Source for java.awt.color.ICC_ProfileGray

   1: /* ICC_ProfileGray.java -- the ICC profile for a Gray colorspace
   2:    Copyright (C) 2002, 2004 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: 
  39: package java.awt.color;
  40: 
  41: /**
  42:  * ICC_ProfileGray - a special case of ICC_Profiles.
  43:  *
  44:  * The ICC_Profile.getInstance() method will return an instance of the 
  45:  * ICC_ProfileGray subclass when all the following conditions are met:
  46:  * The device color space of the profile is TYPE_GRAY.
  47:  * The profile contains a gray TRCTag.
  48:  * The profile contains a mediaWhitePointTag.
  49:  *
  50:  * As per the ICC specification, the color space conversion can then
  51:  * be done through the following method:
  52:  * linearGray = grayTRC[deviceGray]
  53:  *
  54:  * Note that if the profile contains a CLUT for the color space conversion,
  55:  * it should be used instead, and the TRC information ignored. 
  56:  *
  57:  * @author Sven de Marothy
  58:  * @since 1.2
  59:  */
  60: public class ICC_ProfileGray extends ICC_Profile
  61: {
  62:   /**
  63:    * Compatible with JDK 1.2+.
  64:    */
  65:   private static final long serialVersionUID = -1124721290732002649L;
  66:   private transient float[] whitePoint;
  67: 
  68:   /**
  69:    * Package-private constructor used by ICC_ColorSpace for creating an
  70:    * ICC_ProfileGray from a predefined ColorSpace (CS_GRAY)
  71:    */
  72:   ICC_ProfileGray(int cspace)
  73:   {
  74:     super(cspace);
  75:     whitePoint = getXYZData(icSigMediaWhitePointTag);
  76:   }
  77: 
  78:   /**
  79:    * Package-private constructor used by ICC_ColorSpace for creating an
  80:    * ICC_ProfileGray from profile data.
  81:    */
  82:   ICC_ProfileGray(byte[] data)
  83:   {
  84:     super(data);
  85:     whitePoint = getXYZData(icSigMediaWhitePointTag);
  86:   }
  87: 
  88: 
  89:   /**
  90:    * Returns the media white point of the profile.
  91:    */
  92:   public float[] getMediaWhitePoint()
  93:   {
  94:     float[] wp = new float[3];
  95:     wp[0] = whitePoint[0];
  96:     wp[1] = whitePoint[1];
  97:     wp[2] = whitePoint[2];
  98:     return wp;
  99:   }
 100: 
 101:   /**
 102:    * Returns the TRC gamma value.
 103:    * @throws ProfileDataException if the TRC is described by a lookup
 104:    * table and not a gamma value.
 105:    */
 106:   public float getGamma()
 107:   {
 108:     short[] data = getCurve(icSigGrayTRCTag);
 109:     if (data == null)
 110:       throw new IllegalArgumentException("Couldn't read Gray TRC data.");
 111:     if (data.length != 1)
 112:       throw new ProfileDataException("TRC is a table, not a gamma value.");
 113: 
 114:     // convert the unsigned 7.8 fixed-point gamma to a float.
 115:     double gamma = (double) (data[0] & (0xFFFF)) / 256.0;
 116:     return (float) gamma;
 117:   }
 118: 
 119:   /**
 120:    * Returns the TRC lookup table.
 121:    * @throws ProfileDataException if the TRC is described by a gamma value
 122:    * and not a lookup table.
 123:    */
 124:   public short[] getTRC()
 125:   {
 126:     short[] data = getCurve(icSigGrayTRCTag);
 127:     if (data == null)
 128:       throw new IllegalArgumentException("Couldn't read Gray TRC data.");
 129:     if (data.length <= 1)
 130:       throw new ProfileDataException("Gamma value, not a TRC table.");
 131:     return data;
 132:   }
 133: } // class ICC_ProfileGray