答案1
欢迎使用 TeX-SE!使用 Ti钾Z 这很简单。
\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}[t]
\frametitle{Example}
\foreach \X in {1,...,90} {Example }
\pause
\begin{tikzpicture}[overlay,remember picture]
\fill[gray,opacity=0.2] (current page.south west)
rectangle (current page.north east)
node[midway,opacity=0.8,fill=gray!80,scale=pi]
{DIAGRAM};
\end{tikzpicture}
\end{frame}
\end{document}