beamer: Determine the Last Frame Before Appendix Starts (Even if There Are <Overlay Specifications>)

Question

• Normally I have something like Frame 4 / 30 in the footline.
• The total frame count is done by the command \insertframenumber.
• In my beamer presentation, I have an extensive appendix/backup.
• Therefore I didn't want the appendix frames to be counted to the total frame count.
• I used this and that question to do that -- leading to a new custom command called \myLastContentFrame.
• Everything was good.
• Now I used overlay specifications like [<+->] and the \myLastContentFrame sadly also considers the overlays into account.

How to determine the last frame before the appendix even if overlay specifications are used? In the appendix frames I want e. g. 34 / 30 (where 30 is the last content frame count).

\documentclass[c]{beamer}

%% Appearance
% -----------------------
\setbeamercolor{block title}{fg=white,bg=red}
\setbeamercolor{block body}{fg=black,bg=gray}
\setbeamercolor{background canvas}{bg=pink}
% -----------------------

%% Functionality
% -----------------------
\usepackage{xparse}

% https://tex.stackexchange.com/questions/347560
\ExplSyntaxOn
\DeclareExpandableDocumentCommand{\myLastContentFrame}{}
 {
  \fp_to_int:n
   {
     (
      \use:c{beamer@startpageofappendix} - 1 > 0
      ?
      \use:c{beamer@startpageofappendix} - 1 
      :
      \inserttotalframenumber
     )
   }
 }
\ExplSyntaxOff
% -----------------------

\begin{document}

\begin{frame}
\frametitle{Content Frame 1}
\begin{itemize}
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myLastContentFrame
\end{itemize}
\end{frame}

\begin{frame}
\frametitle{Content Frame 1}
\begin{itemize}[<+->]
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myLastContentFrame
\end{itemize}
\end{frame}

\begin{frame}
\frametitle{Last Content Frame}
\begin{itemize}[<+->]
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myLastContentFrame
\end{itemize}

\begin{block}{Last Content Frame}
The number of this frame -- the last frame befpore the appendix starts -- should be the value of \texttt{\textbackslash myLastContentFrame}.
\end{block}

\end{frame}

\appendix

\begin{frame}
\frametitle{First Appendix Frame}
\Huge \textcolor{red}{Start of Appendix!}
\begin{itemize}
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myLastContentFrame
\end{itemize}
\end{frame}

\end{document}

Answer 1

You might suspend the counter framenumber with the command \SuspendCounters from the xassoccnt package, i.e.

with \SuspendCounters{framenumber}.

If the counting should be reenabled, say \ResumeSuspendedCounters{framenumber} later on.

I also changed to using total counters, i.e. with \DeclareTotalAssociatedCounters (requires xassoccnt v1.2)

\documentclass[c]{beamer}

\usepackage{xassoccnt}

% Pre version 1.1 of xassoccnt version
\NewTotalDocumentCounter{totalframenumbers}
\DeclareAssociatedCounters{framenumber}{totalframenumbers}

% Version 1.2. of xassoccnt allows this in one go...
%\DeclareTotalAssociatedCounters{framenumber}{totalframenumbers}

%% Appearance
% -----------------------
\setbeamercolor{block title}{fg=white,bg=red}
\setbeamercolor{block body}{fg=black,bg=gray}
\setbeamercolor{background canvas}{bg=pink}
% -----------------------

%% Functionality
% -----------------------
\usepackage{xparse}

% http://tex.stackexchange.com/questions/347560

\newcommand{\myReallyLastContentFrame}{%
  \TotalValue{totalframenumbers}
}
\ExplSyntaxOn
\DeclareExpandableDocumentCommand{\myLastContentFrame}{}
 {
  \fp_to_int:n
   {
     (
      \use:c{beamer@startpageofappendix} - 1 > 0
      ?
      \use:c{beamer@startpageofappendix} - 1 
      :
      \inserttotalframenumber
     )
   }
 }
\ExplSyntaxOff
% -----------------------

\begin{document}

\begin{frame}
\frametitle{Content Frame 1}
\begin{itemize}
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myReallyLastContentFrame 
\end{itemize}
\end{frame}

\begin{frame}
\frametitle{Content Frame 1}
\begin{itemize}[<+->]
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myReallyLastContentFrame
\end{itemize}
\end{frame}

\begin{frame}
\frametitle{Last Content Frame}
\begin{itemize}[<+->]
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myReallyLastContentFrame
\end{itemize}

\begin{block}{Last Content Frame}
The number of this frame -- the last frame befpore the appendix starts -- should be the value of \texttt{\textbackslash myLastContentFrame}.
\end{block}

\end{frame}

\appendix

\SuspendCounters{framenumber}
\begin{frame}
\frametitle{First Appendix Frame}
\Huge \textcolor{red}{Start of Appendix!}
\begin{itemize}
\huge
\item \texttt{\textbackslash insertframenumber:} \insertframenumber
\item \texttt{\textbackslash inserttotalframenumber:} \inserttotalframenumber
\item \texttt{\textbackslash myLastContentFrame:} \myReallyLastContentFrame
\end{itemize}
\end{frame}

\end{document}

Answer 2

No need to reinvent the wheel, appendixnumberbeamer already did this for you:

(the only thing I changed is to comment two lines from the original appendix definition, otherwise the appendix would restart counting from 1)

\documentclass[c]{beamer}

\usepackage{appendixnumberbeamer}

\setbeamertemplate{footline}{\insertframenumber~/~\inserttotalframenumber}

\makeatletter
\def\appendix{
  \xdef\mainend{\theframenumber}
  \immediate\write\@auxout{\string\global\string\@namedef{mainendframenumber}{\mainend}}
  \appendixorig
%  \gdef\inserttotalframenumber{\appendixtotalframenumber}%
%  \setcounter{framenumber}{0}
}
\makeatother

\begin{document}

\begin{frame}
test
\pause[3]
\end{frame}

\begin{frame}
test
\end{frame}

\appendix

\begin{frame}
Appendix
\end{frame}

\end{document}