This topic is included for completeness. For more detail see the source code located in the VC\atlmfc\src\mfc folder of your Visual Studio installation.
virtual SIZE OnCalculateSize(
CDC* pDC,
const CSize& sizeDefault,
BOOL bHorz
);
Parameters
[in] pDC
[in] sizeDefault
[in] bHorz
Requirements
Header: afxtoolbarmenubutton.h