SetWindowRgn
The SetWindowRgn
function sets the window region of a window. 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
int SetWindowRgn(
|
HWND hWnd, |
// handle to window
whose window region is to be set |
|
HRGN hRgn, |
// handle to region
|
|
BOOL bRedraw |
// window redraw
flag |
|
); |
|
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
Boolean value
that specifies whether the operating system redraws the window after setting
the window region. If bRedraw is TRUE, the operating system does so;
otherwise, it does not.
Typically,
you set bRedraw to TRUE if the window is visible.
Return Values
If the
function succeeds, the return value is nonzero.
If the
function fails, the return value is zero.
Remarks
If the bRedraw
parameter is TRUE, 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 operating system owns the region
specified by the region handle hRgn. The operating 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 close this region handle.
To obtain the
window region of a window, call the GetWindowRgn function.
See Also