InterViews is a native C++ toolkit for X Windows developed by Mark Linton and his team at Stanford University and later Silicon Graphics. The last major release was InterViews 3.1 in 1993, and included the Unidraw drawing editor application framework which was the basis of John Vlissides' thesis work at Stanford. InterViews also has lightweight glyphs with switchable look-and-feel (Apple monochrome, Motif, OpenLook, and SGI Motif). It has been ported to most any Unix which runs X11. Other programmers known to have worked on InterViews include Paul Calder, John Interrante, Steven Tang, and Scott Stanton. Later Mark Linton released an InterViews 3.2a with minor bug fixes and platform-specific changes. That is the source tree we started with for ivtools.
Several members of the InterViews team went on to work on Fresco, a separate package that borrows many ideas from InterViews and Unidraw (and has a shared lineage of source, so you could say it is one of the things with InterViews-inside). It unifies glyphs (i.e. menu/button/scrollbar) and graphics programming, and extends them with CORBA to support embeddability (i.e. plugins). Fujitsu Software Labs was a primary developer of Fresco up to the Fresco 96 tar file. Then maintenance/extension/porting was taken over by others on the net, notably Thomas Hiller in Germany who has put out a Fresco97 and a Fresco98 tar file (Fresco98 announcement) (a Fresco advocacy page). Alternate Fresco download site.
GE Corporate R&D created an add-on layer to Fresco called Parmesan. It is distributed as part of the IUE and Target Jr, two related environments for image understanding. It incorporates optimizations to the baseline Fresco mechanisms for raster display and 3d display, especially under Windows NT. It is the foundation on which the IUE/TargetJr vistool example program is built. It supports a multi-plane, multi-tile-window architecture with special optimizations for refresh of double-buffered graphics in front of a complex background graphic (i.e. an image). These extensions may or may not be incorporated into a future version of Fresco.