SDPGTK wraps GTK using simple, clean C++ classes and a straightforward hierarchy. It integrates well with existing GTK code, and, unlike existing wrappers for GTK, does not force the developer into a UI "framework". Of particular interest is the sdpGtkObjectContainer class, which implements the proposed GTKML standard, for loading a GTK hierarchy and events from an XML document.
GTKExtra is a useful set of widgets for creating GUIs for the X Window System using GTK+. It is written in C and includes the following widgets: GtkSheet, GtkPlot, GtkPlotCanvas, GtkItemEntry, GtkComboBox, GtkColorCombo, GtkBorderCombo, GtkFontCombo, GtkDirTree, GtkIconList, GtkFileList, GtkIconFileSelection, and GtkCheckItem.
DiaCanvas is a generalized version of the drawing canvas used by DIA. It extends some features used by DIA and adds new ones, while preserving as many of the original features as possible. This project is no longer actively maintained. It is suggested that you try DiaCanvas2 instead.
The Texttools packages are an ncurses-based library for the Linux console written in Ada 95. It contains more than 600 procedures and functions to create windows, draw scroll bars, handle the mouse and keyboard events, play sounds, and much more. It also provides a thick binding to Linux kernel calls. You can create a wide variety of application programs using Texttools alone.
Fl_Editor is a word-wrapping text editor widget for the FLTK toolkit. It supports CUA-style editing keys, automatic scrollbar display, load and save to file or buffer, and more. Fl_Editor includes subclasses with status and position display, find and replace, a couple of utility widgets, a status panel and a progress bar that can be used independent of any of the editors.