How can I change the font size of the footer in Beamer without modifying the font of the title (on the title page)? Also, when I try to change the title's font with \title{\fontsize{20}{25} My Title} it doesn't seem to work. Thank you.
[Tex/LaTex] Beamer Font Size for Footer
beamerfontsizeheader-footer
Related Solutions
The Berlin theme uses internally the miniframes outer theme; this outer theme explicitly sets the height of the color box used for the subsection in head/foot as 2.5ex, and its depth as 1.125ex. A change in the size font for the subsections won't therefore increase the height and depth of this box and will produce the undesired effect you noticed.
To change this behaviour, one can make the height and depth of this box font size-aware, by setting their values according to the height and depth of some appropriate characters with the desired font size, as I did in my example code below.
Notice also that I changed the order of \usetheme and \setbeamerfont so you don't have to declare the font size inside \subsection:
\documentclass[compress]{beamer}
\usetheme[]{Berlin}
\setbeamerfont*{section in head/foot}{size=\huge}
\setbeamerfont*{subsection in head/foot}{size=\huge}
\newlength\SubHt
\settoheight\SubHt{\usebeamerfont{subsection in head/foot}S}
\newlength\SubDh
\settodepth\SubDh{\usebeamerfont{subsection in head/foot}g}
\makeatletter
\setbeamertemplate{headline}
{%
\begin{beamercolorbox}[colsep=1.5pt]{upper separation line head}
\end{beamercolorbox}
\begin{beamercolorbox}{section in head/foot}
\vskip2pt\insertnavigation{\paperwidth}\vskip2pt
\end{beamercolorbox}%
\ifbeamer@theme@subsection%
\begin{beamercolorbox}[colsep=1.5pt]{middle separation line head}
\end{beamercolorbox}
\begin{beamercolorbox}[ht=1.5\SubHt,dp=1.5\SubDh,%defaults: ht=2.5ex, dp=1.125ex
leftskip=.3cm,rightskip=.3cm plus1fil]{subsection in head/foot}
\usebeamerfont{subsection in head/foot}\insertsubsectionhead
\end{beamercolorbox}%
\fi%
\begin{beamercolorbox}[colsep=1.5pt]{lower separation line head}
\end{beamercolorbox}
}
\makeatother
\begin{document}
\section{Section 1}\subsection{Subsection g1}
\begin{frame}{Frame}
Content
\end{frame}
\end{document}
In this case, I propose you a more sophisticated definition for the footline template:
\documentclass{beamer}
\usetheme{Frankfurt}
\newcommand\mytext{some text}
\makeatother
\setbeamertemplate{footline}
{%
\leavevmode%
\hbox{\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm]{author in head/foot}%
\mytext
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm plus1fil]{author in head/foot}%
\usebeamerfont{author in head/foot}\insertshortauthor\hfill\insertpagenumber
\end{beamercolorbox}}%
\vskip0pt%
}
\makeatletter
\author[JD]{John Doe}
\begin{document}
\begin{frame}
Test
\end{frame}
\end{document}
I used two beamercolorboxes (one for the additional text, the other one for the short author and page number) to give you the possibility to customize each one separately, but of course, you could only use one and distribute the information to suit your needs.
To change the color used for the beamerboxes, set a beamer color and then use it in the mandatory argument for beamercolorbox; for example:
\documentclass{beamer}
\usetheme{Frankfurt}
\setbeamercolor{footlinecolor}{bg=black!70,fg=white}
\newcommand\mytext{some text}
\makeatother
\setbeamertemplate{footline}
{%
\leavevmode%
\hbox{\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm]{footlinecolor}%
\mytext
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm plus1fil]{footlinecolor}%
\usebeamerfont{author in head/foot}\insertshortauthor\hfill\insertpagenumber
\end{beamercolorbox}}%
\vskip0pt%
}
\makeatletter
\author[JD]{John Doe}
\begin{document}
\begin{frame}
Test
\end{frame}
\end{document}
Best Answer
You need the command
\selectfontafterfontsizeDetailed information are documented in the Docmentation of LaTeX font commands
EDIT: Use the theme
AnnArborand the optional argument of\title.