graydicon.java

Java中Swing界面库中几个类使用的例子

package jp.gr.java_conf.tame.swing.icon;


import java.awt.*;
import java.awt.image.*;
import javax.swing.*;


/**
 * @version 1.0 04/30/99
 */
public class GraydIcon implements Icon {
  Icon icon;
  Image image;
  
  public GraydIcon(Icon icon) {
    this.icon = icon;
  }

  public void paintIcon(Component c, Graphics g, int x, int y) {
    if (image == null) {
      Image orgImage  = c.createImage(getIconWidth(), getIconHeight());
      Graphics imageG = orgImage.getGraphics();	
      Color background = c.getBackground();
      imageG.setColor(background);
      imageG.fillRect(0,0, getIconWidth(), getIconHeight() );
      
      icon.paintIcon(c,imageG,x,y);
      
      ImageFilter colorfilter = new GrayFilter();
      image = c.createImage(
        new FilteredImageSource(orgImage.getSource(),colorfilter));
      
    }
    g.drawImage(image, x, y, null);
  }
  
  public int getIconWidth()  { return icon.getIconWidth();  }
  public int getIconHeight() { return icon.getIconHeight(); }
 



  class GrayFilter extends RGBImageFilter {
    
    public GrayFilter() {
      // If I set ture, black is gone?!
      //canFilterIndexColorModel = true;
    }
    
    public int filterRGB(int x, int y, int rgb) {
      int r = (rgb & 0xff0000) >> 16;
      int g = (rgb & 0x00ff00) >>  8;
      int b = (rgb & 0x0000ff);
      int iy = (int)(r + g + b)/3;
      iy = Math.min(255, iy);
      return ((rgb & 0xff000000)
           | (iy << 16)
           | (iy <<  8)
           | iy);
    }
  }

}