CPoint OffsetViewportOrg( int nWidth, int nHeight );
nWidth
Specifies the number of device units to add to the current origin's x-coordinate.
nHeight
Specifies the number of device units to add to the current origin's y-coordinate.
Modifies the viewport origin relative to the coordinates of the current viewport origin.
The previous viewport origin (in device coordinates) as a CPoint object.
CDC::GetViewportOrg, CDC::OffsetWindowOrg, CDC::SetViewportOrg, ::OffsetViewportOrg