Using Grammar-based Recognizers for Symbol Completion in Diagrammatic Sketches

Sketching is considered as a way to naturally express ideas during the early phases of design. For this reason, many efforts have been made to develop user interfaces and recognizers, which enable users to create sketches using pen-based devices. However, in some domains, such as in architectural and engineering fields, the drawing process turns out to be particularly tedious and time-consuming, since the symbols to be drawn may have a complex shape and recur many times in the sketches. In this paper we present a technique for symbol completion that allows users to rapidly draw diagrammatic sketches. The completion technique recovers the information on missing strokes by interacting with symbol recognizers, which are automatically generated from grammar specifications. Moreover, in order to maintain the sketch layout more familiar to the users, the added strokes are drawn according to the user drawing style.