001    /* Copyright (C) 2000, 2002, 2004  Free Software Foundation
002    
003    This file is part of GNU Classpath.
004    
005    GNU Classpath is free software; you can redistribute it and/or modify
006    it under the terms of the GNU General Public License as published by
007    the Free Software Foundation; either version 2, or (at your option)
008    any later version.
009    
010    GNU Classpath is distributed in the hope that it will be useful, but
011    WITHOUT ANY WARRANTY; without even the implied warranty of
012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013    General Public License for more details.
014    
015    You should have received a copy of the GNU General Public License
016    along with GNU Classpath; see the file COPYING.  If not, write to the
017    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
018    02110-1301 USA.
019    
020    Linking this library statically or dynamically with other modules is
021    making a combined work based on this library.  Thus, the terms and
022    conditions of the GNU General Public License cover the whole
023    combination.
024    
025    As a special exception, the copyright holders of this library give you
026    permission to link this library with independent modules to produce an
027    executable, regardless of the license terms of these independent
028    modules, and to copy and distribute the resulting executable under
029    terms of your choice, provided that you also meet, for each linked
030    independent module, the terms and conditions of the license of that
031    module.  An independent module is a module which is not derived from
032    or based on this library.  If you modify this library, you may extend
033    this exception to your version of the library, but you are not
034    obligated to do so.  If you do not wish to do so, delete this
035    exception statement from your version. */
036    
037    
038    package java.awt.image;
039    
040    import gnu.java.awt.BitMaskExtent;
041    
042    import java.awt.Point;
043    import java.awt.color.ColorSpace;
044    
045    /**
046     * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)
047     */
048    public abstract class PackedColorModel extends ColorModel
049    {
050      private int masks[];
051      
052      /* Package accessibility, the DirectColorModel needs this array */
053      int shifts[];
054    
055      public PackedColorModel(ColorSpace cspace, int pixelBits,
056                              int[] colorMaskArray, int alphaMask,
057                              boolean isAlphaPremultiplied,
058                              int transparency,
059                              int transferType)
060      {
061        super(pixelBits, calcBitsPerComponent(colorMaskArray, alphaMask),
062              cspace, (alphaMask != 0), isAlphaPremultiplied, transparency,
063              transferType);
064        initMasks(colorMaskArray, alphaMask);
065        if ((pixelBits<1) || (pixelBits>32)) {
066          throw new IllegalArgumentException("pixels per bits must be " +
067                                             "in the range [1, 32]");
068        }
069      }
070        
071      private static int[] calcBitsPerComponent(int[] colorMaskArray,
072                                                int alphaMask)
073      {
074        int numComponents = colorMaskArray.length;
075        if (alphaMask != 0) numComponents++;
076        
077        int[] bitsPerComponent = new int[numComponents];
078        
079        BitMaskExtent extent = new BitMaskExtent();
080        for (int b=0; b<colorMaskArray.length; b++)
081          {
082            extent.setMask(colorMaskArray[b]);
083            bitsPerComponent[b] = extent.bitWidth;
084          }
085        if (alphaMask != 0)
086          {
087            extent.setMask(alphaMask);
088            bitsPerComponent[numComponents-1] = extent.bitWidth;
089          }
090        return bitsPerComponent;
091      }
092    
093      /** Initializes the masks.  */
094      private void initMasks(int[] colorMaskArray, int alphaMask)
095      {
096        int numComponents = colorMaskArray.length;
097        if (alphaMask == 0)
098          {
099            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    }