On 06/13/2016 02:53 PM, Ulrike Fischer wrote:
Am Mon, 13 Jun 2016 11:35:11 +0200 schrieb Arno Trautmann:
Hi all,
I encountered some strange behaviour regarding the subscript and
superscripts in LuaLaTeX compared to pdfLaTeX. Consider the following
small example:
%\RequirePackage{luatex85}
\documentclass{scrartcl}
%\usepackage{subdepth}
%\usepackage{unicode-math}
\begin{document}
\[a_ia_i^+a^+a_i^\dagger\]
\[M_n M_n^\dagger M_n^+\]
\end{document}
Compilation with pdfLaTeX results in shifted positions for the sub and
super scripts according to the TeXbook. The package subdepth equalizes
them, which in this case looks nicer.
With LuaLaTeX, the subdepth package does not work, and has no effect on
the positioning whatsoever. David suggested to ask for a reason for this
behaviour on the luatex-list.
As far as I understand the documentation (and the result of some
tests) luatex uses the relevant \fontdimens only when loading the
font to setup some primitive parameters. If you later want to change
the values you have to change the primitives and not the \fontdimens
(as the subdepth package does).
This here works with and without unicode-math and moves one of the
subscripts n down:
\documentclass{scrartcl}
%\usepackage{subdepth}
%\usepackage{unicode-math}
\begin{document}
\[M_n M_n^\dagger M_n^+\]
\Umathsubshiftdown\displaystyle=5pt
\Umathsubshiftdown\textstyle=5pt
$M_n M_n^\dagger M_n^+$
\[M_n M_n^\dagger M_n^+\]
\end{document}
For more parameters see 6.4 Math parameter settings in the luatex
documentation.
Thank you very much, I had read that section indeed (after posting here
…) and found the following working solution, basically the same as yours:
\documentclass{minimal}
\begin{document}
\[M_n M_n^\dagger M_n^+\]
\Umathsubshiftdown\displaystyle=2.84pt
\Umathsubsupshiftdown\displaystyle=2.84pt
\Umathsubsupvgap\displaystyle=1pt
\[M_n M_n^\dagger M_n^+\]
\end{document}
One question remains here (besides asking the authors of subdepth to
adapt the package to LuaLaTeX if possible) – When I try to apply the
\Umath... settings before the first equation, they are ignored. So
setting them in the preamble does not work. In plainLuaTeX, otoh, it works:
\Umathsubshiftdown\displaystyle=2.84pt
\Umathsubsupshiftdown\displaystyle=2.84pt
\Umathsubsupvgap\displaystyle=1pt
$$M_n M_n^\dagger M_n^+$$
\bye
Is that related to font loading in LuaLaTeX?
Best,
Arno
