Emerald

A compositing window manager like Compiz does not draw its own decorations. A separate process does, delivering the frames as images so they can have transparency and shadows. Compiz had gtk-window-decorator, which mimicked the current GTK theme, and kde-window-decorator. When Quinn Storm's branch became Beryl in the autumn of 2006 it brought its own decorator, Emerald, which read its own themes instead: a .emerald file was an archive holding an ini file and images, and a handful of engines, legacy, pixmap, truglass and vrunner, decided whether the title bar was drawn from gradients, from bitmaps or as glass. emerald-theme-manager let users fiddle with every colour and shadow, and gnome-look filled up with themes sporting reflections and six-pixel drop shadows.

The decorations were what made Beryl so recognisable in 2006–2007, and when the projects merged into Compiz Fusion, Emerald was kept as an optional decorator. Maintenance faded along with Compiz itself; the decoration interface changed in the 0.9 series and Emerald lagged behind. Today it is maintained by Compiz Reloaded, the group keeping the 0.8 branch alive, complete with a theme collection from an era when the Linux desktop was happy to look like a bottle of Bombay Sapphire.