001/* ICC_ProfileRGB.java -- the ICC profile for a RGB colorspace
002   Copyright (C) 2002, 2004 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package 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 */
072public 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