Set lateral margins to official values.

Work around Beamer bug #614 (appears when left margin > right margin).

model.tex

@@ -20,6 +20,8 @@
 % • nohelvet garde les polices par défaut.
 % • latex garde les polices par défaut et les symboles de navigation Beamer.
 
+% Vous pouvez aussi ajuster les marges en décommentant :
+% \setbeamersize{text margin left=1cm, text margin right=1cm}
 
 % Gestion des fontes.  (FIXME incompatible LuaTeX.)
 \usepackage[T1]{fontenc}
@@ -371,7 +373,7 @@
 \begin{frame}
   \frametitle{Dimensions modifiables}
   \newcommand*\Xtt{\ttfamily\textbackslash}
-  \centering
+  \hspace*{-2cm}%
   \begin{tikzpicture}[scale=0.5,font=\tiny,>=stealth]
     %
     % On inclut un frame standard précompilé.

texinputs/beamerthemetptnew.sty

@@ -17,7 +17,7 @@
 \RequirePackage{beamerouterthemeinfolines}
 \setbeamertemplate{headline}[default]
 \setbeamertemplate{footline}[default]
-\setbeamersize{text margin left=1cm,text margin right=1cm}
+\setbeamersize{text margin left=24mm,text margin right=8mm}
 
 % Désactivation de la sidebar par défaut, packages divers.
 \defbeamertemplate*{sidebar right}{tpt default}{}
@@ -748,6 +748,91 @@
 \email{}
 \newcommand\dept[1]{\institute{#1}}
 
+%
+% On répare un bug de certaines versions de Beamer, qui pose problème
+% avec les marges par défaut.  (Code dérivé de beamerbasecolor.sty.)
+%
+\@tempswafalse
+\@ifclasslater{beamer}{2017/08/22}{\@tempswatrue}{}
+\@ifclasslater{beamer}{2020/07/25}{\@tempswafalse}{}
+\if@tempswa
+\renewenvironment{beamercolorbox}[2][]{%
+  \def\beamer@vmode{\leavevmode}%
+  \setkeys{beamercolbox}{wd=\textwidth,ht={},dp={},%
+    leftskip=0pt,rightskip=0pt plus1fil,%
+    sep=0pt,colsep=0pt,colsep*=0pt,%
+    shadow=false,rounded=false,ignorebg=false}%
+  \setkeys{beamercolbox}{#1}%
+  \ifbeamercolorempty[bg]{#2}{\@tempswafalse}{\@tempswatrue}%
+  \ifbeamer@colbox@ignorebg\@tempswafalse\fi%
+  \def\beamer@colbox@color{#2}%
+  \setbox\beamer@tempbox=\hbox\bgroup\color@begingroup
+    \ifbeamer@colbox@ignorebg%
+      \colorlet{beamer@temp@color}{bg}%
+      \usebeamercolor[fg]{#2}%
+      \colorlet{bg}{beamer@temp@color}%
+    \else%
+      \usebeamercolor[fg]{#2}%
+    \fi%
+    \vbox\bgroup%
+    \hsize=\beamer@colbox@wd%
+    \@arrayparboxrestore%
+    \leftskip=\beamer@colbox@ls%
+    \ifdim\beamer@colbox@sep>\z@\advance\leftskip\beamer@colbox@sep\fi%
+    \rightskip=\beamer@colbox@rs%
+    \ifdim\beamer@colbox@sep>\z@\advance\rightskip\beamer@colbox@sep\fi%
+    \if@tempswa\ifdim\beamer@colbox@colsep>\z@%
+      \advance\leftskip by\beamer@colbox@colsep%
+      \advance\rightskip by\beamer@colbox@colsep%
+      \vskip\beamer@colbox@colsep%
+    \fi%
+      \ifdim\beamer@colbox@colseps>\z@\vskip\beamer@colbox@colseps\fi%
+    \fi%
+    \ifdim\beamer@colbox@sep>\z@\vskip\beamer@colbox@sep\fi%
+    \beamer@vmode\ignorespaces}{%
+    \ifdim\beamer@colbox@sep>\z@\vskip\beamer@colbox@sep\fi%
+    \if@tempswa
+      \ifdim\beamer@colbox@colsep>\z@\vskip\beamer@colbox@colsep\fi%
+      \ifdim\beamer@colbox@colseps>\z@\vskip\beamer@colbox@colseps\fi%
+    \fi%
+  \egroup\color@endgroup\egroup%
+  \wd\beamer@tempbox=\beamer@colbox@wd%
+  \ifx\beamer@colbox@ht\@empty\else\ht\beamer@tempbox=\beamer@colbox@ht\fi%
+  \ifx\beamer@colbox@dp\@empty\else\dp\beamer@tempbox=\beamer@colbox@dp\fi%
+  \ifbeamer@colbox@rounded%
+    \if@tempswa%
+      \begin{beamerboxesrounded}[%
+        shadow=\beamer@colbox@shadow,%
+        lower=\beamer@colbox@color,%
+        upper=normal text,%
+        width=\beamer@colbox@wd]{}%
+        \box\beamer@tempbox%
+      \end{beamerboxesrounded}%
+    \else%
+      \ifdim\wd\beamer@tempbox>\textwidth%
+        \setbox\beamer@tempbox=\hbox to\textwidth{\hss\box\beamer@tempbox\hss}%
+      \fi%
+      \box\beamer@tempbox%
+    \fi%
+  \else%
+    \if@tempswa\setbox\beamer@tempbox=\hbox{%
+      \usebeamercolor{\beamer@colbox@color}%
+      \hskip-\beamer@colbox@colseps%
+      \fboxsep=\z@\colorbox{bg}{%
+        \hskip\beamer@colbox@colseps%
+        \box\beamer@tempbox%
+        \hskip\beamer@colbox@colseps%
+      }%
+      \hskip-\beamer@colbox@colseps%
+      }\fi%
+    \ifdim\wd\beamer@tempbox>\textwidth%
+      \setbox\beamer@tempbox=\hbox to\textwidth{\hskip0pt minus\beamer@leftmargin\relax\box\beamer@tempbox\hskip0pt minus\beamer@rightmargin\relax}%
+    \fi%
+    \box\beamer@tempbox%
+  \fi%
+}
+\fi
+
 
 \mode<all>