Overview of GTK and its Libraries
Over time GTK has been built up to be based on various libraries, also developed by the GTK team.
GLib is a low-level core library that forms the basis of GTK. It provides data structure handling for C, portability wrappers and interfaces for such run-time functionality as an event loop, threads, dynamic loading and an object system.
Pango is a library for layout and rendering of text with an emphasis on internationalization. It forms the core of text and font handling for GTK.
Cairo is a library for 2D graphics with support for multiple output devices (including the X Window System, Win32) while producing a consistent output on all media while taking advantage of display hardware acceleration when available.
GdkPixbuf is a library for loading graphical assets like icons in various formats, like PNG, JPEG, and GIF.
ATK is a library for a set of interfaces providing accessibility. By supporting the ATK interfaces, an application or toolkit can be used with tools such as screen readers, magnifiers, and alternative input devices.