001 /* ICC_ProfileGray.java -- the ICC profile for a Gray colorspace
002 Copyright (C) 2002, 2004 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
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012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
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017 along with GNU Classpath; see the file COPYING. If not, write to the
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019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
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033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.awt.color;
040
041 /**
042 * ICC_ProfileGray - a special case of ICC_Profiles.
043 *
044 * The ICC_Profile.getInstance() method will return an instance of the
045 * ICC_ProfileGray subclass when all the following conditions are met:
046 * The device color space of the profile is TYPE_GRAY.
047 * The profile contains a gray TRCTag.
048 * The profile contains a mediaWhitePointTag.
049 *
050 * As per the ICC specification, the color space conversion can then
051 * be done through the following method:
052 * linearGray = grayTRC[deviceGray]
053 *
054 * Note that if the profile contains a CLUT for the color space conversion,
055 * it should be used instead, and the TRC information ignored.
056 *
057 * @author Sven de Marothy
058 * @since 1.2
059 */
060 public class ICC_ProfileGray extends ICC_Profile
061 {
062 /**
063 * Compatible with JDK 1.2+.
064 */
065 private static final long serialVersionUID = -1124721290732002649L;
066 private transient float[] whitePoint;
067
068 /**
069 * Package-private constructor used by ICC_ColorSpace for creating an
070 * ICC_ProfileGray from a predefined ColorSpace (CS_GRAY)
071 */
072 ICC_ProfileGray(int cspace)
073 {
074 super(cspace);
075 whitePoint = getXYZData(icSigMediaWhitePointTag);
076 }
077
078 /**
079 * Package-private constructor used by ICC_ColorSpace for creating an
080 * ICC_ProfileGray from profile data.
081 */
082 ICC_ProfileGray(byte[] data)
083 {
084 super(data);
085 whitePoint = getXYZData(icSigMediaWhitePointTag);
086 }
087
088
089 /**
090 * Returns the media white point of the profile.
091 */
092 public float[] getMediaWhitePoint()
093 {
094 float[] wp = new float[3];
095 wp[0] = whitePoint[0];
096 wp[1] = whitePoint[1];
097 wp[2] = whitePoint[2];
098 return wp;
099 }
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