libjava/java/awt/color/ICC_ProfileGray.java

   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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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