com.github.jaiimageio.impl.plugins.tiff.TIFFYCbCrColorConverter Maven / Gradle / Ivy

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Java Advanced Imaging Image I/O Tools API core, but without the classes involved with javax.media.jai dependencies, JPEG2000 or codecLibJIIO, meaning that this library can be distributed under the modified BSD license and should be GPL compatible.
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/*
 * $RCSfile: TIFFYCbCrColorConverter.java,v $
 *
 * 
 * Copyright (c) 2005 Sun Microsystems, Inc. All  Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met: 
 * 
 * - Redistribution of source code must retain the above copyright 
 *   notice, this  list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in 
 *   the documentation and/or other materials provided with the
 *   distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL 
 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF 
 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR 
 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES. 
 * 
 * You acknowledge that this software is not designed or intended for 
 * use in the design, construction, operation or maintenance of any 
 * nuclear facility. 
 *
 * $Revision: 1.2 $
 * $Date: 2006/04/11 22:10:37 $
 * $State: Exp $
 */
package com.github.jaiimageio.impl.plugins.tiff;

import com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
import com.github.jaiimageio.plugins.tiff.TIFFColorConverter;
import com.github.jaiimageio.plugins.tiff.TIFFField;

/**
 */
public class TIFFYCbCrColorConverter extends TIFFColorConverter {

    private float LumaRed = 0.299f;
    private float LumaGreen = 0.587f;
    private float LumaBlue = 0.114f;

    private float referenceBlackY = 0.0f;
    private float referenceWhiteY = 255.0f;

    private float referenceBlackCb = 128.0f;
    private float referenceWhiteCb = 255.0f;

    private float referenceBlackCr = 128.0f;
    private float referenceWhiteCr = 255.0f;

    private float codingRangeY = 255.0f;
    private float codingRangeCbCr = 127.0f;

    public TIFFYCbCrColorConverter(TIFFImageMetadata metadata) {
        TIFFImageMetadata tmetadata = (TIFFImageMetadata)metadata;

        TIFFField f =
           tmetadata.getTIFFField(BaselineTIFFTagSet.TAG_Y_CB_CR_COEFFICIENTS);
        if (f != null && f.getCount() == 3) {
            this.LumaRed = f.getAsFloat(0);
            this.LumaGreen = f.getAsFloat(1);
            this.LumaBlue = f.getAsFloat(2);
        }

        f =
          tmetadata.getTIFFField(BaselineTIFFTagSet.TAG_REFERENCE_BLACK_WHITE);
        if (f != null && f.getCount() == 6) {
            this.referenceBlackY = f.getAsFloat(0);
            this.referenceWhiteY = f.getAsFloat(1);
            this.referenceBlackCb = f.getAsFloat(2);
            this.referenceWhiteCb = f.getAsFloat(3);
            this.referenceBlackCr = f.getAsFloat(4);
            this.referenceWhiteCr = f.getAsFloat(5);
        }
    }

    /*
      The full range component value is converted from the code by:

      FullRangeValue = (code - ReferenceBlack) * CodingRange
                / (ReferenceWhite - ReferenceBlack);

      The code is converted from the full-range component value by:

      code = (FullRangeValue * (ReferenceWhite - ReferenceBlack)
                / CodingRange) + ReferenceBlack;

     */
    public void fromRGB(float r, float g, float b, float[] result) {
        // Convert RGB to full-range YCbCr.
        float Y = (LumaRed*r + LumaGreen*g + LumaBlue*b);
        float Cb = (b - Y)/(2 - 2*LumaBlue);
        float Cr = (r - Y)/(2 - 2*LumaRed);

        // Convert full-range YCbCr to code.
        result[0] = Y*(referenceWhiteY - referenceBlackY)/codingRangeY +
            referenceBlackY;
        result[1] = Cb*(referenceWhiteCb - referenceBlackCb)/codingRangeCbCr +
            referenceBlackCb;
        result[2] = Cr*(referenceWhiteCr - referenceBlackCr)/codingRangeCbCr +
            referenceBlackCr;
    }

    public void toRGB(float x0, float x1, float x2, float[] rgb) {
        // Convert YCbCr code to full-range YCbCr.
        float Y = (x0 - referenceBlackY)*codingRangeY/
            (referenceWhiteY - referenceBlackY);
        float Cb = (x1 - referenceBlackCb)*codingRangeCbCr/
            (referenceWhiteCb - referenceBlackCb);
        float Cr = (x2 - referenceBlackCr)*codingRangeCbCr/
            (referenceWhiteCr - referenceBlackCr);

        // Convert YCbCr to RGB.
        rgb[0] = Cr*(2 - 2*LumaRed) + Y;
        rgb[2] = Cb*(2 - 2*LumaBlue) + Y;
        rgb[1] = (Y - LumaBlue*rgb[2] - LumaRed*rgb[0])/LumaGreen;
    }
}