Draw Panel - Java Sample Program

//  DrawPanel.java
//  Using drawLine to connect the corners of a panel.
import java.awt.Graphics; 
import javax.swing.JPanel;

public class DrawPanel extends JPanel
{
   // draws an X from the corners of the panel
   public void paintComponent( Graphics g )
   {
      // call paintComponent to ensure the panel displays correctly
      super.paintComponent( g );
      
      int width = getWidth(); // total width   
      int height = getHeight(); // total height

      // draw a line from the upper-left to the lower-right
      g.drawLine( 0, 0, width, height );
      
      // draw a line from the lower-left to the upper-right
      g.drawLine( 0, height, width, 0 );
   } // end method paintComponent
} // end class DrawPanel

// DrawPanelTest.java

// Application to display a DrawPanel.

import javax.swing.JFrame;

public class DrawPanelTest

{

   public static void main( String[] args )

   {

      // create a panel that contains our drawing

      DrawPanel panel = new DrawPanel();

      

      // create a new frame to hold the panel

      JFrame application = new JFrame();

      

      // set the frame to exit when it is closed

      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

      application.add( panel ); // add the panel to the frame      

      application.setSize( 250, 250 ); // set the size of the frame

      application.setVisible( true ); // make the frame visible    

   } // end main

} // end class DrawPanelTest