GIGA: a pen-based constraint drawing system

Traditional sketching/drawing tools on computers lacked the freedom of real pens. They also ignore human perception. In order to avoid such limitation, we developed new techniques such as interactive beautification with extended pie-menu (PieSlider), sketch with perceptual recognition (PerSketch), the function of layout according to human perception (PerLayout), and new data structure for PerSketch. Prototype implementation on IBM pen PC and Xerox Liveboard has shown that the system is fast and easy to use.