As of the current release, the pinch gesture is implemented using the Leap::Hand::PinchStrength variable however this gesture calcuates the pinch gesture based on all fingers, its probably prefered to use Leap::Hand::PinchDistance which returns the same values but filters only the thumb and index finger to be calculated, which is more preferable and harder to misclick.
Docs for both of these are embed on the words itself and can also be found here
As of the current release, the pinch gesture is implemented using the Leap::Hand::PinchStrength variable however this gesture calcuates the pinch gesture based on all fingers, its probably prefered to use Leap::Hand::PinchDistance which returns the same values but filters only the thumb and index finger to be calculated, which is more preferable and harder to misclick.
Docs for both of these are embed on the words itself and can also be found here