fontconfig doesn't list/find XITS font even after updating config

Question

I would like to use XITS/XITS Math within my LaTeX project (which uses XeTeX). Following the answers to this question, I created a file /etc/fonts/conf.avail/76-texlive-fonts.conf with the following content:

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
    <dir>/usr/share/texlive/texmf-dist/fonts/opentype</dir>
    <dir>/usr/share/texlive/texmf-dist/fonts/truetype</dir>
</fontconfig>

I had checked the above paths before to make sure that they are correct:

$ ls -l /usr/share/texlive/texmf-dist/fonts/opentype/public/xits
-rw-r--r-- 1 root root 111280 Nov 25  2016 xits-bolditalic.otf
-rw-r--r-- 1 root root 151692 Nov 25  2016 xits-bold.otf
-rw-r--r-- 1 root root 115536 Nov 25  2016 xits-italic.otf
-rw-r--r-- 1 root root 248956 Nov 25  2016 xits-mathbold.otf
-rw-r--r-- 1 root root 530128 Nov 25  2016 xits-math.otf
-rw-r--r-- 1 root root 249372 Nov 25  2016 xits-regular.otf

Afterwards, I added a symlink to /etc/fonts/conf.d/:

$ ls -l /etc/fonts/conf.d/76-texlive-fonts.conf 
lrwxrwxrwx 1 root root 35 Jan 10 13:15 /etc/fonts/conf.d/76-texlive-fonts.conf -> ../conf.avail/76-texlive-fonts.conf

…and ran $ fc-cache -fv. Its output, among others was:

/usr/share/texlive/texmf-dist/fonts/opentype/public/xits: caching, new cache contents: 6 fonts, 0 dirs

Still, when I run fc-list | grep -i xits now, there is no output and compiling the below MWE gives the following error, as expected:

…
main.tex:11: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! [\setmainfont{XITS}]
main.tex:11: Font TU/XITS(0)/m/n/12=XITS at 12.0pt not loadable: Metric (TFM) file or installed font not found. [\setmainfont{XITS}]
…
main.tex:12: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! [\setmathfont{XITS Math}]
main.tex:12: Font TU/XITSMath(0)/m/n/12="XITS Math/OT" at 12.0pt not loadable: Metric (TFM) file or installed font not found.
…

Here is the MWE:

\documentclass[12pt,a4paper]{article}

\usepackage{fontspec}
\usepackage{unicode-math}


\setmainfont{XITS}
\setmathfont{XITS Math}

\begin{document}
  Hello! Some math: $y = f(x)$

\end{document}

I would very much appreciate any pointers to how I could fix or at least debug this problem!

---

[UPDATE]: Turns out none of the fonts in /usr/share/texlive/texmf-dist/fonts/ show up in fc-list: The output of $ fc-list | grep /usr/share/texlive/texmf-dist/fonts is completely empty. Nevertheless, dozens of fonts get recognized when running sudo fc-cache -fv | grep /usr/share/texlive/texmf-dist/fonts. What is going on here?

Answer 1

An update for 2024: While you fixed this, the recommended way to load fonts in fontspec and unicode-math is now by filename. (See also §2.2 of the fontspec manual.) You’ve given an example of how XeTeX can’t look up the display names of fonts in the TeX tree out of the box on some systems, and there are several other situations in which I’ve seen a font’s display name fail, or XeTeX and LuaTeX behave differently.

\defaultfontfeatures[XITS]{
    Ligatures=Default,
    UprightFont=*-Regular,
    BoldFont=*-Bold,
    ItalicFont=*-Italic,
    BoldItalicFont=*-BoldItalic,
    Extension=.otf}

\setmainfont{XITS}
\setmathfont{XITSMath-Regular.otf}
\setmathfont[version=bold]{XITSMath-Bold.otf}

This tells fontspec that the files are named XITS-Regular.otf, XITS-Bold.otf and so on. It will search for system fonts, as well as in the TeX tree and the current folder. You can also specify a Path=, which should normally be something like ./fonts/ to archive the files your document uses in a subdirectory, rather than count on the correct version to always be available under the correct name on every system where someone will try to compile the document, forever.

Remember that filenames are case-sensitive on Linux. Here, I’ve used the filenames from the CTAN distribution, but the OP says that, on their box, the filenames should be in lowercase.

If you are only loading XITS through \setmainfont, you could instead pass the options there, but \defaultfontfeatures[XITS] will work even if you load the font multiple times. You could also put the command into a file named XITS.fontspec.

Finally, the commands to load a font from a .ttc collection by filename, if the display name does not work for you, are in §3.4 of the fontspec manual.

Answer 2

I was being a moron: I ran fc-cache as root and fc-list as a regular user without realizing that the cache would then be built for the root user and not the regular user. Running both commands as regular user fixed the issue.

Answer 3

for xetex use the file names instead of the symbolic names:

\setmainfont{xits-regular.otf}
\setmathfont{xits-math.otf}
\setmathfont[version=bold]{xits-mathbold.otf}