1 /* ByteLookupTable.java -- Java class for a pixel translation table.
2 Copyright (C) 2004 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
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7 it under the terms of the GNU General Public License as published by
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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.
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18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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
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
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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
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36 exception statement from your version. */
39 package java.awt.image;
42 * ByteLookupTable 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.
47 * @author <a href="mailto:jlquinn@optonline.net">Jerry Quinn</a>
50 public class ByteLookupTable extends LookupTable
52 // Array of translation tables.
53 private byte data[][];
56 * Creates a new <code>ByteLookupTable</code> instance.
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
62 * @param offset Offset to be subtracted.
63 * @param data Array of lookup tables.
64 * @exception IllegalArgumentException if offset < 0 or data.length < 1.
66 public ByteLookupTable(int offset, byte[][] data)
67 throws IllegalArgumentException
69 super(offset, data.length);
74 * Creates a new <code>ByteLookupTable</code> instance.
76 * Offset is subtracted from pixel values when looking up in the translation
77 * table. The same table is applied to all pixel components.
79 * @param offset Offset to be subtracted.
80 * @param data Lookup table for all components.
81 * @exception IllegalArgumentException if offset < 0.
83 public ByteLookupTable(int offset, byte[] data)
84 throws IllegalArgumentException
87 this.data = new byte[][] {data};
91 * Return the lookup tables.
95 public final byte[][] getTable()
101 * Return translated values for a pixel.
103 * For each value in the pixel src, use the value minus offset as an index
104 * in the component array and copy the value there to the output for the
105 * component. If dest is null, the output is a new array, otherwise the
106 * translated values are written to dest. Dest can be the same array as
109 * For example, if the pixel src is [2, 4, 3], and offset is 1, the output
110 * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the
111 * translation arrays.
113 * @param src Component values of a pixel.
114 * @param dst Destination array for values, or null.
115 * @return Translated values for the pixel.
117 public int[] lookupPixel(int[] src, int[] dst)
118 throws ArrayIndexOutOfBoundsException
121 dst = new int[src.length];
123 if (data.length == 1)
124 for (int i=0; i < src.length; i++)
125 dst[i] = data[0][src[i] - offset];
127 for (int i=0; i < src.length; i++)
128 dst[i] = data[i][src[i] - offset];
134 * Return translated values for a pixel.
136 * For each value in the pixel src, use the value minus offset as an index
137 * in the component array and copy the value there to the output for the
138 * component. If dest is null, the output is a new array, otherwise the
139 * translated values are written to dest. Dest can be the same array as
142 * For example, if the pixel src is [2, 4, 3], and offset is 1, the output
143 * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the
144 * translation arrays.
146 * @param src Component values of a pixel.
147 * @param dst Destination array for values, or null.
148 * @return Translated values for the pixel.
150 public byte[] lookupPixel(byte[] src, byte[] dst)
151 throws ArrayIndexOutOfBoundsException
154 dst = new byte[src.length];
156 if (data.length == 1)
157 for (int i=0; i < src.length; i++)
158 dst[i] = data[0][((int)src[i]) - offset];
160 for (int i=0; i < src.length; i++)
161 dst[i] = data[i][((int)src[i]) - offset];