1 /* 2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.awt.image; 27 28 29 /** 30 * This abstract class defines a lookup table object. ByteLookupTable 31 * and ShortLookupTable are subclasses, which 32 * contain byte and short data, respectively. A lookup table 33 * contains data arrays for one or more bands (or components) of an image 34 * (for example, separate arrays for R, G, and B), 35 * and it contains an offset which will be subtracted from the 36 * input values before indexing into the arrays. This allows an array 37 * smaller than the native data size to be provided for a 38 * constrained input. If there is only one array in the lookup 39 * table, it will be applied to all bands. All arrays must be the 40 * same size. 41 * 42 * @see ByteLookupTable 43 * @see ShortLookupTable 44 * @see LookupOp 45 */ 46 public abstract class LookupTable { 47 48 /** 49 * Constants 50 */ 51 52 int numComponents; 53 int offset; 54 int numEntries; 55 56 /** 57 * Constructs a new LookupTable from the number of components and an offset 58 * into the lookup table. 59 * @param offset the offset to subtract from input values before indexing 60 * into the data arrays for this {@code LookupTable} 61 * @param numComponents the number of data arrays in this 62 * {@code LookupTable} 63 * @throws IllegalArgumentException if {@code offset} is less than 0 64 * or if {@code numComponents} is less than 1 65 */ LookupTable(int offset, int numComponents)66 protected LookupTable(int offset, int numComponents) { 67 if (offset < 0) { 68 throw new 69 IllegalArgumentException("Offset must be greater than 0"); 70 } 71 if (numComponents < 1) { 72 throw new IllegalArgumentException("Number of components must "+ 73 " be at least 1"); 74 } 75 this.numComponents = numComponents; 76 this.offset = offset; 77 } 78 79 /** 80 * Returns the number of components in the lookup table. 81 * @return the number of components in this {@code LookupTable}. 82 */ getNumComponents()83 public int getNumComponents() { 84 return numComponents; 85 } 86 87 /** 88 * Returns the offset. 89 * @return the offset of this {@code LookupTable}. 90 */ getOffset()91 public int getOffset() { 92 return offset; 93 } 94 95 /** 96 * Returns an {@code int} array of components for 97 * one pixel. The {@code dest} array contains the 98 * result of the lookup and is returned. If dest is 99 * {@code null}, a new array is allocated. The 100 * source and destination can be equal. 101 * @param src the source array of components of one pixel 102 * @param dest the destination array of components for one pixel, 103 * translated with this {@code LookupTable} 104 * @return an {@code int} array of components for one 105 * pixel. 106 */ lookupPixel(int[] src, int[] dest)107 public abstract int[] lookupPixel(int[] src, int[] dest); 108 109 } 110