CWnd::GetUpdateRgn

Retrieves the update region into a region identified by pRgn.

int GetUpdateRgn(
   CRgn* pRgn,
   BOOL bErase = FALSE 
);

Parameters

  • pRgn
    Identifies the update region.

  • bErase
    Specifies whether the background will be erased and nonclient areas of child windows will be drawn. If the value is FALSE, no drawing is done.

Return Value

Specifies a short-integer flag that indicates the type of resulting region. The value can take any one of the following:

  • SIMPLEREGION   The region has no overlapping borders.

  • COMPLEXREGION   The region has overlapping borders.

  • NULLREGION   The region is empty.

  • ERROR   No region was created.

Remarks

The coordinates of this region are relative to the upper-left corner (client coordinates).

The BeginPaint member function automatically validates the update region, so any call to GetUpdateRgn made immediately after a call to BeginPaint retrieves an empty update region.

Requirements

Header: afxwin.h

See Also

Concepts

CWnd Class

CWnd Members

Hierarchy Chart

CWnd::BeginPaint

GetUpdateRgn