C-QWERTY: A text entry method for circular smartwatches

We present a study aimed at comparing different circular layouts for entering text on smartwatches. In particular, we measured the extent through which the use of a QWERTY layout increases user performance in the earliest sessions of use. To this aim, we designed C-QWERTY, a soft keyboard designed for circular smartwatches in which the keys are arranged along the edge of the screen in a circular layout. In order to make the keyboard more familiar to users, the order of the keys is similar to the one of traditional rectangular QWERTY keyboards. The method supports two interaction modes: tapping and gesture, in which a whole word can be written with a single gesture. As an evaluation, we compared the C-QWERTY layout with Cirrin, another circular layout in witch the order of the characters has been optimized to minimize the distance between successive keys during writing. The experimental results showed that the C-QWERTY, with a text entry speeds of 9.1 wpm and 7.7 wpm (tapping and gesture mode, respectively), outperformed the Cirrin layout with entry speeds of 6.6 wpm and 5.5 wpm. The increase in text entry speed due to the use of the QWERTY layout was 38 percent