To read MSDN :CDC::GetClipBox virtual int GetClipBox( LPRECT lpRect ) const;Return ValueThe clipping region’s type. It can be any of the following values: COMPLEXREGION Clipping region has overlapping borders. ERROR Device context is not valid. NULLREGION Clipping region is empty. SIMPLEREGION Clipping region has no overlapping borders. ParameterslpRectPoints to the RECT structure or CRect object that is to receive the rectangle dimensions.ResRetrieves the dimensions of the tightest bounding rectangle around the current clipping boundary. The dimensions are copied to the buffer pointed to by lpRect.
virtual int GetClipBox( LPRECT lpRect ) const;Return ValueThe clipping region’s type. It can be any of the following values: COMPLEXREGION Clipping region has overlapping borders.
ERROR Device context is not valid.
NULLREGION Clipping region is empty.
SIMPLEREGION Clipping region has no overlapping borders.
ParameterslpRectPoints to the RECT structure or CRect object that is to receive the rectangle dimensions.ResRetrieves the dimensions of the tightest bounding rectangle around the current clipping boundary. The dimensions are copied to the buffer pointed to by lpRect.