libjava/java/awt/image/PackedColorModel.java

   1 /* Copyright (C) 2000, 2002, 2004  Free Software Foundation
   2
   3 This file is part of GNU Classpath.
   4
   5 GNU Classpath is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 GNU Classpath is distributed in the hope that it will be useful, but
  11 WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with GNU Classpath; see the file COPYING.  If not, write to the
  17 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18 02111-1307 USA.
  19
  20 Linking this library statically or dynamically with other modules is
  21 making a combined work based on this library.  Thus, the terms and
  22 conditions of the GNU General Public License cover the whole
  23 combination.
  24
  25 As a special exception, the copyright holders of this library give you
  26 permission to link this library with independent modules to produce an
  27 executable, regardless of the license terms of these independent
  28 modules, and to copy and distribute the resulting executable under
  29 terms of your choice, provided that you also meet, for each linked
  30 independent module, the terms and conditions of the license of that
  31 module.  An independent module is a module which is not derived from
  32 or based on this library.  If you modify this library, you may extend
  33 this exception to your version of the library, but you are not
  34 obligated to do so.  If you do not wish to do so, delete this
  35 exception statement from your version. */
  36
  37
  38 package java.awt.image;
  39
  40 import gnu.java.awt.BitMaskExtent;
  41
  42 import java.awt.Point;
  43 import java.awt.color.ColorSpace;
  44
  45 /**
  46  * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)
  47  */
  48 public abstract class PackedColorModel extends ColorModel
  49 {
  50   private int masks[];
  51
  52   /* Package accessibility, the DirectColorModel needs this array */
  53   int shifts[];
  54
  55   public PackedColorModel(ColorSpace cspace, int pixelBits,
  56                           int[] colorMaskArray, int alphaMask,
  57                           boolean isAlphaPremultiplied,
  58                           int transparency,
  59                           int transferType)
  60   {
  61     super(pixelBits, calcBitsPerComponent(colorMaskArray, alphaMask),
  62           cspace, (alphaMask != 0), isAlphaPremultiplied, transparency,
  63           transferType);
  64     initMasks(colorMaskArray, alphaMask);
  65     if ((pixelBits<1) || (pixelBits>32)) {
  66       throw new IllegalArgumentException("pixels per bits must be " +
  67                                          "in the range [1, 32]");
  68     }
  69   }
  70
  71   private static int[] calcBitsPerComponent(int[] colorMaskArray,
  72                                             int alphaMask)
  73   {
  74     int numComponents = colorMaskArray.length;
  75     if (alphaMask != 0) numComponents++;
  76
  77     int[] bitsPerComponent = new int[numComponents];
  78
  79     BitMaskExtent extent = new BitMaskExtent();
  80     for (int b=0; b<colorMaskArray.length; b++)
  81       {
  82         extent.setMask(colorMaskArray[b]);
  83         bitsPerComponent[b] = extent.bitWidth;
  84       }
  85     if (alphaMask != 0)
  86       {
  87         extent.setMask(alphaMask);
  88         bitsPerComponent[numComponents-1] = extent.bitWidth;
  89       }
  90     return bitsPerComponent;
  91   }
  92
  93   /** Initializes the masks.
  94    *
  95    * @return an array containing the number of bits per color
  96    * component.
  97    */
  98   private void initMasks(int[] colorMaskArray, int alphaMask)
  99   {
 100     int numComponents = colorMaskArray.length;
 101     if (alphaMask == 0)
 102       {
 103         masks = colorMaskArray;
 104       }
 105     else
 106       {
 107         masks = new int[numComponents+1];
 108         System.arraycopy(colorMaskArray, 0,
 109                          masks, 0,
 110                          numComponents);
 111         masks[numComponents++] = alphaMask;
 112       }
 113
 114     shifts = new int[numComponents];
 115
 116     // Bit field handling have been moved to a utility class
 117     BitMaskExtent extent = new BitMaskExtent();
 118     for (int b=0; b<numComponents; b++)
 119       {
 120         extent.setMask(masks[b]);
 121         shifts[b] = extent.leastSignificantBit;
 122       }
 123   }
 124
 125   public PackedColorModel(ColorSpace cspace, int pixelBits,
 126                           int rmask, int gmask, int bmask,
 127                           int amask, boolean isAlphaPremultiplied,
 128                           int transparency,
 129                           int transferType)
 130   {
 131     this(cspace, pixelBits, makeColorMaskArray(rmask, gmask, bmask),
 132          amask, isAlphaPremultiplied, transparency, transferType);
 133   }
 134
 135   /* TODO: If there is a alpha mask, it is inefficient to create a
 136      color mask array that will be discarded when the alpha mask is
 137      appended. We should probably create a private constructor that
 138      takes a complete array of masks (color+alpha) as an
 139      argument. */
 140
 141   private static int[] makeColorMaskArray(int rmask, int gmask, int bmask)
 142   {
 143     int[] colorMaskArray = { rmask, gmask, bmask };
 144     return colorMaskArray;
 145   }
 146
 147   public final int getMask(int index)
 148   {
 149     return masks[index];
 150   }
 151
 152   public final int[] getMasks()
 153   {
 154     return masks;
 155   }
 156
 157   public SampleModel createCompatibleSampleModel(int w, int h)
 158   {
 159     return new SinglePixelPackedSampleModel(transferType, w, h, masks);
 160   }
 161
 162   public boolean isCompatibleSampleModel(SampleModel sm)
 163   {
 164     if (!super.isCompatibleSampleModel(sm)) return false;
 165     if (!(sm instanceof SinglePixelPackedSampleModel)) return false;
 166
 167     SinglePixelPackedSampleModel sppsm =
 168       (SinglePixelPackedSampleModel) sm;
 169     return java.util.Arrays.equals(sppsm.getBitMasks(), masks);
 170   }
 171
 172   public WritableRaster getAlphaRaster(WritableRaster raster) {
 173     if (!hasAlpha()) return null;
 174
 175     SampleModel sm = raster.getSampleModel();
 176     int[] alphaBand = { sm.getNumBands() - 1 };
 177     SampleModel alphaModel = sm.createSubsetSampleModel(alphaBand);
 178     DataBuffer buffer = raster.getDataBuffer();
 179     Point origin = new Point(0, 0);
 180     return Raster.createWritableRaster(alphaModel, buffer, origin);
 181   }
 182
 183   public boolean equals(Object obj)
 184   {
 185     if (!super.equals(obj)) return false;
 186     if (!(obj instanceof PackedColorModel)) return false;
 187
 188     PackedColorModel other = (PackedColorModel) obj;
 189
 190     return java.util.Arrays.equals(masks, other.masks);
 191   }
 192 }