Picture Zooming in Java Swing Example

import java.awt.*; 
 import java.awt.event.*; 
 import javax.swing.*; 
 public class JPictureJavaExample extends JApplet implements ActionListener 
      { 
                      private ImageIcon img = new ImageIcon("Koala.jpg"); 
                      private JButton ZoomBtn = new JButton("Zoom..!"); 
                      private int Hght,Wdth; 
                      Container cntnr = getContentPane(); 
                      public void init() 
                             { 
                                    cntnr.setLayout(new FlowLayout()); 
                                    ZoomBtn.addActionListener(this); 
                                    cntnr.add(ZoomBtn); 
                                    Wdth = img.getIconWidth(); 
                                    Hght = img.getIconHeight(); 
                             } 
                                    public void actionPerformed(ActionEvent event) 
                                    { 
                                        Wdth = Wdth * 2; 
                                        Hght = Hght * 2; 
                                        repaint(); 
                                    } 
                                        public void paint(Graphics gp) 
                                         { 
                                            super.paint(gp); 
                                            gp.drawImage(img.getImage(), 0, 0, Wdth, Hght, this); 
                                         } 
    }