/**************************************
* Source & Further Reading: J. W. Muchow (2002), Core J2ME Technology & MIDP, Sun MICROSYSTEMS
***************************************/


// Animate a moving image to simulate the timer

import javax.microedition.lcdui.*;

public class TimerCanvas extends Canvas implements Runnable, CommandListener{

  private AnimTimer midlet; // main midlet
  private Command cmExit; // exit command
  private Command cmOptions; // display options command
  private Image im=null; // sequence of images
  private int imageCnt = 4; // four images for the squence
  private int imageWidth; // width of the image sequence
  private int imageHeight; // image sequence height
  private int imageIndex; // current image
  private int transImage_x, transImage_y ; //Translated x & y coordinates
  private int viewPort_x, viewPort_y; // location of the view port
  private int sleepTime = 450; // current sleep time
  private boolean active = false; // timer active
  private boolean Stoprequest = false; // request to stop timer

  // constructor
  public TimerCanvas(AnimTimer midlet){
    // call canvas constructor
    super();

    // save reference to midlet to access the DisplayManager
    this.midlet = midlet;

    // create commands and listen for events
    cmExit = new Command("Exit", Command.EXIT, 1);
    cmOptions = new Command("Options:", Command.SCREEN, 1);
    addCommand(cmExit);
    addCommand(cmOptions);

    setCommandListener(this);
  }

  // Application manager to display canvas
  protected void showNotify(){
    if(im == null){
    try{
      // Read the image file and get width & height
      im = Image.createImage("/sand.png");
      imageHeight = im.getHeight();
      imageWidth = im.getWidth()/imageCnt;

      // get the coordinates for x & y of viewport
      // put the viweport at the centre of display
      viewPort_x = (getWidth() / 2) - (imageWidth / 2);
      viewPort_y = (getHeight() / 2) - (imageHeight / 2);

      // set the first translated coordinate to match viewport
      transImage_x = viewPort_x;
      transImage_y = viewPort_y;

    }
    catch (Exception e){
      System.err.println("Unable to detect sand.png");
    }

    // start with the first image in the sequence
    imageIndex = 0;
  }
  // check if user has not stopped the timer if so keep timer active
  if(!Stoprequest)
    active = true;

    new Thread(this).start();
}
  // Application manager is not displaying canvas
  protected void hideNotify(){
    active = false;
}

 // Draw next timer in sequence
protected void paint (Graphics g){
   if(im !=null){
     // Viewport to be put at centre of dicplay
     g.setClip(viewPort_x, viewPort_y, imageWidth, imageHeight);
     // Draw image at translated coordinates
     g.drawImage(im, transImage_x, transImage_y, Graphics.TOP | Graphics.LEFT);
   }
 }

 // Loop and translate coordinates

 public void run(){
   try{
     while(active){
       Thread.sleep(sleepTime);
       repaint();

       // Reached the last sequence in image
       if(imageIndex == imageCnt -1){
         // rest translate coordinate
         transImage_x = viewPort_x;
         transImage_y = viewPort_y;

       }
       else{
         // translate coordinate system to the left
         transImage_x -=imageWidth;
       }
       // check wich image is next in the sequence
       imageIndex = (imageIndex + 1) % imageCnt;
     }
   }
   catch(InterruptedException e){

   }
 }

 // call from Options menu

 public void startTimer(){
   Stoprequest = false;
   active = true;
   repaint();
 }

 public void stopTimer(){
   Stoprequest = true;
   active = false;
   repaint();
 }

 // call from Form/gauge to adjust sleep
 public void setSleep(int sleepTime){
   this.sleepTime = sleepTime;
 }

 public int getSleep(){
   return sleepTime;
 }

 // command for event handling
 public void commandAction(Command c, Displayable d){
   if(c == cmOptions){
     // push diplayable and show the options
     midlet.displayMgr.pushDisplayable(midlet.lsOpt);
   }
   else if (c == cmExit){
     midlet.exitMIDlet();
   }
 }
 }