Partager via

CBaseControlVideo::IsDefaultSourceRect

  • Article
 
Microsoft DirectShow 9.0

CBaseControlVideo::IsDefaultSourceRect

The IsDefaultSourceRect method determines if the renderer is using the default source rectangle (pure virtual).

Syntax

  virtual HRESULT IsDefaultSourceRect(void) PURE;

Return Value

Returns S_OK if the renderer is using the default source; otherwise, returns S_FALSE.

Remarks

This member function must be implemented in the derived class. It is called by the CBaseControlVideo::IsUsingDefaultSource member function.

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

// Return S_OK if using the default source; otherwise, S_FALSE.
HRESULT CVideoText::IsDefaultSourceRect()
{
    RECT SourceRect;

    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    m_pRenderer->m_DrawImage.GetSourceRect(&SourceRect);

    // Check the coordinates that match the video dimensions.

    if (SourceRect.left != 0 || SourceRect.top != 0 ||
            SourceRect.right != pHeader->biWidth ||
                SourceRect.bottom != pHeader->biHeight) {
                    return S_FALSE;
    }
    return S_OK;
}

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 the media type of the input pin.

Requirements

**  Header:** Declared in Ctlutil.h; include Streams.h.

**  Library:** Use Strmbase.lib (retail builds) or Strmbasd.lib (debug builds).

See Also