Rubbing and tapping for precise and rapid selection on touch-screen displays

We introduce two families of techniques, rubbing and tapping, that use zooming to make possible precise interaction on passive touch screens, and describe examples of each. Rub-Pointing uses a diagonal rubbing gesture to integrate pointing and zooming in a single-handed technique. In contrast, Zoom-Tapping is a two-handed technique in which the dominant hand points, while the non-dominant hand taps to zoom, simulating multi-touch functionality on a single-touch display. Rub-Tapping is a hybrid technique that integrates rubbing with the dominant hand to point and zoom, and tapping with the non-dominant hand to confirm selection. We describe the results of a formal user study comparing these techniques with each other and with the well-known Take-Off and Zoom-Pointing selection techniques. Rub-Pointing and Zoom-Tapping had significantly fewer errors than Take-Off for small targets, and were significantly faster than Take-Off and Zoom-Pointing. We show how the techniques can be used for fluid interaction in an image viewer and in Google Maps.