Draws a border around the region specified by pRgn using the brush specified by pBrush.
BOOL FrameRgn( CRgn* pRgn, CBrush* pBrush, int nWidth, int nHeight );
Points to the CRgn object that identifies the region to be enclosed in a border. The coordinates for the given region are specified in logical units.
Points to the CBrush object that identifies the brush to be used to draw the border.
Specifies the width of the border in vertical brush strokes in device units.
Specifies the height of the border in horizontal brush strokes in device units.
Nonzero if the function is successful; otherwise 0.
See the example for CRgn::CombineRgn.