Drawing on the Back of an Envelope: a framework for interacting with application programs by freehand drawing

The Back of an Envelope project demonstrates how a calligraphic interface ( one that employs a pen or stylus to input freehand drawing marks) can be us ed in a wide variety of domains, from databases to simulation programs, to 3D modeling, from mostly symbolic diagrams to freeform sketches. The wide v ariety of drawing types and domains calls for a diverse range of approaches . We describe some of the functionality of our systems, including contextua l recognition of symbols and configurations and emergent shape recognition, and some of the calligraphic interfaces we've built. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.