// Example of Java Applet using Swing Classes : centralized event handling
import java.io.*;
import java.awt.*;
import java.awt.event.*; 
import java.applet.*;
import javax.swing.*;

public class Scribble extends JApplet implements ActionListener, 
			 MouseListener, MouseMotionListener
{
  private int last_x=0;
  private int last_y=0;
  private Color current_color=Color.black;
  private JButton clear_button;
  private JComboBox color_choices;

  public void init () 
  {
    Container c = getContentPane();
    c.setLayout(new FlowLayout());

    clear_button = new JButton("Clear");
    clear_button.setForeground(Color.black); 
    clear_button.setBackground(Color.gray); 
    c.add(clear_button);

    color_choices = new JComboBox();
    color_choices.addItem("black"); 
    color_choices.addItem("red"); 
    color_choices.addItem("yellow"); 
    color_choices.addItem("green");
    color_choices.addItem("blue");
    color_choices.addItem("cyan");
    color_choices.setForeground(Color.black); 
    color_choices.setBackground(Color.lightGray);
    c.add(new Label("Color:")); 
    c.add(color_choices);

    // addMouseMotionListener(this);
    // addMouseListener(this);

    clear_button.addActionListener(this);
    color_choices.addActionListener(this);
  }

  private void write_error (String x)
  {
    Graphics g = this.getGraphics();
    g.drawString(x, 100, 100);
  }

  // implements the ActionListener interface (the only method in 
  //      the ActionListener interface)
  public void actionPerformed (ActionEvent evt)
  {
    if (evt.getSource() == clear_button){
      System.err.println("clear clicked...");
      Container c = getContentPane();
      Graphics g = c.getGraphics();
      // Rectangle r = this.bounds();
      g.setColor(c.getBackground());
      int width = c.getInsets().right - c.getInsets().left;
      int height = c.getInsets().bottom - c.getInsets().top;
      System.err.println("height: " + c.getHeight() + " width: " + 
			 c.getWidth());
      g.fillRect(0, 0, c.getHeight(), c.getWidth());

    }
    else if (evt.getSource() == color_choices){
      String arg = 
	(String)(((JComboBox)evt.getSource()).getSelectedItem());
      if (arg.equals("black")) current_color = Color.black;
      else if (arg.equals("red")) current_color = Color.red;
      else if (arg.equals("yellow")) current_color = Color.yellow;
      else if (arg.equals("green")) current_color = Color.green;
      else if (arg.equals("blue")) current_color = Color.blue;
      else if (arg.equals("cyan")) current_color = Color.cyan;
    }
  }

  // MouseListener interface
  public void mousePressed(MouseEvent e)
  {
	last_x = e.getX(); last_y = e.getY();
  }
  public void mouseClicked(MouseEvent e) {}
  public void mouseReleased(MouseEvent e) {}
  public void mouseEntered(MouseEvent e) 
  {
  }
  public void mouseExited(MouseEvent e) {}


  // MouseMovementListener interface (do nothing methods MUST be defined)
  public void mouseMoved (MouseEvent ev) {}

  public void mouseDragged(MouseEvent e)
  {
	int x = e.getX();
	int y = e.getY();
	Graphics g = this.getGraphics();
	g.setColor(current_color);
	g.drawLine(last_x,last_y, x,y);
	last_x = x; 
	last_y = y;
  }

}