// Fig. 11.5: SelfContainedCanvas.java
// A self-contained Canvas class that
// handles its own mouse events.
package com.deitel.jhtp2.ch11;

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

public class SelfContainedCanvas extends Canvas
      implements MouseListener, MouseMotionListener {
   private int x1, y1, x2, y2;

   public SelfContainedCanvas()
   {
      addMouseListener( this );
      addMouseMotionListener( this );
   }
                           
   public void paint( Graphics g )
   {
      int x, y, width, height;

      // determine upper-left corner of bounding rectangle
      x = Math.min( x1, x2 );
      y = Math.min( y1, y2 );

      // determine width and height of bounding rectangle
      width = Math.abs( x1 - x2 );
      height = Math.abs( y1 - y2 );

      g.drawOval( x, y, width, height );
   }

   public void mousePressed( MouseEvent e )
   {
      x1 = e.getX();
      y1 = e.getY();
   }

   public void mouseReleased( MouseEvent e )
   {
      x2 = e.getX();
      y2 = e.getY();
      repaint();
   }

   public void mouseDragged( MouseEvent e )
   {
      x2 = e.getX();
      y2 = e.getY();
      repaint();
   }

   // These methods not used but must be defined because
   // we implement MouseListener and MouseMotionListener.
   public void mouseClicked( MouseEvent e ) { }
   public void mouseEntered( MouseEvent e ) { }
   public void mouseExited( MouseEvent e ) { }
   public void mouseMoved( MouseEvent e ) { }
}