I've been running Neon for a few years now. Love it and rarely have any major issues. I can usually figure things out solo by rooting around. Recently though I upgraded to 5.19 and have a strange disparity between KDE system fonts and GTK fonts. I can't seem to find a place to globally change the GTK font size anymore, so fonts in Firefox and Eclipse are always larger than the KDE system fonts. How can I change this? I can't recall the exact details, but prior to 5.19, there was an area in System Settings >> Fonts where the GTK font size could be tweaked. I don't see these types of settings any longer. For a little while I was able to edit ~/.config/gtk-3.0/settings.ini by changing gtk-font-name but that doesn't work any longer. It's annoying little problem because GTK based programs take up more window real estate now.

Specs:
KDE Neon 5.19
User Edition
Plasma, 5.19.2
Framework: 5.71.0
QT: 5.14.2
Kernel: 5.3.0-59-generic

Anybody have this problem recently after upgrading to 5.19?

Same problem. Really, it is unuseabel. Fonts in GTK are much smaller.

On my machine, the fonts settings section disappeared in 5.19.8 on unstable and they are still on my 5.19.4 user edition so it's a bit confusing what's going on. I've looked at gitlab and the fonts app hasn't been changed in years so I was waiting for someone at KDE to say something. Maybe raise a bug report at bugs.kde.org ? It doesn't apply to me any more coz I only used it when Nvidia drivers reduced the font size but for some reason on Neon this doesn't happen.

Workaround is to stop the gtk services in KDE's control center, edit fontsize in the gtkrc2 and 3 files. Logout and Login. And it works. The question is how long this workaround will work.

But the stranged thing is:
I change the font size in the .gtkrc-2.0 file. I saved it, set it to rights 444 and passed ownership to the root user. After logging in again, the file belongs to me again and the content was changed. How can something like that work? Screams for a security breach.

I hope it's ok to join in as a Fedora user... Got the same problem here with Fedora 31, Fonts in GTK Apps are just too big and the option to set font size for GTK seperately was removed. I just use standard Breeze theme with Fedora default font cantarell and configured it size 8 for GTK and size 10 for QT in order to look just the same size.
Regarding this discussion https://www.reddit.com/r/kde/comments/f5culw/plasma_518_gtk_settings_disappeared/ on reddit this option was removed with intent to simplify font configuration. Simplifying user interfaces by removing available options, this somehow reminds me of some brand using fruits in their logo...
So when I get it right, the idea is that setting font size in the fonts option should do it for both QT and GTK and the fonts should be the same size afterwards? But it isn't in GTK it's much bigger.
So I also found some kind of workaround: I just downgraded "kde-gtk-config" to previous version and set the font sizes like they we're before, log out and in again and all looks fine. Also locked the version so it won't be updated with system updates. Maybe this is a temporary workaround for Neon users too, the package name could be slightly different. But at least it's just a matter of time, keeping just this one package on an old version will sooner or later lead to issues with future KDE updates.
So has someone found a way to scale down GTK fonts? Is there any chance that KDE developers will add this option again to settings, I don't mind if it will be moved to font settings or anywhere else? Or even to set it in some config file that won't be overwritten?

Anyone having that problem, can you try to enable "Force Font DPI" in the fonts settings page? I've set mine to 96.
You might have to restart Plasma (i.e. reboot or logout/in) before it will take effect.

I think I had that problem in the past, and this was what fixed it.

nyone having that problem, can you try to enable "Force Font DPI" in the fonts settings page?

Hmm, interessting....

Daphazard wrote:Anyone having that problem, can you try to enable "Force Font DPI" in the fonts settings page?

Tried this and it doesn't fix the problem for me, can't see any difference between enabled or disabled. Did a logout too and compared with screenshot to make sure. While trying I recognized that I was wrong and GTK font in size 8 actually looks a bit smaller than QT 10, so it wasn't the same size, which makes it look even bigger to me after the update. But at least GTK font is bigger than QT now, maybe just one point instead of two. I took a screenshots of old (kde-gtk-config-5.16.5-1 with QT 10pt and GTK 8pt) and new (kde-gtk-config-5.18.5-1 font set to 10pt) settings comparing firefox and falkon browser:

Old: https://ibb.co/wrQhfS8


New: https://ibb.co/M2yNH8C