> I just tested the static and variable fonts in macOS 10.14 TextEdit.
> For the static instances, it presumably takes the hhea metrics, for
> the VF, it always takes typo metrics. (It also adds the line gap at
> the bottom, making text look weird, but maybe that's because the
> layout logic is broken.)
Thanks for testing!
> So that would speak in favor of always using either typo or win
> metrics for variable fonts, even for the default outlines?
Umm. I suggest FreeType be changed to respect OS/2 useTypoMetrics bit. This is my attempt in HB:
and then use same logic for VF and non-VF. There's also the question of whether MVAR tags should apply to whatever was used for ascent/descent. I think yes. And I'll implement that in HB.
> Or maybe this is really the fault of GTK/Pango/something because it
> loads the default outline instead of the default instance, which
> would yield the correct metrics?
This is certainly the most convenient solution for me since I have
nothing to do on the FreeType side :-)
GTK/Pango/Cairo just call into FreeType for metrics.
I'm confused. What does "default outline" vs "default instance" mean?
Your question, however, is a fundamental one: Shall a VF font be
always treated as VF, or is the `VFness' an optional feature?