[XeTeX] Support of variable OpenType fonts

David Jones dmj at ams.org
Tue Jul 12 23:02:22 CEST 2022

STIX Two is distributed in OTF, TTF, and WOFF2 formats:


Only the TTF files are variable fonts.

Only the OTF fonts are distributed via CTAN since none of the TeX engines can use the (variable) TTF fonts. 

The changes in version 2.13 only affected the variable fonts, not the "static" OTF files (although the version numbers were bumped up to match the ttf files).  That's why we didn't push a new version of stix2-otf package to CTAN.

From: XeTeX <xetex-bounces+dmj=ams.org at tug.org> on behalf of Bruno Voisin via XeTeX <xetex at tug.org>
Sent: Tuesday, July 12, 2022 10:17 AM
To: xetex at tug.org
Subject: [XeTeX] Support of variable OpenType fonts

Does XeTeX support variable OpenType fonts, or is the addition of their support planned at some point?

There does not seem to be any clear statement on the net about this, but based on


I have the impression there's no such support yet.

I'm asking because the next version of macOS, currently in public beta, includes the STIX Two fonts in a slightly more recent version than TeX Live (2.13 b171 for macOS vs 2.12 b168 for TL).

The math font is in OTF format, same as in TL, but the text fonts are in variable OpenType format, actually the files


from the official STIX Two distribution renamed as



Loading the fonts with LuaTeX and luaotfload, use of

        \font\testfont="STIX Two Text"
        \font\testfont="STIX Two Text Medium"

works and gets the fonts from TeX Live, while


gets the font from macOS. Similarly

        \fonttest{STIX Two Text Italic}
        \fonttest{STIX Two Text Medium Italic}

for TL becomes


for macOS (for some reason instance= doesn't work in this latter case). See the attached test file.

So I was wondering whether the same could be achieved with XeTeX.

The question is futile regarding STIX Two (the fonts in TeX Live are perfectly fine). But this was my first encounter with variable OpenType fonts ever in the real world, and I imagine the use of such fonts will become more widespread as time goes.

Bruno Voisin

PS Please cc possible answers to me, as I'm no longer subscribed to the list.

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