Source for gnu.javax.imageio.png.PNGGamma

   1: /* PNGGamma.java -- GAMA chunk.
   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: 
  42: /**
  43:  * A PNG gAMA (gamma) chunk.
  44:  */
  45: public class PNGGamma extends PNGChunk
  46: {
  47:   private double gamma;
  48: 
  49:   protected PNGGamma( int type, byte[] data, int crc ) throws PNGException
  50:   {
  51:     super( type, data, crc );
  52:     if( data.length < 4 )
  53:       throw new PNGException("Unexpectedly short time chunk. ("+data.length+" bytes)");
  54:     long g = ((data[0] & 0xFF) << 24) | ( (data[1] & 0xFF) << 16 ) |
  55:       ((data[2] & 0xFF) << 8) | (data[3] & 0xFF);
  56:     gamma = (double)g;
  57:     gamma = 100000.0/gamma;
  58:   }
  59: 
  60:   public PNGGamma( double g )
  61:   {
  62:     super( TYPE_GAMMA );
  63:     data = new byte[ 4 ];
  64:     gamma = g;
  65:     long tmp = (long)(100000.0/gamma);
  66:     data[0] = (byte)((tmp & 0xFF000000) >> 24);
  67:     data[1] = (byte)((tmp & 0xFF0000) >> 16);
  68:     data[2] = (byte)((tmp & 0xFF00) >> 8);
  69:     data[3] = (byte)(tmp & 0xFF);
  70:   }
  71: 
  72:   /**
  73:    * Returns a ColorSpace object corresponding to this gamma value.
  74:    */
  75:   public ColorSpace getColorSpace(boolean grayscale)
  76:   {
  77:     // FIXME.
  78:     return null;
  79:   }
  80: 
  81:   public String toString()
  82:   {
  83:     return "PNG Gamma chunk, value: "+gamma;
  84:   }
  85: }