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Arnaud Fontaine, 02/11/2010 01:31 PM

A compositing manager is a piece of software running along with the window manager and where each graphical program outputs into a separate and independent off-screen buffer that can be manipulated before being shown in order to enhance user experience. Unlike a compositing window manager, a compositing manager does not manage windows but simply implements visual effects such as windows translucency, drop shadows, fading...


Unagi is a modular compositing manager which aims to be efficient, lightweight and responsive. It is currently written in C programming language and based on XCB library client library. Any existing window manager can be used as long as it implements properly EWMH and ICCCM specifications (or at least parts of it which are necessary), which is generally the case nowadays.

This project also aims to provide a functional and stable software to improve window manager usability from an end-user point of view (for instance windows translucency, application-switcher using live thumbnails instead of plain icons, Exposé), therefore it does not intend at all to provide useless eye-candy effects.

Unagi relies on a modular architecture as the code is split up in three parts: core code, rendering backends (only one backend relying on Render X extension has been implemented so far) and effect plugins. Thus, it provides a small and fast compositing manager from a codebase and footprint point of view, besides allowing to easily write other rendering backend which would work better on certain hardware. It also tries to take advantage of the asynchronous XCB model to be able to be used through a network.


Further information can be found in the source:INSTALL and source:README files.

Git repository

The Git repository is available there. You can clone the repository by running the folllowing command:

$ git clone git://


  • Core code, rendering and visual effects seem stable
  • One rendering backend, based on Render X extension) has been implemented so far
  • Two plugins have been implemented, namely Opacity and Exposé


  • Early stage of development
  • Tested almost only with Awesome Window Manager
  • Performance issues which will be addressed in the next release though


If you wish to contribute, you can find further information in Master thesis: Writing an X compositing manager and general information about XCB in Bachelor thesis: Porting a window manager from Xlib to XCB. You can also have a look at the documentation generated from the source code available there.


Here are some screenshots of Unagi running with Awesome Window Manager.

Opacity plugin

Unagi with opacity plugin enabled

Expose plugin

Expose plugin before being enabled

Unagi before Expose is enabled

Expose plugin when enabled

Unagi with Expose is enabled

Updated by Arnaud Fontaine over 14 years ago · 14 revisions