CDrawImage.ScaleSourceRect method

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 ScaleSourceRect method scales a rectangle, if there is a difference between the native video size and the media type format.

Syntax

virtual RECT ScaleSourceRect(
   const RECT *pSource
);

Parameters

pSource

Pointer to an unscaled rectangle.

Return value

Returns the scaled rectangle.

Remarks

In the CDrawImage class, this method returns pSource without any change. You can override this method if the filter stretches the incoming video image. For example, the native video size might be 320 240, but the media type on the input pin might be 640 480. In that case the filter would need to scale the source rectangle by a factor of 2.

Requirements

See also

CDrawImage Class