font size of \footcite of biblatex in beamer

Question

I have unsuccessfully tried to control the font size of \footcite with \renewcommand{\bibfont}{\tiny}? Is there any other way?

Answer 1

Changing the fontsize with \citesetup will affect all citations, not only those in footnotes. Simply redefining \footnotesize to \scriptsize wouldn't be advisable for article or book documents because the standard \footnotesize command includes settings for the vertical spacing of lists and displayed equations, while \scriptsize doesn't. This, on the other hand, shouldn't be of concern in a beamer document. So I'd say that

\renewcommand{\footnotesize}{\scriptsize}

is the way to go.

EDIT: I had forgotten about the biblatex conditional \iffootnote. I still think that redefining \footnotesize is preferable because it will also affect non-citation footnotes.

Answer 2

You can use \iffootnote in combination with \AtEveryCitekey.

Here the example:

\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@book{test,
  author="John Smith",
  title="The title",
  year=1099,
  publisher="nobody",  
}
\end{filecontents*}
\documentclass[12pt]{beamer}
\usepackage[backend=biber,style=authortitle]{biblatex}
\AtEveryCitekey{\iffootnote{\color{red}\scriptsize}{\color{blue}}}
\bibliography{\jobname}
\begin{document}
\begin{frame}
Text on the frame\footcite{test}\quad\cite{test}

\textbf{\bibname}
\printbibliography
\end{frame}
\end{document}

The command \citesetup is used in front of the cite-command. In such cases you can use:

\appto\citesetup{\Huge}

The test \iffootnote failse because citesetup is used before foot.. works. You can only test things like: \footnote{Bla \cite{..}}.