// Lars Sorensen TYJava in 21 days
// excode from pg 186, The Checkers animation
//
//  SHELL FOR ANIMATION APPLETS
//

  import java.awt.Graphics;
  import java.awt.Color;
 
  public class Checkers extends java.applet.Applet
         implements Runnable
     {
	
	Thread runner;
	int xpos, ux1, ux2;

      public void start()
        {
	  if (runner == null )
            {
              runner = new Thread(this);
              runner.start();
            }
        } // end of start

      public void stop()
        {
	  if (runner != null )
            {
              runner.stop();
              runner = null;
            }
        } // end of stop

       public void run()
         {

          setBackground(Color.blue);
 	  while(true)
	   {
             for( xpos = 5; xpos <= 105; xpos +=4)
               {
                 ux2 = xpos + 90;
		 repaint();
		 try { Thread.sleep(100); }
 		 catch (InterruptedException e) { }
		 if ( ux1 == 0 ) ux1 = xpos;
	       }
             for( xpos = 105; xpos > 5; xpos -=4)
               {
                 ux1 = xpos;
		 repaint();
		 try { Thread.sleep(100); }
 		 catch (InterruptedException e) { }
		 if ( ux2 == 0 ) ux2 = xpos + 90;
	       }
            }
          } // end of run

        public void update(Graphics g)
          {

            g.clipRect(ux1, 5, ux2 - ux1, 95);
            paint(g);

          } // end of overriden update

	public void paint(Graphics g)
          {
	    // draw the background
            g.setColor(Color.black);
	    g.fillRect(0,0,100,100);
            g.setColor(Color.white);
            g.fillRect(101,0,100,100);

            // Draw the Checker....
            g.setColor(Color.red);
            g.fillOval(xpos,5,90,90);

            // reset the drawing area
            ux1 = ux2 = 0;

          } // end of paint


     } // end of class Checkers...