Source for gnu.javax.imageio.png.PNGPalette

   1: /* PNGPalette.java --
   2:    Copyright (C) 2006 Free Software Foundation
   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.png;
  39: 
  40: import java.awt.color.ColorSpace;
  41: import java.awt.image.IndexColorModel;
  42: 
  43: /**
  44:  * A PNG Palette chunk.
  45:  */
  46: public class PNGPalette extends PNGChunk
  47: {
  48:   private int[] red,green,blue;
  49: 
  50:   protected PNGPalette( int type, byte[] data, int crc ) throws PNGException
  51:   {
  52:     super( type, data, crc );
  53:     double l = data.length;
  54:     l /= 3.0;
  55:     // Check if it's divisible by 3. (Yuck.)
  56:     if( l - Math.floor(l) != 0.0 )
  57:       throw new PNGException("Invalid size of palette chunk.");
  58:     int nEntries = (int)l;
  59: 
  60:     red = new int[ nEntries ];
  61:     green = new int[ nEntries ];
  62:     blue = new int[ nEntries ];
  63:     for( int i = 0; i < nEntries; i++ )
  64:       {
  65:         red[i] = (data[ i * 3 ] & 0xFF);
  66:         green[i] = (data[ i * 3 + 1 ] & 0xFF);
  67:         blue[i] = (data[ i * 3 + 2] & 0xFF);
  68:       }
  69:   }
  70: 
  71:   public PNGPalette( IndexColorModel cm )
  72:   {
  73:     super( TYPE_PALETTE );
  74:     int n = cm.getMapSize();
  75:     data = new byte[ n * 3 ];
  76:     red = new int[ n ];
  77:     green = new int[ n ];
  78:     blue = new int[ n ];
  79:     for(int i = 0; i < n; i++ )
  80:       {
  81:         red[i] = data[i * 3] = (byte)cm.getRed(i);
  82:         green[i] = data[i * 3 + 1] = (byte)cm.getGreen(i);
  83:         blue[i] = data[i * 3 + 2] = (byte)cm.getBlue(i);
  84:       }
  85:   }
  86: 
  87:   public IndexColorModel getPalette( ColorSpace cs )
  88:   {
  89:     int nc = red.length;
  90:     byte[] r = new byte[nc];
  91:     byte[] g = new byte[nc];
  92:     byte[] b = new byte[nc];
  93: 
  94:     if( cs == null )
  95:       {
  96:         for(int i = 0; i < nc; i ++ )
  97:           {
  98:             r[i] = (byte)red[i];
  99:             g[i] = (byte)green[i];
 100:             b[i] = (byte)blue[i];
 101:           }
 102:       }
 103:     else
 104:       {
 105:         for(int i = 0; i < nc; i ++ )
 106:           {
 107:             float[] in = new float[3];
 108:             in[0] = (((float)red[i]) / 255f);
 109:             in[1] = (((float)green[i]) / 255f);
 110:             in[2] = (((float)blue[i]) / 255f);
 111:             float[] out = cs.toRGB( in );
 112:             r[i] = (byte)( Math.round(out[0] * 255.0) );
 113:             g[i] = (byte)( Math.round(out[1] * 255.0) );
 114:             b[i] = (byte)( Math.round(out[2] * 255.0) );
 115:           }
 116:       }
 117:     return new IndexColorModel(8, nc, r, g, b);
 118:   }
 119: 
 120:   public String toString()
 121:   {
 122:     String s = "PNG Palette:\n";
 123:     for( int i = 0; i < red.length; i++)
 124:       s = s + "Index " + i + ": ["+ red[i] +", "+green[i]+", "+blue[i]+"]\n";
 125:     return s;
 126:   }
 127: }