Increasing the expressive power of gesture-based interaction on mobile devices. (Augmenter le pouvoir d'expression de l'interaction gestuelle sur les appareils mobiles)

Current mobile interfaces let users directly manipulate the objects displayed on the screen with simple stroke gestures, e.g. tap on soft buttons or menus or pinch to zoom. To access a larger command space, the users are often forced to go through long steps, making the interaction cumbersome and inefficient. More complex gestures offer a powerful way to access information quickly and to perform a command more efficiently [5]. However, they are more difficult to learn and control. Gesture typing [78] is an interesting alternative to input text: it lets users draw a gesture on soft keyboards to enter text, from the first until the final letter in a word. In this thesis, I increase the expressive power of mobile interaction by leveraging the gesture’s shape and dynamics and the screen space to produce rich output, to invoke commands, and to facilitate appropriation in different contexts of use. I design "Expressive Keyboard" that transforms the gesture variations into rich output, and demonstrate several applications in the context of textbased communication. As well, I propose "CommandBoard", a gesture keyboard that lets users efficiently select commands from a large command space while supporting the transition from novices to experts. I demonstrate different applications of "CommandBoard", each offers users a choice, based on their cognitive and motor skills, as well as the size and organization of the current command set. Altogether, these techniques give users more expressive power by leveraging human’s motor control and cognitive ability to learn, to control, and to appropriate.