/* This application inteds to create a small gaming with guessing what is
on display - use of random numbers for starting the coordinates */

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import java.util.*;

public class Clipping extends MIDlet{
  private Display display;
  private ClippingCanvas canvas;

  // constructor
  public Clipping(){
    display = Display.getDisplay(this);
    canvas = new ClippingCanvas(this);
  }

  // startApp
  protected void startApp(){
    display.setCurrent(canvas);
  }

  // pauseApp
  protected void pauseApp(){

  }

  // destroyApp
  protected void destroyApp(boolean unconditional){

  }

  // exitMIDlet
  public void exitMIDlet(){
    destroyApp(true);
    notifyDestroyed();

  }

  // create ClippingCanvas class
  class ClippingCanvas extends Canvas implements CommandListener{
    private Command cmExit;
    private Clipping midlet;
    private Image photo = null; // image for display
    private Random ran; // random number
    private int clx = 50; // clip start coordinates
    private int cly = 50; // clip start coordinates
    private int clw = 100; // clipping area
    private int clh = 100; // clipping srea
    private int oldclx = 50; // previous clipping area
    private int oldcly = 50; // previous clipping are

    public ClippingCanvas(Clipping midlet){
      this.midlet = midlet;

      // create command and listen for events
      cmExit = new Command("Exit", Command.EXIT, 1);
      addCommand(cmExit);
      setCommandListener(this);

      // Provide a random number as a starting point
      ran = new java.util.Random();

      // make the entire clipping are on the display
      clx = Math.min((getWidth()-clw), (ran.nextInt() >>> 1) % getWidth());
      cly = Math.min((getHeight() - clh), (ran.nextInt() >>> 1) % getHeight());

      // try and catch - immutable image
      try {
        photo = Image.createImage("/photo.png");
      }

      catch(java.io.IOException e){
        System.err.print("Unable to read or access file");
      }
    }

    protected void paint(Graphics g){
      if(photo != null) {

        // clear the previous clipping area
        g.setColor(255, 255, 255);
        g.fillRect(oldclx, oldcly, clw, clh);

        // set the new clipping area
        g.setClip(clx, cly, clw, clh);

        // draw the image
        g.drawImage(photo, 0, 0, Graphics.LEFT | Graphics.TOP);
      }
    }

    public void commandAction(Command c, Displayable d){
      if(c == cmExit)
        midlet.exitMIDlet();
    }
    protected void keyPressed(int keyCode){

      // store the last clipping area
      oldclx = clx;
      oldcly = cly;

      switch(getGameAction(keyCode)){
        case UP:
          // transfer clipping area up 4 pixel
          if(cly >0)
            cly = Math.max(0, cly - 4);
            break;

          case DOWN:
            // move the clipping area 4 pxels down
            if(cly + clh < getHeight())
              cly = Math.min(getHeight(), cly + 4);
              break;

            case LEFT:
              // move clipping area 4 pixels left
              if(clx > 0)
                clx = Math.max(0, clx - 4);
                break;

              case RIGHT:
                // move clipping 4 pixels
                if(clx + clw < getWidth())
                  clx = Math.min(getWidth(), clx + 4);
                  break;

              // Use fire to show the complete image
              case FIRE:
                clx = cly = 0;
                clw = getWidth();
                clh = getHeight();
      }
      repaint();
    }

  }
}