/* Rotator - an applet that animates a sequence of frames
   stored as a horizontal strip in a single image. 

   http://rsb.info.nih.gov/nih-image/Java/Rotator/

Parameters:
   image   Name of image file, no default
   rate    Rate in frames per second, default = "6"
   bgcolor Background color, default = "ffffff" (white)

This example animates 10 55x68 frames stored in a single
550x68 gif file.

   <applet code="Rotator.class" width=55 height=68>
   <param name=image value="Duke.gif">
   <param name=rate value="4">
   </applet>
*/

import java.awt.* ;

public class Rotator extends java.applet.Applet implements Runnable {

  int   frameWidth;
  int   delay = 167;  // milliseconds (6 frames/sec)
  int   frame = 0;
  int   bgcolor = 0xffffff; //white
  boolean suspended = false;
  Thread  runThread;
  Image   img;

  public void init() {
      String p = getParameter("width");
      frameWidth = Integer.parseInt(p);
      p = getParameter("rate");
      if (p != null)
          delay = 1000 / Integer.parseInt(p);
      if (delay < 10)
           delay = 10;
      p = getParameter("bgcolor");
      if (p != null)
          bgcolor = Integer.parseInt(p, 16);
      setBackground(new Color(bgcolor));
      img = getImage(getCodeBase(), getParameter("image"));
  }

  public void start() {
      if (runThread == null) {
          runThread = new Thread (this);
          runThread.start();
      }
  }

  public void run() {
      while (runThread != null) {
          repaint();
          try {runThread.sleep(delay);}
          catch (InterruptedException e) { }
      }
  }

  public void update(Graphics g) {
      paint(g);
  }

  public void paint(Graphics g) {
      g.drawImage(img, -frame * frameWidth, 0, null);
      if (++frame  == img.getWidth(this) / frameWidth)
         frame = 0;
  }

  public boolean mouseDown(Event evt, int x, int y) {
      if (suspended)
          runThread.resume();
      else
          runThread.suspend();
      suspended = !suspended;
      return true;
  }

  public void stop() {
      if (runThread != null) {
         runThread.stop();
         runThread = null;
      }
  }

}// Rotator