[NumLock]

Код:

HRGN CreatePolygonRgn(
    CONST POINT *lppt,	// pointer to array of points 
    int cPoints,	// number of points in array 
    int fnPolyFillMode 	// polygon-filling mode 
   );

Код:

BOOL PtInRegion(
    HRGN hrgn,	// handle of region 
    int X,	// x-coordinate of point  
    int Y 	// y-coordinate of point  
   );