import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JApplet;
import javax.swing.JFrame;
public class DoubleBufferedImage extends JApplet {
private Image dbImage;
private Image originalImage;
private int xLocation = 0;
private int imageWidth, imageHeight;
private Graphics dbImageGraphics;
private String imageURLString = "file:/peppers.png";
public void init() {
URL url = null;
try {
url = new URL(imageURLString);
} catch (MalformedURLException me) {
showStatus("Malformed URL: " + me.getMessage());
}
originalImage = getImage(url);
MediaTracker mt = new MediaTracker(this);
mt.addImage(originalImage, 0);
try {
mt.waitForID(0);
} catch (InterruptedException ie) {
}
imageWidth = originalImage.getWidth(null);
imageHeight = originalImage.getHeight(null);
dbImage = this.createImage(imageWidth, imageHeight);
dbImageGraphics = dbImage.getGraphics();
}
public void update(Graphics g) {
paint(g);
}
public void paint(Graphics g) {
if (xLocation == imageWidth)
xLocation = 0;
dbImageGraphics.clearRect(0, 0, imageWidth, imageHeight);
dbImageGraphics.drawImage(originalImage, 0, 0, this);
dbImageGraphics.setColor(Color.red);
dbImageGraphics.fillOval(xLocation, imageHeight / 2, 20, 20);
//now dbImage's drawing area appears
g.drawImage(dbImage, 0, 0, this);
xLocation++;
repaint(10);
}
public static void main(String[] argv) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DoubleBufferedImage a = new DoubleBufferedImage();
frame.getContentPane().add(a);
frame.setSize(300, 300);
a.init();
a.start();
frame.setVisible(true);
}
}
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