color2grayfilterapplet.java

简单色彩过滤。可进行以点阵为基础的灰度模式转换。

// Color2GrayFilterApplet.javaimport java.applet.Applet;import java.awt.image.*;
import java.awt.*;public class Color2GrayFilterApplet extends Applet{
  Image image;  Image gray;  Color2GrayFilter filter;  public void init() {
    image = getImage (getCodeBase (), "images/keyb.jpg");
    System.out.println (getCodeBase ());    filter = new Color2GrayFilter ();
    gray = createImage (new FilteredImageSource (image.getSource(), filter)); }
  public void paint (Graphics g) {    g.drawImage (image, 0, 0, this);
    g.drawImage (gray, 310, 0, this); }}
class Color2GrayFilter extends RGBImageFilter{  public Color2GrayFilter () {
    canFilterIndexColorModel = true; }
  public int filterRGB (int x, int y, int rgb) {
    int red   = (rgb & 0xff0000) >>16;    int green = (rgb &   0xff00) >>  8;
    int blue  =  rgb &     0xff;        int gray  = (red + green + blue) / 3;
        return (0xff000000 | (gray << 16) | (gray <<  8) |  gray); } }  
// End of class Color2GrayFilter definition