Use a single toolkit for all the standard widgets in your application
Create fast, visually rich graphical interfaces
Have high quality, antialiased and resolution-independent graphics
Easily add web functionality to your application
Access built-in assistive technologies
Use the powerful foundations of the GNOME platform to create consistent and flexible user interfaces. Make your applications available to the widest audience by deploying them to other platforms. Standard UI elements are accessible by default, and it is easy to add accessibility support to any custom UI elements that you create.
For applications with standard controls which would be familiar to most users, use GTK+. Every application that is part of GNOME uses GTK+, so use it to be consistent, and to access the many widgets and features such as printing support and CSS theming.
Animations, effects and fluid layouts are easy with Clutter, and it also supports touch input and gestures.
High quality, antialiased and resolution-independent 2D graphics are provided by Cairo. Cairo is used for drawing widgets in GTK+, and can also be used to output to PDF and SVG.
WebKitGTK+ makes it easy to add web functionality to your application, whether that is rendering an HTML file or having a complete HTML5 UI.
GTK+, Clutter and WebKitGTK+ have built-in support for assistive technologies with ATK. Use Orca, Caribou OSK, and the GTK+ built-in accessibility tools, or build custom tools on top of ATK.
You can see lots of real-world applications of GNOME UI technologies in open source projects, like the examples given below.
Web is the GNOME browser, which uses GTK+ and WebKitGTK+, and is fully accessible.
( Website | Source code )
MonoDevelop is a cross-platform IDE designed for C# and other .NET languages. It works on Linux, Mac OS X and Windows
( Website | Screenshots | Source code )
Videos is the GNOME multimedia player, and uses Clutter to display video content.
( Website | Source code )