An Object-Oriented Architecture for Constraint-Based Graphical Editing

Direct-manipulation graphics editors are useful tools for a wide variety of domains such as technical drawing, computer-aided design, application building, and music composition. Constraints can be a powerful mechanism for specifying complex semantics declaratively in these domains. To date, few domain-specific graphics editors have provided constraint-based specification and manipulation facilities. Part of the reason is that graphical editors are hard enough to develop without implementing a constraint system as well. Even though graphical editing frameworks can reduce the difficulty of constructing domain specific graphical editors, a fundamental problem remains: there do not exist general constraint solving architectures that are efficient enough to support highly interactive editing, yet suitably flexible and extensible to adapt to different editing domains.