// A freehand application on canvas using pointer events to draw onto canvas

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

public class Freehand extends MIDlet {
  
  private Display display; // A display
  private DoodleCanvas canvas; // A canvas providing doodling with pen and paper
  
  public Freehand() {
    
    display = Display.getDisplay(this);
    canvas = new DoodleCanvas(this);
  }
  
  protected void startApp(){
    display.setCurrent(canvas);
  }
  
  protected void pauseApp(){
    
  }
  
  protected void destroyApp(boolean unconditional){

  }
  public void exitMidlet(){
    destroyApp(true);
    notifyDestroyed();
  }
}

// pointer event handle - Class DoodleCanvas

class DoodleCanvas extends Canvas implements CommandListener{
  
  private Command cmExit; // Exit
  private Command cmClear; // clear canvas command
  private int startx = 0,
              starty = 0,
              currentx = 0,
              currenty = 0;
  
  private Freehand midlet;
  private boolean clearDisplay = false; // set the clearDisplay to false
  
  // constructor
  public DoodleCanvas(Freehand midlet) {
    this.midlet = midlet;
    
    // create exit command & listen for events
    cmExit = new Command("Exit", Command.EXIT, 1);
    cmClear = new Command("Clear", Command.SCREEN, 1);
    addCommand(cmExit);
    addCommand(cmClear);
    setCommandListener(this);
  }
  
  // Print the text illustrating the key code
  protected void paint(Graphics g){
    // Clear background
    if(clearDisplay){
      g.setColor(255,255,255);
      g.fillRect(0, 0, getWidth(),getHeight());
      
      clearDisplay = false;
      startx = currentx = starty = currenty = 0; // start from 0,0 
      
      return;
    }
    // draw with blue pen
    g.setColor(0, 0, 255);
    
    //draw line
    g.drawLine(startx, starty, currentx, currenty);
    
    // New starting point is current position
    startx = currentx;
    starty = currenty;
  }
  
  // event handling
  public void commandAction(Command c, Displayable d) {
  if (c == cmExit)
    midlet.exitMidlet();
    else if (c == cmClear){
      clearDisplay = true;
      repaint();
    } 
   }
// pointer pressed
protected void pointerPressed(int x, int y) {
  startx = x;
  starty = y;
}

// pointer moved
protected void pointerDragged(int x, int y) {
  currentx = x;
  currenty = y;
  repaint();
  }
}