[Tex/LaTex] Redefine block environment in beamer

beamerenvironmentsmacros

I'm trying to redefine the block environment in beamer so that the itemize/enumerate bullets follow the color of block title instead of structure:

\documentclass{beamer}

\renewenvironment<>{block}[1]{%
    \begin{actionenv}#2%
      \def\insertblocktitle{#1}%
      \par%
      \mode<presentation>{%
        \setbeamercolor{local structure}{use=block title,%
           fg=block title.bg}}%
      \usebeamertemplate{block begin}}
    {\par%
      \usebeamertemplate{block end}%
    \end{actionenv}}

But this immediately throws the error

ERROR: LaTeX Error: Command \beamerx@\block already defined.

This seems very similar to the problem discussed at: How to redefine the \emph command in Beamer?

The aforementioned thread culminated in the discovery of a bug in beamer which was patched 4 years ago, and I'm wondering if this might be a similar bug in beamer's renewenvironment.

Best Answer

Yes, this seems to be also a similar bug with \newenvironment in beamer. The problem is the same mentioned by Loop Space in his answer to How to redefine the \emph command in Beamer?. The problem seems to be the same mentioned in the linked answer and the "solution" is similar.

Below, I replaced \newcommand by \renewcommand in two places in the definition of \beamer@newenvnoopt (original definition in the file beamerbaselocalstructure.sty); the places were the change were made were marked %<- here.

Please, use at your own risk.

\documentclass{beamer}

% ``Fix'' for possible bug
\makeatletter
\long\def\beamer@newenvnoopt#1#2#3#4{%
  \expandafter\renewcommand\expandafter<\expandafter>\csname#1\endcsname[#2]{#3}%<- here
  \expandafter\long\expandafter\def\csname end#1\endcsname{#4}%
}
\long\def\beamer@newenvopt#1#2[#3]#4#5{%
  \expandafter\renewcommand\expandafter<\expandafter>\csname#1\endcsname[#2][#3]{#4}%<- here
  \expandafter\long\expandafter\def\csname end#1\endcsname{#5}%
}
\makeatother

\renewenvironment<>{block}[1]{%
    \begin{actionenv}#2%
      \def\insertblocktitle{#1}%
      \par%
      \mode<presentation>{%
        \setbeamercolor{local structure}{use=block title,%
           fg=block title.bg}}%
      \usebeamertemplate{block begin}}
    {\par%
      \usebeamertemplate{block end}%
    \end{actionenv}}

\begin{document}

\begin{frame}
\begin{block}{A test new block}
test
\end{block}
\end{frame}

\end{document}

I've contacted one of the beamer maintainers about this.

Related Solutions

[Tex/LaTex] Beamer block environment without title

You could use an exampleblock environment with empty title:

\documentclass{beamer}
\usetheme{Warsaw}

\begin{document}

\begin{frame}
\begin{exampleblock}{}
  {\large ``To be, or not to be: that is the question.''}
  \vskip5mm
  \hspace*\fill{\small--- William Shakespeare, Hamlet}
\end{exampleblock}
\end{frame}

\end{document}

enter image description here

[Tex/LaTex] Redefine block template for Beamer theorem-like environment

You can set the theorem begin and theorem end templates to use an exampleblock:

\documentclass{beamer}
\usetheme{CambridgeUS}

\makeatletter
\setbeamertemplate{theorem begin}
{%
  \begin{exampleblock}
  {%
%    \inserttheoremheadfont% uncomment if you want amsthm-like formatting
    \inserttheoremname
    \inserttheoremnumber
    \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi%
    \inserttheorempunctuation
  }%
}
\setbeamertemplate{theorem end}{\end{exampleblock}}
\makeatother

\begin{document}

\begin{frame}
\begin{definition}
Test text.
\end{definition}
\begin{exampleblock}{Definition}
(Definition here)
\end{exampleblock}
\end{frame}

\end{document}

enter image description here

The above solution makes all theorem-like environments inherit the settings for exampleblock; if just the default definition environment must behave like exampleblock, all one has to do is to change the default style used for definition to make it equal to the example style; a simple way to achieve this is to \let both commands \definition and \enddefinition to \relax and then use \newtheorem to define the definition structure using the example style.

An example showing this approach; definition behaves as an exampleblock, but all other theorem-like structures preserve theis default behaviour:

\documentclass{beamer}
\usetheme{CambridgeUS}

\let\definition\relax
\let\enddefinition\relax

\theoremstyle{example}
\newtheorem{definition}[theorem]{\translate{Definition}}

\begin{document}

\begin{frame}
\begin{definition}
Test text.
\end{definition}
\begin{exampleblock}{Definition}
Test text.
\end{exampleblock}
\begin{theorem}
Test text.
\end{theorem}
\end{frame}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Beamer block environment without title

[Tex/LaTex] Redefine block template for Beamer theorem-like environment

Related Question