ICameraControl::get_RollRelative method (vidcap.h)
[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 get_RollRelative method returns the camera's relative roll. The relative roll is expressed as a number of steps, where the size of each step depends on the camera model.
Syntax
HRESULT get_RollRelative(
[out] long *pValue,
[out] long *pFlags
);
Parameters
[out] pValue
Receives the relative roll. The size of the value represents the desired rotation speed; a higher value represents a higher speed. To get the range of possible values, call ICameraControl::getRange_RollRelative.
| Value | Description |
|---|---|
| 0 | Stopped. |
| Positive value | Rotating clockwise around the viewing axis. |
| Negative value | Rotating counterclockwise around the viewing axis. |
[out] pFlags
Receives one or more flags. See CameraControlFlags.
Return value
Returns an HRESULT value.
Requirements
| Minimum supported client | Windows XP with SP2 [desktop apps only] |
| Minimum supported server | Windows Server 2003 [desktop apps only] |
| Target Platform | Windows |
| Header | vidcap.h |
| Library | Strmiids.lib |