ICameraControl::put_FocusRelative 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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 put_FocusRelative method sets the relative focus. The relative focus indicates the direction in which the lens group is moving.
Syntax
HRESULT put_FocusRelative(
[in] long Value,
[in] long Flags
);
Parameters
[in] Value
Specifies the relative focus. The size of the value represents the speed at which the focal point changes; a higher value represents a higher speed. To get the possible range of values, call ICameraControl::getRange_FocusRelative.
| Value | Description |
|---|---|
| 0 | Stop focus motion. |
| Positive value | Start moving the focus closer to the object. |
| Negative value | Start moving the focus farther away from the object. |
[in] Flags
Zero or more flags. See CameraControlFlags. If the CameraControl_Flags_Auto flag is used, the Value parameter is ignored and the camera sets the default value.
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 |