[AUCTeX] preview-latex: problems with beamer and TikZ

[Frederik]

Hello there!

1. I experience problems when I want to preview equations in a beamer
presentation. Imagine the following LaTeX document:

---------8<-----------8<------------------------------------------

\documentclass{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath,amssymb}

\usepackage[displaymath,textmath,graphics]{preview}
\PreviewEnvironment*{frame}

\begin{document}

\begin{frame}
  \frametitle{Lambacher Schweizer -- Das Integral (2)}
  \begin{align*}
    A_n &= \left(\frac{1}{n}\right)^3\cdot [0^2 + 1^2 + \ldots{} +
    (n-1)^2] \\
    \intertext{\scl{Summenformel: $\sum_{k=1}^{n-1}k^2 =
        \frac{1}{6}(n-1)n(n-2)$}}
    &= \frac{1}{n^3}\cdot \frac{1}{6}(n-1)n(2n-1) = \frac{1}{6}\cdot
    \left( 1-\frac{1}{n} \right)\cdot 1\cdot \left( 2-\frac{1}{n}
    \right) \\
    \lim_{n\to \infty}A_n &= \frac{1}{6}\cdot 1\cdot 1\cdot 2 =
    \frac{1}{3}
  \end{align*}
\end{frame}
\end{document}

%%% Local Variables:
%%% mode: latex
%%% TeX-master: t
%%% End:

---------8<-----------8<------------------------------------------

After invoking preview via C-c C-p C-b the short equation in
\intertext{...} is shown just behind \end{align*}.

However, changing the documentclass from beamer to scrartcl, removing
the preview images and reapplying style hooks results in a correct
behaviour after regenerating the previews.

So the problem seems to lie in the different treatments of the different
document classes. What do I have to do, in order to make preview-latex
treat beamer just like scrartcl?



2. I've found a rather odd behaviour of preview-latex when using TikZ.

I've got a dark background colour for emacs buffers. Normally this is no
problem at all for preview images; the background colour of the images
is just the same as the background colour of the buffer. But when I use
TikZ to draw a picture and use the "opacity=VALUE" option for e.g. a
\fill command, the preview images get a white background and become
absolutely unreadable.

Imagine the following LaTeX document:

---------8<-----------8<------------------------------------------

\documentclass{scrartcl}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}

\usepackage[displaymath,textmath,graphics]{preview}

\begin{document}

\begin{tikzpicture}
  \fill[green,opacity=0.5] (0,0) circle (1cm);
\end{tikzpicture}

Eine Gleichung:
\[ A = B  \]

\end{document}

%%% Local Variables:
%%% mode: latex
%%% TeX-master: t
%%% End:

---------8<-----------8<------------------------------------------

Removing the option "opacity=0.5" next to the fill command makes the
preview images display as usual.

How to avoid preview-latex misinterpreting this option?

Thanks and regards

-- 
Frederik