XForms is a GUI toolkit based on Xlib. It comes with a rich set of objects such as buttons, browsers, sliders, and menus integrated into an elegant event/object callback execution model that allows for fast and easy construction of X applications. In addition, the library supports loading and writing images, format conversion, and simple image processing. It consists of a flexible set of C-routines that can be used in C and C++ programs, is efficient and portable, and runs on all major Unix platforms and OpenVMS, OS/2, and Windows NT.
Papyrus is a 2D C++ scenegraph (canvas) library that utilizes the cairo library to perform drawing operations. Similar canvas libraries are the Gnome Canvas, Diacanvas, and the QT Canvas. Numerous canvas primitives are available, including arcs, rectangles, polylines, and line markers. An optional companion library, Papyrusmm, provides a set of Gtkmm widgets which includes viewports (a canvas display widget similar to Gtk::DrawingArea) and other UI widgets related to drawing interfaces.
Sigma Grid is an AJAX-based data grid for displaying data and editing it inline in a scrollable and sortable table. It supports IE 6.0+, FireFox 2.0+, Safari 3.0+, and Opera9.0+. It seamlessly integrates with any server side solution, such as J2EE, .NET, PHP, or Perl. It features keyboard data navigation, nested multiline headers, and sortable and frozen columns. Slice rendering and built-in paginated output allow you to manipulate huge datasets.
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.
conexus is a generalized C++ I/O library that includes network support for IPv4 and IPv6 sockets, serial/TTY communications, kernel message queues, pipes, and files. Objects use sigc++ for signaling property changes and other information. Sub-libraries include conexus-gtkmm (provides a set of gtkmm widgets), conexus-dbus (provides dbus support for endpoints), conexus-nspr (provides NSPR endpoints), conexus-nss (provides NSS endpoints), and conexus-ssl (provides OpenSSL endpoints).