libjava/java/awt/image/ByteLookupTable.java

   1 /* ByteLookupTable.java -- Java class for a pixel translation table.
   2    Copyright (C) 2004, 2005  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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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  * 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.
  46  *
  47  * @author Jerry Quinn (jlquinn@optonline.net)
  48  * @version 1.0
  49  */
  50 public class ByteLookupTable extends LookupTable
  51 {
  52   // Array of translation tables.
  53   private byte data[][];
  54
  55   /**
  56    * Creates a new <code>ByteLookupTable</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 &lt; 0 or data.length &lt; 1.
  65    */
  66   public ByteLookupTable(int offset, byte[][] data)
  67     throws IllegalArgumentException
  68   {
  69     super(offset, data.length);
  70     this.data = data;
  71   }
  72
  73   /**
  74    * Creates a new <code>ByteLookupTable</code> instance.
  75    *
  76    * Offset is subtracted from pixel values when looking up in the translation
  77    * table.  The same table is applied to all pixel components.
  78    *
  79    * @param offset Offset to be subtracted.
  80    * @param data Lookup table for all components.
  81    * @exception IllegalArgumentException if offset &lt; 0.
  82    */
  83   public ByteLookupTable(int offset, byte[] data)
  84     throws IllegalArgumentException
  85   {
  86     super(offset, 1);
  87     this.data = new byte[][] {data};
  88   }
  89
  90   /**
  91    * Return the lookup tables.
  92    *
  93    * @return the tables
  94    */
  95   public final byte[][] getTable()
  96   {
  97     return data;
  98   }
  99
 100   /**
 101    * Return translated values for a pixel.
 102    *
 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
 107    * src.
 108    *
 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.
 112    *
 113    * @param src Component values of a pixel.
 114    * @param dst Destination array for values, or null.
 115    * @return Translated values for the pixel.
 116    */
 117   public int[] lookupPixel(int[] src, int[] dst)
 118     throws ArrayIndexOutOfBoundsException
 119   {
 120     if (dst == null)
 121       dst = new int[src.length];
 122
 123     if (data.length == 1)
 124       for (int i=0; i < src.length; i++)
 125         dst[i] = data[0][src[i] - offset];
 126     else
 127       for (int i=0; i < src.length; i++)
 128         dst[i] = data[i][src[i] - offset];
 129
 130     return dst;
 131   }
 132
 133   /**
 134    * Return translated values for a pixel.
 135    *
 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
 140    * src.
 141    *
 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.
 145    *
 146    * @param src Component values of a pixel.
 147    * @param dst Destination array for values, or null.
 148    * @return Translated values for the pixel.
 149    */
 150   public byte[] lookupPixel(byte[] src, byte[] dst)
 151     throws ArrayIndexOutOfBoundsException
 152   {
 153     if (dst == null)
 154       dst = new byte[src.length];
 155
 156     if (data.length == 1)
 157       for (int i=0; i < src.length; i++)
 158         dst[i] = data[0][((int)src[i]) - offset];
 159     else
 160       for (int i=0; i < src.length; i++)
 161         dst[i] = data[i][((int)src[i]) - offset];
 162
 163     return dst;
 164
 165   }
 166 }