// file:   EZdraw.java
// adapted from code in "Java in a Nutshell" 
// by David Flanagan, O'Reilly & Associates, Inc.

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

/** Class for a drawing tablet applet **/

public class EZdraw extends Applet
{
  private int last_x = 0, last_y = 0;	// The previous click or drag point
  private Button clear_button;		// A button to clear the screen


  /** init is called before the applet is started **/

  public void init()
    {
    make_button();
    set_drawing_colors();
    }


  /** Create button and add to applet **/

  public void make_button()
    {
    clear_button = new Button("Clear");
    clear_button.setForeground(Color.black);
    clear_button.setBackground(Color.lightGray);
    add(clear_button);
    }


  /** set the colors of background and pen **/

  public void set_drawing_colors()
    {
    this.setBackground(Color.blue);
    this.setForeground(Color.white);
    }


  /* remember the current mouse coordinates */

  private void remember(int x, int y)
    {
    last_x = x; last_y = y;
    }


  /** mouseDown is called when user clicks the mouse to start a drawing **/

  public boolean mouseDown(Event e, int x, int y)
    {
    remember(x, y);
    return true;
    }


  /** mouseDrag is called when user drags the mouse **/

  public boolean mouseDrag(Event e, int x, int y)
    {
    Graphics g = getGraphics();
    g.drawLine(last_x, last_y, x, y);
    remember(x, y);
    return true;
    }


  /** action is called when the user clicks a button **/

  public boolean action(Event e, Object arg)
    {
    if( e.target == clear_button )
      {
      // Handle clear button

      Graphics g = getGraphics();
      Rectangle r = bounds();
      g.setColor(getBackground());
      g.fillRect(r.x, r.y, r.width, r.height);
      return true;
      }
    return super.action(e, arg);
    }
  }