Source for javax.swing.GrayFilter

   1: /* GrayFilter.java -- Java class for filtering Pixels to produce Gray Pictures
   2:    Copyright (C) 1999, 2004  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10:  
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package javax.swing;
  40: 
  41: import java.awt.Image;
  42: import java.awt.Toolkit;
  43: import java.awt.image.FilteredImageSource;
  44: import java.awt.image.RGBImageFilter;
  45: 
  46: /**
  47:  * Produces grayscale images out of colored images. This is used to provide
  48:  * default disabled icons for buttons.
  49:  *
  50:  * @author original author unknown
  51:  */
  52: public class GrayFilter extends RGBImageFilter
  53: {
  54:   private boolean b;
  55:   private double p;
  56: 
  57:   /**
  58:    * Create a GrayFilter. If b is true then brighten. Also, indicate how much
  59:    * gray.
  60:    *    
  61:    * @param b if brighten
  62:    * @param p percent of gray, 0 - 100
  63:    */
  64:   public GrayFilter(boolean b, int p)
  65:   {
  66:     this.b = b; //FIXME - HANDLE THIS
  67:     this.p = (1. - (p / 100.)) / 3.;
  68:   }
  69: 
  70:   /**
  71:    * Create grayed image
  72:    *
  73:    * @param src image to gray
  74:    *
  75:    * @return a grayed image
  76:    */
  77:   public static Image createDisabledImage(Image src)
  78:   {
  79:     return (Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(
  80:         src.getSource(), new GrayFilter(true, 0))));
  81:   }
  82:   
  83:   /**
  84:    * Filter RGB to gray
  85:    */
  86:   public int filterRGB(int x, int y, int rgb)
  87:   {
  88:     int alpha = 0xff000000 & rgb;
  89:     int red = (0xff0000 & rgb) >> 16;
  90:     int green = (0xff00 & rgb) >> 8;
  91:     int blue = (0xff & rgb);
  92:     int gray = (int) ((0.299 * red + 0.587 * green + 0.114 * blue) * p);
  93:     if (b)
  94:       gray = Math.min(gray + 128, 255);
  95:     return gray | gray << 8 | gray << 16 | alpha ;
  96:   }
  97: }