[Tex/LaTex] Horizontal dashed line on page break in listings environment

listingspage-breakingrules

Well, the title says it all. I have code scripts that span over multiple pages. Is it possible to display a dashed line at the bottom and/or top of the page in which the listings environment experience a page break, and keep the solid line at the very top and very bottom of the environment?

A screen dump illustrating my question is given below. I would like to add dashed lines where the listings environment break.

enter image description here

I use mcode in combination with the listings enivorment, providing a set of lstset parameters. The following MWE illustrates where I would prefer to have horizontal, dashed lines, avoiding that the lstlistings environment just breaks to white.

\documentclass{article}
\usepackage{mcode, listings}
\definecolor{cornsilk}{RGB}{255,248,220}
\begin{document}
\section{Section Something}

The following code is just a really long list of comments, really. 

\begin{lstlisting}
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % It would be nice with a horisontal dashed line below me. 
    % Another dashed above me, too.
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
\end{lstlisting}
\end{document}

Best Answer

To draw such a frame you should use an other package which allows such modifications. The default packages are mdframed or tcolorbox. In the example below I provided a solution using tcolorbox whereby a new listings environment lstmcode is defined. Please note that I am using the version 2.22 for the example below.

enter image description here

\documentclass{article}
\usepackage{mcode, listings}
\lstdefinestyle{mymcode}{%
  basicstyle=\fontfamily{pcr}\fontseries{m}\selectfont\footnotesize,
  numbers=left,
  numberstyle=\color{gray}\fontfamily{pcr}\fontseries{m}\selectfont\tiny,
  stepnumber=1,
  numbersep=5pt,
  showspaces=false,
  showstringspaces=false,
  showtabs=false,
  tabsize=2,
  breaklines=true,
  breakatwhitespace=false,
  belowskip=0pt,
 aboveskip=0pt,
}

\definecolor{cornsilk}{RGB}{255,248,220}

\usepackage[breakable,listings,skins,hooks]{tcolorbox}
\newtcblisting{lstmcode}{%
 breakable,
 colback=cornsilk,
 listing options={style=mymcode},
 listing only,
 enhanced,
 overlay first app={%
   \draw[dashed,line width=1pt,xshift=1pt] (frame.south east) -- (frame.south west);%
  },
 overlay middle app={%
   \draw[dashed,line width=1pt,xshift=-1pt] (frame.north east) -- (frame.north west);
   \draw[dashed,line width=1pt,xshift=1pt] (frame.south east) -- (frame.south west);%
  },
 overlay last app={%
   \draw[dashed,line width=1pt,xshift=-1pt] (frame.north east) -- (frame.north west);
  },
}
\begin{document}
\section{Section Something}

The following code is just a really long list of comments, really. 

\begin{lstmcode}
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % It would be nice with a horisontal dashed line below me. 
    % Another dashed above me, too.
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
\end{lstmcode}

\end{document}

Here an other approach using mdframed. The output is equal:

\documentclass{article}
\usepackage[framemethod=tikz]{mdframed}
\usepackage{mcode, listings}
\lstdefinestyle{mymcode}{%
  basicstyle=\fontfamily{pcr}\fontseries{m}\selectfont\footnotesize,
  numbers=left,
  numberstyle=\color{gray}\fontfamily{pcr}\fontseries{m}\selectfont\tiny,
  stepnumber=1,
  numbersep=5pt,
  showspaces=false,
  showstringspaces=false,
  showtabs=false,
  tabsize=2,
  breaklines=true,
  breakatwhitespace=false,
  belowskip=0pt,
 aboveskip=0pt,
}

\definecolor{cornsilk}{RGB}{255,248,220}



\mdfdefinestyle{mcode}{%
 roundcorner=5pt,
 skipabove=10pt,skipbelow=10pt,
 middlelinewidth=1pt,
 backgroundcolor=cornsilk,
 firstextra={\draw[dashed,line width=1pt,xshift=1pt] (O) -- (P|-O);},
 secondextra={\draw[dashed,line width=1pt,xshift=-1pt] (O|-P) -- (P);},
 middleextra={\draw[dashed,line width=1pt,xshift=1pt] (O) -- (P|-O);\draw[dashed,line width=1pt,xshift=-1pt] (O|-P) -- (P);},
}
\lstnewenvironment{lstmcode}
 {\lstset{style=mymcode}}{}
\surroundwithmdframed[style=mcode]{lstmcode}
\begin{document}
\section{Section Something}

The following code is just a really long list of comments, really. 

\begin{lstmcode}
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % It would be nice with a horisontal dashed line below me. 
    % Another dashed above me, too.
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
    % Matlab code 
\end{lstmcode}

\end{document}

Workaround `\smash`

\smash creates a box, where the height and depth are zero:

\documentclass{article}
\usepackage{listings}
\usepackage{color}
\begin{document}
\definecolor{light-gray}{gray}{0.95}
\lstset{basicstyle=\ttfamily\footnotesize,
    backgroundcolor=\color{light-gray}, xleftmargin=0.7cm,
    frame=tlbr, framesep=0.2cm, framerule=0pt,
}
\begin{lstlisting}[mathescape]
k = $\smash{\lfloor (10\log n \cdot \log\log n)^{1/3}\rfloor}$;
k = $\smash{\lfloor (4\log n \cdot \log n)^{1/3} \rfloor}$;
\end{lstlisting}
\end{document}

Workaround via increasing the line spacing

If you fear, the lines are too narrow and might touch, then a larger line spacing can be used. Setting of \baselineskip in basicstyle does not have an effect, but \fontsize or \linespread with explicit/implicit \selectfont work. The following example uses \linespread (see egreg's answer). \footnotesize contains the implicit \selectfont:

