Reducing the size of greek letters in TeX Gyre Schola Math?

Question

I've been experimenting with TeX Gyre Schola (and its math font), and I've noticed that the greek letters are noticeably larger than normal letters and numbers. For example, consider the following:

\documentclass[12pt]{article}

\usepackage{fontspec}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Schola}
\setmathfont{TeX Gyre Schola Math}
\usepackage{lualatex-math}

\begin{document}

\[
\phi = \tan^{-1} 2\theta
\]

\end{document}

This yields the following:

where the the theta appears to me as abnormally large. Theta is the most noticeable to me (so far), but some of the other greek letters are also a bit larger than I'd expect. Contrast this with what is obtained with Latin Modern (Math):

Here, the height of the theta is not so much more than than height of the numbers or letters.

My question is therefore the following: Is there a way to reduce the size of the greek characters in the Schola math font? Or am I doing something wrong (or not doing something I ought to)?

Answer 1

The Greek lowercase letter chosen for TeX Gyre Schola Math are, in my opinion, not matching the main font: they are too thin and, of course, some of them are too tall.

You have some strategies available. First, scaling down all the Greek lowercase letters:

\documentclass[12pt]{article}

\usepackage{fontspec}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Schola}
\setmathfont{TeX Gyre Schola Math}
%%% Scale down!
\setmathfont[range=\mathit/greek,Scale=.8]{TeX Gyre Schola Math}
%%% Circumvent a bug in unicode-math
\setmathfont[range=\int]{TeX Gyre Schola Math}
\usepackage{lualatex-math}

\begin{document}

\[
\phi = \tan^{-1} 2\theta
\]
\[
a\alpha\beta\gamma c
\]

\end{document}

This has the defect that the alpha becomes too small.

Second strategy: scale down only the letters that are too tall: change the code above into

%%% Scale down!
\setmathfont[range={\mittheta,\mitbeta},Scale=.8]{TeX Gyre Schola Math}

You'll have to augment the list with the letters you want to use and scale down.

Third: use XITS Math or another font for Greek:

%%% Scale down!
\setmathfont[range=\mathit/greek,Scale=MatchLowercase]{XITS Math}