5 of the Best Free Linux Screen Capture Tools The phrase "A picture is worth a thousand words" refers to the idea that a solitary still image can provide as much information as a large amount of descriptive text. Essentially, pictures convey information more effectively and efficiently than words can. (Read more) GTK+ GTK+ is a multi-platform toolkit for creating graphical user interfaces. Offering a complete set of widgets, GTK+ is suitable for projects ranging from small one-off projects to complete application suites. GTK+ is based on three libraries: GLib is the low-level core library that forms the basis of GTK+ and GNOME, Pango is a library for layout and rendering of text, with an emphasis on internationalization, and the ATK library provides a set of interfaces for accessibility.