WIP: Add support for Plasma 6

[swomf]

These should be non-breaking changes designed to port this theme for plasma6.

In general, my changes were simply using desktoptojson, some manual .json tweaks, and changing the decoration.svg aurorae boxes in Inkscape to correctly render window border outlines.

Addresses #23.

---

Flaws

1. The default "Graphite" theme does not work under these changes. Use Graphite-dark or Graphite-light or their respective nord variants.

2. The SDDM theme does not work. I chose to exclude fixing it, because it is a breaking change. Perhaps this can be resolved by adding a plasma6 version of each sddm theme, as well as a separate option in SDDM's install.sh.

EDIT: I have started work on porting the SDDM theme, see below

[swomf]

Try this PR out for yourself!

git clone https://github.com/vinceliuice/Graphite-kde-theme
cd Graphite-kde-theme
# Fetch pull request as branch
git fetch origin pull/24/head
git checkout -b pull-request-24 FETCH_HEAD

[swomf]

Update: I made a preliminary fix for the SDDM theme by comparing import statements and objects to /usr/share/sddm/themes/breeze.

Flaws

Wrong size

Original: reference

Fix:

You can test and debug via sddm-greeter-qt6 --test-mode --theme sddm/Graphite-nord-plasma6.

[irv]

Using plasma 6.1, installing your branch kept falling back to the default, even though --test-mode worked fine.

Took me a while to track down why it kept trying to load it through the (now non-existent) sddm-greeter rather than sddm-greeter-qt6, but the sddm repo does explain

Themes are run by a Qt 5 built sddm-greeter, unless the QtVersion property in metadata.desktop specifies a different version, such as QtVersion=6 for using sddm-greeter-qt6.

--- a/sddm/Graphite-nord-plasma6/metadata.desktop
+++ b/sddm/Graphite-nord-plasma6/metadata.desktop
@@ -5,7 +5,7 @@ Author=Vince Liuice
 Copyright=(c) 2019, Vince Liuice
 License=CC-BY-SA
 Type=sddm-theme
-Version=0.1.0
+Version=0.2.0
 Website=https://github.com/vinceliuice/Graphite-kde-theme
 Screenshot=preview.png
 MainScript=Main.qml
@@ -14,3 +14,4 @@ TranslationsDirectory=translations
 Email=vinceliuice@hotmail.com
 Theme-Id=Graphite-nord
 Theme-API=2.0
+QtVersion=6

I have to say, the docs aren't great! https://develop.kde.org/docs/plasma/theme/theme-porting-to-plasma6/ seems very incomplete, and when it gets to SDDM it just says consult their docs (which don't seem to exist!)

[Rerum02]

Is their any update on getting this merged soon @swomf? Love the project, one of the best themes.