CMYKColorSpace.java

/*
 * $Id: CMYKColorSpace.java,v 1.2 2007-12-20 18:33:34 rbair Exp $
 *
 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package com.sun.pdfview.colorspace;

import java.awt.color.ColorSpace;

/**
 * A ColorSpace for the CMYK color space.
 *
 * @author Mike Wessler
 */
public class CMYKColorSpace extends ColorSpace {

    private final ColorSpace csRgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);

    /**
     * create a new CMYK color space:  a ColorSpace with 4 components
     */
    public CMYKColorSpace() {
	super(TYPE_CMYK, 4);
    }

    /**
     * Convert from CIEXYZ to RGB.
     */    
    public float[] fromCIEXYZ(float[] colorvalue) {
	return fromRGB(csRgb.fromCIEXYZ(colorvalue));
    }

    /**
     * Convert from RGB to CMYK.
     * @param rgbvalue the red, green, and blue values (0-1)
     * @return the CMYK values (0-1)
     */
    public float[] fromRGB(float[] rgbvalue) {
	float color[]= new float[4];
	float c= 1-rgbvalue[0];
	float m= 1-rgbvalue[1];
	float y= 1-rgbvalue[2];
	float k= Math.min(c, Math.min(m, y));
	float ik= 1-k;
	if (ik==0) {
	    c= 1;
	    m= 1;
	    y= 1;
	} else {
	    c= (c-k)/ik;
	    m= (m-k)/ik;
	    y= (y-k)/ik;
	}
	color[0]= c;
	color[1]= m;
	color[2]= y;
	color[3]= k;
	return color;
    }

    /**
     * the number of components
     */
    @Override public int getNumComponents() {
	return 4;
    }

    /**
     * the name of this color space
     */
    @Override public String getName(int idx) {
	return "CMYK";
    }
    
    /**
     * the type of this color space (TYPE_CMYK)
     */
    @Override public int getType() {
	return TYPE_CMYK;
    }

    /**
     * Convert from CMYK to CIEXYZ.
     */
    public float[] toCIEXYZ(float[] colorvalue) {
	return csRgb.toCIEXYZ(toRGB(colorvalue));
    }

    /**
     * Convert from CMYK to RGB.
     * @param colorvalue the CMYK values (0-1)
     * @return the RGB values (0-1)
     */
    public float[] toRGB(float[] colorvalue) {
	if (colorvalue.length==4) {
	    float[] color= new float[3];
	    float k= colorvalue[3];
	    float ik= 1-k;
	    color[0]= (1-(colorvalue[0]*ik+k));
	    color[1]= (1-(colorvalue[1]*ik+k));
	    color[2]= (1-(colorvalue[2]*ik+k));
	    return color;
	} else {
	    return new float[3];
	}
    }
}