[Tex/LaTex] Center block on frame with Beamer

Question

I wanted to change the block width in my presentations so, after a quick search on the website, I found the varblock solution : Changing default width of blocks in beamer

It consists in adding :

\newenvironment<>{varblock}[2][.9\textwidth]{%
  \setlength{\textwidth}{#1}
  \begin{actionenv}#3%
    \def\insertblocktitle{#2}%
    \par%
    \usebeamertemplate{block begin}}
  {\par%
    \usebeamertemplate{block end}%
  \end{actionenv}}

to the preamble. Now, in my .tex document, I have blocks like this :

\begin{varblock}[8cm]{Title}
Some content...
\end{varblock}

But I cannot center the block horizontally on the frame. I tried to put these three lines between \begin{center}...\end{center} and \begin{centering}...\end{centering} but the block still remains on the left side of the frame. Thanks for your help.

Answer 1

If the shortened block is put inside a minipage, you can center it easily

\documentclass{beamer}
\usetheme{Warsaw}

\newenvironment<>{varblock}[2][.9\textwidth]{%
    \setlength{\textwidth}{#1}
    \begin{actionenv}#3%
        \def\insertblocktitle{#2}%
        \par%
        \usebeamertemplate{block begin}}
    {\par%
        \usebeamertemplate{block end}%
    \end{actionenv}}

\begin{document}
    \begin{frame}
        \begin{center}
            \begin{minipage}{4cm}
                \begin{varblock}[4cm]{New block}
                    Variable width, here 4cm
                \end{varblock}
            \end{minipage}
        \end{center}
    \end{frame}
\end{document}