Drawing - Mouse - Java AWT - Internet & Web Programming Lab

Program:

import java.awt.*;
import java.awt.event.*;

class ex9 extends Frame implements ActionListener
{
 Canvas c;
 Button b;
 int x1,x2,y1,y2;
 ex9()
 {
   super("Drawing");
   setLayout(null);
   setSize(500,500);
   setVisible(true);
   c=new Canvas();
   c.setBackground(Color.white);
   b=new Button("Clear");
   c.setBounds(50,50,300,300);
   add(c);
   b.setBounds(200,400,50,20);
   add(b);
   b.addActionListener(this);
   c.addMouseListener(new MouseAdapter()
   {
    public void mousePressed(MouseEvent ae)
    {
     x1=ae.getX();
     y1=ae.getY();
     c.getGraphics().drawLine(x1, y1, x1, y1);
    }
   }
   );
   c.addMouseMotionListener(new MouseAdapter()
   {
    public void mouseDragged(MouseEvent ae)
    {
     x2=ae.getX();
     y2=ae.getY();
     c.getGraphics().drawLine(x1, y1, x2, y2);
     x1=x2;
     y1=y2;
    }
   }
   );  
   addWindowListener(new WindowAdapter()
   {
    public void windowClosing(WindowEvent we)
    {
     System.exit(0);
    }
   });
 }

 public void actionPerformed(ActionEvent ae)
 {
  c.repaint();
 }

 public static void main(String s[])
 {
  ex9 ob=new ex9();
 }
}

Output:

nn@linuxmint ~/Desktop/java 7 $ javac ex9.java
nn@linuxmint ~/Desktop/java 7 $ java ex9
nn@linuxmint ~/Desktop/java 7 $