DOC: Add explicit font filenames for some TeX systems.

QuLogic · QuLogic · commit 2fd6983a9541 · 2020-12-08T05:20:45.000-05:00
On macOS, xelatex uses the system font directories, but MacTeX fonts are
not added there. However, these files can be found by specifying the
file name instead of the font name, so do so on macOS.

On Linux, it is mostly better to continue to specify the font name, as
different distros ship different extensions. This should still work on
systems that don't do this, using the same fallback as macOS.
diff --git a/doc/conf.py b/doc/conf.py
@@ -358,32 +358,52 @@ def _check_dependencies():
 \usepackage{fontspec}
 \defaultfontfeatures[\rmfamily,\sffamily,\ttfamily]{}
 '''
+
 # Sphinx 2.0 adopts GNU FreeFont by default, but it does not have all
 # the Unicode codepoints needed for the section about Mathtext
 # "Writing mathematical expressions"
-latex_elements['fontpkg'] = r"""
-\setmainfont{XITS}[
+fontpkg = r"""
+\IfFontExistsTF{XITS}{
+ \setmainfont{XITS}
+}{
+ \setmainfont{XITS}[
+  Extension      = .otf,
   UprightFont    = *-Regular,
   ItalicFont     = *-Italic,
   BoldFont       = *-Bold,
   BoldItalicFont = *-BoldItalic,
-]
-\setsansfont{FreeSans}[
+]}
+\IfFontExistsTF{FreeSans}{
+ \setsansfont{FreeSans}
+}{
+ \setsansfont{FreeSans}[
+  Extension      = .otf,
   UprightFont    = *,
   ItalicFont     = *Oblique,
   BoldFont       = *Bold,
   BoldItalicFont = *BoldOblique,
-]
-\setmonofont{FreeMono}[
+]}
+\IfFontExistsTF{FreeMono}{
+ \setmonofont{FreeMono}
+}{
+ \setmonofont{FreeMono}[
+  Extension      = .otf,
   UprightFont    = *,
   ItalicFont     = *Oblique,
   BoldFont       = *Bold,
   BoldItalicFont = *BoldOblique,
-]
+]}
 % needed for \mathbb (blackboard alphabet) to actually work
 \usepackage{unicode-math}
-\setmathfont{XITS Math}
+\IfFontExistsTF{XITS Math}{
+ \setmathfont{XITS Math}
+}{
+ \setmathfont{XITSMath-Regular}[
+  Extension      = .otf,
+]}
 """
+latex_elements['fontpkg'] = fontpkg
+
 # Sphinx <1.8.0 or >=2.0.0 does this by default, but the 1.8.x series
 # did not for latex_engine = 'xelatex' (as it used Latin Modern font).
 # We need this for code-blocks as FreeMono has wide glyphs.
