GcPinchZoomGesture class constructor
DOM element, target container, used to listen touch events and used for zoom distance calculations
Handler for zoom in event callback
Handler zoom out event callback
Handler for zoom in event callback.
Handler zoom out event callback.
Activate pinch gesture utility and enable zoom in / zoom out events.
Deactivate pinch gesture utility and disable zoom in / zoom out events.
Utility to listen two finger zoom gesture events for mobile devices.