/*

 * Copyright 1997-1998 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

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

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing;

import java.awt.*;

import java.awt.image.*;

/**

 * An image filter that "disables" an image by turning

 * it into a grayscale image, and brightening the pixels

 * in the image. Used by buttons to create an image for

 * a disabled button.

 *

 * @author      Jeff Dinkins

 * @author      Tom Ball

 * @author      Jim Graham

 */

public class GrayFilter extends RGBImageFilter {

    private boolean brighter;

    private int percent;

    /**

     * Creates a disabled image

     */

    public static Image createDisabledImage (Image i) {

        GrayFilter filter = new GrayFilter(true, 50);

        ImageProducer prod = new FilteredImageSource(i.getSource(), filter);

        Image grayImage = Toolkit.getDefaultToolkit().createImage(prod);

        return grayImage;

    }

    /**

     * Constructs a GrayFilter object that filters a color image to a

     * grayscale image. Used by buttons to create disabled ("grayed out")

     * button images.

     *

     * @param b  a boolean -- true if the pixels should be brightened

     * @param p  an int in the range 0..100 that determines the percentage

     *           of gray, where 100 is the darkest gray, and 0 is the lightest

     */

    public GrayFilter(boolean b, int p) {

        brighter = b;

        percent = p;

        // canFilterIndexColorModel indicates whether or not it is acceptable

        // to apply the color filtering of the filterRGB method to the color

        // table entries of an IndexColorModel object in lieu of pixel by pixel

        // filtering.

        canFilterIndexColorModel = true;

    }

    /**

     * Overrides <code>RGBImageFilter.filterRGB</code>.

     */

    public int filterRGB(int x, int y, int rgb) {

        // Use NTSC conversion formula.

        int gray = (int)((0.30 * ((rgb >> 16) & 0xff) +

                         0.59 * ((rgb >> 8) & 0xff) +

                         0.11 * (rgb & 0xff)) / 3);

        if (brighter) {

            gray = (255 - ((255 - gray) * (100 - percent) / 100));

        } else {

            gray = (gray * (100 - percent) / 100);

        }

        if (gray < 0) gray = 0;

        if (gray > 255) gray = 255;

        return (rgb & 0xff000000) | (gray << 16) | (gray << 8) | (gray << 0);

    }

}