A study on default font in emacs on macos

An unconfigured Emacs on an unconfigured MacOS will use this font:

--Menlo-regular-normal-normal--12---*-m-0-iso10646-1

Why?

The x-create-frame emacs lisp function will use the userFixedPitchFontOfSize case to identify the default monospace font.

This is defined in the nsfns.m file.

  int main(int argc, const char * argv[]) {
    @autoreleasepool {
      CTFontRef name = CTFontCreateUIFontForLanguage(kCTFontUIFontUserFixedPitch, 0, NULL);
      CGFloat size = CTFontGetSize(name);
      NSLog(@"User Fixed Pitch Font: %@, Default Size: %.2f", name, size);
    }
    return 0;
  }

2024-11-21 23:56:50.349 a.out[19798:994265] User Fixed Pitch Font: <CTFont: 0x135f06a70>{name = Menlo-Regular, size = 10.000000, matrix = 0x0, descriptor = <CTFontDescriptor: 0x600000808960>{attributes = { NSFontNameAttribute = "Menlo-Regular"; }>}}, Default Size: 10.00

I'm able to resolve correctly the font name, but the default size doesn't reflect the above.

It's late so I'll call it a night :)