Beamer: get the total number of frames

Question

I try to put a colored bar on the bottom of each frame of a Beamer document the lenght of which increases during the presentation. I wrote the following code:

\setbeamertemplate{footline}{%
\leavevmode%
  \hbox{%
        \begin{tikzpicture}
            \draw[-, ultra thick, yellow!50!green] (0,0) -- (\paperwidth*\value{framenumber}/\total,0) ;
        \end{tikzpicture}
  }
}

and its works well, but the \total command is the total number of frames which I previousely manually defined (I need it because I want the bar to reach the right side of the screen at the last frame). If I can get the current frame number with \value{framenumber}, I do not find an equivalent command to get the value of the total frame number. I would like to know if there exists a solution (I think it is possible since \inserttotalframenumber can print it, but I do not know how it really works to calculate it since it does not seem to be related to some counter "totalframenumber"...).

Answer 1

You can use \inserttotalframenumber not only to print the total number of frames, you can also use it in your calculation:

\documentclass{beamer}
\usepackage{tikz}

\setbeamertemplate{footline}{%
  \begin{tikzpicture}[overlay,remember picture]
      \draw[-, line width=0.2cm, yellow!50!green] (current page.south west) -- (\paperwidth*\value{framenumber}/\inserttotalframenumber,0) ;
  \end{tikzpicture}
}

\begin{document}
\begin{frame}
test
\end{frame}
\begin{frame}
test
\end{frame}
\end{document}

Answer 2

I finally found a solution by discovering the package totcount which deals with .aux files. Here is an ECM of what I have wrote:

\documentclass[t]{beamer}

\usepackage{totcount}
\regtotcounter{framenumber}

\usepackage{tikz}
\usepackage{lipsum}

\setbeamertemplate{footline}{%
\leavevmode%
  \hbox{%
    \hspace{-0.3cm}        
    \begin{tikzpicture}
        \draw[-, line width = 5pt, yellow!50!green] (0,0) -- (\paperwidth*\value{framenumber}/\totvalue{framenumber}+4,0) ;
    \end{tikzpicture}
  }
}

\setbeamertemplate{navigation symbols}{}

\begin{document}

\begin{frame}
\lipsum[1]
\end{frame}

\begin{frame}
\lipsum[2]
\end{frame}

\begin{frame}
\lipsum[3]
\end{frame}

\begin{frame}
\lipsum[4]
\end{frame}

\begin{frame}
\lipsum[5]
\end{frame}

\end{document}

It needs to be compiled two times to update the total frame number. The \hspace{-0.3cm} and the +4 are little adjustments to make the bar touch the border of the frame.