publicvoid paint(Graphics g){
     //Downcast the Graphics object to a 
     // Graphics2D object
     Graphics2D g2 = (Graphics2D)g;
     
     //Scale device space to produce inches on
     // the screen  based on actual screen
     // resolution.
     g2.scale((double)res/72,(double)res/72);
  
     //Translate origin to center of Frame
     g2.translate((hSize/2)*ds,(vSize/2)*ds);
  
     //Draw x-axis
     g2.draw(new Line2D.Double(
                             -1.5*ds,0.0,1.5*ds,0.0));
     //Draw y-axis
     g2.draw(new Line2D.Double(
                             0.0,-1.5*ds,0.0,1.5*ds));

Figure 1