IOleInPlaceSiteWindowless::InvalidateRgn

Enables an object to invalidate a specified region of its in-place image on the screen.

HRESULT InvalidateRgn(

HRGN hRGN,

//Region to be invalidated

BOOL fErase

//Indicates whether to erase the background

);

Parameters

hRGN: [in] Region to invalidate, in client coordinates of the containing window. If this parameter is NULL, the object’s full extent is invalidated.
fErase: [in] Specifies whether the background within the update region is to be erased when the region is updated. If this parameter is TRUE, the background is erased. If this parameter is FALSE, the background remains unchanged.

Return Values

S_OK: The specified region was successfully invalidated.

Remarks

An object is only allowed to invalidate pixels contained in its own site region. Any attempt to invalidate an area outside of that region should result in a no-op.

HRGN hRGN,	//Region to be invalidated
BOOL fErase	//Indicates whether to erase the background
);