The Juno-2 Constraint-Based Drawing Editor

Abstract

Constraints are an important enabling technology for interactive graphics applications. However, today's constraint-based systems are plagued by several limitations, and constraints have yet to live up to their potential. Juno-2 is a constraint-based double-view drawing editor that addresses some of these limitations. Constraints in Juno-2 are declarative, and they can include non-linear functions and ordered pairs. Moreover, the Juno-2 solver is not limited to acyclic constraint systems. Juno-2 also includes a powerful extension language that allows users to define new constraints. The system demonstrates that fast constraint solving is possible with a highly extensible, fully declarative constraint language. The report describes what it is like to use Juno-2, outlines the methods that Juno-2 uses to solve constraints, and discusses its performance. Perspective Computers now handle the words in the documents that we write, and that is good: Revising, indexing, and formatting are lots...