/** After checking out the difference in behavior between 
 ** AnimatorApplet2.java and AnimatorApplet3.java, use JWS 
 ** to change the version of MyApplet10.java that you have
 ** created to a new file called MyApplet11.java, which 
 ** includes double buffering as in AnimatorApplet3.java.
 **
 ** NOTE:  Other than the instructions you are reading,
 ** I have NOT provided you with any code or files--you
 ** are completely on your own. Good luck !               **/
import java.awt.*;
import java.applet.Applet;

/** EXTEND THE JAVA APPLET CLASS AND IMPLEMENT THE RUNNABLE INTERFACE **/

public class MyApplet11 extends Applet implements Runnable
   {int frameNumber = -1;                // Define and/or initialize some
    int delay;                           // AnimatorApplet1 class variables.
    Thread animatorThread;
    boolean frozen = true;
    Font font=new Font("TimesRoman",Font.BOLD,48);
    String framestr = "";
    Dimension preImageDim;
    Image preImage;
    Graphics preImageGraphics;
    
    /** INITIALIZE THE APPLET **/

    public void init()
       {String str;
        int fps = 7;                      // Define the default fps (frames per second).
        str = getParameter("fps");         // Possibly, get HTML string specifying the
        try                                // fps.
         {if (str != null)
           {fps = Integer.parseInt(str);}  // If possible, convert HTML fps to an
          }                                // integer.
        catch (Exception e) {}             // In case the try caused something strange.
        delay = (fps > 0) ? (1000/fps): 100; // Convert fps to the milisecond delay
        }                                    // time between frames.

    /** CLICK TO START OR STOP THE APPLET **/

    public boolean mouseDown(Event e, int x, int y)
       {if (frozen)
         {frozen = false;
          start();}
        else
         {frozen = true;
          stop();}
        return true;
        }

    /** GENERATE AND/OR START THE ANIMATION THREAD **/

    public void start()
       {if (frozen) { }                    // The animation is supposed to stay frozen.
        else                               // Otherwise, generate and/or start the
         {if (animatorThread == null)      // animation thread. Apparently, if run
           {animatorThread = new Thread(this);}  // breaks after catching an exception,
          animatorThread.start();                // the animatorThread though not null
          }                                      // will still need to be restarted.
        }

    /** CREATE AND DISPLAY FRAMES OF THE ANIMATION THREAD **/

    public void run()
       {setBackground(Color.cyan);
        Thread.currentThread().setPriority(Thread.MIN_PRIORITY); // Set the priority low.
        long startTime = System.currentTimeMillis();             // Remember start time.
        while (Thread.currentThread() == animatorThread)         // The animation loop.
           {frameNumber++;                               // Advance the frame number.
                      // Create the frame string.
            repaint();                                   // Display the frame.
            try                                          // Sleep for the delay period.
             {startTime += delay;
              Thread.sleep(Math.max(0,
                                    startTime-System.currentTimeMillis()));
              }
            catch (InterruptedException e) {break;}     // In case the try caused
            }                                           // something strange, exit
        }                                               // the while loop.


    /** CREATE THE CURRENT FRAME OF THE ANIMATION THREAD **/

    public void paint(Graphics g)
       {if (!frozen)update(g);}
       
    public void update(Graphics g)
	{Dimension d = size();
	if((preImageGraphics == null)||
	    (d.width!=preImageDim.width)||
	    (d.height!=preImageDim.height))
	{preImageDim=d;
	preImage=createImage(d.width,d.height);
	preImageGraphics=preImage.getGraphics();
	}
	preImageGraphics.setColor(getBackground());
	preImageGraphics.fillRect(0,0,d.width,d.height);
	preImageGraphics.setFont(font);
	preImageGraphics.setColor(Color.yellow);
	                        
	preImageGraphics.setColor(Color.blue);               
	preImageGraphics.drawString(framestr,frameNumber,frameNumber);   
  
        preImageGraphics.setColor(Color.blue);
        preImageGraphics.drawOval(frameNumber,frameNumber,frameNumber,frameNumber);
	preImageGraphics.setColor(Color.yellow);
	preImageGraphics.setFont(font);
	preImageGraphics.drawString("It's Glenda,",15,110);
	preImageGraphics.drawString("the Good Witch!",10,150);
	g.drawImage(preImage,0,0,this);
        }

/** STOP THE ANIMATION THREAD **/

    public void stop()
       {animatorThread = null;}  // The user either clicked to stop or left the page,
    }                            // so wipe out the current thread.