Distros and Wayland
While it isn’t 100% sure if Ubuntu 13.04, Fedora 19 and Mageia 3 will use Wayland by default, it is the most likely scenario. And even if that doesn’t happen, you will still get the option to switch on it. For Arch, Gentoo, Debian derivatives from indie distributors, things will be totally up to them, as the parent distros already support Wayland.
Not all Tool-Kits run under Wayland. Some of them they will never be ported to Wayland (i.e GTK2 and others). So there will be a fallback/compatibility mode to XServer that will run on the top of Wayland.
I won’t expand to Wayland here. I set up a Wayland/Weston environment and I tested some GTK Apps on it, so I will write in detail about it on another post.
I talked with Lucas Baudin which he is a Libre Office developer that also works on LO GTK3 port. Lucas revealed some cool news that I was ignoring.
Libre Office will run on Wayland!
Libre Office in GTK3
The current state of GTK3 plugin in Libre Office is quite unstable. This is not critical at the moment as LO doesn’t depend on GTK anyway, and we don’t have a “working/usable” Wayland. I am optimistic that this situation will be much different in 6 months (on next Gnome release).
Libre Office Writer with GTK3 dark Theme
Libre Office SpreadSheet with GTK3 dark Theme
Libre Office Writer with GTK3 Light/Default Theme
As you can see from the above figures Libre Office with GTK3 is pretty much unusable at the time. However if you want to try it you need to install “libre-office-gtk3” package and set “SAL_USE_VCLPLUGIN” variable to “gtk3”.
Libre Office in GTK3 and Wayland
Lucas Baudin told us a few things about GTK and Libre Office:
LibreOffice doesn’t use GTK2, nor Qt directly. It uses a custom one called VCL. LibreOffice has some code to render the widgets using several toolkit (GTK2, Qt, Aqua). One of the major changes in GTK3 was the new rendering mechanism with the port to Cairo instead of GdkDrawable. So, for LibreOffice, this port changed everything, and most of the code to render VCL widgets had to be re-written.
This rewrite was the opportunity to do a lot of cleanup in the code, in order to be able to use more GTK3 functions than before, i.e. no X functions to do the windowing. This may bring a better integration to our desktops. But another feature is interesting: GTK3 has also a new backend  to render to HTML5 and WebSockets. This port will also bring a LibreOffice on line . This new GTK3 front end will also provide more cleanliness, GTK3 drawing mechanism is cleaner than the GTK2 ones.
And later I asked him about Wayland support.
HTML5 (broadway) backend is at the same level than Wayland. So, if LibreOffice can use broadway with GTK3 without any code change, it can also use the Wayland GTK backend (which is not finalized if I recall correctly).
However I didn’t find any RoadMap (LO GTK3 Git) about Libre Office and GTK3. By the way Broadway is that cool backend of GTK3 that we can run Apps directly from our Web-Browser. However you need to have a GTK3 build with Broadway enabled.
Libre Office is one of the most important Applications of Open Source. It runs everywhere, Windows, Mac, Linux and uses Standard Open Formats. It is also quite popular among Windows platform. It is great that LO will get- sooner or later- a full Gnome 3 support!
*Gimp GTK3 port is in a better state. We will try it later!