/*
 * This example is from the book "Java Foundation Classes in a Nutshell".
 * Written by David Flanagan. Copyright (c) 1999 by O'Reilly & Associates.  
 * You may distribute this source code for non-commercial purposes only.
 * You may study, modify, and use this example for any purpose, as long as
 * this notice is retained.  Note that this example is provided "as is",
 * WITHOUT WARRANTY of any kind either expressed or implied.
 */

import java.applet.*;
import java.awt.*;

/** A simple applet using the Java 1.0 event handling model */
public class Scribble extends Applet {
  private int lastx, lasty;    // Remember last mouse coordinates.
  Button erase_button;         // The Erase button.
  Graphics g;                  // A Graphics object for drawing.

  /** Initialize the button and the Graphics object */
  public void init() {
    erase_button = new Button("Erase");
    this.add(erase_button);
    g = this.getGraphics();
    this.requestFocus();  // Ask for keyboard focus so we get key events
  }
  /** Respond to mouse clicks */
  public boolean mouseDown(Event e, int x, int y) {
    lastx = x; lasty = y;             // Remember where the click was
    return true;
  }
  /** Respond to mouse drags */
  public boolean mouseDrag(Event e, int x, int y) {
    g.setColor(Color.black);
    g.drawLine(lastx, lasty, x, y);   // Draw from last position to here
    lastx = x; lasty = y;             // And remember new last position
    return true;
  }
  /** Respond to key presses: Erase drawing when user types 'e' */
  public boolean keyDown(Event e, int key) {
    if ((e.id == Event.KEY_PRESS) && (key == 'e')) {
      g.setColor(this.getBackground());   
      g.fillRect(0, 0, bounds().width, bounds().height);
      return true;
    }
    else return false;
  }
  /** Respond to Button clicks: erase drawing when user clicks button */
  public boolean action(Event e, Object arg) {
    if (e.target == erase_button) {
      g.setColor(this.getBackground());   
      g.fillRect(0, 0, bounds().width, bounds().height);
      return true;
    }
    else return false;
  }
}