|Microsoft DirectX 9.0|
The OnPositionChange method provides notification that the position has changed.
HRESULT OnPositionChange( const RECT *pSourceRect, const RECT *pDestinationRect );
[in] Pointer to the source video rectangle.
[in] Pointer to the destination video rectangle. Note that this is not clipped to the visible display area.
Returns S_OK if successful. If the method fails, it returns an HRESULT error code.
This method is a callback intended for use by hardware overlay cards that do not want the expense of synchronous clipping updates, and just want to know when the source or destination video positions change.
Unlike the IOverlayNotify::OnClipChange method, this method is not called in synchronization with the window changing but, rather, at some point after the window has changed (basically in time with WM_SIZE messages received). This is therefore suitable for overlay cards that do not inlay their data to the frame buffer.