public WritableRaster filter(Raster src, WritableRaster dest) { 109 if (dest == null) 110 dest = createCompatibleDestRaster(src); 111 else if (dest.getNumBands() != src.getNumBands() 112 || dest.getTransferType() != src.getTransferType()) 113 throw new IllegalArgumentException("Destination raster is incompatible with source raster"); 114 115 // Filter the pixels 116 int[] spix = new int[matrix[0].length - 1]; 117 int[] spix2 = new int[matrix[0].length - 1]; 118 int[] dpix = new int[matrix.length]; 119 for (int y = src.getMinY(); y < src.getHeight() + src.getMinY(); y++) 120 for (int x = src.getMinX(); x < src.getWidth() + src.getMinX(); x++) 121 { 122 // In case matrix rows have implicit translation 123 spix[spix.length - 1] = 1; 124 src.getPixel(x, y, spix); 125 126 // Do not re-calculate if pixel is identical to the last one 127 // (ie, blocks of the same colour) 128 if (!Arrays.equals(spix, spix2)) 129 { 130 System.arraycopy(spix, 0, spix2, 0, spix.length); 131 for (int i = 0; i < matrix.length; i++) 132 { 133 dpix[i] = 0; 134 for (int j = 0; j < matrix[0].length - 1; j++) 135 dpix[i] += spix[j] * (int)matrix[i][j]; 136 } 137 } 138 dest.setPixel(x, y, dpix); 139 } 140 141 return dest; 142 } 143 144 /* (non-Javadoc) 145 * @see java.awt.image.RasterOp#getBounds2D(java.awt.image.Raster) 146 */ 147 public final Rectangle2D getBounds2D(Raster src) 148 { 149 return src.getBounds(); 150 } 151 152 /** 153 * Creates a new WritableRaster that can be used as the destination for this 154 * Op. The number of bands in the source raster must equal the number of rows 155 * in the op matrix, which must also be equal to either the number of columns 156 * or (columns - 1) in the matrix. 157 * 158 * @param src The source raster. 159 * @return A compatible raster. 160 * @see java.awt.image.RasterOp#createCompatibleDestRaster(java.awt.image.Raster) 161 * @throws IllegalArgumentException if the raster is incompatible with the 162 * matrix. 163 */ 164 public WritableRaster createCompatibleDestRaster(Raster src) 165 { 166 // Destination raster must have same number of bands as source 167 if (src.getNumBands() != matrix.length) 168 throw new IllegalArgumentException("Number of rows in matrix specifies an " 169 + "incompatible number of bands"); 170 171 // We use -1 and -2 because we previously padded the rows with a trailing 0 172 if (src.getNumBands() != matrix[0].length - 1 173 && src.getNumBands() != matrix[0].length - 2) 174 throw new IllegalArgumentException("Incompatible number of bands: " 175 + "the number of bands in the raster must equal the number of " 176 + "columns in the matrix, optionally minus one"); 177 178 return src.createCompatibleWritableRaster(); 179 } 180 181 /** 182 * Return corresponding destination point for source point. Because this is 183 * not a geometric operation, it simply returns a copy of the source. 184 * 185 * @param src The source point. 186 * @param dst The destination point. 187 * @return dst The destination point. 188 * @see java.awt.image.RasterOp#getPoint2D(java.awt.geom.Point2D, 189 *java.awt.geom.Point2D) 190 */ 191 public final Point2D getPoint2D(Point2D src, Point2D dst) 192 { 193 if (dst == null) 194 return (Point2D)src.clone(); 195 196 dst.setLocation(src); 197 return dst; 198 } 199 200 /* (non-Javadoc) 201 * @see java.awt.image.RasterOp#getRenderingHints() 202 */ 203 public final RenderingHints getRenderingHints() 204 { 205 return hints; 206 } 207 208 /** 209 * Return the matrix used in this operation. 210 * 211 * @return The matrix used in this operation. 212 */ 213 public final float[][] getMatrix() 214 { 215 return matrix; 216 } 217 218}