Addendum: Changes to Garnet Since November, 1990

Publisher Summary This chapter discusses changes to Garnet Toolkit project since November, 1990. There have been a number of improvements to the constraint system. In particular, it was discovered that an important problem was the space overhead of constraints, but that up to 95% of the constraints were evaluated only once at object creation time. Therefore, a unique mechanism was added that eliminates the constraints that only depend on constant values. The Opal object system has been enhanced with objects to support multiple-font, multiple-line text editing, including embedding arbitrary graphical objects in the string, and a special mode to support Lisp code editing. This new object removes the restriction that Garnet not be used for applications with significant text components. To make Garnet practical for use for maps and visualizations with thousands of graphical objects, a special feature was added to eliminate most of the per-object overhead when there are lots of similar objects.