GNOME

From the web site[1 ]:

The GNOME project has built a complete, free and easy-to-use desktop environment for the user, as well as a powerful application framework for the software developer. GNOME is part of the GNU project, and is free software (sometimes referred to as open source software). It is included in almost every BSD and GNU/Linux distribution and works on many other UNIX systems.

Uses GTK toolkit

Use gnocl ! A Tcl extension (package) that implements gtk+/gnome, not to be a direct mapping from gtk 2.0, but to provide easy-to-use commands to build quickly gnome-compliant user interfaces (including canvas widget).