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1: /* ShortLookupTable.java -- Java class for a pixel translation table. 2: Copyright (C) 2004, 2005, 2006, Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.awt.image; 40: 41: /** 42: * ShortLookupTable represents translation arrays for pixel values. It wraps 43: * one or more data arrays for each layer (or component) in an image, such as 44: * Alpha, R, G, and B. When doing translation, the offset is subtracted from 45: * the pixel values to allow a subset of an array to be used. 46: * 47: * @author Jerry Quinn (jlquinn@optonline.net) 48: * @version 1.0 49: */ 50: public class ShortLookupTable extends LookupTable 51: { 52: // Array of translation tables. 53: private short data[][]; 54: 55: /** 56: * Creates a new <code>ShortLookupTable</code> instance. 57: * 58: * Offset is subtracted from pixel values when looking up in the translation 59: * tables. If data.length is one, the same table is applied to all pixel 60: * components. 61: * 62: * @param offset Offset to be subtracted. 63: * @param data Array of lookup tables. 64: * @exception IllegalArgumentException if offset < 0 or data.length < 1. 65: */ 66: public ShortLookupTable(int offset, short[][] data) 67: throws IllegalArgumentException 68: { 69: super(offset, data.length); 70: 71: // tests show that Sun's implementation creates a new array to store the 72: // references from the incoming 'data' array - not sure why, but we'll 73: // match that behaviour just in case it matters... 74: this.data = new short[data.length][]; 75: for (int i = 0; i < data.length; i++) 76: this.data[i] = data[i]; 77: } 78: 79: /** 80: * Creates a new <code>ShortLookupTable</code> instance. 81: * 82: * Offset is subtracted from pixel values when looking up in the translation 83: * table. The same table is applied to all pixel components. 84: * 85: * @param offset Offset to be subtracted. 86: * @param data Lookup table for all components (<code>null</code> not 87: * permitted). 88: * @exception IllegalArgumentException if offset < 0. 89: */ 90: public ShortLookupTable(int offset, short[] data) 91: throws IllegalArgumentException 92: { 93: super(offset, 1); 94: if (data == null) 95: throw new NullPointerException("Null 'data' argument."); 96: this.data = new short[][] {data}; 97: } 98: 99: /** 100: * Return the lookup tables. This is a reference to the actual table, so 101: * modifying the contents of the returned array will modify the lookup table. 102: * 103: * @return The lookup table. 104: */ 105: public final short[][] getTable() 106: { 107: return data; 108: } 109: 110: /** 111: * Return translated values for a pixel. 112: * 113: * For each value in the pixel src, use the value minus offset as an index 114: * in the component array and copy the value there to the output for the 115: * component. If dest is null, the output is a new array, otherwise the 116: * translated values are written to dest. Dest can be the same array as 117: * src. 118: * 119: * For example, if the pixel src is [2, 4, 3], and offset is 1, the output 120: * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the 121: * translation arrays. 122: * 123: * @param src Component values of a pixel. 124: * @param dst Destination array for values, or null. 125: * @return Translated values for the pixel. 126: */ 127: public int[] lookupPixel(int[] src, int[] dst) 128: throws ArrayIndexOutOfBoundsException 129: { 130: if (dst == null) 131: dst = new int[src.length]; 132: 133: if (data.length == 1) 134: for (int i = 0; i < src.length; i++) 135: dst[i] = data[0][src[i] - offset]; 136: else 137: for (int i = 0; i < src.length; i++) 138: dst[i] = data[i][src[i] - offset]; 139: 140: return dst; 141: } 142: 143: /** 144: * Return translated values for a pixel. 145: * 146: * For each value in the pixel src, use the value minus offset as an index 147: * in the component array and copy the value there to the output for the 148: * component. If dest is null, the output is a new array, otherwise the 149: * translated values are written to dest. Dest can be the same array as 150: * src. 151: * 152: * For example, if the pixel src is [2, 4, 3], and offset is 1, the output 153: * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the 154: * translation arrays. 155: * 156: * @param src Component values of a pixel. 157: * @param dst Destination array for values, or null. 158: * @return Translated values for the pixel. 159: * 160: */ 161: public short[] lookupPixel(short[] src, short[] dst) 162: throws ArrayIndexOutOfBoundsException 163: { 164: if (dst == null) 165: dst = new short[src.length]; 166: 167: if (data.length == 1) 168: for (int i = 0; i < src.length; i++) 169: dst[i] = data[0][((int) src[i]) - offset]; 170: else 171: for (int i = 0; i < src.length; i++) 172: dst[i] = data[i][((int) src[i]) - offset]; 173: 174: return dst; 175: 176: } 177: }