On Thu, Dec 20, 2018 at 5:32 AM Werner LEMBERG <[email protected]> wrote:

>
> > 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?
>
> Behdad?
>

Umm.  I suggest FreeType be changed to respect OS/2 useTypoMetrics bit.
This is my attempt in HB:

https://github.com/harfbuzz/harfbuzz/blob/master/src/hb-ot-hmtx-table.hh#L194

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?
>
>
>     Werner
>


-- 
behdad
http://behdad.org/
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