com.github.jaiimageio.impl.plugins.tiff.TIFFCIELabColorConverter 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: TIFFCIELabColorConverter.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: 1.1 $
 * $Date: 2005/02/11 05:01:44 $
 * $State: Exp $
 */
package com.github.jaiimageio.impl.plugins.tiff;

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

/**
 */
public class TIFFCIELabColorConverter extends TIFFColorConverter {

    // XYX coordinate or reference white (CIE D65)
    private static final float Xn = 95.047f;
    private static final float Yn = 100.0f;
    private static final float Zn = 108.883f;

    private static final float THRESHOLD = (float)Math.pow(0.008856, 1.0/3.0);

    public TIFFCIELabColorConverter() {}


    private float clamp(float x) {
        if (x < 0.0f) {
            return 0.0f;
        } else if (x > 100.0f) {
            return 255.0f;
        } else {
            return x*(255.0f/100.0f);
        }
    }

    private float clamp2(float x) {
        if (x < 0.0f) {
            return 0.0f;
        } else if (x > 255.0f) {
            return 255.0f;
        } else {
            return x;
        }
    }

    public void fromRGB(float r, float g, float b, float[] result) {
        float X =  0.412453f*r + 0.357580f*g + 0.180423f*b;
        float Y =  0.212671f*r + 0.715160f*g + 0.072169f*b;
        float Z =  0.019334f*r + 0.119193f*g + 0.950227f*b;

        float YYn = Y/Yn;
        float XXn = X/Xn;
        float ZZn = Z/Zn;

        if (YYn < 0.008856f) {
            YYn = 7.787f*YYn + 16.0f/116.0f;
        } else {
            YYn = (float)Math.pow(YYn, 1.0/3.0);
        }
        
        if (XXn < 0.008856f) {
            XXn = 7.787f*XXn + 16.0f/116.0f;
        } else {
            XXn = (float)Math.pow(XXn, 1.0/3.0);
        }
        
        if (ZZn < 0.008856f) {
            ZZn = 7.787f*ZZn + 16.0f/116.0f;
        } else {
            ZZn = (float)Math.pow(ZZn, 1.0/3.0);
        }
        
        float LStar = 116.0f*YYn - 16.0f;
        float aStar = 500.0f*(XXn - YYn);
        float bStar = 200.0f*(YYn - ZZn);

        LStar *= 255.0f/100.0f;
        if (aStar < 0.0f) {
            aStar += 256.0f;
        }
        if (bStar < 0.0f) {
            bStar += 256.0f;
        }

        result[0] = clamp2(LStar);
        result[1] = clamp2(aStar);
        result[2] = clamp2(bStar);
    }

    public void toRGB(float x0, float x1, float x2, float[] rgb) {
        float LStar = x0*100.0f/255.0f;
        float aStar = (x1 > 128.0f) ? (x1 - 256.0f) : x1;
        float bStar = (x2 > 128.0f) ? (x2 - 256.0f) : x2;

        float YYn; // Y/Yn
        float fY; // 'F' value for Y
        
        if (LStar < 8.0f) {
            YYn = LStar/903.3f;
            fY = 7.787f*YYn + 16.0f/116.0f;
        } else {
            float YYn_cubeRoot = (LStar + 16.0f)/116.0f;
            YYn = YYn_cubeRoot*YYn_cubeRoot*YYn_cubeRoot;
            fY = (float)Math.pow(YYn, 1.0/3.0);
        }
        float Y = YYn*Yn;
        
        float fX = fY + (aStar/500.0f);
        float X;
        if (fX <= THRESHOLD) {
            X = Xn*(fX - 16.0f/116.0f)/7.787f;
        } else {
            X = Xn*fX*fX*fX;
        }
        
        float fZ = fY - bStar/200.0f;
        float Z;
        if (fZ <= THRESHOLD) {
            Z = Zn*(fZ - 16.0f/116.0f)/7.787f;
        } else {
            Z = Zn*fZ*fZ*fZ;
        }

        float R =  3.240479f*X - 1.537150f*Y - 0.498535f*Z;
        float G = -0.969256f*X + 1.875992f*Y + 0.041556f*Z;
        float B =  0.055648f*X - 0.204043f*Y + 1.057311f*Z;

        rgb[0] = clamp(R);
        rgb[1] = clamp(G);
        rgb[2] = clamp(B);
    }
}