import java.awt.*;

public class MouseCanvas extends java.applet.Applet
{
   boolean boolDraw;

   int lastx, lasty;
   int newx, newy;

   public void init()
   {
      add(new Canvas());

      boolDraw = false;

      lastx = size().width / 2;
      lasty = size().height / 2;

      newx = newy = 0;
   }

   public boolean mouseEnter(Event e, int x, int y)
   {
      boolDraw = true;

      repaint();

      return true;
   }

   public boolean mouseExit(Event e, int x, int y)
   {
      boolDraw = false;

      repaint();

      return true;
   }

   public boolean mouseMove(Event e, int x, int y)
   {
      newx = x;
      newy = y;

      repaint();

      return true;
   }

   public boolean mouseDown(Event e, int x, int y)
   {
      lastx = newx;
      lasty = newy;

      repaint();

      return true;
   }

   public void paint(Graphics g)
   {
      if (boolDraw) g.drawLine(lastx, lasty, newx, newy);
   }

   public Dimension preferredSize()
   {
      return new Dimension(400, 100);
   }

   public static void main(String [] args)
   {
      Frame f = new Frame("Mouse Canvas");

      MouseCanvas mc = new MouseCanvas();

      mc.init();

      f.add("Center", mc);

      f.pack();
      f.show();
   }
}