Gesturecalc: an Eyes-Free Calculator for Touch Screens
Paper Session 2: Inviscible Interactions ASSETS '19, October 28–30, 2019, Pittsburgh, PA, USA GestureCalc: An Eyes-Free Calculator for Touch Screens Bindita Chaudhuri1*, Leah Perlmutter1*, Justin Petelka2, Philip Garrison1 James Fogarty1, Jacob O. Wobbrock2, Richard E. Ladner1 1Paul G. Allen School of Computer Science & Engineering, 2The Information School DUB Group | University of Washington, Seattle, WA 98195, USA 1{bindita, lrperlmu, philipmg, jfogarty, ladner}@cs.washington.edu, 2{jpetelka, wobbrock}@uw.edu ABSTRACT A digital calculator is one of the most frequently used touch screen applications. However, keypad-based character input in existing calculator applications requires precise, targeted key presses that are time-consuming and error-prone for many screen readers users. We introduce GestureCalc, a digital calculator that uses target-free gestures for arithmetic tasks. It allows eyes-free target-less input of digits and operations through taps and directional swipes with one to three fngers, guided by minimal audio feedback. We conducted a mixed methods longitudinal study with eight screen reader users and found that they entered characters with GestureCalc 40.5% faster on average than with a typical touch screen calculator. Participants made more mistakes but also corrected more errors with GestureCalc, resulting in 52.2% fewer erroneous calculations than the baseline. Over the three sessions in the (a) GestureCalc (b) Baseline study, participants were able to learn the GestureCalc gestures Figure 1. (a) Performing a three-fnger tap on GestureCalc our novel and effciently perform short calculations. From our interviews eyes-free app with target-free rich gestures, versus (b) typing “5” on after the second session, participants recognized the effort in ClassicCalc (a typical touch screen calculator), the baseline.
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