pgfplots：如何从轴图坐标到轴环境之外的节点画一条线

Question

如何从轴图坐标绘制一条线到轴环境之外的节点？
像这样：

\documentclass[margin=4mm, tikz]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}

\begin{document}
\begin{tikzpicture}[]
\node[name=MyNode, fill=yellow, draw, minimum size=22mm]{Node};

\begin{axis}[shift={(MyNode.south west)}, anchor=north west, yshift=-6mm, 
ymin=0, ymax=5,
]
\addplot[thick, -|,] plot coordinates { (2,0) (2,3)} coordinate[](X);

\draw[red, thick, <->](X) -- (MyNode); % not nice
\end{axis}

\end{tikzpicture}
\end{document}

Answer 1

\draw只需在环境之外使用该命令axis：

\documentclass[border=10pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}

\begin{document}
\begin{tikzpicture}

\node[fill=yellow, draw, minimum size=22mm] (MyNode) {Node};

\begin{axis}[
    shift={(MyNode.south west)},
    anchor=north west, 
    yshift=-6mm, 
    ymin=0, ymax=5,
]

\addplot[thick, -|] plot coordinates { (2,0) (2,3) } coordinate (X);

\end{axis}

\draw[violet, thick, ->] (MyNode) -- +(0,-1.5) -| (X) 
    node[pos=0.75, right] {this};

\end{tikzpicture}
\end{document}