我正在使用 tikz 和 beamer 创建一种凯撒密码动画。
我可以得到我想要的，但是由于我对 tikz 不是很熟练，结果有点奇怪，因为它的编译速度非常慢：这是一个很大的缺点，因为在一个包含许多 tikz 的大文档中，它的速度会变得非常慢。
我的代码如下（嗯，一个小的工作示例）
\documentclass{beamer}
\usetheme{Berkeley}
\usepackage{graphicx}
\usepackage{ifthen}
\usepackage{tikz}
\tikzset{
invisible/.style={opacity=0},
visible on/.style={alt={#1{}{invisible}}},
alt/.code args={<#1>#2#3}{\alt<#1>{\pgfkeysalso{#2}}{\pgfkeysalso{#3}}
},
}
\begin{document}
\begin{frame}
\centering
\begin{tikzpicture}[scale=0.3, every node/.style={scale=0.3}]
\pgfmathsetmacro{\alphsize}{26}
\pgfmathsetmacro{\ang}{360/\alphsize}
\pgfmathsetmacro{\d}{3}
\pgfmathsetmacro{\op}{98 + \ang/2 - 1.2}
\pgfmathsetmacro{\e}{\ang + \ang*\d}
\pgfmathsetmacro{\ep}{\op + \ang*\d}
\foreach \x in {0,\ang,...,360} {\draw[gray] (\x:8em) -- (\x:12em);}
\foreach \x [count=\xi] in {A,...,Z} {
\node[rotate=\ang - \ang*\xi,visible on=<1>] at (\op - \ang*\xi:11em) {{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<2>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{T}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<3>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<4>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{L}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<5>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<6>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{P}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<7>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{H}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<8>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{O}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<9>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{N}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<10>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\e - \ang*\xi,visible on=<1>] at (\ep - \ang*\xi:9em) {{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<2>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{W}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<3>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<4>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{O}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<5>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<6>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{S}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<7>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{K}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<8>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{R}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<9>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{Q}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<10>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
}
\draw[thick] (0cm,0cm) circle(12em);
\draw[gray] (0cm,0cm) circle(10em);
\draw[thick] (0cm,0cm) circle(8em);
\end{tikzpicture}
\bigskip
\centering
\begin{tikzpicture}[every node/.style={scale=0.6}]
\draw[step=1em,gray,thin] (0em,0em) grid (9em,2em);
\node at (0.5em,1.5em) {\textcolor<2> {green}T};
\node at (1.5em,1.5em) {\textcolor<3> {green}E};
\node at (2.5em,1.5em) {\textcolor<4> {green}L};
\node at (3.5em,1.5em) {\textcolor<5> {green}E};
\node at (4.5em,1.5em) {\textcolor<6> {green}P};
\node at (5.5em,1.5em) {\textcolor<7> {green}H};
\node at (6.5em,1.5em) {\textcolor<8> {green}O};
\node at (7.5em,1.5em) {\textcolor<9> {green}N};
\node at (8.5em,1.5em) {\textcolor<10>{green}E};
\node[visible on=<2->] at (0.5em,0.5em) {\textcolor<2> {red}W};
\node[visible on=<3->] at (1.5em,0.5em) {\textcolor<3> {red}H};
\node[visible on=<4->] at (2.5em,0.5em) {\textcolor<4> {red}O};
\node[visible on=<5->] at (3.5em,0.5em) {\textcolor<5> {red}H};
\node[visible on=<6->] at (4.5em,0.5em) {\textcolor<6> {red}S};
\node[visible on=<7->] at (5.5em,0.5em) {\textcolor<7> {red}K};
\node[visible on=<8->] at (6.5em,0.5em) {\textcolor<8> {red}R};
\node[visible on=<9->] at (7.5em,0.5em) {\textcolor<9> {red}Q};
\node[visible on=<10->] at (8.5em,0.5em) {\textcolor<10>{red}H};
\end{tikzpicture}
\end{frame}
\end{document}
问题是：有没有更聪明的方法可以获得与上述相同的结果并且编译速度更快？
答案1
我没有发现任何可能严重减慢代码速度的重大问题。由于重新编译大量复杂的 TikZ 图片可能非常麻烦，因此有一个库external可以强制 TikZ 保存图片，并在可能的情况下重复使用图片。具体操作如下。
\usetikzlibrary{external}
\tikzexternalize
编辑：正如@brad 在评论中所建议的那样，使用\tikzexternalize[prefix=tikz/]来为临时 TikZ 图片设置一个文件夹会很有利。
由于您使用的是 beamer\only构造，因此这不会按预期工作，只会渲染第一帧。但是，有一个“黑客”：
用 where包裹整个
tikzpicture环境\only<m-M>m最小并且M是最大\only命令引用的帧号之内tikz图片。
由于该[visible on=<m-M>]选项与命令“等同” \only，因此您可以这样使用它。
\only<1-10>{%
\begin{tikzpicture}
\node[visible on=<1>] {};
% ...
