code: function getInterimData(ev) {
      var lastEvent = this.current.lastEvent
        , angle
        , direction;
  
      // end events (e.g. dragend) don't have useful values for interimDirection & interimAngle
      // because the previous event has exactly the same coordinates
      // so for end events, take the previous values of interimDirection & interimAngle
      // instead of recalculating them and getting a spurious '0'
      if(ev.eventType == EVENT_END) {
        angle = lastEvent && lastEvent.interimAngle;
        direction = lastEvent && lastEvent.interimDirection;
      }
      else {
        angle = lastEvent && Utils.getAngle(lastEvent.center, ev.center);
        direction = lastEvent && Utils.getDirection(lastEvent.center, ev.center);
      }
  
      ev.interimAngle = angle;
      ev.interimDirection = direction;
    }
docs: calculate interim angle and direction
  @param   {Object}  ev