[walterbell]

Thanks for the reference. Has there been research on radial menus for this use case? E.g. touch anywhere in the middle of the screen to define the center of the radial menu, then move in a circle to discover the radial menu options. This would reduce the surface area to be traversed. If we ever get haptic feedback on mobile devices, this could be used to signal transition between "pie slices" of the radial menu.

http://en.m.wikipedia.org/wiki/Fitts's_law

[robin_reala]

Have you used VoiceOver? Both iOS and OS X versions have a rotor menu that activates with a two finger touch and twist motion to give access to various sets of items.

[walterbell]

I've enabled VoiceOver for testing but had not seen that gesture, thanks for the pointer. It is useful but slightly awkward as you need both fingers to retain contact with the screen while rotating, which is challenging for a 360 degree rotation :)

[M4v3R]

You don't have to do full rotation in one go. It's hard to explain, but you basically need to do this (assuming right hand): put your thumb and index finger on the screen, and then do a swipe left motion with your index finger, while having thumb in place. Then lift the index finger, move it back to starting position and repeat. With that gesture you can advance the rotor by one position at time.