beamerheader-footersectioning
Is there a way to make \frametitle automatically take the \subsection heading?
Or maybe equivalently, is there a way to make the section\subsection titles in the header larger? I am afraid the audience may not follow the section\subsection title.
Thanks! (FWIW, so far I've been using the Warsaw theme)
To use section and subsection names in frame title in beamer, one can use \secname and \subsecname as shown below:
\section{About project}
\subsection{Easy stuff}
\begin{frame}{\secname : \subsecname}
...
\end{frame}
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}
Best Answer
Adding
will replace all frame titles, as far as they exist, but will not magically make a frame title appear if you don't give the argument to the frame environment or give a \frametitle{} command.
ETA: Additionally adding
makes every frame have a title, even if it is \relax by default. (This is somewhat hackish.)