Move section page, progress bar to inner theme

beamerinnerthememetropolis.dtx

@@ -171,8 +171,80 @@
 % \end{macro}
 %
 %
-
+%
-
+% \subsection{Section page}
+%
+% \begin{macro}{section page}
+%   Template for the section title slide at the beginning of each section.
+%    \begin{macrocode}
+\setbeamertemplate{section page}{
+  \vspace{2em}
+  \centering
+  \begin{minipage}{22em}
+    \usebeamercolor[fg]{section title}
+    \usebeamerfont{section title}
+    \insertsectionHEAD\\[-1ex]
+    \usebeamertemplate*{progress bar in section page}
+  \end{minipage}
+  \par
+}
+\if@noSectionSlide\else%
+  \AtBeginSection{
+    \ifbeamer@inframe
+      \sectionpage
+    \else
+      \frame[plain,c]{\sectionpage}
+    \fi
+  }
+\fi
+%    \end{macrocode}
+%
+%   To give users the option to \MakeUppercase or \MakeLowercase the section
+%   title, we need to expand |\insertsectionhead| before applying the relevant
+%   formatting command. This solution was suggested by Enrico Gregorio in an
+%   answer to \href{http://tex.stackexchange.com/questions/112526/}{this
+%   StackExchange question}.
+%
+%    \begin{macrocode}
+\newcommand{\insertsectionHEAD}{\expandafter\formatsectionhead\insertsectionhead}
+\newcommand{\formatsectionhead}[3]{#1{#2}{\mthemetitleformat{#3}}}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{progress bar in section page}
+%   Template for the progress bar displayed by default on the section page.
+%    \begin{macrocode}
+\RequirePackage{calc}
+\newlength{\metropolis@progressonsectionpage}
+\setbeamertemplate{progress bar in section page}{
+  \setlength{\metropolis@progressonsectionpage}{%
+    \textwidth * \ratio{\insertframenumber pt}{\inserttotalframenumber pt}%
+  }%
+  \begin{tikzpicture}[tight background]
+    \usebeamercolor{progress bar}
+    \draw[bg, fill=bg] (0,0) rectangle (\textwidth, 0.4pt);
+    \draw[fg, fill=fg] (0,0) rectangle (\metropolis@progressonsectionpage, 0.4pt);
+  \end{tikzpicture}%
+}
+%    \end{macrocode}
+%
+%   The above code assumes that |\insertframenumber| is less than or equal to
+%   |\inserttotalframenumber|. However, this is not true on the first compile;
+%   in the absence of an |.aux| file, |\inserttotalframenumber| defaults to 1.
+%   This behaviour could cause fatal errors for long presentations, as
+%   |\metropolis@progressonsectionpage| would exceed \TeX's maximum length
+%   (16383.99999pt, roughly 5.75 metres or 18.9 feet).
+%   To avoid this, we increase the default value for |\inserttotalframenumber|;
+%   presentations with over 4000 slides will still break on first compile, but
+%   users in that situation likely have deeper problems to solve.
+%
+%    \begin{macrocode}
+\def\inserttotalframenumber{100}
+%    \end{macrocode}
+% \end{macro}
+%
+%
+%
 % \iffalse
 %</package>
 % \fi

beamerthemem.dtx

@@ -162,54 +162,6 @@
 }
 
 %    \end{macrocode}
-
-%    \end{macrocode}
-%
-% Progressbar
-%
-%    \begin{macrocode}
-\RequirePackage{calc}
-%    \end{macrocode}
-%
-% \begin{macro}{\inserttotalframenumber}
-%    \begin{macrocode}
-\def\inserttotalframenumber{100}  % prevent \progressbar@percent from getting too big on first compile
-%    \end{macrocode}
-% \end{macro}
-%
-%    \begin{macrocode}
-\newlength{\progressbar@percent}
-%    \end{macrocode}
-%
-% \begin{macro}{\progressbar}
-%    \begin{macrocode}
-\newcommand{\progressbar}[1]{%
-  \setlength{\progressbar@percent}{%
-    #1 * \ratio{\insertframenumber pt}{\inserttotalframenumber pt}%
-  }%
-  \begin{tikzpicture}[tight background]
-    \usebeamercolor{progress bar}
-    \draw[bg, fill=bg] (0,0) rectangle (#1, 0.4pt);
-    \draw[fg, fill=fg] (0,0) rectangle (\progressbar@percent, 0.4pt);
-  \end{tikzpicture}%
-}
-%    \end{macrocode}
-% \end{macro}
-%
-% Commands
-%
-% \begin{macro}{\insertsectionHEAD}
-%    \begin{macrocode}
-\newcommand{\insertsectionHEAD}{%
-  \expandafter\insertsectionHEADaux\insertsectionhead}
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\insertsectionHEADaux}
-%    \begin{macrocode}
-\newcommand{\insertsectionHEADaux}[3]{\mthemetitleformat{#3}}%
-%    \end{macrocode}
-% \end{macro}
 %
 % Create a plain frame with dark background
 %
@@ -338,38 +290,6 @@
 }
 %    \end{macrocode}
 %
-% Sections
-%
-%    \begin{macrocode}
-\setbeamertemplate{section page}
-{
-  \vspace{2em}
-  \centering
-  \begin{minipage}{22em}
-    \usebeamercolor[fg]{section title}
-    \usebeamerfont{section title}
-    \insertsectionHEAD\\[-1ex]
-    \progressbar{\textwidth}
-  \end{minipage}
-  \par
-}
-%    \end{macrocode}
-%
-% Insert frame with section title at every section start
-%
-%    \begin{macrocode}
-\if@noSectionSlide\else%
-  \AtBeginSection[]
-  {
-    \ifbeamer@inframe
-      \sectionpage
-    \else
-      \frame[plain,c]{\sectionpage}
-    \fi
-  }
-\fi
-%    \end{macrocode}
-%
 % Captions
 %
 %    \begin{macrocode}