csquotes -- How to customize/change blockquote features -- indentation, fontsize, linewidth

Question

Quotation requirements can be very variable and I've not found a way to adapt the csquotes standard for my puropse. For a thesis/paper it is required to fulfill following blockquotation standards:

• fontsize 10pt (different from the normal fontsize)
• indentation 1cm (relative to normal text)
• linewidth 1.0 (normal text is 1.5 -- \onehalfspacing with the setspace package)
• inside the quotation marks (set by csquotes)
• use italics for the quotation

Since specific language settings are also required, it would be very facile if the proposed solution would use the same ´csquotes´ package.

I've found

• [1] How to change the fontsize of a csquotes' quotation? and
• [2] \blockquote customization

While the first is setting the fontsize only relative to the nomrla font size, the second is almost not commented and so practically impossible to adapt for a novice like me.

Here you find a minimal example:

\documentclass{article}    

\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage{parskip}

\usepackage{setspace}       
\onehalfspacing

\usepackage[autostyle,german=guillemets]{csquotes}

\begin{document}
    Here comes a blockquotation:

    \begin{displayquote}
        Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.
    \end{displayquote}

\end{document}

Answer 1

I believe this covers your requirements. I commented it so that hopefully it's easy to follow.

\makeatletter
%Take the original environment definition and change the leftmargin to 1cm
\renewenvironment*{displayquote}
  {\begingroup\setlength{\leftmargini}{1cm}\csq@getcargs{\csq@bdquote{}{}}}
  {\csq@edquote\endgroup}
\makeatother
%Hooks
%Use single spacing, set 10pt font, and begin beginning quotes

%%%Curly quotes version
%\renewcommand{\mkbegdispquote}
    %{\singlespacing\fontsize{10pt}{10pt}\selectfont\setquotestyle{quote}\textooquote}%
%%%German guillemets version
\renewcommand{\mkbegdispquote}
    {\singlespacing\fontsize{10pt}{10pt}\selectfont\textooquote}%
%%%German guillemets version plus italics
%\renewcommand{\mkbegdispquote}
    %{\singlespacing\fontsize{10pt}{10pt}\selectfont\itshape\textooquote}%
\renewcommand{\mkenddispquote}{\textcoquote}

I could not find any way to change the indent size... so I searched csquotes for the displayquote definition. I copied that and threw it between \makeatletter...\makeatother (because it contains the @ character. Then, I put \begingroup and \endgroup, so that the \leftmargini dimension change would only apply within displayquote environments.

Next, I renewed the two hook commands that are applicable to displayquote: \mkbegdispquote and \mkenddispquote. Basically, you just put whatever changes you need here. In this case, you wanted single space, font size of 10pt, quote style (if needed, see version 2), and quotes. Then, you put the beginning quotes and the ending quotes.

Here is a complete version from your example:

\documentclass{article}

\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage{parskip}

\usepackage{setspace}       
\onehalfspacing

\usepackage[autostyle,german=guillemets]{csquotes}
\makeatletter
%Take the original environment definition and change the leftmargin to 1cm
\renewenvironment*{displayquote}
  {\begingroup\setlength{\leftmargini}{1cm}\csq@getcargs{\csq@bdquote{}{}}}
  {\csq@edquote\endgroup}
\makeatother
%Hooks
%Use single spacing, set 10pt font, and beginning quotes
\renewcommand{\mkbegdispquote}
    {\singlespacing\fontsize{10pt}{10pt}\selectfont\textooquote}
%End displayquote environment with ending quotes
\renewcommand{\mkenddispquote}{\textcoquote}


\usepackage{geometry}
\geometry{lmargin=25mm,rmargin=25mm,}

\begin{document}
    Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

    \begin{displayquote}
        Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.
    \end{displayquote}

Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

\end{document}

And, if you want to change the quotes to be “ and ”, you can change the quote style:

\documentclass{article}

\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage{parskip}

\usepackage{setspace}       
\onehalfspacing

\usepackage[autostyle,german=guillemets]{csquotes}
\makeatletter
%Take the original environment definition and change the leftmargin to 1cm
\renewenvironment*{displayquote}
  {\begingroup\setlength{\leftmargini}{1cm}\csq@getcargs{\csq@bdquote{}{}}}
  {\csq@edquote\endgroup}
\makeatother
%Hooks
%Use single spacing, set 10pt font, set quote style curly quotes, and beginning quotes
\renewcommand{\mkbegdispquote}
    {\singlespacing\fontsize{10pt}{10pt}\selectfont\setquotestyle{quote}\textooquote}
%End displayquote environment with ending quotes
\renewcommand{\mkenddispquote}{\textcoquote}


\usepackage{geometry}
\geometry{lmargin=25mm,rmargin=25mm,}

\begin{document}
    Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

    \begin{displayquote}
        Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.
    \end{displayquote}

Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

\end{document}

And version with italics (and German-style quotes):

\documentclass{article}

\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage{parskip}

\usepackage{setspace}       
\onehalfspacing

\usepackage[autostyle,german=guillemets]{csquotes}
\makeatletter
%Take the original environment definition and change the leftmargin to 1cm
\renewenvironment*{displayquote}
  {\begingroup\setlength{\leftmargini}{1cm}\csq@getcargs{\csq@bdquote{}{}}}
  {\csq@edquote\endgroup}
\makeatother
%Hooks
%Use single spacing, set 10pt font, set italics, and beginning quotes
\renewcommand{\mkbegdispquote}
    {\singlespacing\fontsize{10pt}{10pt}\selectfont\itshape\textooquote}%\setquotestyle{quote}
%End displayquote environment with ending quotes
\renewcommand{\mkenddispquote}{\textcoquote}


\usepackage{geometry}
\geometry{lmargin=25mm,rmargin=25mm,}

\begin{document}
    Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

    \begin{displayquote}
        Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.  Dies ist ein Zitat das nichts sagt. Und wenn sie noch nicht gestorben sind dann denken sie daran für immer zu sein.
    \end{displayquote}

Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation Here comes a blockquotation:

\end{document}

Answer 2

We can avoid some patching if we use the method to customise displayquote shown in csquotes.cfg.

The idea is to first define a new environment based on quote that does most of what we want. Then we use our new environment instead of the standard quote with \SetBlockEnvironment.

\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{parskip}

\usepackage{setspace}       
\onehalfspacing

\usepackage[autostyle,german=guillemets]{csquotes}

\newenvironment*{innerquote}
  {\setlength{\leftmargini}{1cm}%
   \quote
   \singlespacing\fontsize{10pt}{10pt}\selectfont\itshape}
  {\endquote}

\SetBlockEnvironment{innerquote}

\renewcommand{\mkbegdispquote}[2]{\textooquote}
\renewcommand{\mkenddispquote}[2]{\textcoquote#1#2}


\usepackage{lipsum}

\begin{document}
\lipsum[1]

\begin{displayquote}
\lipsum[2]
\end{displayquote}

\lipsum[3]
\end{document}

Note that technically \mkbegdispquote and \mkenddispquote are defined as taking two arguments.