Highlighting a Chunk of Code within a lstlisting by specifying the line number

Question

This question in somehow related to https://stackoverflow.com/questions/1304315/highlighting-a-chunk-of-code-within-a-lstlisting but not exactly the same.

I want to make some slides with animation where one can see the execution of a program. The code is printed with lstlisting.

In order to make the code more readable, I want to highlight the line that is currently executed. The URL I show above has a solution where one modifies the code. Since I want to make animations, the code itself remains the same. Therefore it would be useful that I can just specify the line number and LaTeX will do the rest.

Is there some way to do this?

Answer 1

As discussed in the comment you want to use pygmentize. A solution with listings is provided here: highlight lines in listings

The package minted and verbments are using the parser pygmentize (see: minted vs. texments vs. verbments). I am using verbments here. Both packages require the package fancyvrb to print the contents. So you can manipulate some commands of fancyvrb without influencing the output of pygmentize.

In the example below I provide two new keys:

• bgrlinenbr - accepts a comma list representing the line numbers. These lines will be highlighted by the given color of bgrlineclr
• bgrlineclr - defines the background color of the highlighted line.

Here the result and code:

\documentclass[]{article}

\usepackage[T1]{fontenc}
\usepackage{beramono}
\usepackage{xparse}

\usepackage{verbments}
\makeatletter

\def\highlightedlines{}
\def\highlightedcolor{white}
\define@cmdkey{pyglist}[pl@]{bgrlinenbr}{\def\highlightedlines{#1}}%number
\define@cmdkey{pyglist}[pl@]{bgrlineclr}{\def\highlightedcolor{#1}}%color
\makeatother
\ExplSyntaxOn
\DeclareDocumentCommand \FancyVerbFormatLine { m }
{
 \clist_if_in:NVTF  \highlightedlines  { \the\value{FancyVerbLine} }
   { 
    \colorbox{\highlightedcolor}{#1}
  }
  {
     #1
  }
}
\ExplSyntaxOff
\begin{document}
Test
\begin{pyglist}[language=c,numbers=right,bgrlinenbr={1,2,4},bgrlineclr=red!20]
/**
* Prints Hello World.
**/
#include <stdio.h>

int main(void) {
   printf("Hello World!");
   return 0;
}
\end{pyglist}
\end{document}