change the footnote's length (increase footnotes right margin)

Question

I'm using Book (KOMA-Script), By default, the footnote runs roughly from left margin to the right margin of the page, I used the following to control the left margin:

\deffootnote[8em]{8em}{8em} {\textsuperscript{\thefootnotemark}}

Result is as following:

I wondered if there is a way to control the right margin of the footnote? or in another word, the length of the footnote itself? i.e. 2em spacing to the right margin of the page?

Answer 1

Do you really mean 2em from the right margin of the page?

\documentclass{scrbook}
\usepackage{lipsum}

\deffootnote[8em]{8em}{8em} {\textsuperscript{\thefootnotemark}}

\makeatletter
\@ifdefinable{\org@makefntext}{%
  \let\org@makefntext\@makefntext
  \renewcommand*{\@makefntext}{%
    \ifthispageodd{%
      \setlength{\hsize}{\dimexpr\paperwidth-\oddsidemargin-1in-2em}%
    }{%
      \setlength{\hsize}{\dimexpr\paperwidth-\evensidemargin-1in-2em}%
    }%
    \org@makefntext
  }%
}
\makeatother

\begin{document}
\lipsum[1] Hello\footnote{\lipsum[2]}
world.\footnote{\lipsum[3]} \lipsum[4]
\end{document}

If you have meant 2em to the right margin of the text body, then the redefinition of \@makefntext simplifies to:

\documentclass{scrbook}
\usepackage{lipsum}

\deffootnote[8em]{8em}{8em} {\textsuperscript{\thefootnotemark}}

\makeatletter
\@ifdefinable{\org@makefntext}{%
  \let\org@makefntext\@makefntext
  \renewcommand*{\@makefntext}{%
    \addtolength{\hsize}{-2em}%
    \org@makefntext
  }%
}
\makeatother

\begin{document}
\lipsum[1] Hello\footnote{\lipsum[2]}
world.\footnote{\lipsum[3]} \lipsum[4]
\end{document}