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/* RgbProfileConverter.java -- RGB Profile conversion class

   Copyright (C) 2004 Free Software Foundation

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GNU Classpath is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package gnu.java.awt.color;

import java.awt.color.ICC_Profile;

import java.awt.color.ICC_ProfileRGB;

import java.awt.color.ProfileDataException;

/**

 * RgbProfileConverter - converts RGB profiles (ICC_ProfileRGB)

 *

 * This type of profile contains a matrix and three

 * tone reproduction curves (TRCs).

 *

 * Device RGB --> CIE XYZ is done through first multiplying with

 * a matrix, then each component is looked-up against it's TRC.

 *

 * The opposite transform is done using the inverse of the matrix,

 * and TRC:s.

 *

 * @author Sven de Marothy

 */

public class RgbProfileConverter implements ColorSpaceConverter

{

  private float[][] matrix;

  private float[][] inv_matrix;

  private ToneReproductionCurve rTRC;

  private ToneReproductionCurve gTRC;

  private ToneReproductionCurve bTRC;

  private ColorLookUpTable toPCS;

  private ColorLookUpTable fromPCS;

  /**

   * CIE 1931 D50 white point (in Lab coordinates)

   */

  private static float[] D50 = { 0.96422f, 1.00f, 0.82521f };

  /**

   * Constructs an RgbProfileConverter from a given ICC_ProfileRGB

   */

  public RgbProfileConverter(ICC_ProfileRGB profile)

  {

    toPCS = fromPCS = null;

    matrix = profile.getMatrix();

    // get TRCs

    try

      {

        rTRC = new ToneReproductionCurve(profile.getGamma(ICC_ProfileRGB.REDCOMPONENT));

      }

    catch (ProfileDataException e)

      {

        rTRC = new ToneReproductionCurve(profile.getTRC(ICC_ProfileRGB.REDCOMPONENT));

      }

    try

      {

        gTRC = new ToneReproductionCurve(profile.getGamma(ICC_ProfileRGB.GREENCOMPONENT));

      }

    catch (ProfileDataException e)

      {

        gTRC = new ToneReproductionCurve(profile.getTRC(ICC_ProfileRGB.GREENCOMPONENT));

      }

    try

      {

        bTRC = new ToneReproductionCurve(profile.getGamma(ICC_ProfileRGB.BLUECOMPONENT));

      }

    catch (ProfileDataException e)

      {

        bTRC = new ToneReproductionCurve(profile.getTRC(ICC_ProfileRGB.BLUECOMPONENT));

      }

    // If a CLUT is available, it should be used, and the TRCs ignored.

    // Note: A valid profile may only have CLUTs in one direction, and

    // TRC:s without useful info, making reverse-transforms impossible.

    // In this case the TRC will be used for the reverse-transform with

    // unpredictable results. This is in line with the Java specification,

    try

      {

        toPCS = new ColorLookUpTable(profile, ICC_Profile.icSigAToB0Tag);

      }

    catch (Exception e)

      {

        toPCS = null;

      }

    try

      {

        fromPCS = new ColorLookUpTable(profile, ICC_Profile.icSigBToA0Tag);

      }

    catch (Exception e)

      {

        fromPCS = null;

      }

    // Calculate the inverse matrix if no reverse CLUT is available

    if(fromPCS == null)

        inv_matrix = invertMatrix(matrix);

    else

      {

        // otherwise just set it to an identity matrix

        inv_matrix = new float[3][3];

        inv_matrix[0][0] = inv_matrix[1][1] = inv_matrix[2][2] = 1.0f;

      }

  }

  public float[] toCIEXYZ(float[] in)

  {

    // CLUT takes precedence

    if (toPCS != null)

      return toPCS.lookup(in);

    float[] temp = new float[3];

    float[] out = new float[3];

    // device space --> linear gamma

    temp[0] = rTRC.lookup(in[0]);

    temp[1] = gTRC.lookup(in[1]);

    temp[2] = bTRC.lookup(in[2]);

