import javax.swing.JApplet;

import java.awt.Graphics;
import java.awt.Graphics2D;

import java.awt.geom.Line2D;

import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JButton;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

/**
 * Class ButtonDemo - write a description of the class here
 * 
 * @author John Paxton
 * @version January 30, 2004
 */

public class ButtonDemo extends JApplet
{
    /**
     * init method for applet.
     */
      
    public void init()
    {
        JPanel panel = new JPanel();   // the button panel
        JFrame frame = new JFrame();   // the button frame
        
        panel.add(makeButton("North", 0, -10));
        panel.add(makeButton("South", 0, 10));
        panel.add(makeButton("East", 10, 0));
        panel.add(makeButton("West", -10, 0));
        
        frame.setContentPane(panel);
        frame.pack();
        frame.show();
        
        x = getWidth() / 2;
        y = getHeight() / 2;
    }
    
    /**
     * This method enables a button to be created
     * 
     * @param label A string indicating the label of the button.
     * @param xInc  An int that shows how to change the x-coordinate of the cursor.
     * @param yInc  An int that shows how to change the y-coordinate of the cursor.
     * 
     * @return A JButton that is the button created.
     */
    
    private JButton makeButton (String label, final int xInc, final int yInc)
    {
        JButton button = new JButton(label);   // the new button
        
        class myButtonListener implements ActionListener
        {
            public void actionPerformed (ActionEvent e)
            {
                if ( ((x + xInc) >= SIZE) && ((x + xInc) <= getWidth() - SIZE) )
                {
                    x += xInc;
                }
                if ( ((y+ yInc) >= SIZE) && ((y + yInc) <= getHeight() - SIZE) )
                {
                    y += yInc;
                }
                repaint();
            }
        }
        
        button.addActionListener (new myButtonListener());
        return button;
    }
    
    
    /**
     * Paint method for applet.
     * 
     * @param  g   the Graphics object for this applet
     */
    
    public void paint(Graphics g)
    {
        Graphics2D g2 = (Graphics2D) g;   // the Graphics2D context
        int distance = SIZE / 2;          // the distance from the center of the cursor
        
        g2.draw(new Line2D.Double(x-distance, y, x+distance, y));
        g2.draw(new Line2D.Double (x, y-distance, x, y+distance));
    }
    
    private int x;      // x coordinate of center of cursor
    private int y;      // y coordinate of center of cursor
    
    private static final int SIZE = 10;     // height and width of cursor

}