Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

Jazztache · 2023-07-08 03:29:43

[Full Title]: Qt + KDE + Arch: Broken Breeze System Theming On OBS/PrismLauncher/qBitTorrent
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Hello!

I am using KDE Plasma (`plasma-workspace 5.27.6-2`) on Arch Linux (`linux 6.4.1.arch2-1`). On various different Qt apps, the system theme reverts to a user-colour version of the default Qt theme.

I looked at some of the optional dependencies for the offending apps and none of them seem to have any pertaining to KDE Plasma or the Breeze Qt theme.

After doing some looking around I am at a loss, and I do not know how to fix this. At one point I tried KVantum but I found that too hacky and it didn't really resolve the actual underlying issue.

I also read https://wiki.archlinux.org/title/Qt, and checked my 'breeze' Qt package was installed *just to make absolute sure*. I'm on `breeze 5.27.6-1`.

If I had to take a wild guess, I recon it's still some kind of file linking issue where generic Qt apps cannot read the custom Breeze theme and revert to using the default Qt one, but the colours are correctly referenced.

Attached below are 3 screenshots, one from each piece of software. I'm sure there's more but these are the main ones.

If anyone could give me any pointers on debugging this I would be very grateful, as this is one of those really annoying issues that has persisted through multiple Arch updates.

Thankyou!
-Jazz

The screenshots are on this pixelfed post: https://pixelfed.social/i/web/post/583133944754624852

kokoko3k · 2023-07-08 04:08:02

I know qBittorrent uses Qt 6; has Breeze been ported to Qt 6?

Jazztache · 2023-07-08 11:17:03

Well... Looks like I am waiting until Plasma 6 releases. ;-;

PrismLauncher
https://github.com/PrismLauncher/PrismL … issues/991
https://prismlauncher.org/wiki/developm … tructions/

qBitTorrent
https://www.reddit.com/r/kde/comments/r … e_and_qt6/
https://www.mail-archive.com/kde-bugs-d … 41843.html

OBS
https://news.itsfoss.com/obs-studio-28-release/

Qt
https://news.ycombinator.com/item?id=30800108

ALL of these mention Qt 6. The ycombinator article also talks about there being no Breeze theme in Qt6. Very sadge.
I think this is also why KeePassXC doesn't have this issue... nothing listed in the deps for Qt6. https://archlinux.org/packages/extra/x86_64/keepassxc/

Is there any way I can install the Plasma 6 Beta version of Breeze early on 5.27? I might actually try the P6 beta. No use backporting when this will solve itself in a few months.

Last edited by Jazztache (2023-07-08 11:19:03)

arojas · 2023-07-08 13:00:02

There is no Plasma 6 beta yet

Jazztache · 2023-07-09 08:09:20

There is a beta for Plasma 6. It's part of KDE Neon Unstable. You can also compile Plasma 6 directly from source, but from what I have learned it's non trivial.

https://files.kde.org/neon/images/testi … 4-0253.iso

For anyone else who has this issue: here are some options.

1. Wait until Plasma 6 releases, then there will be a Qt6 port of Breeze. KDE Frameworks 6 (a dep for most newer KDE/Kirigami apps) and any of the other new KDE + Qt6 stuff will inevitably be there when Plasma 6 releases
2. Try out the Plasma 6 beta through KDE Neon Unstable Edition, and see if they work. This is less recommended unless you want to be a beta tester.
3. Downgrade the offending apps to versions that use Qt6 to the respective versions that use Qt5. This is likely a little bit buggy.

Once I fix my Virtual Machine I'll be able to try it out

arojas · 2023-07-09 08:41:43

Jazztache wrote:

There is a beta for Plasma 6.

No, there is no beta for Plasma 6. A git snapshot is not a beta.

Jazztache · 2023-07-09 23:43:21

Semantics aside, there is a way to get Plasma 6 early, but it's unstable.

