Changing the font based on availability to fontspec

Question

I would like to distribute a class that uses a professional font loaded via fontspec, and falls back to one of the default fonts in TeX Live if this is not available. I know that one can detect fonts packaged with TeX Live:

\documentclass{article}
\usepackage{fontspec}
\IfFileExists{tgpagella.sty}{\setmainfont{TeX Gyre Pagella}}{}

\begin{document}

\fontname\font\ at \the\fontdimen6\font

\end{document}

This doesn't work, however, if one instead tries to detect a font file in the same directory:

\documentclass{article}
\usepackage{fontspec}
\IfFileExists{texgyrepagella-regular.otf}{\setmainfont{TeX Gyre Pagella}}{}

\begin{document}

\fontname\font\ at \the\fontdimen6\font

\end{document}

Is there a mechanism somewhere to include .otf files in what \IfFileExists is able to detect?

fontspec has a fallback mechanism these days older answer but Will added a proper interface to that if I recall correctly — David Carlisle, Jan 21 '19 at 16:38
\fontspec_font_if_exist:nTF and similar commands look to be the right thing.... — David Carlisle, Jan 21 '19 at 16:43
@DavidCarlisle the documentation suggests \IfFontExistsTF. — Ulrike Fischer, Jan 21 '19 at 16:44
@UlrikeFischer but it looks much more impressive with _ and : — David Carlisle, Jan 21 '19 at 16:45
@DavidCarlisle Only for people not really used to _ and : ;-). — Ulrike Fischer, Jan 21 '19 at 16:47
Note that silently loading a different font to avoid an error can seriously confuse people, see https://tex.stackexchange.com/q/446425/35864 for example. — moewe, Jan 21 '19 at 17:11

score 10 · Accepted Answer · edited Jan 21 '19 at 19:23

10

Recent fontspec releases allow you to test for a font being loadable with \IfFontExistsTF or its internal expl3 version \fontspec_font_if_exist:nTF:

\documentclass{article}
\usepackage{fontspec}
\IfFontExistsTF{texgyrepagella-regular.otf}{\setmainfont{TeX Gyre Pagella}}{}

\begin{document}

\fontname\font\ at \the\fontdimen6\font

\end{document}

edited Jan 21 '19 at 19:23

Andrew Dunning

1,714
13
21

answered Jan 21 '19 at 17:26

David Carlisle

757,742

Changing the font based on availability to fontspec

1 Answers1