Command strokes with and without preview: Using pen gestures on keyboard for command selection

Abstract

This paper presents a new command selection method that provides an alternative to pull-down menus in pen-based mobile interfaces. Its primary advantage is the ability forusers to directly select commands from a very large set without the need to traverse menu hierarchies. The proposed method maps the character strings representing the commands onto continuous pen-traces on a stylus keyboard. The user enters a command by stroking part of its character string. We call this method "command strokes." We present the results of three experiments assessing the usefulness of the technique. The first experiment shows that command strokes are 1.6 times faster than the de-facto standard pull-down menus and that users find command strokes more fun to use. The second and third experiments investigate the effect of displaying a visual preview of the currently recognized command while the user is still articulating the command stroke. These experiments show that visual preview does not slow users down and leads to significantly lower error rates and shorter gestures when users enter new unpracticed commands. Copyright 2007 ACM.