Looks like you have 4 sizes to choose from, but no...

# tornadofx

[carlw]

Looks like you have 4 sizes to choose from, but none of them are 12, 30, or 40 so you'll probably end up with aliasing. The difference is probably platform-dependent in addition to the differences that you're seeing.

http://font.ubuntu.com/

Maybe use 16 if you need a Font right away?