# Customizing highlighting from soul

I am using the following customization from make soul highlight span lines for the \hl from soul to get rid of the gaps between the highlighted zones:

\documentclass[a8paper, landscape]{scrartcl}
\usepackage{soul}

\usepackage[svgnames]{xcolor}

\sethlcolor{LightBlue}
\makeatletter
\def\SOUL@hlpreamble{%
\setul{\dp\strutbox}{\dimexpr\ht\strutbox+\dp\strutbox\relax}
\let\SOUL@stcolor\SOUL@hlcolor
\SOUL@stpreamble
}
\makeatother

\begin{document}
This is some \hl{highlighted text with a formula $q=\frac{p}{r}$.
Notice how nicely it is highlighted.}

Writting something more fancy, say, \hl{$|a|=\inf_{\overline{f}=a}|f|$,
gives an obvious gap problem.}
\end{document}


Which produces

However, if there are symbols that extend below/above too much, the \hl does not fully highlight the gap, as the above example shows. I tried to fiddle with the \setul part but nothing seems to give a good result. I also tried to \smash the inf construction, but then the line below just overlaps with the one above.

What would be the right setup to highlight that gap?

Add some more to the depth (and the thickness), also setting \lineskip to zero. Note that this changes the interline space, but there's no way that I know for convincing soul and \hl to cover something that exceeds the stated depth for the underline (the background color is realized as underlining with a very thick rule).

\documentclass[a8paper, landscape]{scrartcl}
\usepackage{soul}

\usepackage[svgnames]{xcolor}

\sethlcolor{LightBlue}
\makeatletter
\def\SOUL@hlpreamble{%
\setul{\dimexpr\dp\strutbox+2pt}{\dimexpr\ht\strutbox+\dp\strutbox+2pt\relax}
\let\SOUL@stcolor\SOUL@hlcolor
\SOUL@stpreamble
}
\makeatother

\begin{document}
\setlength{\lineskip}{0pt}

This is some \hl{highlighted text with a formula $q=\frac{p}{r}$.
Notice how nicely it is highlighted.}

Writting something more fancy, say, \hl{$|a|=\inf_{\overline{f}=a}|f|$,
gives an obvious gap problem.}

\end{document}


Don't use \hl in your final document.

• Thanks for the answer. What do you mean by "Don't use \hl in your final document" ? Is there a better method to do this kind of highlighting without using soul? – Lukas Jan 17 '17 at 13:56