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

public class Trace extends JFrame {
    private java.util.List points = new ArrayList();
    private Dimension dim = new Dimension(300, 300);
    private int numColor = 0;
    private static final Color [] COLORS = {Color.black, Color.red, Color.yellow, Color.blue, Color.green};    

    Trace() {
	super("Tracés");

	addWindowListener(new WindowAdapter() {
		public void windowClosing(WindowEvent e) {  
		    System.exit(0);
		}
	    });

	JPanel graphics = new JPanel() {
		private Color foreground = Color.black;

		public Color getBackground() {
		    return Color.white;
		}
		public void setForeground(Color c) {
		    foreground = c;
		}
		public Color getForeground() {
		    return foreground;
		}
		public void paintComponent(Graphics g) {
		    super.paintComponent(g);
		    if (! points.isEmpty()) {
			Iterator i = points.iterator();
			Point p1 = (Point) i.next();
			while (i.hasNext()) {
			    Point p2 = (Point) i.next();
			    g.drawLine(p1.x, p1.y, p2.x, p2.y);
			    p1 = p2;
			}
		    }
		}
	    };

	graphics.addMouseListener(new MouseAdapter() {
		public void mousePressed(MouseEvent e) {
		    if ((e.getModifiers() & MouseEvent.BUTTON3_MASK) != 0) {
			points.clear();
		    }
		    points.add(e.getPoint());
		    if (e.isShiftDown()) {
			numColor = ++numColor % COLORS.length;
			((Component) e.getSource()).setForeground(COLORS[numColor]);
		    }
		    ((Component) e.getSource()).repaint();
		}
	    });

	setContentPane(graphics);
	pack();
        setVisible(true);
    }

    public Dimension getPreferredSize() {
	return dim;
    }

    public static void main(String [] args) {
	new Trace();
    }	
}