我想用来pgfkeys处理类似
label={[scale=.8,pos=.9]above right:$-2\pi i$}
（通常作为节点中的标签出现），并根据模式从中提取三个参数[#1]#2:#3。我还想使#1和成为#2可选的（再次作为节点中的标签），以便像#2:#3、[#1]#3和这样的内容#3成为有效的模式。
更新：我一直在阅读tikz执行此解析的代码，并想出了适用于许多情况的代码（它甚至允许#3可选）。代码附在下面（这是一个工作示例，但远非最简单：抱歉！）。
那么，到底是什么不起作用呢？嗯，是选项（参数#1）。如果我只指定一个值（例如label={[blue]above:hola}），它就可以正常工作。但如果我尝试将其变成列表（label={[blue,thick]above:hola}）或键值对（label={[scale=.8]above:hola}），代码就会中断（我收到类似这样的错误I do not know the key /tikz/scale=.8）。我必须修改什么才能使其正常工作？
\documentclass[tikz,border=2mm]{standalone}
\usetikzlibrary{arrows.meta,shapes.misc,decorations.pathmorphing,calc,bending}
\pgfdeclarelayer{top}
\pgfsetlayers{main,top}
\tikzset{
branch point/.style={cross out,draw=black,fill=none,minimum size=2*(#1-\pgflinewidth),inner sep=0pt,outer sep=0pt},
branch point/.default=5,
branch cut/.style={
decorate,decoration=snake
}
}
\makeatletter
\catcode`\$=11\relax%
\gdef\parse@label[#1]#2:#3\empty{%
% Extract options
\if\relax\detokenize{#1}\relax
\relax%
\else
\pgfkeyssetvalue{/branch cut jump/label/options}{#1}%
\fi%
% Do we have an angle?
\if\relax\detokenize{#3}\relax
% Nope!
\if\relax\detokenize{#2}\relax
% We also don't have a label text
\relax%
\else
% But we do have a label text, so let's extract it
\pgfkeyssetvalue{/branch cut jump/label/text}{#2}%
\fi%
\else
% Yup!
\parse@@label#2:#3\empty%
\fi%
}
\gdef\parse@@label#1:#2:\empty{%
% Do we have an angle?
\if\relax\detokenize{#1}\relax
\relax%
\else
\pgfkeyssetvalue{/branch cut jump/label/angle}{#1}%
\fi%
% Do we have a label text?
\if\relax\detokenize{#2}\relax
\relax%
\else
\pgfkeyssetvalue{/branch cut jump/label/text}{#2}%
\fi%
}
\catcode`\$=3\relax%
\pgfkeys{/branch cut jump/.cd,
pos/.initial = .8,
amplitude/.initial = 10,
color/.initial = green!60!black,
label/.code = {
\@ifnextchar[%
{\parse@label}%
{\parse@label[]}#1:\empty%
},
label/options/.initial = green!60!black,
label/angle/.initial = above right,
label/text/.initial = $-2\pi i$
}
\tikzset{
place arrow/.style={
to path={
(\tikztostart) -- (\tikztotarget) \tikztonodes
},
execute at begin to={
\coordinate (A) at ($(\tikztostart)!\pgfkeysvalueof{/branch cut jump/pos}!-\pgfkeysvalueof{/branch cut jump/amplitude}:(\tikztotarget)$);
\coordinate (B) at ($(\tikztostart)!\pgfkeysvalueof{/branch cut jump/pos}!\pgfkeysvalueof{/branch cut jump/amplitude}:(\tikztotarget)$);
\coordinate (AB/3) at ($(A)!1/3!(B)$);
\coordinate (2AB/3) at ($(A)!2/3!(B)$);
\coordinate (C) at ($(AB/3)!2/(3*sqrt(3))!-90:(B)$);
\coordinate (D) at ($(2AB/3)!4/(3*sqrt(3))!-90:(B)$);
\begin{pgfonlayer}{top}
\draw[thick,\pgfkeysvalueof{/branch cut jump/color},-{Stealth[]}] (A) .. controls (C) and (D) .. (B) node[\pgfkeysvalueof{/branch cut jump/label/options},\pgfkeysvalueof{/branch cut jump/label/angle}]{\pgfkeysvalueof{/branch cut jump/label/text}};
\end{pgfonlayer}
}
},
branch cut jump/.style={
/branch cut jump/.cd,#1,
/tikz/.cd,place arrow
}
}
\makeatother
\begin{document}
\begin{tikzpicture}[x=90pt,y=90pt]
\begin{scope}
% Axes
\draw[thin,gray,->] (-1,0) -- (1,0) node[right] {$x$};
\draw[thin,gray,->] (0,-1) -- (0,1) node[above] {$y$};
% Branch point
\draw[thick] (0,0) node[branch point,draw=red,thick] {};
% Branch cut
\draw[thick,red,branch cut,branch cut jump] (0,0) to (0:1.2);
\draw[thick,red,branch cut,branch cut jump={label={hola}}] (0,0) to (30:1.2);
\draw[thick,red,branch cut,branch cut jump={label={:}}] (0,0) to (60:1.2);
