我目前正在制作一个自定义的 Beamer 主题，我非常喜欢这个smoothbars主题。但是，我想做的改变是，我希望将栏本身分成几个水平隔间，每个部分一个，每个部分都有从循环中选择的不同颜色，而不是整个栏都是单色的。
因为我认为这需要我研究smoothbars主题的实际代码，所以这就是我所做的。
我开始查看代码，并找到以下行
\insertnavigation{\paperwidth}
它扩展为具有大量跳过和装箱命令的表达式，但还包含
\dohead
然后展开为一个循环
\beamer@headcounter =0\relax
\loop
\ifnum \beamer@headcounter <\beamer@totalheads \advance\beamer@headcounter by1\relax
\csname @@head\the \beamer@headcounter \endcsname
\repeat
我天真地以为这个循环会遍历各个部分，并在某些框环境中打印部分标题，所以我查看了的内容\csname @@head\the \beamer@headcounter \endcsname。有趣的是，这些内容精确地扩展到文件行的内容*.nav，例如
\sectionentry {1}{Introduction}{2}{Introduction}{0}
这是有道理的，因为该.nav文件包含了所有必要的信息 - 但我感到困惑的是，不仅出现了章节标题，还出现了各种其他内容，比如
\beamer@framepages {1}{1}
或者
\beamer@sectionpages {1}{1}
\beamer@subsectionpages {1}{1}
smoothbar我真的不明白这里发生了什么。为了以5 种不同颜色为周期改变每个部分的背景颜色，最合理的干预部分是什么？
编辑
根据要求，这里是 MWE。它并不是真正的 MWE，因为它会产生问题，因为我不太了解发生了什么，无法认真尝试正确着色。但是，我不明白为什么取消注释命令会导致布局\colorbox完全中断，所以这可能是一个不错的起点。
\documentclass{beamer}
\usecolortheme{orchid}
\usecolortheme{whale}
\makeatletter
% this code is the result of me collecting the bits & pieces
% from the macro definitions in `beamerouterthemesmoothbars.sty`
\defbeamertemplate*{headline}{smoothbars theme}{%
\vbox {%
\beamer@xpos =0\relax \beamer@ypos=1\relax
\hbox to \paperwidth{
% this is some spacing that I don't really understand what it does
\hskip .3cm\setbox\beamer@sectionbox =\hbox {\kern 1sp}
\hskip -1.875ex plus-1fill
\global \beamer@section@min@dim \z@
% loop over the entries of the *.nav file
\beamer@headcounter =0\relax
\loop
\ifnum \beamer@headcounter <\beamer@totalheads\advance \beamer@headcounter by1\relax
% I would have expected that putting a 'colorbox' here would do the trick of coloring the individual section headings
% however, very strange things happen when uncommenting the following line, which probably has to do with the fact
% that the loop runs over 17 entries (instead of just 2, as I would have expected)
%\colorbox{red}{
\csname @@head\the \beamer@headcounter \endcsname
%}
\repeat
% some more spacing commands
\beamer@section@set@min@width \box \beamer@sectionbox
\hfil \hskip .3cm
}
}
}%
\makeatother
% now comes some dummy code just to have some slides to look at
\title{Hello World}
\begin{document}
\maketitle
\section{Introduction}
\begin{frame}{Hello!}
\begin{itemize}
\item Hello!
\end{itemize}
\end{frame}
\section{Further stuff}
\begin{frame}{Hello!}
\begin{itemize}
\item Hello!
\end{itemize}
\end{frame}
\end{document}
答案1
我怎么没
colorseries早点发现呢？它们真的很方便！
以下假设各部分的长度相似：
\documentclass{beamer}
\usecolortheme{orchid}
\usecolortheme{whale}
\useoutertheme{smoothbars}
\setbeamerfont{section in head/foot}{series=\bfseries}
\setbeamercolor{section in head/foot}{fg=black, bg=}
\usepackage{tikz}
\definecolorseries{foo}{rgb}{last}{red}{blue}
\resetcolorseries[3]{foo}
\makeatletter
\setbeamertemplate{headline}{%
\foreach \i in {1,...,\number\totvalue{totalsection}}{%
{\color{foo!![\i]}\rule{\dimexpr\paperwidth/\number\totvalue{totalsection}\relax}{7ex}}%
}
\vskip-7ex%
\begin{beamercolorbox}[ignorebg,ht=2.25ex,dp=3.75ex]{section in head/foot}
\insertnavigation{\paperwidth}
\end{beamercolorbox}%
}%
\makeatother
\usepackage{totcount}
\newcounter{totalsection}
\regtotcounter{totalsection}
\AtBeginDocument{%
\pretocmd{\section}{\refstepcounter{totalsection}}{\typeout{Yes, prepending was successful}}{\typeout{No, prepending was not it was successful}}%
}%
\title{Hello World}
\begin{document}
\maketitle
\section{Introduction}
\begin{frame}{Hello!}
\begin{itemize}
\item Hello!
\end{itemize}
\end{frame}
\section{Further stuff}
\begin{frame}{Hello!}
\begin{itemize}
\item Hello!
\end{itemize}
\end{frame}
\section{some stuff}
\begin{frame}{Hello!}
\begin{itemize}
\item Hello!
\end{itemize}
\end{frame}
\end{document}
