Something needs to be done about Qt themes (Kvantum?)

[moloch1994]

The state of theming is dire in the Linux world in 2026. When I first began using Linux, all you had to care about was GTK2, GTK3 and Qt5. Now also Qt6 and GTK4/LibAdwaita (which is a major pain in the behind) have been added. Theming something across 5 toolkits is a lot of work, not to mention it's near-impossible to find a theme that supports all 5 toolkits.

For as limiting as LibAdwaita is, I'm happy that at least there's an automatic recoloring solution that the Mint team implemented, so there's at least SOME consistency. But Qt apps now launch with Fusion, which, being skeuomorphic, clashes wildly with Mint's flat theme. Selecting Mint-X would in turn make the flat LibAdwaita clash skeuomorphic Mint-X and Qt's Fusion. There's no winning.

In the past versions of Linux Mint you had qt5ct set up with murrine engines and gtk2 style plugin. That was until Qt6 came out and Mint stopped shipping qt5ct with murrine engines. You could still install it manually, and then get and build qt6gtk2 by grabbing it off a GitHub page. Not the best solution.

In LMDE7 (and I suspect all future releases), gtk2 style plugin for Qt5 applications is no longer even in the repositories. I assume because it's outdated and unmaintained.

To my knowledge, the only other way to theme Qt apps is Kvantum. I was able to find an unmaintaned Mint-Y Kvantum theme from 2023 (meaning its colors are a little different). Also ChatGPT gave me a script to make Kvantum automatically switch to the dark theme when I switch my GTK3 theme to dark. You do need to relaunch Qt apps for the theme to apply though. It's not perfect, but I think it's still better than having Fusion as the theme.

I'm not a developer, and I don't know what can be done here other than having Mint come with Kvantum and an officially maintained Kvantum theme, as well as a script that would detect the dark mode, like the one I'm using. I'm hoping there is a better solution, but I would prefer that at least there's SOME solution in the future releases. Theming has become a stressful, time-consuming endeavor, and I'm hoping that distro maintainers can come through and save the day somehow.

At the very least I think a discussion should be held about this.