Source for gnu.javax.imageio.bmp.DecodeRGB4

   1: /* DecodeRGB4.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.IndexColorModel;
  44: import java.awt.image.Raster;
  45: import java.awt.image.WritableRaster;
  46: import java.awt.image.DataBuffer;
  47: import java.awt.image.DataBufferByte;
  48: import java.awt.image.MultiPixelPackedSampleModel;
  49: import java.awt.image.SampleModel;
  50: import java.awt.Dimension;
  51: 
  52: public class DecodeRGB4 extends BMPDecoder {
  53: 
  54:     public DecodeRGB4(BMPFileHeader fh, BMPInfoHeader ih){
  55:         super(fh, ih);
  56:     }
  57: 
  58:     public BufferedImage decode(ImageInputStream in) throws IOException, BMPException {
  59:         IndexColorModel palette = readPalette(in);
  60:         skipToImage(in);
  61: 
  62:         Dimension d = infoHeader.getSize();
  63:         int h = (int)d.getHeight();
  64:         int w = (int)d.getWidth();
  65:         int size = (w*h) >> 1;
  66: 
  67:         // Scanline padded to dword offsets
  68:         int wbytes = (w + (w & 1)) >> 1;
  69:         int scansize = ((wbytes & 3) != 0)? (wbytes + 4 - (wbytes&3)) : wbytes;
  70: 
  71:         byte[] data = new byte[wbytes*h];
  72: 
  73:         for(int y=h-1;y>=0;y--){
  74:             byte[] scanline = new byte[scansize];
  75:             if(in.read(scanline) != scansize)
  76:                 throw new IOException("Couldn't read image data.");
  77: 
  78:             for(int x=0;x<wbytes;x++)
  79:                 data[x + y*wbytes] = scanline[x];
  80:         }
  81:         SampleModel sm = new MultiPixelPackedSampleModel(DataBuffer.TYPE_BYTE,
  82:                                                          w, h, 4);
  83: 
  84:         DataBuffer db = new DataBufferByte(data, w*h, 0);
  85:         WritableRaster raster = Raster.createWritableRaster(sm, db, null);
  86: 
  87:         return new BufferedImage(palette, raster, false, null);
  88:     }
  89: 
  90: }