def pi_zoom(self, viewer, event, msg=True):
        """Zoom and/or rotate the viewer by a pinch gesture.
        (the back end must support gestures)
        """
        return self._pinch_zoom_rotate(viewer, event.state, event.rot_deg,
                                       event.scale, msg=msg)
def pi_zoom ( self , viewer , event , msg = True ) : return self . _pinch_zoom_rotate ( viewer , event . state , event . rot_deg , event . scale , msg = msg )
Zoom and/or rotate the viewer by a pinch gesture.
        (the back end must support gestures)