箭头指向多部分矩形

Question

我想做这样的事：

但是我在箭头方面遇到了困难。我想知道是否有一种方法可以做到这一点，而无需对每个坐标进行硬编码。

以下是多部分矩形的代码：

\documentclass[]{article}
\usepackage{tikz}
\usepackage[skip=2pt]{caption}
\usetikzlibrary{positioning,decorations.pathreplacing, shapes, arrows}
\settowidth{\textwidth}{Multipart rectangles with no line shortening}
\begin{document}

\begin{tikzpicture}[auto, node distance=1cm,
rect/.style={
    rectangle split,
    rectangle split parts=3,
    rectangle split horizontal,
    rectangle split part fill={green!50,green!50,gray!50},
    draw=black,
    rounded corners,
    text width = 3cm
}]

% Split Rectangle
\node[rect] {
    \centerline{ether}
        \nodepart  {two} \centerline{ip}
        \nodepart[text width=5cm]{three}
};

\end{tikzpicture}
\end{document}

Answer 1

如手册第 70.6 节所述具有多个文本部分的形状，节点部分之间的边界处有预定义的锚点。如果你将节点命名为foo，那么foo.two split north就是箭头指向的点，因此你可以这样做

\draw [<-] (foo.two split north) -- +(0,1cm) node[above]{bar};

要得到

\documentclass[]{article}
\usepackage{tikz}
\usepackage[skip=2pt]{caption}
\usetikzlibrary{positioning,decorations.pathreplacing, shapes, arrows}
\settowidth{\textwidth}{Multipart rectangles with no line shortening}
\begin{document}

\begin{tikzpicture}[auto, node distance=1cm,
rect/.style={
    rectangle split,
    rectangle split parts=3,
    rectangle split horizontal,
    rectangle split part fill={green!50,green!50,gray!50},
    draw=black,
    rounded corners,
    text width = 3cm,
    align=center % <- alternative to \centerline everywhere
}]

% Split Rectangle
\node[rect] (foo) {
    ether
    \nodepart  {two} ip
    \nodepart[text width=5cm]{three}
};

\draw [<-] (foo.two split north) -- +(0,1cm) node[above]{bar};
\end{tikzpicture}
\end{document}