I prepared a public repository on GitHub with all the code of the crystal window decoration, from crystal-0.5 for KDE-3.2 to the current crystal-2.2.0 for KDE-4.9 beta.
Please feel free to contribute:
There are also ongoing discussions about integrating the crystal window decoration into the official KDE SC, moving all development into the offical KWin tree, next to the current default Oxygen deco.
Currently all major distributions ship optional binary crystal packages. If not, see the official crystal project page on kde-look.org.
I just added shadow support in Crystal-2.1.1 (for KDE 4.8) and Crystal-2.2.0 (for KDE 4.9), as well as some minor fixes. Since KDE 4.8 the window decoration itself is responsible for rendering shadows when compositing. Because Crystal uses an unstable kwin API to support tabbing, versions before 2.2.0 are unable to compile, which has the exact same features than 2.1.1.
The shadows aren’t the prettiest but better than none. Hopefully I’ll have time to do further improvements, refactoring, increased speed, stability and graphical improvements.
I hope to get a stable crystal release, which would blend in well with the rest of KDE SC.
Get crystal from the project page on kde-look.org or wait for your distribution to catch up: