ExcludeUpdateRgn info  Overview  Group

The ExcludeUpdateRgn function prevents drawing within invalid areas of a window by excluding an updated region in the window from a clipping region.

int ExcludeUpdateRgn(

HDC hDC,	// handle to device context
HWND hWnd	// handle to window
);

Parameters

hDC

Identifies the device context associated with the clipping region.

hWnd

Identifies the window to update.

Return Values

The return value specifies the complexity of the excluded region; it can be any one of the following values:

Value	Meaning
COMPLEXREGION	Region consists of more than one rectangle.
ERROR	An error occurred.
NULLREGION	Region is empty.
SIMPLEREGION	Region is a single rectangle.

See Also

BeginPaint, GetUpdateRect, GetUpdateRgn, UpdateWindow