Ok. I'm not experienced enough to make that shorter than
86 lines. I ommited the lines that create the JFrame
instance.

---- Start code ----
package peti;
import javax.swing.JFrame;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;

public class TMainWindow extends JFrame {
    static final long serialVersionUID = 422323L;
    game gameFace;
    public static void main(String[] args) {
        JFrame windo = new TMainWindow();
        windo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        windo.setVisible(true);
    }//end main
    public TMainWindow() {
        Container content = this.getContentPane();
        content.setLayout(new BorderLayout());
        gameFace = new game();
        content.add(gameFace, BorderLayout.CENTER);
        this.pack();
        gameFace.start();
    }//end constructor
}//end class gameAnalogBuf
class game extends JPanel {
    static final long serialVersionUID = 422324L;
    private static Image[] TileGfx;
    private BufferedImage gameImage,lightmap;
    private javax.swing.Timer t;
    private Graphics2D gc;
    public game() {
        this.setPreferredSize(new Dimension(694,612));
        this.setBackground(Color.white);
        this.setForeground(Color.black);
        t = new javax.swing.Timer(10,
              new ActionListener() {
                  public void actionPerformed(ActionEvent e) {
                      update();
                  }
              });
        TileGfx = new Image[1];
        ClassLoader loader = this.getClass().getClassLoader();
        // load a floor tile 32 x 32 pixelsj
        TileGfx[0] = new
ImageIcon(loader.getResource("peti/images/0196.png")).getImage();
     }//end constructor
    public void update() {
        this.repaint();
    }//end update
    public void start() {
        t.start();
    }//end start
    public void stop() {
        t.stop();
    }//end stop
    public void paintComponent(Graphics g) {
        super.paintComponent(g);  // paint background, borders
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = getWidth();
        int h = getHeight();
        if (gameImage == null
                || gameImage.getWidth() != w
                || gameImage.getHeight() != h) {
            gameImage = (BufferedImage)(this.createImage(w, h));
                  }
        if (gc == null)
         { gc = gameImage.createGraphics();
           gc.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
           lightmap = (BufferedImage)(this.createImage(w, h));
           Graphics gi = lightmap.getGraphics();
           gi.setColor(new Color(0,0,0));
           gi.fillRect(0,0,gameImage.getWidth(),gameImage.getHeight());
           gi.setColor(new Color(255,255,255,90));
           gi.fillOval(0,0,100,100);
         }
       int x,y,ofs;
       for (x=0;x<15;x++) // draw tiles
         for (y=0;y<12;y++)
           gc.drawImage(TileGfx[0],18+x*32,8+(y*32),32,32,null);
       //gc.drawImage(lightmap,0,0,null); // mask with lightmap
       g2.drawImage(gameImage, null, 0, 0); // show result
    }//end paintComponent
}//endclass game

--- end code ---
This will show a map of 15*12 tiles (whatever 32x32 pixel
0196.png you provided).

If i uncomment the

       //gc.drawImage(lightmap,0,0,null); // mask with lightmap

line,

it shows a black rectangle with a gray circle instead.
What i want:
A gray circle filled with tiles, everything out of that
circle, black:

+--+--+--+

+--+--+--+

+--+--+--+

+--+--+--+

plus

##########
###  #####
##    ####
#      ###
#      ###
##    ####
###  #####

should become

##########
###| #####
##-+--####
#  |  |###
#--+--+###
## |  ####
###+-#####

Hope this makes things clear enough :-)

Any ideas, now?

thanks,
  Andreas