Verbatim environment with background color (PDFLaTeX and tex4ht)

Question

I need to make a verbatim environment with gray background color, such as:

That needs to work with PDFTeX and tex4ht on an older TeX installation (from 2009 I believe). My approach so far is

\documentclass{article}

\usepackage{framed,color,verbatim}
\definecolor{shadecolor}{rgb}{.9, .9, .9}

\newenvironment{code}%
   {\snugshade\verbatim}%
   {\endverbatim\endsnugshade}


\begin{document}
text

\begin{code}
line one
line two
\end{code}


\end{document}

which works when I run it with pdftex main.tex. But when I give the command htlatex main xhtml,4,next I get errors:

(/opt/texlive2011/texmf-dist/tex/generic/tex4ht/html4-math.4ht)) (./main.aux)
! You can't use `\prevdepth' in horizontal mode.
\nointerlineskip ->\prevdepth 
                              -\@m \p@ 
l.17 \end{code}

? 
! Emergency stop.
\nointerlineskip ->\prevdepth 
                              -\@m \p@ 
l.17 \end{code}

No pages of output.

What can I do to get the custom gray background verbatim environment as in the example (called "code") with PDFTeX and tex4ht with TeXlive from 2009?

Answer 1

The credits should go to Martin Scharrer. It is possible with the listings package:

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

\definecolor{verbgray}{gray}{0.9}

\lstnewenvironment{code}{%
  \lstset{backgroundcolor=\color{verbgray},
  frame=single,
  framerule=0pt,
  basicstyle=\ttfamily,
  columns=fullflexible}}{}

\definecolor{shadecolor}{rgb}{.9, .9, .9}

\begin{document}
text

\begin{code}
line one
line two
\end{code}

\end{document}

This document works with tex4ht and pdftex.

Answer 2

Another solution is to use tex4ht hook system.

Put the definition of the environment to the code.sty file:

\ProvidesPackage{mycode.sty}
\RequirePackage{framed,color,verbatim}
\definecolor{shadecolor}{rgb}{.9, .9, .9}

\newenvironment{code}%
   {\snugshade\verbatim}%
   {\endverbatim\endsnugshade}

then create file code.4ht which is called only with tex4ht:

\renewenvironment{code}{\:tempa\verbatim}{\endverbatim\:tempb}
\ConfigureEnv{code}{\HCode{<div class="code">}}{\HCode{</div>}}{}{}
\Css{.code{
border:1px solid black;
background-color: \#999;
}}

you need to redefine code environment, remove code that cause problems and put hooks \:tempa and \:tempb. Configurations from \ConfigureEnv will be inserted here.

Answer 3

Another solution is to check if I need the PDF or the HTML document.

\documentclass{article}
\usepackage{ifpdf,verbatim}

\ifpdf
\usepackage{framed,color}
\definecolor{shadecolor}{gray}{0.9}

\newenvironment{code}%
   {\snugshade\verbatim}%
   {\endverbatim\endsnugshade}

\else

\newenvironment{code}
    {\HCode{<div class='code'>}\verbatim}
    {\endverbatim\HCode{</div>}}

\fi

\begin{document}
text

\begin{code}
line one
line two
\end{code}

\end{document}

Answer 4

Of course you can always use adjustbox to add the background color. Here you have to be careful not to take the \begin{adjustbox}{..} form but the \adjustbox{..}\bgroup .. \egroup form. I added some padding and margin.

\documentclass{article}

\usepackage{xcolor}
\usepackage{adjustbox}
\usepackage{verbatim}
\definecolor{shadecolor}{rgb}{.9, .9, .9}

\newenvironment{code}%
   {\par\noindent\adjustbox{margin=1ex,bgcolor=shadecolor,margin=0ex \medskipamount}\bgroup\varwidth\linewidth\verbatim}%
   {\endverbatim\endvarwidth\egroup}

\newenvironment{code2}%
   {\par\noindent\adjustbox{margin=1ex,bgcolor=shadecolor,margin=0ex \medskipamount}\bgroup\minipage\linewidth\verbatim}%
   {\endverbatim\endminipage\egroup}


\begin{document}
text text text text text text text text text
text text text text text text text text text

\begin{code}
line one
line two
\end{code}

text text text text text text text text text
text text text text text text text text text

\begin{code2}
line one
line two
\end{code2}


text text text text text text text text text
text text text text text text text text text

\end{document}