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IOverlay::Advise

  • Articolo
 
Microsoft DirectShow 9.0

IOverlay::Advise

The Advise method sets up an advise link for the overlay events specified by the dwInterests parameter.

Syntax

  HRESULT Advise(
  IOverlayNotify *pOverlayNotify,
  DWORD dwInterests
);

Parameters

pOverlayNotify

[in] Pointer to the notification interface.

dwInterests

[in] Callbacks of interest, which can be any subset of the following events.

Event Description
ADVISE_NONE No changes.
ADVISE_CLIPPING Change in clipping region (synchronized with the window).
ADVISE_PALETTE Change in palette.
ADVISE_COLORKEY Change of chroma key value.
ADVISE_POSITION Change in position of video window (not synchronized with the window).
ADVISE_DISPLAY_CHANGE Called on WM_DISPLAYCHANGE. The WM_DISPLAYCHANGE message is sent to all windows when the display resolution has changed.
ADVISE_ALL2 All of the above.

Return Value

Returns S_OK if successful. If the method fails, it returns an HRESULT error code.

Remarks

This method sets up an advise link for the IOverlayNotify interface to receive notifications. If one of these events occurs, the appropriate entry point in the pOverlayNotify parameter passed in is called (IOverlayNotify::OnClipChange, IOverlayNotify::OnColorKeyChange, IOverlayNotify::OnPaletteChange, or IOverlayNotify::OnPositionChange).

Only one advise link can be set on any given IOverlay interface. Trying to set another notification interface on second and subsequent calls returns VFW_E_ADVISE_ALREADY_SET. You can cancel an advise link by using IOverlay::Unadvise.

Requirements

Header: Declared in Strmif.h; include Dshow.h.

Library: Use Strmiids.lib.

See Also