import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Ardoise extends JPanel {
        protected int oldX, oldY;
        Color couleurTrace = Color.black;
    
        public Ardoise() {
	setPreferredSize(new Dimension(500,300));

	addMouseListener(new MouseAdapter() {
		public void mousePressed(MouseEvent e){
		    oldX=e.getX();
                    oldY=e.getY();
           }
	    });

	addMouseMotionListener(new MouseMotionAdapter() {
		public void mouseDragged(MouseEvent e)
	            { ... }
	    });

	addKeyListener(new KeyAdapter() {
		public void keyPressed(KeyEvent e) {
		    if (e.getKeyCode() == KeyEvent.VK_C) effacer();
		}
	    });
    }

    public void effacer()
        { ... }  
 
    public void setColor(Color couleur)
        { ... } 

    public Color getColor()
        { ... } 
}