Widget and windeco themes for Plasma Next

[David Edmundson]

> - The Oxygen QtQuickControls style in its current condition (at least from
> any Plasma Next screenshots and videos I've seen) looks unpolished as hell.
> Labels in buttons aren't aligned correctly and there are other problems as
> well. If we ship Plasma Next like this, everything looks beautiful... until
> someone opens a GUI which was made with QML/QtQuickControls (which is all of
> Plasma's own GUIs iirc). As soon as people do, what they get looks like a
> crappy version of Plasma Current (aka "KDE 4").
> I don't think we want this. So if we want to at least be visually on par
> with current Plasma, additional work would have to go into the Oxygen
> QtQuickControls style (and according to David, a bug in Qt would have to be
> fixed)

That particular bug in Qt has been fixed (by me) and is now merged.
I'm not sure in which version of Qt though.

> - If we get the QtQuickControls theme to look exactly like Oxygen QtWidgets,
> Plasma Next will look at least as good as Plasma Current (presumably
> slightly better for various reasons I don't need to repeat here), but it
> doesn't really look "new".
> - The "flatness" of Breeze doesn't really fit the "3D-ness" of Oxygen.
>
> So what options do we have?
> According to Martin Gräßlin, wie should not ship an Aurorae theme as default
> window decoration due to performance reasons.
> What about a QML-based one? Would that be better, or does it absolutely have
> to be C++?
>
> Would a QtCurve preset instead of a C++ widget theme work at least as an
> interim solution, or would that cause too many problems?

I've been running the QtCurve preset on both Qt4 and Qt5 for a while.
It looks pretty good, even with the oxygen window deco. Performance
'feels' at least as good as Oxygen. Maybe someone can do some
benchmarks (Alex ;) )

To me whether we switch theme is more a matter of whether we want to
be conservative with the UI or all out exciting; there's sides to
both, but no technical ones.

The only problem I see is that we'd have to change the ~/.kde4 config
so once they load plasma 2, if they then go back to plasma1 their apps
would look different till the user changed it back.


> Would it be okay to ship the new QtQuickControls style for QML-based GUIs,
> but Oxygen for QtWidgets-based ones?

That would be a /really/ bad idea. We don't want the user to have to
care which tech happened to be used when we developed something.  The
kwin KCMs or Muon Discover would look /really/ broken as they are
hybrid.