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This function retrieves the update region of a window by copying it into the specified region. The coordinates of the update region are relative to the upper-left corner of the window; that is, they are client coordinates.
int GetUpdateRgn( HWND hWnd , HRGN hRgn , BOOL bErase );
Parameters
- hWnd
- Handle to the window with an update region that is to be retrieved.
- hRgn
- Handle to the region to receive the update region.
- bErase
- Boolean that specifies whether the window background should be
erased and whether nonclient areas of child windows should be
drawn. If this parameter is FALSE, no drawing is done.
Return Values
The return value indicates the complexity of the resulting region. COMPLEXREGION indicates that the region consists of more than one rectangle. ERROR indicates that an error occurred. NULLREGION indicates that the region is empty. SIMPLEREGION indicates that the region is a single rectangle.
Remarks
The bEraseparameter is ignored, the window background is not erased and no drawing is done.
The BeginPaintfunction automatically validates the update region, so any call to GetUpdateRgnmade immediately after the call to BeginPaintretrieves an empty update region.
Requirements
Runs on Versions Defined in Include Link to Windows CE OS 1.0 and later Winuser.h Coredll.lib, Winmgr.lib Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.
See Also
BeginPaint, GetUpdateRect, UpdateWindow