Cutter: Check default font

[xarkes]

Monospace is not a valid font for stock Mac.
Use "Andale Mono" for Mac, or Courier or maybe use the ones that were bundled with iaito before.
Or just use QFontDatabase::systemFont(QFontDatabase::FixedFont) if it works

[xarkes]

Also we must have at most 1 or 2 fonts (one for disasm one for UI), and that they are all synchronized (size and font face)

[thestr4ng3r]

I would not change the normal UI font at all, that should be defined by the system.

[xarkes]

Ok then we have to sync the disassembly font for Hex/Graph/Disas and use the system font for any other thing.

[thestr4ng3r]

Using QFontDatabase::systemFont(QFontDatabase::FixedFont) since https://github.com/radareorg/cutter/commit/79c57929be20f6e1db51d46ce233a513378f87c8.
I tested on Linux Mint (Cinnamon), macOS and Windows 10 and get a nice monospace font on each of them.