libjava/java/awt/image/ShortLookupTable.java

   1 /* ShortLookupTable.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  * 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 &lt; 0 or data.length &lt; 1.
  65    */
  66   public ShortLookupTable(int offset, short[][] data)
  67     throws IllegalArgumentException
  68   {
  69     super(offset, data.length);
  70     this.data = data;
  71   }
  72
  73   /**
  74    * Creates a new <code>ShortLookupTable</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 ShortLookupTable(int offset, short[] data)
  84     throws IllegalArgumentException
  85   {
  86     super(offset, 1);
  87     this.data = new short[][] {data};
  88   }
  89
  90   /** Return the lookup tables. */
  91   public final short[][] getTable()
  92   {
  93     return data;
  94   }
  95
  96   /**
  97    * Return translated values for a pixel.
  98    *
  99    * For each value in the pixel src, use the value minus offset as an index
 100    * in the component array and copy the value there to the output for the
 101    * component.  If dest is null, the output is a new array, otherwise the
 102    * translated values are written to dest.  Dest can be the same array as
 103    * src.
 104    *
 105    * For example, if the pixel src is [2, 4, 3], and offset is 1, the output
 106    * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the
 107    * translation arrays.
 108    *
 109    * @param src Component values of a pixel.
 110    * @param dst Destination array for values, or null.
 111    * @return Translated values for the pixel.
 112    */
 113   public int[] lookupPixel(int[] src, int[] dst)
 114     throws ArrayIndexOutOfBoundsException
 115   {
 116     if (dst == null)
 117       dst = new int[src.length];
 118
 119     if (data.length == 1)
 120       for (int i=0; i < src.length; i++)
 121         dst[i] = data[0][src[i] - offset];
 122     else
 123       for (int i=0; i < src.length; i++)
 124         dst[i] = data[i][src[i] - offset];
 125
 126     return dst;
 127   }
 128
 129   /**
 130    * Return translated values for a pixel.
 131    *
 132    * For each value in the pixel src, use the value minus offset as an index
 133    * in the component array and copy the value there to the output for the
 134    * component.  If dest is null, the output is a new array, otherwise the
 135    * translated values are written to dest.  Dest can be the same array as
 136    * src.
 137    *
 138    * For example, if the pixel src is [2, 4, 3], and offset is 1, the output
 139    * is [comp1[1], comp2[3], comp3[2]], where comp1, comp2, and comp3 are the
 140    * translation arrays.
 141    *
 142    * @param src Component values of a pixel.
 143    * @param dst Destination array for values, or null.
 144    * @return Translated values for the pixel.
 145    */
 146   public short[] lookupPixel(short[] src, short[] dst)
 147     throws ArrayIndexOutOfBoundsException
 148   {
 149     if (dst == null)
 150       dst = new short[src.length];
 151
 152     if (data.length == 1)
 153       for (int i=0; i < src.length; i++)
 154         dst[i] = data[0][((int)src[i]) - offset];
 155     else
 156       for (int i=0; i < src.length; i++)
 157         dst[i] = data[i][((int)src[i]) - offset];
 158
 159     return dst;
 160
 161   }
 162 }