以不同角度倾斜的来回箭头

Question

我想画出如下图所示不同角度倾斜的来回箭头（不是双向箭头）。图中不必显示的灰色点用于定位。

\documentclass[UTF8,fontset=windows]{ctexart}
\usepackage{tikz}
\usepackage{amsmath}
\usetikzlibrary{calc,positioning}
\newcommand\lrreturn[3][]{%left right 
\draw[->,#1]($(#2.0)+(0,2pt)$)--($(#3.180)+(0,2pt)$);
\draw[<-,#1]($(#2.0)+(0,-2pt)$)--($(#3.180)+(0,-2pt)$);
}
\newcommand\udreturn[3][]{%up down 
\draw[->,#1]($(#2.-90)+(2pt,0)$)--($(#3.90)+(2pt,0)$);
\draw[<-,#1]($(#2.-90)+(-2pt,0)$)--($(#3.90)+(-2pt,0)$);
}
\begin{document}
\tikz[node distance=1.5em and 2em,line width=1pt,>=latex]{
\node[red,font=\bfseries] (a) {Center};

\node[right=of a,blue] (b) {0};

\node[below=of a,blue] (c) {$-\pi/2$};


\lrreturn[red]ab
\udreturn[red]ac

}

\tikz{
\node[draw] (o) at (0,0) {Center};
\foreach \i in {0,30,...,180} {
\node[draw] (x\i) at (\i:2) {\i};
\draw[latex-latex] (o) to (x\i);
}}

\end{document}

Answer 1

如果未绘制节点（或节点为圆形），则此解决方案有效。此外，它仅适用于直线。

用法是\draw[twoway] (A) to (B);在坐标（A）和（B）之间绘制来回箭头。

基本上，计算垂直于给定线的向量，然后使用与pathreplacing原始线的短垂直距离绘制两个箭头。箭头之间的距离由 全局控制\arsp。

\documentclass[UTF8,fontset=windows]{ctexart}
\usepackage{tikz}
\usepackage{amsmath}
\usetikzlibrary{calc,positioning,decorations.pathreplacing}

\newcommand{\arsp}{.8mm}

\tikzset{
    twoway/.style={
        decoration={
            show path construction,
            lineto code={
                \path (\tikzinputsegmentfirst); \pgfgetlastxy{\a}{\b};
                \path (\tikzinputsegmentlast); \pgfgetlastxy{\x}{\y};
                \coordinate (uu) at ($(0,0)!.5*\arsp!(\b-\y,\x-\a)$);
                \draw[-latex]($(\a,\b)+(uu)$) to ($(\x,\y)+(uu)$);
                \draw[latex-]($(\a,\b)-(uu)$) to ($(\x,\y)-(uu)$);
            }
        }, decorate
    } 
}

\begin{document}

\tikz{
\node[draw,circle] (o) at (0,0) {Center};
\foreach \i in {0,30,...,180} {
    \node[draw,circle] (x\i) at (\i:2) {\i};
    \draw[twoway] (o) to (x\i);
}}

\end{document}