This function sets the window region of a window. The window region determines the area within the window where the system permits drawing. The system does not display any portion of a window that lies outside of the window region
At a Glance
| Header file: | Winuser.h |
| Windows CE versions: | 2.12 and later |
Syntax
int SetWindowRgn(HWND hWnd, HRGN hRgn, BOOL bRedraw);
Parameters
hWnd
Handle to the window whose window region is to be set.
hRgn
Handle to a region. The function sets the window region of the window to this region.
If hRgn is NULL, the function sets the window region to NULL.
bRedraw
Specifies whether the system redraws the window after setting the window region. If bRedraw is TRUE, the system does so; otherwise, it does not.
Typically, you set bRedraw to TRUE if the window is visible.
Return Values
Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.
Remarks
When this function is called, the system sends the WM_WINDOWPOSCHANGING and WM_WINDOWPOSCHANGED messages to the window.
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.
After a successful call to SetWindowRgn, the system owns the region specified by the region handle hRgn. The system does not make a copy of the region. Thus, you should not make any further function calls with this region handle. In particular, do not delete this region handle. The system deletes the region handle when it no longer needed.
To obtain the window region of a window, call the GetWindowRgn function.