Return alphas shaded color. - Java 2D Graphics

Java examples for 2D Graphics:Color Alpha

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Description

Return alphas shaded color.

Demo Code

/*/*from   w  ww .j  ava  2s . c o m*/
 * Copyright (c) 2007-2011 by The Broad Institute of MIT and Harvard.  All Rights Reserved.
 *
 * This software is licensed under the terms of the GNU Lesser General Public License (LGPL),
 * Version 2.1 which is available at http://www.opensource.org/licenses/lgpl-2.1.php.
 *
 * THE SOFTWARE IS PROVIDED "AS IS." THE BROAD AND MIT MAKE NO REPRESENTATIONS OR
 * WARRANTES OF ANY KIND CONCERNING THE SOFTWARE, EXPRESS OR IMPLIED, INCLUDING,
 * WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, NONINFRINGEMENT, OR THE ABSENCE OF LATENT OR OTHER DEFECTS, WHETHER
 * OR NOT DISCOVERABLE.  IN NO EVENT SHALL THE BROAD OR MIT, OR THEIR RESPECTIVE
 * TRUSTEES, DIRECTORS, OFFICERS, EMPLOYEES, AND AFFILIATES BE LIABLE FOR ANY DAMAGES
 * OF ANY KIND, INCLUDING, WITHOUT LIMITATION, INCIDENTAL OR CONSEQUENTIAL DAMAGES,
 * ECONOMIC DAMAGES OR INJURY TO PROPERTY AND LOST PROFITS, REGARDLESS OF WHETHER
 * THE BROAD OR MIT SHALL BE ADVISED, SHALL HAVE OTHER REASON TO KNOW, OR IN FACT
 * SHALL KNOW OF THE POSSIBILITY OF THE FOREGOING.
 */
import org.apache.log4j.Logger;
import java.awt.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.*;

public class Main{
    public static Map<Object, Color> colorCache = new WeakHashMap<Object, Color>(
            100);
    public static Map<Color, float[]> componentsCache = Collections
            .synchronizedMap(new HashMap<Color, float[]>());
    /**
     * Return  alphas shaded color.  This method is used, rather than the Color constructor, so that
     * the alpha is not lost in postscript output.
     *
     * @param alpha
     * @return
     */
    public static Color getCompositeColor(Color backgroundColor,
            Color foregroundColor, float alpha) {

        float[] dest = getRGBColorComponents(backgroundColor);
        float[] source = getRGBColorComponents(foregroundColor);

        int r = (int) ((alpha * source[0] + (1 - alpha) * dest[0]) * 255 + 0.5);
        int g = (int) ((alpha * source[1] + (1 - alpha) * dest[1]) * 255 + 0.5);
        int b = (int) ((alpha * source[2] + (1 - alpha) * dest[2]) * 255 + 0.5);
        int a = 255;
        int value = ((a & 0xFF) << 24) | ((r & 0xFF) << 16)
                | ((g & 0xFF) << 8) | ((b & 0xFF) << 0);

        Color c = colorCache.get(value);
        if (c == null) {
            c = new Color(value);
            colorCache.put(value, c);
        }
        return c;
    }
    /**
     * Return  alphas shaded color for a white background.  This method is used, rather than the Color constructor, so that
     * the alpha is not lost in postscript output.
     *
     * @param source
     * @param alpha
     * @return
     */
    public static Color getCompositeColor(Color source, float alpha) {
        return getCompositeColor(Color.white, source, alpha);
    }
    public static float[] getRGBColorComponents(Color color) {
        float[] comps = componentsCache.get(color);
        if (comps == null) {
            comps = color.getRGBColorComponents(null);
            componentsCache.put(color, comps);
        }
        return comps;

    }
}

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