IVideoWindow::put_MessageDrain

  • Article

This method specifies a window to which the video window will post messages.

HRESULT put_MessageDrain(
  OAHWND Drain
);

Parameters

  • Drain
    [in] Window to which messages will be posted.

Return Values

Returns an HRESULT value.

Remarks

The video renderer passes messages to the specified message drain by calling the Win32 PostMessage function. These messages allow you to write applications that include user interaction, such as applications that require mouse clicks on specific areas of the video display. An application can have a close relationship with the video window and know at certain time points to look for user interaction. When the renderer passes a message to the drain, it sends the parameters, such as the client-area coordinates, exactly as generated.

DirectShow passes the following messages to the window specified by the Drain parameter, if and when the application generates them:

  • WM_KEYDOWN
  • WM_KEYUP
  • WM_LBUTTONDBLCLK
  • WM_LBUTTONDOWN
  • WM_LBUTTONUP
  • WM_MBUTTONDBLCLK
  • WM_MBUTTONDOWN
  • WM_MBUTTONUP
  • WM_MOUSEACTIVATE
  • WM_MOUSEMOVE
  • WM_RBUTTONDBLCLK
  • WM_RBUTTONDOWN
  • WM_RBUTTONUP

Because this member function does not make the message drain window a child window, applications with full-screen capabilities can use it.

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

IVideoWindow Interface

Last updated on Wednesday, April 13, 2005

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