SRC Research Report 131a
SRC Research Report 131aConstraints 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.
A videotape (131b) accompanies Report 131a:
Computers now handle the words in the documents that we write, and that is good: Revising, indexing, and formatting are lots easier, while hyperlinks have opened up shining vistas. Computers also handle the illustrations in our documents, but the news on that front is not so good. Producing accurate drawings is still a tedious task in many cases, revising them later is worse, and animations are not taking off as fast as hypertext. Even if we grant that a picture is worth a thousand words to the reader, why is its cost to the writer more like ten thousand?
If computers are ever to help illustrators as effectively as they help authors, some new ideas will be required. Juno-2 is a drawing editor that explores an intriguing collection of ideas about two-view editing, constraint-solving, and extension languages. This brief report gives some early indications of the strengths and weaknesses of those ideas. (Lyle Ramshaw)
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