4.12 Default Gtk+ theme

[Simon Steinbeiß]

Dear all,

I'd quickly like to address the topic of our default Gtk+ theme for the 4.12 release. I have worked on a draft a year ago already [1], which relies on an enhanced Xfce engine for Gtk2 [2] and no engine (as in: relying only on Gtk3's CSS drawing capabilities) for Gtk3.8-3.12. However, even if we agree to ship this as the default theme, there are several open questions, mostly related to Gtk3, that I would like us to discuss.
Note: I'm not looking for user-feedback or opinions on the art and style of the theme! I need feedback from distributors and people with good knowledge of the goings-on in the Gtk3/Gnome world.

So, the first issue is that – as most of you will know – Gtk3 has developed a nasty habit of breaking themes with each major release. So themes targeted at Gtk3.6 break with Gtk3.8 and vice versa. However, this is not entirely true, as one can write themes that support Gtk3.8, 3.10 and potentially 3.12 that might throw warnings in the console (no way around that) but that visually work fine. With Gtk3.14 things went awry again though and I presume for Gtk3.16 we'll need more modifications again.
So if we want to avoid lots of complaints, bugreports or users storming the mailinglist, forum or irc, we probably have to decide what we want to support and make that very explicit.

I see the following scenarios:
1) We decide to support *one* Gtk3 release with the theme. (E.g. Gtk3.6-only, Gtk3.8-3.12, Gtk3.14-only)
2) We decide to support multiple Gtk3 releases and offer a compile-time switch to build the themes with the support needed.
3) We decide to not support Gtk3 with our theme, because Xfce core relies Gtk2 in 4.12.

Option 1) is already implemented for the proposed theme I linked to.
Obviously, option 2) is the most laborious and comprehensive. It provides distributors with a way to decide how to ship it.
Option 3) is also viable, given that many distributions ship with Gnome's Adwaita as default (e.g. Fedora afaik) and others have their own themes (e.g. Xubuntu).

So basically I want to know whether it's really worth the effort to go through the pains of option 2), whether you're fine with 1) or whether we should be even more drastic to avoid misunderstandings and go for 3).

Another important note: While all this applies to our new default theme, there are more themes around that some users appreciate (e.g. I've heard of some using Xfce-dusk) and I'm not entirely sure what to do about those. I can imagine adding engine-less Gtk3 support to maybe one more theme until release-time, but at least as long as I'm alone on this, that's about it.
(The issue of what to do about Gtk3 support in our engine should likely be discussed separately.)

So, thanks for your attention! (..and sorry writing such a behemoth email)
Cheers
Simon


[1] https://github.com/shimmerproject/Xfce-refresh
[2] http://git.xfce.org/xfce/gtk-xfce-engine/log/?h=peter/refresh