具有可变尺寸和框架位置的 Beamer 框

Question

我想构建灵活的投影仪盒，以便可以更改框架内的宽度和对齐方式。传递选项width=和alignment=，其中宽度是有效值，对齐方式可以是左对齐、居中对齐和右对齐。

我有以下 MWE，但是它不起作用。

\documentclass{beamer}

\usepackage{xstring}
\usepackage{xparse}

\ExplSyntaxOn

\NewDocumentCommand{\processlist}{ m m }
    {%
        \clist_map_inline:nn { #1 } {%
            \IfSubStr{##1}{#2}{%
                \StrBehind{##1}{=}
            }{}
        }
    }

\ExplSyntaxOff

\setbeamercolor{block title alerted}{fg=blue,bg=green}
\setbeamercolor{block body alerted}{bg=red}

\newenvironment<>{varalertblockA}[2][0.9\textwidth]{%
  \setlength{\textwidth}{#1}
  \begin{actionenv}#3%
    \def\insertblocktitle{#2}%
    \par%
    \setbeamercolor{local structure}{parent=alerted text}%
    \usebeamertemplate{block alerted begin}}
  {\par%
  \usebeamertemplate{block alerted end}%
  \end{actionenv}}

\newcommand{\cvaralertblock}[3][0.9\textwidth]{%
    \hfill{}\vbox{%
        \begin{varalertblockA}[#1]{#2}%
            #3%
        \end{varalertblockA}%
    }\hfill{}%
}

\newenvironment<>{varalertblockB}[2][]{%
    \ifnum\pdfstrcmp{\processlist{#1}{align}}{center}=0%
    \hfill{}%
    \else%
    \fi%
    \setbox0=\hbox{\processlist{#1}{width}}\ifdim\wd0=0pt%
    \else%
        \setlength{\textwidth}{\processlist{#1}{width}}%
    \fi%
    \hfill{}%
  \begin{actionenv}#3%
    \def\insertblocktitle{#2}%
    \par%
    \setbeamercolor{local structure}{parent=alerted text}%
    \usebeamertemplate{block alerted begin}}
  {\par%
  \usebeamertemplate{block alerted end}%
  \end{actionenv}
    \ifnum\pdfstrcmp{\processlist{#1}{align}}{center}=0%
        \hfill{}%
    \else%
    \fi%
    }


\begin{document}
%\processlist{align=right,a,b,c, d z}{align}

% No working
\begin{varalertblockB}[width=2cm,align=center]{Test}
    Test
\end{varalertblockB}{Test}

\cvaralertblock[0.5\textwidth]{Test}{Test}

\begin{varalertblockA}{Test}
    Test
\end{varalertblockA}

\end{document}

Answer 1

为什么要重新发明轮子？tcolorbox已经提供了所有这些功能！

\documentclass{beamer}
\usepackage[most]{tcolorbox}

\newtcolorbox{myblock}[2][]{%
    beamer,breakable,colback=blue!10!white,colframe=blue!50!black,#1,title=#2
}%

\begin{document}


\begin{frame}

\begin{myblock}{test}
    bla
\end{myblock}

\begin{myblock}[width=3cm]{test}
    bla
\end{myblock}

\begin{myblock}[halign=center]{test}
    bla
\end{myblock}

\end{frame}

\end{document}

使用 tcolorbox 内部主题您可以保留正常的block环境语法：

\documentclass{beamer}
\usetheme{Warsaw}

\useinnertheme{tcolorbox}

\begin{document}
\begin{frame}

\begin{block}{test}
    bla
\end{block}

{
\tcbset{width=4cm}
\begin{block}{test}
    bla
\end{block}
}

{
\tcbset{halign=center}
\begin{block}{test}
    bla
\end{block}
}
\end{frame}
\end{document}