IOverlayNotify::OnPositionChange

  • 项目

This method provides notification that the position has changed.

HRESULT OnPositionChange(
  const RECT* pSourceRect,
  const RECT* pDestinationRect
);

Parameters

  • pSourceRect
    [in] Source video rectangle.
  • pDestinationRect
    [in] Destination video rectangle. Note that this is not clipped to the visible display area.

Return Values

Returns an HRESULT value that depends on the implementation. HRESULT can be one of the following standard constants, or other values not listed.

Value Description
E_FAIL Failure.
E_POINTER Null pointer argument.
E_INVALIDARG Invalid argument.
E_NOTIMPL Method is not supported.
S_OK or NOERROR Success.

Remarks

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.

Requirements

DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.

See Also

IOverlayNotify Interface

Last updated on Wednesday, April 13, 2005

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