Create environment that sets minimum size of its contents

Question

How can I create environment that makes its content at least x units high? It should add white space under its content.

Answer 1

Here a possible realization (if I have understood the request): the environment is basically a minipage, but before the latter starts there is an invisible rule with a given depth. The minimum depth can be passed as optional parameter to the environment. Here I have set the width of the rule to 1pt in order to show what is happening (which of course results in overfull \hboxes) but it should be of course 0pt.

% twocolumn for smaller snapshot
\documentclass[twocolumn]{article}
\newenvironment{foo}[1][8ex]{%
   \par\noindent
   \vrule depth#1 width1pt% <-- WRITE width0pt HERE
   \minipage[t]{\linewidth}%
  }{%
   \par\xdef\next{\the\prevdepth}\endminipage
   \par
   \prevdepth\next
   \ignorespacesafterend
}
\begin{document}
See this and that,
\begin{foo}
Some text here.
\end{foo}
Some other text here.
\begin{foo}
Some longer text here which will take more than one line and in total more
than the 5ex fixed by the invisible (well, not quite) rule on the left of this
strange environment.
\end{foo}
Some other text here.
\end{document}

Answer 2

I think what you are looking for is a minipage, which has the option to set the height. The problem is that a minipage will set the the indention and paragraph skipping to zero, but you may want to continue with the same format as your document. The solution is to save those settings and set them in the minipage. I have also made the environment height an optional parameter.

\documentclass[12pt]{article}
% For saving the current parskip and parindent
\newlength{\saveparskip}
\newlength{\saveparindent}
% Environment with option to set height
\newenvironment{foo}[1][]
    {%
    \par\noindent%
    \setlength{\saveparskip}{\parskip}%
    \setlength{\saveparindent}{\parindent}%
    \begin{minipage}[t][#1]{\linewidth}%
    \setlength{\parskip}{\saveparskip}\setlength{\parindent}{\saveparindent}
    }
    {\strut\end{minipage}\par}
\setlength{\parskip}{2.5ex plus 0.5ex minus 0.2ex}
\setlength{\parindent}{0.0in}
\begin{document}
Outside text
\begin{foo}
    This is in the new environment
\end{foo}
outside text
\begin{foo}[1in]
    This is in the new environment with set height
\end{foo}
outside text
\end{document}