Begins a smooth transition from the current zoom factor to another.
- iOS 7.0+
The new magnification factor.
The rate at which to transition to the new magnification factor, specified in powers of two per second.
Allowed values for
factor range from
1 (full field of view) to the
video specified by the active capture format.
During a ramp, the zoom factor changes at an exponential rate, but this yields a visually linear transition. The
rate parameter controls the speed of this transition independent of direction; for example, a value of
1 causes zoom factor to double every second if zooming in (that is, if the specified
factor is greater than the current
video) or halve every second if zooming out.
Before calling this method, you must call
lock to acquire exclusive access to the device’s configuration properties. If you do not, calling this method raises an exception. When you are done configuring the device, call
unlock to release the lock and allow other devices to configure the settings.