MovingScreen: selecting hard-to-reach targets with automatic comfort zone calibration on mobile devices

Abstract

Smartphone screen size becomes larger nowadays. However, it causes users hard to reach a target with the thumb when using the smartphone in one hand. We propose an interaction method MovingScreen to solve the hard-to-reach problem by making the smartphone screen view movable. Users move the screen view to make the target into their comfort zone, an area users comfortably performing touch input with the thumb. They then select a target easily. Using the proposed triggering gesture bezel-scroll, MovingScreen automatically calibrates the comfort zone. Bezel-scroll detects the comfort zone and provides different screen moving ratios for users in different poses to hold the smartphone. Users are even allowed to adjust screen moving speed by altering bezel-scroll length. We evaluate performance of MovingScreen and other methods in a user study. The results show that MovingScreen has similar selection time (1030.58ms) but lower error rate (4.57%) to the other methods.