Microsoft Foundation Classes (mfc.hlp) (Table of Contents; Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
CRgn::CreatePolygonRgn
CRgn                                        Up Contents Index Back
──Microsoft Foundation Classes──────────────────────────────────────────────
 
  BOOL CreatePolygonRgn( LPPOINT lpPoints, int nCount, int nMode );
 
  Parameter   Description
 
  <lpPoints>  Points to an array of POINT structures or an array of CPoint
              objects. Each structure specifies the x- and y-coordinate of
              one vertex of the polygon.
 
  <nCount>    Specifies the number of POINT structures or CPoint objects
              in the array pointed to by <lpPoints>.
 
  <nMode>     Specifies the filling mode for the region. This parameter
              may be either ALTERNATE or WINDING.
 
  Remarks
 
  Creates a polygonal region. The system closes the polygon automatically,
  if necessary, by drawing a line from the last vertex to the first. The
  resulting region is stored in the CRgn object.
 
  When the polygon-filling mode is ALTERNATE, the system fills the area
  between odd-numbered and even-numbered polygon sides on each scan line.
  That is, the system fills the area between the first and second side,
  between the third and fourth side, and so on.
 
  When the polygon-filling mode is WINDING, the system uses the direction
  in which a figure was drawn to determine whether to fill an area. Each
  line segment in a polygon is drawn in either a clockwise or a
  counterclockwise direction. Whenever an imaginary line drawn from an
  enclosed area to the outside of a figure passes through a clockwise line
  segment, a count is incremented. When the line passes through a
  counterclockwise line segment, the count is decremented. The area is
  filled if the count is nonzero when the line reaches the outside of the
  figure.
 
  Return Value
 
  TRUE if the operation succeeded; otherwise FALSE.
 
  See Also
 
  CRgn::CreatePolyPolygonRgn, ::CreatePolygonRgn
 
 
                                     -♦-