import java.awt.*;
import java.applet.*;

public class DoubleBuf extends Applet {

    int appwidth, appheight;

    // the actual buffers
    Image ibuf;
    Graphics gbuf;

    public void setAppWidth(int w) {
	appwidth = w;
    }

    public void setAppHeight(int h) {
	appheight = h;
    }

    // initialization for the offscreen buffer
    final public void init() {
	appwidth  = this.getSize().width;
	appheight = this.getSize().height;
	setBackground(Color.black);
	ibuf = createImage(appwidth, appheight);
	gbuf = ibuf.getGraphics();
    }

    // a repaint that sleeps a given number of milliseconds
    public void repaint(int ms) {
	try { Thread.sleep(ms); } catch(Exception e) { };
	super.repaint();
    }

    // a double buffered version of update
    public void update(Graphics g) {
	gbuf.setColor(Color.black);
	gbuf.fillRect(0,0,appwidth,appheight);
	paint(gbuf);
	g.drawImage(ibuf,0,0,this);
    }

}