\draw[thick,red,branch cut,branch cut jump={label={:adios}}] (0,0) to (90:1.2);
\draw[thick,red,branch cut,branch cut jump={label={left:}}] (0,0) to (120:1.2);
\draw[thick,red,branch cut,branch cut jump={label={below:$\times (-1)$}}] (0,0) to (150:1.2);
\draw[thick,red,branch cut,branch cut jump={label={[blue]hola}}] (0,0) to (180:1.2);
\draw[thick,red,branch cut,branch cut jump={label={[blue]:}}] (0,0) to (210:1.2);
\draw[thick,red,branch cut,branch cut jump={label={[blue]:adios}}] (0,0) to (240:1.2);
\draw[thick,red,branch cut,branch cut jump={label={[blue]left:}}] (0,0) to (270:1.2);
\draw[thick,red,branch cut,branch cut jump={label={[blue]below:$\times (-1)$}}] (0,0) to (300:1.2);
\end{scope}
\end{tikzpicture}
\end{document}
答案1
也许这有帮助：
\documentclass[tikz,border=2mm]{standalone}
\usetikzlibrary{arrows.meta,shapes.misc,decorations.pathmorphing,calc,bending}
\pgfdeclarelayer{top}
\pgfsetlayers{main,top}
\tikzset{
branch point/.style={cross out,draw=black,fill=none,minimum size=2*(#1-\pgflinewidth),inner sep=0pt,outer sep=0pt},
branch point/.default=5,
branch cut/.style={
decorate,decoration=snake
}
}
\makeatletter
\catcode`\$=11\relax%
\gdef\parse@label[#1]#2:#3\empty{%
% Extract options
\if\relax\detokenize{#1}\relax
\relax%
\else
\tikzset{/branch cut jump/label/options=#1}%
\fi%
% Do we have an angle?
\if\relax\detokenize{#3}\relax
% Nope!
\if\relax\detokenize{#2}\relax
% We also don't have a label text
\relax%
\else
% But we do have a label text, so let's extract it
\pgfkeyssetvalue{/branch cut jump/label/text}{#2}%
\fi%
\else
% Yup!
\parse@@label#2:#3\empty%
\fi%
}
\gdef\parse@@label#1:#2:\empty{%
% Do we have an angle?
\if\relax\detokenize{#1}\relax
\relax%
\else
\pgfkeyssetvalue{/branch cut jump/label/angle}{#1}%
\fi%
% Do we have a label text?
\if\relax\detokenize{#2}\relax
\relax%
\else
\pgfkeyssetvalue{/branch cut jump/label/text}{#2}%
\fi%
}
\catcode`\$=3\relax%
\pgfkeys{/branch cut jump/.cd,
pos/.initial = .8,
amplitude/.initial = 10,
color/.initial = green!60!black,
label/.code = {
\@ifnextchar[%
{\parse@label}%
{\parse@label[]}#1:\empty%
},
label/options/.store in = \branch@label@options,
label/options=green!60!black,
label/angle/.initial = above right,
label/text/.initial = $-2\pi i$
}
\tikzset{
place arrow/.style={
to path={
(\tikztostart) -- (\tikztotarget) \tikztonodes
},
execute at begin to={
\coordinate (A) at ($(\tikztostart)!\pgfkeysvalueof{/branch cut jump/pos}!-\pgfkeysvalueof{/branch cut jump/amplitude}:(\tikztotarget)$);
\coordinate (B) at ($(\tikztostart)!\pgfkeysvalueof{/branch cut jump/pos}!\pgfkeysvalueof{/branch cut jump/amplitude}:(\tikztotarget)$);
\coordinate (AB/3) at ($(A)!1/3!(B)$);
\coordinate (2AB/3) at ($(A)!2/3!(B)$);
\coordinate (C) at ($(AB/3)!2/(3*sqrt(3))!-90:(B)$);
\coordinate (D) at ($(2AB/3)!4/(3*sqrt(3))!-90:(B)$);
\begin{pgfonlayer}{top}
\draw[thick,\pgfkeysvalueof{/branch cut jump/color},-{Stealth[]}] (A) .. controls (C) and (D) .. (B) node[\branch@label@options,\pgfkeysvalueof{/branch cut jump/label/angle}]{\pgfkeysvalueof{/branch cut jump/label/text}};
\end{pgfonlayer}
}
},
branch cut jump/.style={
/branch cut jump/.cd,#1,
/tikz/.cd,place arrow
}
}
\makeatother
\begin{document}
\begin{tikzpicture}
\draw[thick,red,branch cut,branch cut jump={label={[blue,thick]above:hola}}] (0,0) to (30:1.2);
\end{tikzpicture}
\end{document}
