PARAMETRIC FONT MODELS BASED ON FEATURES AND CONSTRAINTS

摘要

A new font model based on parameters, features and constraints is provided. The model supports complex non-linear dynamic behaviors of letter shapes and allows font users to dynamically alter the behavior of letters through the manipulation of external parameters. The letters retain their typographical characteristics during the dynamic behavior. The internal constraints mechanism supports constraint states for continuously handling topological changes. The constraints and features are present in the font model itself. The font model is implemented using parametric features and constraints. The constraints evaluation algorithm operates in linear time in the size of a glyph and guarantees finding a single solution. Constraints are represented using a special novel type of constraints graph, a mixed ratio graph, which can deal with most constraints cycles of the kind arising in the font domain. In addition, a novel constraint state machine enables modification of the shape's underlying topology during dynamic behavior.