For the past few month, Ruslan Kabatsayev, Cédric Bellegarde and I have been working on writing (yet another) Gtk port of KDE's oxygen widget style.
Unlike previous attempts we decided to:
* start a new gtk-engine from scratch (as opposed to re-using an existing one). All painting is performed using Cairo; there is no hidden interfacing to Qt, nor hard-coded pixmaps.
stick as close as possible to KDE's and oxygen's options. Amongst other things, the engine loads kde palette, icons, and fonts; it respects the color contrast setting, and a number of oxygen's display options (such as the tab style, the list's expander style, the scrollbar width, etc.)
* try implement at least some of the fancy features of KDE's Oxygen style. Amongst other things, we added mouse-over effects on almost all widgets; support for ARGB colormap (in order to have nice non-pixelated corners for menus, combo boxes or tooltips), and full support for grabbing windows from empty areas (a feature that is in KDE's Oxygen since KDE SC 4.5). We also have plans for adding a large number of the animations found in KDE's Oxygen style, but that will be for the next release.
The primary goal of this port is to improve significantly the integration of Gtk/Gnome applications in KDE. However, we also aim to provide Oxygen as a modern, professional and polished theme for other desktop environments, that works seamlessly without having KDE even installed.