Hmm, this means that when the user has customized the text size in their own user account, the text size will be different on the Login screen (which does not follow user settings) vs the lock and logout screens (which do). Looks like there's really no way around that unless we stay with sizes that are hardcoded in all three. Depends on which issue we want to have, I guess.

In D19547#425306, @ngraham wrote:

Hmm, this means that when the user has customized the text size in their own user account, the text size will be different on the Login screen (which does not follow user settings) vs the lock and logout screens (which do). Looks like there's really no way around that unless we stay with sizes that are hardcoded in all three. Depends on which issue we want to have, I guess.

Actually the problem's even worse than that - there's no GUI geared toward modifying the sddm user settings at present, so we can't set the fonts, font smoothing, scaling or font size on the login screen.
This might be an avenue worth pursuing?

In D19547#425306, @ngraham wrote:

Hmm, this means that when the user has customized the text size in their own user account, the text size will be different on the Login screen (which does not follow user settings) vs the lock and logout screens (which do). Looks like there's really no way around that unless we stay with sizes that are hardcoded in all three. Depends on which issue we want to have, I guess.

Our problem is really that the login screen doesn't respect the user's settings or at least can't be configured according to the admin user's liking. There's always going to be something off about SDDM unless the user uses KDE defaults. IMO the solution offered here is better than forcing people into having fontsizes they might not want to be seeing.