# Can't set empty title page background after beamer upgrade

Update: see this bug report.

I just upgraded to beamer 3.52 and can no longer set an empty background color for title page. Somehow the background color is always white (or I can set it to something else, but if I try to make it empty, it goes back to white). I would like to print the title over a background drawing, and it now looks terrible.

Here is a minimal working example:

\documentclass[12pt]{beamer}

\setbeamerfont*{title}{parent=structure, size=\Huge, series=\bfseries}

\title{My Titlepage That Doesn't Work}
\date{}

\begin{document}

{
\setbeamercolor{background canvas}{bg=black!50}
\setbeamercolor{title page}{bg=} % stays white
\maketitle
}

\end{document}


Here is what it looks like with beamer 3.5:

That's exactly what I want--text printed over background. Now here's what I get with beamer 3.52:

This is presumably some kind of bug, but because the version got deployed with arch linux's texlive package, I would ideally like to find a workaround. Unfortunately, just setting the title page.bg to a solid color won't work in my non-minimal actual use case, because in my real use case I have a more complex drawing in the background.

I looked at the source code for beamerinnerthemedefault.sty and it seems to be making a beamercolorbox with the title page template, so I don't understand why it is getting set to a white background.

• Well, beamer 3.53 seems to work again, so ideally texlive will update this sooner than a year from now... – user3188445 Sep 15 '18 at 5:13
• I run MacTeX2018, and version 3.53 of beamer was installed a week ago on my system. Please clarify what you mean by "ideally texlive will update this sooner than a year from now". FWIW, I can confirm that your MWE runs correctly when compiled with version 3.53 of beamer. (I haven't tried it withan earlier version.) – Mico Sep 15 '18 at 7:09

As suggested by Joseph Wright in the bug report, you can use the newer version 3.53 of beamer. You can install it manually without touching the arch pacman tarballs by creating the folder

~/texmf


Its structure is the same as

/usr/share/texmf-dist


So, you can create the latex folder in there and copy the up-to-date beamer files (from e.g. ctan). Alternatively, you can

$git clone https://github.com/josephwright/beamer$ cd beamer
\$ env texlua ./build.lua install


The bugfix is

diff --git a/base/beamerbasecolor.sty b/base/beamerbasecolor.sty
index 8d21e32..4dce70e 100644
--- a/base/beamerbasecolor.sty
+++ b/base/beamerbasecolor.sty
@@ -207,7 +207,7 @@
\box\beamer@tempbox%
\fi%
\else%
-    \setbox\beamer@tempbox=\hbox{%
+    \if@tempswa\setbox\beamer@tempbox=\hbox{%
\usebeamercolor{\beamer@colbox@color}%
\hskip-\beamer@colbox@colseps%
\fboxsep=\z@\colorbox{bg}{%
@@ -216,7 +216,7 @@
\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@leftmargin\relax}%
\fi%


You can try to patch that via xpatch or regexpatch, too.