question: private void determineGestureOrientation ( MotionEvent e1 , MotionEvent e2 ) { float deltaX = Math . abs ( e2 . getX ( ) - e1 . getX ( ) ) ; float deltaY = Math . abs ( e2 . getY ( ) - e1 . getY ( ) ) ; mGestureOrientation = deltaY * VERTICAL_DETERMINATION_BOOST > deltaX ? GestureOrientation . VERTICAL : GestureOrientation . HORIZONTAL ; mHasDeterminedGestureOrientation = true ; }
target:  Determines the gesture orientation.