The package provides access to the Gtk, Gdk and Gnome libraries and widgets. Additionally, there are several other Gtk-related packages that provide additional or add-on widgets. See the http://www.omegahat.org/RGtk page for a list of available packages.
The bindings in this and other R Gtk-related packages are auto-generated using the RGtkBindingGenerator package. This generates both the S and C code that correspond to the Gtk types and routines.