function calculateDirection(startPoint, endPoint) {

      if( comparePoints(startPoint, endPoint) ) {
        return NONE;
      }

      var angle = calculateAngle(startPoint, endPoint);

      if ((angle <= 45) && (angle >= 0)) {
        return LEFT;
      } else if ((angle <= 360) && (angle >= 315)) {
        return LEFT;
      } else if ((angle >= 135) && (angle <= 225)) {
        return RIGHT;
      } else if ((angle > 45) && (angle < 135)) {
        return DOWN;
      } else {
        return UP;
      }
    }
Calculate the direction of the swipe
This will also call calculateAngle to get the latest angle of swipe
@param {point} startPoint A point object containing x and y co-ordinates
@param {point} endPoint A point object containing x and y co-ordinates
@return string Either {@link $.fn.swipe.directions.LEFT} / {@link $.fn.swipe.directions.RIGHT} / {@link $.fn.swipe.directions.DOWN} / {@link $.fn.swipe.directions.UP}
@see $.fn.swipe.directions
@inner