How to extend the columnseprule on the final page of a multicol environment?

Question

On the final page of a two-column portion of a text that uses multicol, I want to put a one-column notice at the bottom of the page, and I'd like the rule separating the columns to extend all the way until just above the one-column portion. Using vfill outside multicols puts the notice in the right place but the rule only extends as far as the actual multi-column text. Using vfill inside multicols has no effect.

I'd like it to produce something like the following, but obviously without the manual \vspace* command:

\documentclass{article}
\usepackage{multicol}
\usepackage{lipsum}
\setlength{\columnsep}{0.5in}
\setlength{\columnseprule}{0.5pt}
\begin{document}

\begin{multicols}{2}
    \lipsum[1]
    \columnbreak
    \lipsum[2]
    \vspace*{300pt}
\end{multicols}
\centering\Huge\textbf{\textsf{STOP}}

\end{document}

In some respects, this is the opposite problem of the Same page and multicols question, in that I need to ensure that something which comes after the multicols environment is kept on the same page.

Answer 1

You can insert the vertical rule on the last page using eso-pic:

\documentclass{article}

\usepackage{multicol,eso-pic,lipsum,xcolor}

\setlength{\columnsep}{0.5in}
\setlength{\columnseprule}{0.5pt}

\begin{document}

\begin{multicols}{2}
  \sloppy\lipsum[1-15]
\end{multicols}

\AddToShipoutPictureFG*{%
  \AtTextLowerLeft{%
    \makebox[0pt][l]{\makebox[\textwidth]{\Huge\bfseries\sffamily STOP}}% Set STOP
    % Move to the right of the left text column
    \hspace*{.5\dimexpr\textwidth-\columnseprule-2\columnsep}%
    % Skip over column sep
    \hspace*{\columnsep}%
    % Insert vertical rule
    \rule[3\baselineskip]{\columnseprule}{\dimexpr\textheight-3\baselineskip}%
  }%
}

\end{document}

The above example overlays a \rule on the final page 3\baselineskip from the bottom of the text block overtop of whatever is on the final page.

You could add this to \AtEndDocument. However, there is no testing done to see whether STOP will fit on the page or not, and not overlay with the existing text in the columns.

---

The following example sets the STOP content inside a box (called \stopbox) and uses this box as a measure of how far the vertical rule should go down to on the last page (+ one \baselineskip):

\documentclass{article}

\usepackage{multicol,eso-pic,lipsum,xcolor}

\setlength{\columnsep}{0.5in}
\setlength{\columnseprule}{0.5pt}

\newsavebox{\stopbox}
\savebox{\stopbox}{%
  \begin{tabular}[b]{c}
    \Huge\bfseries\sffamily STOP \\
    \small\itshape \ldots right here
  \end{tabular}
}

\begin{document}

\begin{multicols}{2}
  \sloppy\lipsum[1-15]
\end{multicols}

\AddToShipoutPictureFG*{%
  \AtTextLowerLeft{%
    \makebox[0pt][l]{\makebox[\textwidth]{\usebox{\stopbox}}}% Set STOP
    % Move to the right of the left text column
    \hspace*{.5\dimexpr\textwidth-\columnseprule-2\columnsep}%
    % Skip over column sep
    \hspace*{\columnsep}%
    % Insert vertical rule
    \rule[\dimexpr\ht\stopbox+\baselineskip]{\columnseprule}{\dimexpr\textheight-\ht\stopbox-\baselineskip}%
  }%
}

\end{document}

Answer 2

The new package multicolrule (version 1.1) can handle this problem without the need for eso-pic. While Werner's solution was perfectly serviceable for the problem as set out in the MWE, in production documents it required complicated bookkeeping to deal with situations such as having one-column material above the multicols environment, and the original and redrawn rules were slightly misaligned, requiring me to erase the old line before redrawing it. With the new package, these issues don't arise.

\documentclass{article}
\usepackage{multicolrule}
\usepackage{lipsum}
\setlength{\columnsep}{0.5in}

\newsavebox{\stopbox}
\savebox{\stopbox}{%
  \begin{tabular}[b]{c}
    \Huge\bfseries\sffamily STOP \\
    \small\itshape \ldots right here
  \end{tabular}
}

\SetMCRule{width=0.5pt,line-style=solid,extend-fill,extend-reserve=\ht\stopbox}

\begin{document}
\lipsum[1]

\begin{multicols}{2}
  \lipsum[2-3]
\end{multicols}
\centering\usebox{\stopbox}  
\end{document}

And the result: