Retrieves the update region of a window by copying it into the specified region
#include <WinAPIGdi.au3>
_WinAPI_GetUpdateRgn ( $hWnd, $hRgn [, $bErase = True] )
| $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 | [optional] Specifies whether the background in the update region is to be erased, valid values: True - The background is erased (Default). False - The background remains unchanged. |
| Success: | The value that indicates the complexity of the resulting region; it can be one of the following values. $COMPLEXREGION $NULLREGION $SIMPLEREGION |
| Failure: | 0. |
_WinAPI_BeginPaint() automatically validates the update region, so any call to _WinAPI_GetUpdateRgn() made
immediately after the call to _WinAPI_BeginPaint() retrieves an empty update region.
Search GetUpdateRgn in MSDN Library.