增加 Beamer 脚线的高度

Question

tabular当我在演示文稿中添加环境时footline，只显示第一行。如何增加脚注线的高度以显示整个表格？

\documentclass[12pt,ngerman]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\setbeamertemplate{navigation symbols}{}

\begin{document}

\setbeamertemplate{footline}{
{
\tiny\begin{tabular}{p{0.25\textwidth}p{0.25\textwidth}p{0.45\textwidth}}
First line & John Doe & fsdfs\\ 
second line \& Title of the talk & dsdfsd\\
some third line & & 
\end{tabular}
}}

\frame{
\frametitle{fdfsdgdf}

\begin{itemize}
\item 
\item 
\item 
\end{itemize}
}

\end{document}

Answer 1

一个选项是修补\beamer@calculateheadfoot命令（在文件中定义beamerbaseframecomponents.sty）以为新的脚注添加一些空间：

\documentclass[12pt,ngerman]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{etoolbox}
\usepackage{lipsum}

\setbeamertemplate{navigation symbols}{}

\makeatletter
\patchcmd{\beamer@calculateheadfoot}{\advance\footheight by 4pt}{\advance\footheight by 20pt}{}{}
\makeatother

\setbeamertemplate{footline}{
{%
\begin{beamercolorbox}[wd=\paperwidth,ht=1.5ex,dp=20pt,leftskip=.3cm,rightskip=.3cm]{author in head/foot}
\tiny\begin{tabular}[t]{@{}p{0.25\textwidth}p{0.25\textwidth}p{0.38\textwidth}@{}}
First line & John Doe & fsdfs\\ 
second line \& Title of the talk & dsdfsd\\
some third line & & 
\end{tabular}
\end{beamercolorbox}
}}

\begin{document}

\frame{
\frametitle{Test Frame}
\lipsum[4]
}

\end{document}

beamercolorbox我还在定义中添加了，但这是完全可选的。

Answer 2

随着当前 beamer 开发版本（应包含在 beamer v3.70 或更新版本中），beamer 现在会在每帧开始时重新计算头部和脚部的高度，因此您可以按原样使用代码：

\documentclass[12pt,ngerman]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\setbeamertemplate{navigation symbols}{}

\begin{document}

\setbeamertemplate{footline}{
{
\tiny\begin{tabular}{p{0.25\textwidth}p{0.25\textwidth}p{0.45\textwidth}}
First line & John Doe & fsdfs\\ 
second line \& Title of the talk & dsdfsd\\
some third line & & 
\end{tabular}
}}

\frame{
\frametitle{fdfsdgdf}

\begin{itemize}
\item 
\item 
\item 
\end{itemize}
}

\end{document}