/**@author Strongheart */
Dimension SS = getToolkit().getSceeenSize();  
/* 
   for fullscreen graph ,  
or cut a Rectangle out of your monitor, 
new Rectangle(mp,mq,W,H); 
*/
int  mp =0,mq=0 ,W= SS.width ,H.height;
 
/* the min and max values of the graph in real values */
double mx -10,my=-7.5 ,MX =10, MY =7.5;
double 
   horz =  (W -mp)/(MX-mx ),
   vert =  (H -mq)/(MY-my );
 
/* convert real chart coords into pixel coords. */
Point toIntPoints(double x, double y)
{
    int ix,iy;
    ix= (x-mx) * horz + mp;
    iy= (y-my) * vert + mq;
// for flipped coordinates use one or both of these instead. ...
//    ix=  (MX-x) * horz +mp; 
//    iy= (MY-y) * vert +mq;
   return new Point(ix,iy);
}
 
/* converts mouse coordinates into graph space. */
Point2D toRealPoints( int p, int q)
{
      double dx= (p-mp)/horz+mx;
      double dy= (q-mq)/vert+my;
      return new Point2D(dx,dy);
}