[MSDN Library June 1998] InvertRgn (41.7464114832536%)
MSDN Library Visual Studio 6.0 > Platform SDK > Graphics and Multimedia Services > GDI > Regions > Region Reference > Region Functions
[MSDN Library April 2000] InvertRgn (41.7464114832536%)
MSDN Library - April 2000 > Platform SDK > Graphics and Multimedia Services > Windows GDI > Regions > Region Reference > Region Functions