unicode-math should not be the default

[FelixBenning]

It took me a while to figure out why the blackboard font was so much worse using XeTeX and LuaLaTeX than pdflatex. The reason is hidden in the font.latex template partial

quarto-cli/src/resources/formats/pdf/pandoc/fonts.latex

Lines 6 to 18 in 432c04f

	\else % if luatex or xetex
	$if(mathspec)$
	\ifXeTeX
	\usepackage{mathspec} % this also loads fontspec
	\else
	\usepackage{unicode-math} % this also loads fontspec
	\fi
	$else$
	\usepackage{unicode-math} % this also loads fontspec
	$endif$
	\defaultfontfeatures{Scale=MatchLowercase}$-- must come before Beamer theme
	\defaultfontfeatures[\rmfamily]{Ligatures=TeX,Scale=1}
	\fi

unicode-math is a package that allows the usage of unicode symbols in the input but deteriorates the visual quality of the output. There are a bunch of stackexchange questions related to this, e.g.

• unicode-math but ordinary blackboard bold
• How can I get Latin Modern/Computer Modern serif double-struck/blackboard-bold characters which copy/paste as unicode when using unicode-math?
• How do I get normal \mapsto and \colon symbols when using unicode-math?
• XeLaTeX, Latin Modern, \mathbb and \mathcal

Since it is difficult to type these symbols on a keyboard and people coming from a LaTeX background are used to the macros it is probably fair to say that there is only going to be a small set of people that actually use the features of the unicode-math package, but its inclusion significantly deteriorates the visual quality of the pdf output.

TL;DR unicode-math should not be loaded by default.

[cscheid]

but deteriorates the visual quality of the output

It's helpful for us if you are more precise about the distinction between a bug report and a difference in opinion. This is clearly the latter, so I'll move into a discussion.

[cscheid]

This decision comes from Pandoc's own templates: https://github.com/jgm/pandoc/blob/main/data/templates/fonts.latex#L11 We do not deviate from Pandoc's templates unless there's a very strong reason to do so. If you make a convincing case that this should be changed upstream, then when Pandoc updates, we'll pick up the change as well.

[FelixBenning]

• `unicode-math` should not be the default jgm/pandoc#10879