\documentclass{article}
\usepackage{listings}
\usepackage{color}
\begin{document}
\definecolor{light-gray}{gray}{0.95}
\lstset{basicstyle=\ttfamily\linespread{1.15}\footnotesize,   
    backgroundcolor=\color{light-gray}, xleftmargin=0.7cm,
    frame=tlbr, framesep=0.2cm, framerule=0pt,
}
\begin{lstlisting}[mathescape]
k = $\smash{\lfloor (10\log n \cdot \log\log n)^{1/3}\rfloor}$;
k = $\smash{\lfloor (4\log n \cdot \log n)^{1/3} \rfloor}$;
\end{lstlisting}
\end{document}

[Tex/LaTex] Highlight code in lstlisting

I modified your MWE into this:

\documentclass{article}

\def\cccolorbox#1#2{\ifx#2\relax\let\next\allowbreak\else
       \def\next{\colorbox{#1}{#2}\allowbreak\cccolorbox{#1}}\fi\next}
\def\ccolorbox#1#2{\fboxsep0pt\cccolorbox{#1}#2\relax}

\def\!#1{\ifx#1\ccolorbox\allowbreak\expandafter\ccolorbox\else
         \ifx#1\end\expandafter\expandafter\expandafter\end\else
         #1\allowbreak\expandafter\expandafter\expandafter\!\fi\fi}

\def\cccolorbox#1#2{\ifx#2\relax\let\next\allowbreak\else
   \def\next{\colorbox{#1}{\strut #2}\allowbreak\cccolorbox{#1}}\fi\next}

\usepackage{color}
\usepackage[dvipsnames]{xcolor}
\usepackage{listings}
\usepackage{lstlinebgrd}
\usepackage{listings}
\usepackage{lstlinebgrd}

\lstset{columns=fullflexible,
  basicstyle=\small,    
  breakatwhitespace=false,    
  breaklines=true,         
  captionpos=b,        
  commentstyle=\color{ForestGreen},    
frame=single,
  extendedchars=true,       
  keywordstyle=\color{blue},   
  language=Python,              
  numbers=left,           
  numbersep=5pt,    
  numberstyle=\scriptsize\color{gray}, 
  rulecolor=\color{black},        
  showspaces=false,               
  showstringspaces=false,      
  showtabs=false,              
  stepnumber=1,             
  stringstyle=\color{purple},  
  tabsize=2,                 
  title=\lstname,           
  belowskip=-1em,
  aboveskip=1em,
  belowcaptionskip=0em,
  }
\begin{document}

First example
\begin{lstlisting}[escapechar=!]
! \ccolorbox{blue!35}{dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-} !
\end{lstlisting}

second example
\begin{lstlisting}[escapechar=!]
dummycode
!\colorbox{blue!35}{\parbox{0.95\textwidth}{dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-}}!
\end{lstlisting}

\end{document}

The first example is based on this discussion: Listing with background color not line breaking correctly
But the results looks ugly to me. Alternatively, in the second example I used a \parbox inside the \colorbox. It looks better but there is no indentation and the external frame it's still fragmented. Here is what I obtain:

EDIT:
by commenting the line:

frame=single,

and using the framed environment defined in the framed package you could fix the fragmented box issue. Morever using hangpars environment you could indent correctly inside the parbox.

Here is the updated example:

\documentclass{article}

\def\cccolorbox#1#2{\ifx#2\relax\let\next\allowbreak\else
  \def\next{\colorbox{#1}{#2}\allowbreak\cccolorbox{#1}}\fi\next}
\def\ccolorbox#1#2{\fboxsep0pt\cccolorbox{#1}#2\relax}

\def\!#1{\ifx#1\ccolorbox\allowbreak\expandafter\ccolorbox\else
  \ifx#1\end\expandafter\expandafter\expandafter\end\else
#1\allowbreak\expandafter\expandafter\expandafter\!\fi\fi}

\def\cccolorbox#1#2{\ifx#2\relax\let\next\allowbreak\else
  \def\next{\colorbox{#1}{\strut #2}\allowbreak\cccolorbox{#1}}\fi\next}

\usepackage{framed}
\usepackage{color}
\usepackage[dvipsnames]{xcolor}
\usepackage{listings}
\usepackage{lstlinebgrd}
\usepackage{listings}
\usepackage{lstlinebgrd}
\usepackage{hanging}
\lstset{columns=fullflexible,
  basicstyle=\small,    
  breakatwhitespace=false,    
  breaklines=true,         
  captionpos=b,        
  commentstyle=\color{ForestGreen},    
  % frame=single,
  extendedchars=true,       
  keywordstyle=\color{blue},   
  language=Python,              
  numbers=left,           
  numbersep=5pt,    
  numberstyle=\scriptsize\color{gray}, 
  rulecolor=\color{black},        
  showspaces=false,               
  showstringspaces=false,      
  showtabs=false,              
  stepnumber=1,             
  stringstyle=\color{purple},  
  tabsize=2,                 
  title=\lstname,           
  belowskip=-1em,
  aboveskip=1em,
  belowcaptionskip=0em,
}
\begin{document}

First example

\begin{framed}
\begin{lstlisting}[escapechar=!]
    ! \ccolorbox{blue!35}{dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-} !
\end{lstlisting}
\end{framed}

second example
\begin{framed}
\begin{lstlisting}[escapechar=!]
    dummycode
    !\colorbox{blue!35}{\parbox{0.95\textwidth}{\begin{hangparas}{.25in}{1}dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-dummycode-\end{hangparas}}}!
\end{lstlisting}
\end{framed}

\end{document}

which give me this results:

Best Answer

Related Solutions

[Tex/LaTex] Unwanted White Lines in listings environment

Workaround \smash

Workaround via increasing the line spacing

[Tex/LaTex] Highlight code in lstlisting

Related Question

Workaround `\smash`