WinQueryVisibleRegion
This function is similar to WinQueryUpdateRegion. It returns a region which could be NULL, rectangular, or complex, and represents the visible region of the window.
Syntax
WinQueryVisibleRegion(hwnd, hrgn)
Parameters
- hwnd (HWND) - Input
- The window handle.
- hrgn (HRGN) - Input
- Region handle to receive the current visible region.
Returns
- ulretn (ULONG) - returns
- RGN_ERROR An error occurred.
- RGN_NULL The window currently has no visible area on screen.
- RGN_RECT The region contains a series of rectangular areas.
- RGN_COMPLEX The region contains a complex shape.
Remarks
This function returns the current visible region for the given window, even if that window does not receive notification when the visible region is changed. Currently, the region returned will always be a set of rectangular areas.