// EtchASketch Demo
// http://www.dgp.toronto.edu/~mjmcguff/learn/java/04-mouseInput/

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

public class EtchASketch extends Applet implements MouseListener, 
															MouseMotionListener
{

   int width, height;

   // We need a place to store a list of mouse positions.
   // Rather than use an array, we'll use a Vector, because
   // it allows elements to be easily appended and deleted.
   // (Technically, it would probably be more appropriate to
   // use a LinkedList, but they're only supported by Java 1.2)
   Vector listOfPositions;

   public void init()
   {
      width = getSize().width;
      height = getSize().height;
      setBackground(Color.black);

      listOfPositions = new Vector();

      addMouseListener(this);
      addMouseMotionListener(this);
   }

   public void mouseEntered(MouseEvent e) {}
   public void mouseExited(MouseEvent e) {}
   public void mouseClicked(MouseEvent e) {}
   public void mousePressed(MouseEvent e) {}
   public void mouseReleased(MouseEvent e) {}
   
   public void mouseMoved(MouseEvent e)
   {

      if (listOfPositions.size() >= 50)
      {
         // delete the first element in the list
         listOfPositions.removeElementAt(0);
      }

      // add the new position to the end of the list
      listOfPositions.addElement(new Point(e.getX(), e.getY()));

      repaint();
      e.consume();
   }

   public void mouseDragged(MouseEvent e) {}

   public void paint(Graphics g)
   {
      g.setColor(Color.white);

      for (int j = 1; j < listOfPositions.size(); j++)
      {
         Point A = (Point)(listOfPositions.elementAt(j-1));
         Point B = (Point)(listOfPositions.elementAt(j));
         g.drawLine(A.x, A.y, B.x, B.y);
      }
   }
}