CSS implementation for whoever wants it!
Jakub Steiner designed and uploaded (yesterday) some new spinners for GTK+ and Adwaita 3.14 release.
provide a consistent spinner
We are now able to do rotation animation and we can unify the various spinner animations across the various components based on a simple design:
The hicolor theme has a frame based animation (process-working), the cursor theme includes a similar design. Gtk itself uses a different design using CSS animation.
Jakub Steiner #730191
Of course the new Spinners will be in every GTK App, as long as you have the default Adwaita Theme!