001    /* ICC_ProfileRGB.java -- the ICC profile for a RGB 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    
011    GNU Classpath is distributed in the hope that it will be useful, but
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    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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
032    module.  An independent module is a module which is not derived from
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_ProfileRGB - a special case of ICC_Profiles.
043     *
044     * The ICC_Profile.getInstance() method will return an instance of the
045     * ICC_ProfileRGB subclass when all the following conditions are met:
046     * The device color space of the profile is TYPE_RGB.
047     * The profile contains red, green and blue ColorantTags.
048     * The profile contains red, green and blue TRCTags.
049     * The profile contains a mediaWhitePointTag included.
050     *
051     * As per the ICC specification, the color space conversion can then
052     * be done through the following method:
053     * linearR = redTRC[deviceR]
054     * linearG = greenTRC[deviceG]
055     * linearB = blueTRC[deviceB]
056     * TRC curves are either a single gamma value, or a 1-dimensional lookup table.
057     *
058     * Followed by the matrix transform:
059     * PCS = M*linear
060     *
061     * Where PCS is the vector of profile color space (must be XYZ) coordinates,
062     * linear is the vector of linear RGB coordinates, and the matrix M is
063     * constructed from the ColorantTags, where the columns are red, green and
064     * blue respectively, and the rows are X, Y and Z.
065     *
066     * Note that if the profile contains a CLUT for the color space conversion,
067     * it should be used instead, and the TRC information ignored.
068     *
069     * @author Sven de Marothy
070     * @since 1.2
071     */
072    public class ICC_ProfileRGB extends ICC_Profile
073    {
074      /**
075       * Compatible with JDK 1.2+.
076       */
077      private static final long serialVersionUID = 8505067385152579334L;
078    
079      public static final int REDCOMPONENT = 0;
080    
081      public static final int GREENCOMPONENT = 1;
082    
083      public static final int BLUECOMPONENT = 2;
084    
085      private transient float[][] matrix;
086    
087      private transient float[] gamma;
088    
089      private transient float[] whitePoint;
090    
091    
092      /**
093       * Package-private constructor used by ICC_ColorSpace for creating an
094       * ICC_ProfileRGB from a predefined ColorSpace (CS_LINEAR_RGB and CS_sRGB)
095       */
096      ICC_ProfileRGB(int cspace)
097      {
098        super(cspace);
099        matrix = createMatrix();
100        whitePoint = getXYZData(icSigMediaWhitePointTag);
101      }
102    
103      /**
104       * Package-private constructor used by ICC_ColorSpace for creating an
105       * ICC_ProfileRGB from profile data.
106       */
107      ICC_ProfileRGB(byte[] data)
108      {
109        super(data);
110        matrix = createMatrix();
111        whitePoint = getXYZData(icSigMediaWhitePointTag);
112      }
113    
114      /**
115       * Returns the media white point of the profile.
116       */
117      public float[] getMediaWhitePoint()
118      {
119        float[] wp = new float[3];
120        wp[0] = whitePoint[0];
121        wp[1] = whitePoint[1];
122        wp[2] = whitePoint[2];
123        return wp;
124      }
125    
126      /**
127       * Returns the colorant matrix of the conversion.
128       */
129      public float[][] getMatrix()
130      {
131        float[][] mat = new float[3][3];
132        for (int i = 0; i < 3; i++)
133          for (int j = 0; j < 3; j++)
134            mat[i][j] = matrix[i][j];
135        return mat;
136      }
137    
138      /**
139       * Returns the gamma value of a component
140       * @throws ProfileDataException if the TRC is described by a lookup
141       * table and not a gamma value.
142       */
143      public float getGamma(int component)
144      {
145        short[] data;
146        switch (component)
147          {
148          case REDCOMPONENT:
149            data = getCurve(icSigRedTRCTag);
150            break;
151          case GREENCOMPONENT:
152            data = getCurve(icSigGreenTRCTag);
153            break;
154          case BLUECOMPONENT:
155            data = getCurve(icSigBlueTRCTag);
156            break;
157          default:
158            throw new IllegalArgumentException("Not a valid component");
159          }
160        if (data == null)
161          throw new IllegalArgumentException("Error reading TRC");
162    
163        if (data.length != 1)
164          throw new ProfileDataException("Not a single-gamma TRC");
165    
166        // convert the unsigned 7.8 fixed-point gamma to a float.
167        float gamma = (float) (((int) data[0] & 0xFF00) >> 8);
168        double fraction = ((int) data[0] & 0x00FF) / 256.0;
169        gamma += (float) fraction;
170        return gamma;
171      }
172    
173      /**
174       * Returns the TRC lookup table for a component
175       * @throws ProfileDataException if the TRC is described by a gamma
176       * value and not a lookup table.
177       */
178      public short[] getTRC(int component)
179      {
180        short[] data;
181        switch (component)
182          {
183          case REDCOMPONENT:
184            data = getCurve(icSigRedTRCTag);
185            break;
186          case GREENCOMPONENT:
187            data = getCurve(icSigGreenTRCTag);
188            break;
189          case BLUECOMPONENT:
190            data = getCurve(icSigBlueTRCTag);
191            break;
192          default:
193            throw new IllegalArgumentException("Not a valid component");
194          }
195        if (data == null)
196          throw new IllegalArgumentException("Error reading TRC");
197    
198        if (data.length <= 1)
199          throw new ProfileDataException("Gamma value, not a TRC table.");
200    
201        return data;
202      }
203    
204      /**
205       * Creates the colorspace conversion matrix from the RGB tristimulus
206       * values.
207       */
208      private float[][] createMatrix() throws IllegalArgumentException
209      {
210        float[][] mat = new float[3][3];
211        float[] r;
212        float[] g;
213        float[] b;
214        r = getXYZData(icSigRedColorantTag);
215        g = getXYZData(icSigGreenColorantTag);
216        b = getXYZData(icSigBlueColorantTag);
217        if (r == null || g == null || b == null)
218          throw new IllegalArgumentException("Error reading colorant tags!");
219        for (int i = 0; i < 3; i++)
220          {
221            mat[i][0] = r[i];
222            mat[i][1] = g[i];
223            mat[i][2] = b[i];
224          }
225        return mat;
226      }
227    } // class ICC_ProfileRGB