Source for gnu.javax.imageio.bmp.DecodeBF32

   1: /* DecodeBF32.java --
   2:    Copyright (C)  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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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: package gnu.javax.imageio.bmp;
  39: 
  40: import java.io.IOException;
  41: import javax.imageio.stream.ImageInputStream;
  42: import java.awt.image.BufferedImage;
  43: import java.awt.image.ColorModel;
  44: import java.awt.image.DirectColorModel;
  45: import java.awt.image.Raster;
  46: import java.awt.image.WritableRaster;
  47: import java.awt.image.DataBuffer;
  48: import java.awt.image.DataBufferInt;
  49: import java.awt.image.SinglePixelPackedSampleModel;
  50: import java.awt.image.SampleModel;
  51: import java.awt.Dimension;
  52: 
  53: public class DecodeBF32 extends BMPDecoder {
  54:     private int[] bitmasks;
  55:     private boolean useDefaultMasks;
  56: 
  57:     public DecodeBF32(BMPFileHeader fh, BMPInfoHeader ih,
  58:                       boolean udm){
  59:         super(fh,ih);
  60: 
  61:         useDefaultMasks = udm;
  62:         if(useDefaultMasks)
  63:             bitmasks = new int[] { 0x00FF0000, 0x0000FF00, 0x000000FF };
  64:     }
  65: 
  66:     public BufferedImage decode(ImageInputStream in) throws IOException, BMPException {
  67:         if(!useDefaultMasks)
  68:             bitmasks = readBitMasks(in);
  69:         skipToImage(in);
  70: 
  71:         Dimension d = infoHeader.getSize();
  72:         int h = (int)d.getHeight();
  73:         int w = (int)d.getWidth();
  74: 
  75:         // BMP scanlines are padded to dword offsets
  76:         int scansize = w << 2;
  77:         int[] data = new int[w*h];
  78: 
  79: 
  80:         for(int y=h-1;y>=0;y--){
  81:             byte[] scanline = new byte[scansize];
  82:             if(in.read(scanline) != scansize)
  83:                 throw new IOException("Couldn't read image data.");
  84: 
  85:             for(int x=0;x<w;x++)
  86:                 data[x + y*w] = ((scanline[x<<2] & (0xFF)) |
  87:                                  ((scanline[(x<<2)+1] & (0xFF)) << 8) |
  88:                                  ((scanline[(x<<2)+2] & (0xFF)) << 16) |
  89:                                  ((scanline[(x<<2)+3] & (0xFF)) << 24));
  90:         }
  91: 
  92:         ColorModel cm = new DirectColorModel(32,
  93:                                              bitmasks[0], bitmasks[1], bitmasks[2]);
  94:         SampleModel sm = new SinglePixelPackedSampleModel(DataBuffer.TYPE_INT,
  95:                                                           w, h,
  96:                                                           bitmasks);
  97:         DataBuffer db = new DataBufferInt(data, w*h);
  98:         WritableRaster raster = Raster.createWritableRaster(sm, db, null);
  99: 
 100:         return new BufferedImage(cm, raster, false, null);
 101:     }
 102: 
 103: }