\node[visible on=<10>] {};
\end{tikzpicture}
}
我已经尝试过这个代码，第二次（及以后）的编译时间是很多降低。
看使用 tikz 外部功能与 beamer \only了解更多信息。
完整代码：
\documentclass{beamer}
\usetheme{Berkeley}
\usepackage{graphicx}
\usepackage{ifthen}
\usepackage{tikz}
\tikzset{
invisible/.style={opacity=0},
visible on/.style={alt={#1{}{invisible}}},
alt/.code args={<#1>#2#3}{\alt<#1>{\pgfkeysalso{#2}}{\pgfkeysalso{#3}}
},
}
\usetikzlibrary{external}
\tikzexternalize
\begin{document}
\begin{frame}
\centering
\only<1-10>{%
\begin{tikzpicture}[scale=0.3, every node/.style={scale=0.3}]
\pgfmathsetmacro{\alphsize}{26}
\pgfmathsetmacro{\ang}{360/\alphsize}
\pgfmathsetmacro{\d}{3}
\pgfmathsetmacro{\op}{98 + \ang/2 - 1.2}
\pgfmathsetmacro{\e}{\ang + \ang*\d}
\pgfmathsetmacro{\ep}{\op + \ang*\d}
\foreach \x in {0,\ang,...,360} {\draw[gray] (\x:8em) -- (\x:12em);}
\foreach \x [count=\xi] in {A,...,Z} {
\node[rotate=\ang - \ang*\xi,visible on=<1>] at (\op - \ang*\xi:11em) {{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<2>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{T}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<3>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<4>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{L}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<5>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<6>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{P}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<7>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{H}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<8>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{O}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<9>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{N}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\ang - \ang*\xi,visible on=<10>] at (\op - \ang*\xi:11em) {\ifthenelse{\equal{\x}{E}}{\color{green}\Large \x}{\Large \x}};
\node[rotate=\e - \ang*\xi,visible on=<1>] at (\ep - \ang*\xi:9em) {{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<2>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{W}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<3>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<4>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{O}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<5>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<6>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{S}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<7>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{K}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<8>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{R}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<9>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{Q}}{\color{red}\large \x}{\large \x}};
\node[rotate=\e - \ang*\xi,visible on=<10>] at (\ep - \ang*\xi:9em) {\ifthenelse{\equal{\x}{H}}{\color{red}\large \x}{\large \x}};
}
\draw[thick] (0cm,0cm) circle(12em);
\draw[gray] (0cm,0cm) circle(10em);
\draw[thick] (0cm,0cm) circle(8em);
\end{tikzpicture}
}
\bigskip
\centering
\only<1-10>{%
\begin{tikzpicture}[every node/.style={scale=0.6}]
\draw[step=1em,gray,thin] (0em,0em) grid (9em,2em);
\node at (0.5em,1.5em) {\textcolor<2> {green}T};
\node at (1.5em,1.5em) {\textcolor<3> {green}E};
\node at (2.5em,1.5em) {\textcolor<4> {green}L};
\node at (3.5em,1.5em) {\textcolor<5> {green}E};
\node at (4.5em,1.5em) {\textcolor<6> {green}P};
\node at (5.5em,1.5em) {\textcolor<7> {green}H};
\node at (6.5em,1.5em) {\textcolor<8> {green}O};
\node at (7.5em,1.5em) {\textcolor<9> {green}N};
\node at (8.5em,1.5em) {\textcolor<10>{green}E};
\node[visible on=<2->] at (0.5em,0.5em) {\textcolor<2> {red}W};
\node[visible on=<3->] at (1.5em,0.5em) {\textcolor<3> {red}H};
\node[visible on=<4->] at (2.5em,0.5em) {\textcolor<4> {red}O};
\node[visible on=<5->] at (3.5em,0.5em) {\textcolor<5> {red}H};
\node[visible on=<6->] at (4.5em,0.5em) {\textcolor<6> {red}S};
\node[visible on=<7->] at (5.5em,0.5em) {\textcolor<7> {red}K};
\node[visible on=<8->] at (6.5em,0.5em) {\textcolor<8> {red}R};
\node[visible on=<9->] at (7.5em,0.5em) {\textcolor<9> {red}Q};
\node[visible on=<10->] at (8.5em,0.5em) {\textcolor<10>{red}H};
\end{tikzpicture}
}
\end{frame}
\end{document}