make4ht diplaystyle \dfrac command

Question

Is it possible to make the \dfrac command work in inline mode? Or is it possible to force all the math in diplaystyle mode ? I use make4ht with mathml.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\frac12$ $\dfrac22$  $\displaystyle \frac32$
\[  \frac{4}{2} \]
\end{document}

I use the command line make4ht file.tex "mathml"

Answer 1

Fortunately, information about math style is available in the underlying genfrac configuration, which can be used to enclose the dfrac contents in an element with displaystyle="true" attribute:

\Preamble{xhtml}
\catcode`\:=11
\pend:def\dfrac{\Configure{genfrac}{\HCode{<mstyle \mathchoice{displaystyle="true"}{}{}{}>}}{}{}{}{}{\HCode{</mstyle>}}}
\pend:def\tfrac{\Configure{genfrac}{\HCode{<mstyle \mathchoice{displaystyle="false"}{}{}{}>}}{}{}{}{}{\HCode{</mstyle>}}}
\pend:def\dbinom{\Configure{genfrac}{\HCode{<mstyle \mathchoice{displaystyle="true"}{}{}{}>}}{}{}{}{}{\HCode{</mstyle>}}}
\pend:def\tbinom{\Configure{genfrac}{\HCode{<mstyle \mathchoice{displaystyle="false"}{}{}{}>}}{}{}{}{}{\HCode{</mstyle>}}}
\catcode`\:=12
%\Configure{$}{\Configure{@math}{display="inline"}\DviMath\@mathstyle{0}}{\EndDviMath}{}
\makeatother
\begin{document}
\EndPreamble

In this configuration, we add the <mrow> element, and using the \mathchoice command, we can add the displaystyle attribute. This is the result:

If you want to use displaystyle for all inline math delimited by $ $, use this configuration:

\Preamble{xhtml}
\Configure{$}{\Configure{@math}{display="inline" displaystyle="true"}\DviMath}{\EndDviMath}{}
\begin{document}
\EndPreamble

The downside is that it can be too large when used in text.