🚀 go-pugleaf

Hi I'am new to Java and am trying to write an applet that will allows me
to Scroll a large JPEG map but
in a small viewing area, ie I load the whole map but only display small
portions of it depending on whether the user clicks and up, down, left
or right button ( NOT Scroll bars ).
Here is my MainMap code... Can anyone suggest where I'm going wrong.
I'm not sure if I'm using the copyArea function correctly or that my
co-ordinate system is right.


> import java.awt.*;
> import java.awt.event.*;
>
>
> public class MainMap extends Canvas
> {
>   Point TL;
>   int viewwidth, viewheight;
>
>   Image BufferedImage;
>   Image MainMapImage = null;
>
>   Graphics offScreen, mainGraphics;
>
>   public MainMap( Image image, int viewablewidth, int viewableheight )
>   {
>     MainMapImage = image;
>     if( MainMapImage != null)
>     {
>       mainGraphics = MainMapImage.getGraphics( );
>     }
>     // Sort out offscreen Image
>     try
>     {
>       BufferedImage = createImage( viewablewidth, viewableheight );
>       offScreen = BufferedImage.getGraphics( );
>     }
>     catch( Exception e )
>     {
>       offScreen = null;
>     }
>
>     viewwidth = viewablewidth;
>     viewheight = viewableheight;
>
>
>     addMouseListener(new MouseAdapter()
>     {
>       public void mouseEntered(MouseEvent e)
>       {
>         requestFocus();
>       }
>       public void mouseClicked(MouseEvent e)
>       {
>       }
>
>       public void mouseDragged(MouseEvent e)
>       {
>       }
>
>       public void mouseMoved(MouseEvent e)
>       {
>       }
>
>       public void mousePressed(MouseEvent e)
>       {
>       }
>
>       public void mouseReleased(MouseEvent e)
>       {
>       }
>
>       public void mouseExited(MouseEvent e)
>       {
>       }
>     } );
>   }
>
>   public void setImage( Image image )
>   {
>     MainMapImage = image;
>     repaint();
>   }
>
>   public Image getImage(  )
>   {
>     return MainMapImage;
>   }
>
>   public void setTopLeft( Point tl )
>   {
>     this.TL = tl;
>     repaint();
>   }
>
>   public Point getTopLeft(  )
>   {
>     return TL;
>   }
>
>   public Dimension getPreferredSize( )
>   {
>     return new Dimension( viewwidth, viewheight );
>   }
>
>   public Dimension getMinimumSize( )
>   {
>     return getPreferredSize( );
>   }
>
>   public void update( Graphics g )
>   {
>     paint( g );
>   }
>
>   public void paint(Graphics g)
>   {
>     if ( offScreen != null )
>     {
>       MainMapPaint( offScreen );
>       g.drawImage( BufferedImage, 0, 0, this );
>     }
>     else
>     {
>       g.copyArea(TL.x, TL.y, viewwidth , viewheight, 0, 0);
>       MainMapPaint( g );
>     }
>
>   }
>
>   public void MainMapPaint( Graphics g )
>   {
>     g.draw3DRect( 0, 0,  viewwidth, viewheight, true );
>     g.drawImage( MainMapImage, 1, 1, viewwidth - 1, viewheight - 1, this );
>   }
> }
>


--
Ciao,


Dominique Louis
*********************************************************
**  To Do Nothing is to Collaborate with the oppressor **
*********************************************************
===========================================================
From . . . . . . . : Dominique Louis
                     ( Savage Software Solutions )
Web Site . . . . . : http://www.SavageSoftware.com.au
Email. . . . . . . :  Dominique_Louis@BigPond.com
===========================================================