import java.applet.Applet;
import java.awt.Button;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageProducer;
import java.awt.image.RGBImageFilter;
public class MainClass extends Applet implements ActionListener {
private Image originalImage, filteredImage;
private Button btn = new Button("FILTER");
private GrayFilter cropFilter = new GrayFilter();
public void init() {
originalImage = getImage(getDocumentBase(), "emily.gif");
MediaTracker tracker = new MediaTracker(this);
tracker.addImage(originalImage, 0);
try {
tracker.waitForAll();
} catch (Exception e) {
}
filteredImage = originalImage;
btn.addActionListener(this);
add(btn);
}
public void actionPerformed(ActionEvent ev) {
filter();
repaint();
}
private void filter() {
ImageProducer producer = originalImage.getSource();
producer = new FilteredImageSource(producer, cropFilter);
filteredImage = createImage(producer);
}
public void paint(Graphics g) {
g.drawImage(originalImage, 10, 50, this);
g.drawImage(filteredImage, 271, 50, this);
}
}
class GrayFilter extends RGBImageFilter {
int nCalls;
public GrayFilter() {
canFilterIndexColorModel = true;
}
public void setFast(boolean fast) {
canFilterIndexColorModel = fast;
}
public int filterRGB(int x, int y, int rgb) {
int red = (rgb & 0x00ff0000) >> 16;
int green = (rgb & 0x0000ff00) >> 8;
int blue = (rgb & 0x000000ff);
int mean = (red + green + blue) / 3;
return 0xff000000 | mean << 16 | mean << 8 | mean;
}
}