gtk-doc contants should be prefixed by %, not # (types).
GDL planes can be double or triple buffered. Let the user choose between the two modes befored initalizing Clutter.
Intel CE3100 and CE4100 have several planes (framebuffers) and a hardware blender to blend the planes togeteher to produce the final image. clutter_cex100_set_plane() lets you configure which framebuffer clutter will use for its rendering.