GetWindowDC function (winuser.h)
The GetWindowDC function retrieves the device context (DC) for the entire window, including title bar, menus, and scroll bars. A window device context permits painting anywhere in a window, because the origin of the device context is the upper-left corner of the window instead of the client area.
GetWindowDC assigns default attributes to the window device context each time it retrieves the device context. Previous attributes are lost.
HDC GetWindowDC( [in] HWND hWnd );
A handle to the window with a device context that is to be retrieved. If this value is NULL, GetWindowDC retrieves the device context for the entire screen.
If this parameter is NULL, GetWindowDC retrieves the device context for the primary display monitor. To get the device context for other display monitors, use the EnumDisplayMonitors and CreateDC functions.
If the function succeeds, the return value is a handle to a device context for the specified window.
If the function fails, the return value is NULL, indicating an error or an invalid hWnd parameter.
GetWindowDC is intended for special painting effects within a window's nonclient area. Painting in nonclient areas of any window is not recommended.
The GetSystemMetrics function can be used to retrieve the dimensions of various parts of the nonclient area, such as the title bar, menu, and scroll bars.
The GetDC function can be used to retrieve a device context for the entire screen.
After painting is complete, the ReleaseDC function must be called to release the device context. Not releasing the window device context has serious effects on painting requested by applications.
|Minimum supported client||Windows 2000 Professional [desktop apps only]|
|Minimum supported server||Windows 2000 Server [desktop apps only]|
|Header||winuser.h (include Windows.h)|
|API set||ext-ms-win-ntuser-draw-l1-1-0 (introduced in Windows 8)|