I am trying to add blur shadows to a beamer presentation using the pgf-blur package. Here is a minimal working example:
\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{shadows.blur}
\begin{document}
\begin{frame}
\begin{tikzpicture}
\node[minimum height=1cm, minimum width=3cm,
rounded corners, fill=red!30, blur shadow] {};
\end{tikzpicture}
\end{frame}
\end{document}
Unfortunately, when I try to present my slides using any of the poppler-based renderers (like xpdf, evince, okular, impressive), I get an extremely ugly artifact at the border and especially corners. Here is what it looks like:
Interestingly, the problem goes away if I do the same thing in a \documentclass{article}
. Here is a screenshot of the same image without beamer:
Because the problem does not happen with mupdf, this may actually just be a bug in libpoppler. However, libpoppler is so prevalent that I need to find a way to work around it. The fact that the bug goes away without beamer gives me some hope there is a way around this, but I have no idea what beamer might be doing to cause the artifact. I'd also be happy with an alternative to pgf-blur, if there is one.
shadows
library which beamer uses\ifbmb@shadow
? It doesn't seem to be using much of a library but rather implementing a lot of the stuff inline with low-level pgf commands...