Shaded Multicols

Question

Does anyone know how to shade the background and put a border around a multicol environment, where page breaks are needed.

There is a couple of posts around, most notably, multicols within colorbox, but there seems to be problems.

The best looking environment is the tcolorbox, but, cant do pagebreaks.

mdframed appears to overflow when pagebreaks are required (ie when multicol env. across multiple pages)

I really don't have an MWE, given the above comments RE tcolorbox and mdframed.

Answer 1

You might want to play with the spacing a bit but something like this

\documentclass{article}
\usepackage{multicol,color}

\makeatletter
\let\old@page@sofar\page@sofar
\let\old@box\box
\let\old@rlap\rlap
\def\page@sofar{%
\let\box\colorcolumn
\def\rlap{\let\box\old@box\old@rlap}%
\old@page@sofar
}
\def\colorcolumn#1{%
       \kern\dimexpr-\fboxrule-\fboxsep\relax
        {\let\box\old@box\fcolorbox{red}{yellow}{\box#1\llap{\phantom p}}}%
        \kern\dimexpr-\fboxrule-\fboxsep\relax
}

\makeatother


\def\a{Red blue green yellow black white. }
\def\b{One two three four five six. }
\def\c{\stepcounter{enumi} \Roman{enumi}
\a\a\b\b\a\a\b\a\a\b\b\b\b\b\b\a\a\b}
\begin{document}

\begin{multicols}{3}
\c\c\c\c\c\c\c\c\c\c
\end{multicols}

\end{document}