Font appears differently between build environments, why?

[alexeyabel]

I am compiling the same Slint application in two different environments and some of the text in the UI looks slightly different. I tried to replicate the environment perfectly with all dependencies but the font remains different. Can you suggest a way to debug this further and understand the cause of the difference?

Below is part of the UI. On the left (1) is the version from my development environment, on the right (2) is the other build where the text looks different. It seems to be narrower and less antialiased. I copied the text from the right to the left (in magenta circle) and you can see that its narrower than the "original".

The entire code is available here and the slint-UI specifically. I am on NixOS, using KDE Plasma 6.2.5 and Qt 6.8.3. Both environments are on the same account and computer. I also compiled the application on a different machine on Ubuntu 24.04 and it looks different (like 2), too. So it must be something in my development environment that makes the font appear better. This is how I would like it to appear everywhere.

[tronical]

For us to isolate where the problem is, could you try running this with the SLINT_DEBUG_PERFORMANCE="console,refresh_lazy" environment variable set and paste the first line of output here? It shows the selected Slint backend, which may help us identify the code path responsible. Thanks :)