|Microsoft DirectX 9.0|
The OnDraw method instructs the Overlay Mixer to draw the video rectangle.
HRESULT OnDraw( HDC hdcDraw, LPCRECT prcDraw );
[in] Specifies the device context associated with the parent window.
[in] Specifies the rectangle coordinates of the video rectangle.
If the method succeeds, it returns S_OK.
The HDC provided here should not be cached. If an application has set a device context using SetDrawInfo, do not provide a non-NULL argument here.