Clutter

Clutter is a library for doing animations and using a 2.5-D canvas. You create graphical objects out of images, and you can manipulate them later to move them, rotate them, or give them quasi-3D effects.

Clutter uses the OpenGL and OpenGL|ES industry standard API to access the accelerated graphical hardware on both desktop and mobile environments alike, without exposing the complexities of GPU pipeline programming.

Clutter does not specify any visual style, and does not provide any pre-defined complex user interface control; it lets the developer define what is needed, using a flexible scene graph API, with free-form placement of the scene elements (or actors) on the main viewport (or stage).

Clutter comes with pre-defined actors for displaying solid colors, image data, text and custom high-precision 2D drawing using the Cairo API. Clutter also provides generic classes for structuring a user interface using both a box-packing model like GTK+, and a series of free-form constraints.

Clutter provides an extensible animation framework and graphical effects. An animation is associated with a timeline and changes one or more properties of one or more actors over time, for example their rotation in a particular dimension, scale, size, opacity, etc.

A number of third-party libraries allow integration with other technologies, such as: Clutter-GTK, for embedding a Clutter stage inside a GTK+ application; Clutter-GStreamer, for embedding GStreamer video and audio pipelines; Clutter-Box2D and Clutter-Bullet, for adding physics interaction in both 2D and 3D environments.