Seriously though, if I interpret your question to be "How do I know the direction of a drag on a scrollview" then it's actually a bit tricky, since there's no exposed values to easily show you that.
You can look at UICamera.currentTouch.totalDelta but you have to have some assumptions that the scrollview is being interacted with. Look inside UIScrollView.Drag() for the details on how it actually does it.
