Source for gnu.java.awt.color.GrayProfileConverter

   1: /* GrayProfileConverter.java -- Gray profile conversion class
   2:    Copyright (C) 2004 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: 
  39: package gnu.java.awt.color;
  40: 
  41: import java.awt.color.ICC_Profile;
  42: import java.awt.color.ICC_ProfileGray;
  43: import java.awt.color.ProfileDataException;
  44: 
  45: /**
  46:  * GrayProfileConverter - converts Grayscale profiles (ICC_ProfileGray)
  47:  *
  48:  * This type of profile contains a single tone reproduction curve (TRC).
  49:  * Conversion consists of simple TRC lookup.
  50:  *
  51:  * This implementation is very lazy and does everything applying the TRC and
  52:  * utilizing the built-in linear grayscale color space.
  53:  *
  54:  * @author Sven de Marothy
  55:  */
  56: public class GrayProfileConverter implements ColorSpaceConverter
  57: {
  58:   private GrayScaleConverter gc;
  59:   private ToneReproductionCurve trc;
  60:   private ColorLookUpTable toPCS;
  61:   private ColorLookUpTable fromPCS;
  62: 
  63:   /**
  64:    * Constructs the converter described by an ICC_ProfileGray object
  65:    */
  66:   public GrayProfileConverter(ICC_ProfileGray profile)
  67:   {
  68:     try
  69:       {
  70:         trc = new ToneReproductionCurve(profile.getGamma());
  71:       }
  72:     catch (ProfileDataException e)
  73:       {
  74:         trc = new ToneReproductionCurve(profile.getTRC());
  75:       }
  76: 
  77:     // linear grayscale converter
  78:     gc = new GrayScaleConverter();
  79: 
  80:     // If a CLUT is available, it should be used, and the TRCs ignored.
  81:     // Note: A valid profile may only have CLUTs in one direction, and
  82:     // TRC:s without useful info, making reverse-transforms impossible.
  83:     // In this case the TRC will be used for the reverse-transform with
  84:     // unpredictable results. This is in line with the Java specification,
  85:     try
  86:       {
  87:         toPCS = new ColorLookUpTable(profile, ICC_Profile.icSigAToB0Tag);
  88:       }
  89:     catch (Exception e)
  90:       {
  91:         toPCS = null;
  92:       }
  93: 
  94:     try
  95:       {
  96:         fromPCS = new ColorLookUpTable(profile, ICC_Profile.icSigBToA0Tag);
  97:       }
  98:     catch (Exception e)
  99:       {
 100:         fromPCS = null;
 101:       }
 102:   }
 103: 
 104:   public float[] toCIEXYZ(float[] in)
 105:   {
 106:     if (toPCS != null)
 107:       return toPCS.lookup(in);
 108:     float[] gray = new float[1];
 109:     gray[0] = trc.lookup(in[0]);
 110:     return gc.toCIEXYZ(gray);
 111:   }
 112: 
 113:   public float[] toRGB(float[] in)
 114:   {
 115:     float[] gray = new float[1];
 116:     gray[0] = trc.lookup(in[0]);
 117:     return gc.toRGB(gray);
 118:   }
 119: 
 120:   public float[] fromRGB(float[] in)
 121:   {
 122:     // get linear grayscale value
 123:     float[] gray = gc.fromRGB(in);
 124:     gray[0] = trc.reverseLookup(gray[0]);
 125:     return gray;
 126:   }
 127: 
 128:   public float[] fromCIEXYZ(float[] in)
 129:   {
 130:     if (fromPCS != null)
 131:       return fromPCS.lookup(in);
 132: 
 133:     float[] gray = gc.fromCIEXYZ(in);
 134:     gray[0] = trc.reverseLookup(gray[0]);
 135:     return gray;
 136:   }
 137: }