CBaseControlVideo.SetDefaultSourceRect method

Article
07/27/2023

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The SetDefaultSourceRect method sets the default source video rectangle (pure virtual). This in an internal member function that gets called when the source rectangle is reset.

Syntax

virtual HRESULT SetDefaultSourceRect() = 0;

Parameters

This method has no parameters.

Return value

Returns an HRESULT value.

Remarks

Derived classes should override this to reset the source rectangle. It is called from CBaseControlVideo::SetDefaultSourcePosition.

The following example demonstrates an implementation of this function in a derived class.

// This is called when you reset the default source rectangle.
HRESULT CVideoText::SetDefaultSourceRect()
{
    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    RECT SourceRect = {0,0,pHeader->biWidth,pHeader->biHeight};
    m_pRenderer->m_DrawImage.SetSourceRect(&SourceRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object. The m_mtIn data member, also defined in the derived class, holds a CMediaType object with media type of the input pin.

Requirements

Requirement	Value
Header	Ctlutil.h (include Streams.h)
Library	Strmbase.lib (retail builds); Strmbasd.lib (debug builds)