Source for java.awt.image.PackedColorModel

   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., 51 Franklin Street, Fifth Floor, Boston, MA
  18: 02110-1301 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:   private void initMasks(int[] colorMaskArray, int alphaMask)
  95:   {
  96:     int numComponents = colorMaskArray.length;
  97:     if (alphaMask == 0)
  98:       {
  99:         masks = colorMaskArray;
 100:       }
 101:     else
 102:       {
 103:         masks = new int[numComponents+1];
 104:         System.arraycopy(colorMaskArray, 0,
 105:                          masks, 0,
 106:                          numComponents);
 107:         masks[numComponents++] = alphaMask;
 108:       }
 109: 
 110:     shifts = new int[numComponents];
 111: 
 112:     // Bit field handling have been moved to a utility class
 113:     BitMaskExtent extent = new BitMaskExtent();
 114:     for (int b=0; b<numComponents; b++)
 115:       {
 116:         extent.setMask(masks[b]);
 117:         shifts[b] = extent.leastSignificantBit;
 118:       }
 119:   }
 120: 
 121:   public PackedColorModel(ColorSpace cspace, int pixelBits,
 122:                           int rmask, int gmask, int bmask,
 123:                           int amask, boolean isAlphaPremultiplied,
 124:                           int transparency,
 125:                           int transferType)
 126:   {
 127:     this(cspace, pixelBits, makeColorMaskArray(rmask, gmask, bmask),
 128:          amask, isAlphaPremultiplied, transparency, transferType);
 129:   }
 130: 
 131:   /* TODO: If there is a alpha mask, it is inefficient to create a
 132:      color mask array that will be discarded when the alpha mask is
 133:      appended. We should probably create a private constructor that
 134:      takes a complete array of masks (color+alpha) as an
 135:      argument. */
 136: 
 137:   private static int[] makeColorMaskArray(int rmask, int gmask, int bmask)
 138:   {
 139:     int[] colorMaskArray = { rmask, gmask, bmask };
 140:     return colorMaskArray;
 141:   }
 142: 
 143:   public final int getMask(int index)
 144:   {
 145:     return masks[index];
 146:   }
 147: 
 148:   public final int[] getMasks()
 149:   {
 150:     return masks;
 151:   }
 152: 
 153:   public SampleModel createCompatibleSampleModel(int w, int h)
 154:   {
 155:     return new SinglePixelPackedSampleModel(transferType, w, h, masks);
 156:   }
 157: 
 158:   public boolean isCompatibleSampleModel(SampleModel sm)
 159:   {
 160:     if (!super.isCompatibleSampleModel(sm)) return false;
 161:     if (!(sm instanceof SinglePixelPackedSampleModel)) return false;
 162: 
 163:     SinglePixelPackedSampleModel sppsm =
 164:       (SinglePixelPackedSampleModel) sm;
 165:     return java.util.Arrays.equals(sppsm.getBitMasks(), masks);
 166:   }
 167: 
 168:   public WritableRaster getAlphaRaster(WritableRaster raster) {
 169:     if (!hasAlpha()) return null;
 170: 
 171:     SampleModel sm = raster.getSampleModel();
 172:     int[] alphaBand = { sm.getNumBands() - 1 };
 173:     SampleModel alphaModel = sm.createSubsetSampleModel(alphaBand);
 174:     DataBuffer buffer = raster.getDataBuffer();
 175:     Point origin = new Point(0, 0);
 176:     return Raster.createWritableRaster(alphaModel, buffer, origin);
 177:   }
 178: 
 179:   public boolean equals(Object obj)
 180:   {
 181:     if (!super.equals(obj)) return false;
 182:     if (!(obj instanceof PackedColorModel)) return false;
 183: 
 184:     PackedColorModel other = (PackedColorModel) obj;
 185: 
 186:     return java.util.Arrays.equals(masks, other.masks);
 187:   }
 188: }