    // matrix multiplication

    out[0] = matrix[0][0] * temp[0] + matrix[0][1] * temp[1]

             + matrix[0][2] * temp[2];

    out[1] = matrix[1][0] * temp[0] + matrix[1][1] * temp[1]

             + matrix[1][2] * temp[2];

    out[2] = matrix[2][0] * temp[0] + matrix[2][1] * temp[1]

             + matrix[2][2] * temp[2];

    return out;

  }

  public float[] toRGB(float[] in)

  {

    return SrgbConverter.XYZtoRGB(toCIEXYZ(in));

  }

  public float[] fromCIEXYZ(float[] in)

  {

    if (fromPCS != null)

      return fromPCS.lookup(in);

    float[] temp = new float[3];

    float[] out = new float[3];

    // matrix multiplication

    temp[0] = inv_matrix[0][0] * in[0] + inv_matrix[0][1] * in[1]

              + inv_matrix[0][2] * in[2];

    temp[1] = inv_matrix[1][0] * in[0] + inv_matrix[1][1] * in[1]

              + inv_matrix[1][2] * in[2];

    temp[2] = inv_matrix[2][0] * in[0] + inv_matrix[2][1] * in[1]

              + inv_matrix[2][2] * in[2];

    // device space --> linear gamma

    out[0] = rTRC.reverseLookup(temp[0]);

    out[1] = gTRC.reverseLookup(temp[1]);

    out[2] = bTRC.reverseLookup(temp[2]);

    // FIXME: Sun appears to clip the return values to [0,1]

    // I don't believe that is a Good Thing,

    // (some colorspaces may allow values outside that range.)

    // So we return the actual values here.

    return out;

  }

  public float[] fromRGB(float[] in)

  {

    return fromCIEXYZ(SrgbConverter.RGBtoXYZ(in));

  }

  /**

   * Inverts a 3x3 matrix, returns the inverse,

   * throws an IllegalArgumentException if the matrix is not

   * invertible (this shouldn't happen for a valid profile)

   */

  private float[][] invertMatrix(float[][] matrix)

  {

    float[][] out = new float[3][3];

    double determinant = matrix[0][0] * (matrix[1][1] * matrix[2][2]

                         - matrix[2][1] * matrix[1][2])

                         - matrix[0][1] * (matrix[1][0] * matrix[2][2]

                         - matrix[2][0] * matrix[1][2])

                         + matrix[0][2] * (matrix[1][0] * matrix[2][1]

                         - matrix[2][0] * matrix[1][1]);

    if (determinant == 0.0)

      throw new IllegalArgumentException("Can't invert conversion matrix.");

    float invdet = (float) (1.0 / determinant);

    out[0][0] = invdet * (matrix[1][1] * matrix[2][2]

                - matrix[1][2] * matrix[2][1]);

    out[0][1] = invdet * (matrix[0][2] * matrix[2][1]

                - matrix[0][1] * matrix[2][2]);

    out[0][2] = invdet * (matrix[0][1] * matrix[1][2]

                - matrix[0][2] * matrix[1][1]);

    out[1][0] = invdet * (matrix[1][2] * matrix[2][0]

                - matrix[1][0] * matrix[2][2]);

    out[1][1] = invdet * (matrix[0][0] * matrix[2][2]

                - matrix[0][2] * matrix[2][0]);

    out[1][2] = invdet * (matrix[0][2] * matrix[1][0]

                - matrix[0][0] * matrix[1][2]);

    out[2][0] = invdet * (matrix[1][0] * matrix[2][1]

                - matrix[1][1] * matrix[2][0]);

    out[2][1] = invdet * (matrix[0][1] * matrix[2][0]

                - matrix[0][0] * matrix[2][1]);

    out[2][2] = invdet * (matrix[0][0] * matrix[1][1]

                - matrix[0][1] * matrix[1][0]);

    return out;

  }

}