Source of ImageMap.java


  1: // Fig. 21.4: ImageMap.java
  2: // Demonstrating an image map.
  3: import java.awt.event.MouseAdapter;
  4: import java.awt.event.MouseEvent;
  5: import java.awt.event.MouseMotionAdapter;
  6: import java.awt.Graphics;
  7: import javax.swing.ImageIcon;
  8: import javax.swing.JApplet;
  9: 
 10: public class ImageMap extends JApplet 
 11: {
 12:    private ImageIcon mapImage;
 13: 
 14:    private static final String captions[] = { "Common Programming Error",
 15:       "Good Programming Practice", "Graphical User Interface Tip", 
 16:       "Performance Tip", "Portability Tip", 
 17:       "Software Engineering Observation", "Error-Prevention Tip" };
 18: 
 19:    // sets up mouse listeners
 20:    public void init()
 21:    {
 22:       addMouseListener(
 23: 
 24:          new MouseAdapter() // anonymous inner class
 25:          { 
 26:             // indicate when mouse pointer exits applet area
 27:             public void mouseExited( MouseEvent event )
 28:             {
 29:                showStatus( "Pointer outside applet" );
 30:             } // end method mouseExited
 31:          } // end anonymous inner class
 32:       ); // end call to addMouseListener
 33: 
 34:       addMouseMotionListener(
 35: 
 36:          new MouseMotionAdapter() // anonymous inner class
 37:          { 
 38:             // determine icon over which mouse appears
 39:             public void mouseMoved( MouseEvent event )
 40:             {
 41:                showStatus( translateLocation(
 42:                   event.getX(), event.getY() ) );
 43:             } // end method mouseMoved
 44:          } // end anonymous inner class
 45:       ); // end call to addMouseMotionListener
 46: 
 47:       mapImage = new ImageIcon( "icons.png" ); // get image
 48:    } // end method init
 49: 
 50:    // display mapImage
 51:    public void paint( Graphics g )
 52:    {
 53:       super.paint( g );
 54:       mapImage.paintIcon( this, g, 0, 0 );
 55:    } // end method paint
 56: 
 57:    // return tip caption based on mouse coordinates
 58:    public String translateLocation( int x, int y )
 59:    {
 60:       // if coordinates outside image, return immediately
 61:       if ( x >= mapImage.getIconWidth() || y >= mapImage.getIconHeight() ) 
 62:          return "";
 63: 
 64:       // determine icon number (0 - 6)
 65:       double iconWidth = ( double ) mapImage.getIconWidth() / 7.0;
 66:       int iconNumber = ( int )( ( double ) x / iconWidth );
 67: 
 68:       return captions[ iconNumber ]; // return appropriate icon caption
 69:    } // end method translateLocation
 70: } // end class ImageMap
 71: 
 72: /**************************************************************************
 73:  * (C) Copyright 1992-2005 by Deitel & Associates, Inc. and               *
 74:  * Pearson Education, Inc. All Rights Reserved.                           *
 75:  *                                                                        *
 76:  * DISCLAIMER: The authors and publisher of this book have used their     *
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 78:  * development, research, and testing of the theories and programs        *
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