\setbeamertemplate{frametitle} 删除华沙框架标题中的颜色渐变

Question

我有这个例子，为什么颜色渐变效果被删除

\documentclass{beamer} 
\usefonttheme{serif}
\usepackage{lipsum}
\usetheme{Warsaw}

\begin{document}

\begin{frame}{frame title}
lipsum[2]
\end{frame}

\setbeamertemplate{frametitle}[default][right]

\begin{frame}{frame title}
\lipsum[2]
\end{frame}

\setbeamertemplate{frametitle}[default][center]

\begin{frame}{frame title}
\lipsum[2]
\end{frame}

\end{document}

Answer 1

主题warsaw不使用默认的框架标题，而是使用阴影外层主题中的框架标题。通过使用，\setbeamertemplate{frametitle}[default][...]您可以明确地将此框架标题替换为默认主题中的框架标题，该主题没有颜色渐变。

如果您想要改变warsaw框架标题中的某些内容，例如让其右对齐，您可以重新定义模板：

\documentclass{beamer} 
\usefonttheme{serif}
\usepackage{lipsum}
\usetheme{Warsaw}

\makeatletter
\setbeamertemplate{frametitle}
{%
  \nointerlineskip%
  \vskip-2pt%
  \hbox{\leavevmode
    \advance\beamer@leftmargin by -12bp%
    \advance\beamer@rightmargin by -12bp%
    \beamer@tempdim=\textwidth%
    \advance\beamer@tempdim by \beamer@leftmargin%
    \advance\beamer@tempdim by \beamer@rightmargin%
    \hskip-\Gm@lmargin\hbox{%
      \setbox\beamer@tempbox=\hbox{\begin{minipage}[b]{\paperwidth}%
          \vbox{}\vskip-.75ex%
          \leftskip0.3cm%
          \rightskip0.3cm plus1fil\leavevmode
          \hfill% <---- added to make it right aligned
          \insertframetitle%
          \ifx\insertframesubtitle\@empty%
            \strut\par%
          \else
            \par{\usebeamerfont*{framesubtitle}{\usebeamercolor[fg]{framesubtitle}\insertframesubtitle}\strut\par}%
          \fi%
          \nointerlineskip
          \vbox{}%
          \end{minipage}}%
      \beamer@tempdim=\ht\beamer@tempbox%
      \advance\beamer@tempdim by 2pt%
      \begin{pgfpicture}{0pt}{0pt}{\paperwidth}{\beamer@tempdim}
        \usebeamercolor{frametitle right}
        \pgfpathrectangle{\pgfpointorigin}{\pgfpoint{\paperwidth}{\beamer@tempdim}}
        \pgfusepath{clip}
        \pgftext[left,base]{\pgfuseshading{beamer@frametitleshade}}
      \end{pgfpicture}
      \hskip-\paperwidth%
      \box\beamer@tempbox%
    }%
    \hskip-\Gm@rmargin%
  }%
  \nointerlineskip
    \vskip-0.2pt
    \hbox to\textwidth{\hskip-\Gm@lmargin\pgfuseshading{beamer@topshade}\hskip-\Gm@rmargin}
    \vskip-2pt
}
\makeatother

\begin{document}

\begin{frame}{frame title}
lipsum[2]
\end{frame}

\end{document}