The Power of Two (Fingers)

The upcoming release of Apple’s OS X Lion includes a number of new gestures that can be used with the trackpad (watch the gestures video). The one that really caught my eye was Tap to Zoom which makes use of two fingers to enlarge an image or, presumably, a piece of text.

I really like the idea of using a second finger as an amplifier of an action in multitouch systems. It makes logical sense and I’d like to see more of it. Tap to Zoom is really an amplifier of one-fingered Tap to Select. Two fingers to scroll is an amplifier of moving the cursor via one finger.

Another extension of this logic would be in ebooks or digital magazines to be able to flip through chapters or whole articles at a time using two fingers as amplifiers of single page flips using one finger. On mobile devices where one finger is scrolling, two fingers could jump you to anchors in the list (e.g. the next letter in the alphabet) or to the end of the list.

It looks like Apple might be breaking this logic by using three fingers for “Swipe to Navigate,” which is unfortunate. It would be nice if multitouch gestures had an underlying consistency that could be applied to more advanced gestures. As it is, we’re left to just memorize them, as if they are command-line commands or shortcut keys. And while that’s certainly doable, it’s not very discoverable. Being able to guess at what a gesture might do (its feedforward) is important, especially for advanced gestures. A consistent use of gestural logic would help.

Update: I’m being told by “inside sources” that two fingers in Lion does scroll or navigate, depending on context. The video was ambiguous and some message boards I consulted got it wrong.