[Tex/LaTex] Leading spaces are not preserved when pasting text

indentationtexstudio

In TeXstudio, if I paste lines of text that contain leading spaces, they are altered automatically by the editor producing an undesirable layout.

MWE: Copy the following snippet and paste it in the editor.

\begin{verbatim}
    1
  -----
  s + 1
\end{verbatim}

This is how it looks after pasting:

\begin{verbatim}
1
-----
s + 1
\end{verbatim}

Why is this happening?
How can I keep the indentation of the pasted text intact?

Best Answer

TeXstudio offers three indentation modes:

Ignore Indentation: turns auto-indentation off.
Keep Indentation: copies the indentation from the previous line.
Indent and Unindent Automatically: re-indents text automatically to match the context.

From the TeXstudio User Manual:

The selection box "Indentation mode" lets you select, wether indented lines are followed by lines of the same indentation after pressing Enter or letting TeXstudio do automatic indentation.

"Indent and Unindent Automatically" mode is enabled by default. Since you want to preserve the indentation of the text you need to change this setting to "Ignore Indentation".

Go to Options > Configure TeXstudio > Editor

Other sources:

Related Solutions

[Tex/LaTex] How to make listings code indentation remain unchanged when copied from PDF

To prevent random spaces when copying the text from a listing, you need to use

\lstset{columns=flexible}

But you will now note that the text is not neatly aligned anymore; to solve this, you need to also use

\lstset{keepspaces=true}

This will not solve your problem with spaces disappearing at the beginning of lines when copying. The following hack will produce visible spaces and then make them invisible by coloring them in the background color:

\makeatletter
\def\lst@outputspace{{\ifx\lst@bkgcolor\empty\color{white}\else\lst@bkgcolor\fi\lst@visiblespace}}
\makeatother

This hack is not perfect, however, as the typesetted character is really a visible space, not a space (so searching the pdf for char line will not work) and some PDF readers (like Mac's preview) will copy a visible space. It works under Acrobat Reader and it's extremely pleasant to be able to quickly copy/paste code without problem (perhaps the problem can be circumvented by writing direct PDF code to tell that it's a space, I've never had the time to try). It might also not work with all typewriter fonts.

Here's the full code of your example:

\documentclass[12pt,oneside]{memoir}

\usepackage{listings}
\usepackage[T1]{fontenc}
\usepackage{xcolor}
\usepackage{textcomp}

\definecolor{codebg}{HTML}{EEEEEE}
\definecolor{codeframe}{HTML}{CCCCCC}

\lstset{language=Awk}
\lstset{backgroundcolor=\color{codebg}}
\lstset{frame=single}
\lstset{framesep=10pt}
\lstset{rulecolor=\color{codeframe}}
\lstset{upquote=true}
\lstset{basicstyle=\ttfamily}
\lstset{showstringspaces=false}

\lstset{columns=flexible}
\lstset{keepspaces=true}
\makeatletter
\def\lst@outputspace{{\ifx\lst@bkgcolor\empty\color{white}\else\lst@bkgcolor\fi\lst@visiblespace}}
\makeatother

\begin{document}

This code example prints out all users on your system:

\begin{lstlisting}[language=c]
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LINE_LEN 1024

int main() {
    char line[MAX_LINE_LEN];
    FILE *in = fopen("/etc/passwd", "r");
    if (!in) exit(EXIT_FAILURE);

    while (fgets(line, MAX_LINE_LEN, in) != NULL) {
        char *sep = strchr(line, ':');
        if (!sep) exit(EXIT_FAILURE);
        *sep = '\0';
        printf("%s\n", line);
    }
    fclose(in);
    return EXIT_SUCCESS;
}
\end{lstlisting}

\end{document}

[Tex/LaTex] How to automatically skip leading white spaces in listings

A different approach, hence separate answer. Capture the body of the environment (not in a very robust way, but I think you don't nest those environments), and count the number of leading spaces. Somewhat tricky to get right with the \endlinechar and \newlinechar. Alas, if some lines are less indented than the first, they will be trimmed.

\documentclass{article}

\usepackage{listings}
\lstloadlanguages{C}
\lstnewenvironment{CCCC}[1][]
  {\lstset{language=C, basicstyle=\scriptsize\ttfamily, #1}}{}
\makeatletter
% ===== Helper.
% Use some tokens after fully expanding them: for this, redefine
% \use@x within a group, and use it outside using \expandafter.
\newcommand{\use@x}[1]
  {\begingroup\edef\use@x{#1}\expandafter\endgroup\use@x}

% ===== Environment.
% Give "special" characters the catcode "other", and tell TeX
% to insert the "newline" character at the end of every line
% (this "newline" character causes TeX to produce a new line
% when writing to a file (done in \scantokens later)).
\newenvironment{C}
  {%
    \let\do\@makeother\dospecials
    \endlinechar\newlinechar
    \LS@hack@i
  }{}
% Look for an optional argument. 
\newcommand{\LS@hack@i}[1][]{\LS@hack@ii{#1}}
% Expand...
\use@x{%
  % Roughly \def\LS@hack@ii#1#2\end{C}^^J{\LS@hack@iii{#2}{#1}}
  % except that some pieces of \end{C} are converted to strings,
  % and one space is removed from #2.
  \unexpanded{\def\LS@hack@ii#1#2}%
    \expandafter\@gobble\string\\end\string{C\string}^^J%
    \unexpanded{{\expandafter\LS@hack@iii\expandafter{\romannumeral-`0#2}{#1}}}%
  %
  % Essentially,
  % \def\LS@hack@iii{\end{C}
  %   \begin{CCCC}[gobble=numberofspaces]##1\end{CCCC}}
  % Restore catcodes of special characters and reread,
  % with \scantokens, the body of the environment, feeding
  % it to the listing CCCC environment. Note that the user-
  % provided optional argument to begin{C} is transmitted
  % to begin{CCCC} (not tested). All the \noexpand are there
  % to prevent the full expansion of \use@x, necessary
  % for \string\begin and \string\end.
  \noexpand\newcommand{\noexpand\LS@hack@iii}[2]
    {\noexpand\end{C}%
      \noexpand\LS@hack@countspaces{##1}%
      \noexpand\scantokens{%
        \string\begin{CCCC}[gobble=\noexpand\value{LS@hack@spacecount},##2]^^J%
          ##1%
        \string\end{CCCC}}}}

\newcounter{LS@hack@spacecount}
\newcommand{\LS@hack@countspaces@}[1]{%
  \if#1 \else
    \expandafter\remove@to@nnil
  \fi
  +1\LS@hack@countspaces@}
\newcommand{\LS@hack@countspaces}[1]{%
  \setcounter{LS@hack@spacecount}
    {\the\numexpr0\LS@hack@countspaces@#1\@nnil\relax}}


\begin{document}
  A piece of code:
  \begin{C}
    #include <stdio.h>
    int main(){
      printf("tex.stackexchange.com: the coolest community ever!\n");
    }
  \end{C}
  and the same with no gobble:
  \begin{CCCC}
    #include <stdio.h>
    int main(){
      printf("tex.stackexchange.com: the coolest community ever!\n");
    }
  \end{CCCC}
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] How to make listings code indentation remain unchanged when copied from PDF

[Tex/LaTex] How to automatically skip leading white spaces in listings

Related Question