Call this member function to get the window region of a window.
int GetWindowRgn( HRGN hRgn )const;
- A handle to a window region.
The return value specifies the type of the region that the function obtains. It can be one of the following values:
- NULLREGION The region is empty.
- SIMPLEREGION The region is a single rectangle.
- COMPLEXREGION The region is more than one rectangle.
- ERROR An error occurred; the region is unaffected.
The window region determines the area within the window where the operating system permits drawing. The operating system does not display any portion of a window that lies outside of the window region.
The coordinates of a window's window region are relative to the upper-left corner of the window, not the client area of the window.
To set the window region of a window, call CWnd::SetWindowRgn.