import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;

public class MouseDrag extends Applet implements MouseMotionListener
{
private static final long serialVersionUID = 1L;
int w, h, s, t;
Image buffer;

public void init()
	{
	addMouseMotionListener(this);
	w = getSize().width;
	h = getSize().height;
	s = w/2;
	t = h/2;
	}

public void paint(Graphics g)
	{
	g.setColor(Color.white);
	g.fillRect(0, 0, w, h);		//clear the screen
	g.setColor(Color.black);
	g.drawString("Drag your mouse around.", 10, 30);
	g.fillOval(s - 10, t - 10, 20, 20);	//draw a circle
	} //end of paint

public void update(Graphics g)
	{
        if (buffer == null) buffer = createImage(w, h);
        Graphics g1 = buffer.getGraphics();
        paint(g1);
        g.drawImage(buffer, 0, 0, this);
        g1.dispose();
	} //end of update

public void mouseDragged(MouseEvent event)
	{
	s = event.getX();
	t = event.getY();
	repaint();
	} //end of mouseDragged

public void mouseMoved(MouseEvent event) {}

} //end of class MouseDrag