# How do I change the math italic font in XeTeX/fontspec?

I have a document where the main font is Gotham Book. So in my preamble I have:

\usepackage{fontspec}
\setmainfont{Gotham Book}


As the fontspec manual describes, this sets the math roman font to also be Gotham Book. But the math italic font remains from the Computer Modern family.

I know that \setmathrm will change the math roman font, and there are cousins \setmathtt, \setmathsf, and \setboldmathrm. But there's no \setmathit.

What am I missing?

• It seems that mathspec is replaced by unicode-math. commands like \setmathrm are very limited. Feb 14 '11 at 13:55
• @Leo mathspec still has its place. unicode-math goes a little overboard with assuming that you actually have a unicode maths font. Feb 14 '11 at 14:31
• A plain LaTeX solution: The mathastext package. Feb 14 '11 at 16:47

If you do not wish to otherwise change your maths symbols, the best solution is to use the mathspec package:

\documentclass{article}
\usepackage{mathspec}
\setallmainfonts(Digits,Latin){Georgia}
\begin{document}
Hello $a+\mathrm{b}=c$
\end{document}


Here, Georgia will be used for the body text and \mathrm, and Georgia Italic will be used for the italic math glyphs.

The unicode-math package (which I kinda wrote) can also do this, but it's somewhat overkill for your purposes and has the additional downside that you need to also load a Unicode mathematics font. Here's an example:

\documentclass{article}
\usepackage{unicode-math}
\setmainfont{Georgia}
\setmathfont{xits-math.otf}
\setmathfont[range=\mathit]{Georgia Italic}
\begin{document}
Hello $a+b=c$
\end{document}


Note that mathspec will not run (yet) on LuaTeX, so if you need a LuaLaTeX solution then you'll need to use unicode-math for now.

• Thanks, @Will. Do I not need \setmathrm as well? It seems like with my Gotham Book example where the main font is sans serifed it didn't change the operator font without it. Feb 14 '11 at 14:56
• @Matthew Yes, \setmathrm is probably a good idea as well, but that's not what your original question at the top of the page asks :) Feb 14 '11 at 14:59
• \setmainfont with fontspec was changing the math roman font automatically. I didn't mention it because it was doing the thing I wanted anyway, and I was not aware of mathspec. But \setmainfont with mathspec does not change the math roman font without an additional call to \setmathrm. Feb 14 '11 at 15:31

Thanks to Will and Leo for pointing out the mathspec package. So now I use:

\usepackage{mathspec} %loads fontspec as well
\setmainfont{Gotham Book}
\setmathrm{Gotham Book}
\setmathfont(Digits,Latin){Gotham Book}


This snippet may need optimization, but works.

• I was 19 seconds too slow :) Feb 14 '11 at 14:38

As of 2019, fontspec should find the bold and italic fonts, and load \mathrm, \mathbf and \mathit when you \setmathrm.

If you need additional set-up for \mathit, the ItalicFont and ItalicFeatures options of \setmathrm set up \mathit, just as the Boldfont and BoldFeatures options set up \mathbf.

\documentclass{article}
\usepackage[svgnames]{xcolor}
\usepackage{fontspec}
\usepackage[paperwidth=10cm]{geometry}

\setmainfont{TeX Gyre Schola}
\setmathrm{TeX Gyre Schola}[
ItalicFeatures = {Color = green}]

\begin{document}
Text \textit{italic} $$\mathrm{math}$$ $$\mathit{italic}$$
\end{document}


## What You Also Might Have Meant

In practice, someone asking about how to set the \mathit alphabet likely means the alphabet used for $x$.

To set that, you want to load the unicode-math package, set a math font that matches your main font and then, if necessary, add a line such as

\setmathfont[range=it]{Gotham Book Italic}


You can do likewise for up, bfup, bfit and the other math alphabets.

In unicode-math, you would normally use \symit, \symup, etc. for individual letters used as variables, and \mathit, \mathrm, \mathup, etc. for complete words. However, you can give a package option to interpret \mathit as \symit and make migrated code compile correctly.