Copying from https://bugs.freedesktop.org/show_bug.cgi?id=94551 :

 Khaled Hosny 2017-08-03 11:48:13 UTC

(In reply to Akira TAGOH from comment #41)
> (In reply to Behdad Esfahbod from comment #34)
> > (In reply to Akira TAGOH from comment #31)
> > > Okay. updated the orth.
> > 
> > Thanks.  Got orth for math as well?  Don't know what should go there. :)
> 
> Hmm, me neither.. we can get some from
> http://www.unicode.org/Public/math/revision-15/MathClass-15.txt say, I guess
> extra glyphs may be included in even a classification.

Math fonts vary greatly in their coverage and there is no clear cut what a math symbol and what is not. I don’t know if MathClass-XX.txt is used in anything in practice, but I guess we can make an orthography file out of it and test it with the existing math fonts, possibly reducing it until we get them all covering math.

Added und_zmth.orth to git.

$ ./build/fc-list/fc-list :lang=und-zmth
/usr/share/fonts/lm-math/latinmodern-math.otf: Latin Modern Math:style=Regular
/usr/share/fonts/stix/STIX-Regular.otf: STIX:style=Regular
/usr/share/fonts/tex-gyre-math/texgyrebonum-math.otf: TeX Gyre Bonum Math:style=Regular
/usr/share/fonts/tex-gyre-math/texgyretermes-math.otf: TeX Gyre Termes Math:style=Regular
/usr/share/fonts/Asana-Math/Asana-Math.otf: Asana Math:style=Regular
/usr/share/fonts/tex-gyre-math/texgyredejavu-math.otf: TeX Gyre DejaVu Math:style=Regular
/usr/share/fonts/tex-gyre-math/texgyreschola-math.otf: TeX Gyre Schola Math:style=Regular
/usr/share/fonts/gdouros-symbola/Symbola.ttf: Symbola:style=Regular
/usr/share/fonts/tex-gyre-math/texgyrepagella-math.otf: TeX Gyre Pagella Math:style=Regular
/usr/share/fonts/xits/xits-math.otf: XITS Math:style=Regular
/usr/share/fonts/stix/STIXMath-Regular.otf: STIX Math:style=Regular

I couldn't test with Cambria Math, Minion Math and Lucida Math. if anyone can do that, that would be appreciated.

Cambria Math, Minion Math, Lucida Math and Libertinus Math (https://github.com/khaledhosny/libertinus) don’t seem to be recognized as math fonts.

(In reply to Khaled Hosny from comment #3)
> Cambria Math, Minion Math, Lucida Math and Libertinus Math
> (https://github.com/khaledhosny/libertinus) don’t seem to be recognized as
> math fonts.

Thank you for testing. adjusted orth for Libertinus Math. can you give me a log for fc-validate -l und-zmth for Cambria Math and Minion Math? so I can improve it much more...

meant fc-validate -l und-zmth -v /path/to/font

(In reply to Akira TAGOH from comment #5)
> meant fc-validate -l und-zmth -v /path/to/font


cambria.ttc:1 Missing 14 glyph(s) to satisfy the coverage for und-zmth language
  0x03f4
  0x2035
  0x2036
  0x2037
  0x203b
  0x25e6
  0x2662
  0x2663
  0x2664
  0x2665
  0x2667
  0x266d
  0x266e
  0x266f

LucidaBrightMathOT.otf:0 Missing 14 glyph(s) to satisfy the coverage for und-zmth language
  0x0305
  0x033f
  0x03f4
  0x203b
  0x2126
  0x2300
  0x231c
  0x231d
  0x231e
  0x231f
  0x2661
  0x2662
  0x2664
  0x2667

Minion Math seems to be split into multiple font files and I’m not sure if my copy is the latest, so I suggest we ignore it for now.

Thank you. updated. hope I'm not missing anything else.

All good now!

Any other math fonts we should support? maybe getting rid of code points to add und-zmth to all of fonts that has "Math" in their family names isn't a realistic and ends up to have it in lang for non-math fonts. it has to be avoided. that said, if there are anything else having enough coverage to support, good to work before closing this.

I think the current orth files covers pretty much all publicly available OpenType math fonts. I’d have been inclined to say any font that has otlayout:math should be considered as math font, but I have seen broken fonts that has otlayout:math but no usable math support.

Okay. let's close this with it so far. we could revisit or do something on new one to polish the orth file as needed. thank you.