001/* GrayFilter.java -- Java class for filtering Pixels to produce Gray Pictures
002   Copyright (C) 1999, 2004  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing;
040
041import java.awt.Image;
042import java.awt.Toolkit;
043import java.awt.image.FilteredImageSource;
044import java.awt.image.RGBImageFilter;
045
046/**
047 * Produces grayscale images out of colored images. This is used to provide
048 * default disabled icons for buttons.
049 *
050 * @author original author unknown
051 */
052public class GrayFilter extends RGBImageFilter
053{
054  private boolean b;
055  private double p;
056
057  /**
058   * Create a GrayFilter. If b is true then brighten. Also, indicate how much
059   * gray.
060   *
061   * @param b if brighten
062   * @param p percent of gray, 0 - 100
063   */
064  public GrayFilter(boolean b, int p)
065  {
066    this.b = b; //FIXME - HANDLE THIS
067    this.p = (1. - (p / 100.)) / 3.;
068  }
069
070  /**
071   * Create grayed image
072   *
073   * @param src image to gray
074   *
075   * @return a grayed image
076   */
077  public static Image createDisabledImage(Image src)
078  {
079    return (Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(
080        src.getSource(), new GrayFilter(true, 0))));
081  }
082
083  /**
084   * Filter RGB to gray
085   */
086  public int filterRGB(int x, int y, int rgb)
087  {
088    int alpha = 0xff000000 & rgb;
089    int red = (0xff0000 & rgb) >> 16;
090    int green = (0xff00 & rgb) >> 8;
091    int blue = (0xff & rgb);
092    int gray = (int) ((0.299 * red + 0.587 * green + 0.114 * blue) * p);
093    if (b)
094      gray = Math.min(gray + 128, 255);
095    return gray | gray << 8 | gray << 16 | alpha ;
096  }
097}