I've been trying to style my Qt apps since I discovered the old Motif-look Style Plugin still exists; maybe I can have software not made in 1994 that looks like it was!
In the process, I noticed an odd behaviour.
I set up QT_QPA_PLATFORMTHEME=qt5ct so I could use qt5ct to do the basic configuration.
If I set the "general" font as bold, and the "fixed width" value as non-bold, when I reload qt5ct, it's switched to bold. This can also be seen in other Qt programs.
If I manually force the issue by editing qt5ct.conf, manually setting up a block like this, the bold fixed-width font still shows
[Fonts]
fixed="Go Mono,11,-1,5,75,0,0,0,0,0,Regular"
general="Helvetica,11,-1,5,75,0,0,0,0,0,Bold"
I thought this might be some weirdness due to the specific fonts I chose, but swapping in "Liberation Sans" and "Courier 10 Pitch" produce the same situation.
The only way I can have my fixed-width font be "regular" is to also leave the general font as "regular". This is not a connection I expected.
Is this a known issue? Is there a workaround?
Followup in the spirit of documenting it for someone else: If you modify the fonts in qt5ct.conf, removing the last option, for some reason it does exactly what I want: looking at notepadqq, I get a bold menu, but non-bold body text.
[Fonts]
fixed="Go Mono,11,-1,5,50,1,0,0,0,0,0"
general="Helvetica,11,-1,5,75,0,0,0,0,0"
It seems like removing the last paramater treats the specification as less prescriptive-- places in the UI that call for bold get it, and non-bold gets it. This is evident in the Double Commander Qt package, where some parts of the UI are bold and others aren't.