Once I fix up my VMs, I'll try out Neon Unstable and see if the issue is resolved. Thankyou for the heads up kokoko3k

kokoko3k · 2023-07-10 03:47:22

Maybe there are updated qt5 versions of those apps in the aur.
qBittorrent-qt5 and prismlauncher-qt5 seem available.

Last edited by kokoko3k (2023-07-10 03:49:28)

Jazztache · 2023-07-10 07:05:22

A bunch of other Qt6 apps are also having this issue, such as OBS but also (sorry forgot to mention) Dolphin Emulator as well.

I don't think there are up-to-date Qt5 rebuilds of these apps with all of the new features in place. Might check out the qt5 versions of PrismLauncher and qBitTorrent later on, thankyou for suggesting that.

If anything the knowledge that Qt6 is getting a Breeze theme is enough for me to wait, and it's a good excuse to try out the Plasma 6 beta and report back if that solution works as of now. I'll post some screenshots and tell ya how it goes

Jazztache · 2024-03-08 07:01:30

Hello.
Sorry for necro-ing, but I have some bad yet relevant news.

With the release of Plasma 6, this issue is still prevalent. Nothing was fixed in the jump to P6. I tested this on OBS and the Fusion theme is still in use. I am using Breeze.
I was under the impression this issue would be fixed on the release of Plasma 6, and I cannot make sense of this. I just updated an hour ago.

For sanity, I checked the package.
`breeze 6.0.1-3`
Why would it be broken if it's on Breeze 6?

I searched up the issue, and the second result was my own thread (this one). The first one was KDE Docs on porting apps to KF6.
Any help would be appreciated.

V1del · 2024-03-08 10:00:25

What's your

printenv | grep QT

?

Jazztache · 2024-03-08 22:41:04

QT_AUTO_SCREEN_SCALE_FACTOR=0
QT_SCREEN_SCALE_FACTORS=DP-0=1;DP-1=1;DP-2=1;DP-3=1;HDMI-0=1;DP-4=1;DP-5=1;None-1-1=1;
QT_QPA_PLATFORMTHEME=qt5ct

Aha! 'qt5ct'. Alright then, what should I set it to? Plasma has changed a lot under the hood, so it might just be 'qt6ct'.
Any documentation would be appreciated. Thanks again!

arojas · 2024-03-08 23:00:50

Jazztache wrote:

QT_AUTO_SCREEN_SCALE_FACTOR=0
QT_SCREEN_SCALE_FACTORS=DP-0=1;DP-1=1;DP-2=1;DP-3=1;HDMI-0=1;DP-4=1;DP-5=1;None-1-1=1;
QT_QPA_PLATFORMTHEME=qt5ct
Aha! 'qt5ct'. Alright then, what should I set it to? Plasma has changed a lot under the hood, so it might just be 'qt6ct'.
Any documentation would be appreciated. Thanks again!

You should *not* set it at all

Jazztache · 2024-03-08 23:36:57

Cool. Thankyou for the warning. I'll keep it as is.

Are there tools that will correct this? It seems like this value was supposed to update but didn't update for Plasma 6.
Also to note: My KeePassXC theme has also reverted to Fusion. This might be related.

Arch Linux

#1 2023-07-08 03:29:43

Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#2 2023-07-08 04:08:02

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#3 2023-07-08 11:17:03

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#4 2023-07-08 13:00:02

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#5 2023-07-09 08:09:20

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#6 2023-07-09 08:41:43

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#7 2023-07-09 23:43:21

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#8 2023-07-10 03:47:22

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#9 2023-07-10 07:05:22

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#10 2024-03-08 07:01:30

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#11 2024-03-08 10:00:25

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#12 2024-03-08 22:41:04

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#13 2024-03-08 23:00:50

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

#14 2024-03-08 23:36:57

Re: Qt + KDE: Broken Breeze System Theme On OBS/PrismLauncher/qBitTorrent

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