强制在两个范围之间划一条水平线

Question

我有两个范围，我想从一个范围到另一个范围画一个箭头。

我希望红色箭头是水平的，而不是像现在这样倾斜的。

它是倾斜的，因为节点n比节点“低” m，因此它在垂直维度上扩展。

有人对如何使红色箭头变为水平有什么建议吗？

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}

\begin{tikzpicture}
\begin{scope}[local bounding box=scope1]
  \node [anchor=base east] (m) {m};
  \filldraw (0,0) circle (1pt);
  \draw (0,0) rectangle (3,2);
\end{scope}
\begin{scope}[local bounding box=scope2,shift={(scope1.base east)},xshift=2cm]
    \filldraw (0,0) circle (1pt);
  \draw (0,0) rectangle (4,2);
  \node [anchor=north] (n) {n};
\end{scope}
 \draw [->,red] (scope1.east) -- (scope2.west);
\end{tikzpicture}

\end{document}

Answer 1

像这样：

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}

\begin{tikzpicture}
\begin{scope}[local bounding box=scope1]
  \node [anchor=base east] (m) {m};
  \filldraw (0,0) circle (1pt);
  \draw (0,0) rectangle (3,2);
\end{scope}
\begin{scope}[local bounding box=scope2,shift={(scope1.base east)},xshift=2cm]
    \filldraw (0,0) circle (1pt);
  \draw (0,0) rectangle (4,2);
  \node [anchor=north] (n) {n};
\end{scope}
 \draw [->,red] (scope1.east) -- (scope1.east -| scope2.west);
\end{tikzpicture}

\end{document}

附录：

• 目前还不完全清楚使用scope环境的提议
• 获取图像的代码更简单，无需使用它们，而是使用节点而不是绘制矩形：

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                positioning}

\begin{document}
    \begin{tikzpicture}[
node distance = 0mm and 20mm,
   dot/.style = {circle, fill, inner sep=2pt, label=#1},
     N/.style = {rectangle, draw, minimum height=20mm, minimum width=30mm}
                    ]
\node [N,anchor=base east] (m) {};
\node [dot=left:$m$] at (m.south west) {};
%
\node [N,right=of m] (n) {};
\node [dot=below:$n$] at (n.south west) {};
%
\draw [-Straight Barb,red] (m) -- (n);
    \end{tikzpicture}
\end{document}

现在箭头在第二个矩形前没有间隙。如果应该有间隙，只需将箭头页面缩短一点。例如：

\draw [-Straight Barb,red, shorten >=5pt] (m) -- (n);

Answer 2

像这样：

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
    
    \begin{tikzpicture}
        \begin{scope}[local bounding box=scope1]
            \node [anchor=base east] (m) {m};
            \filldraw (0,0) circle (1pt);
            \draw (0,0) rectangle (3,2);
        \end{scope}
        \begin{scope}[local bounding box=scope2,shift={(scope1.base east)},xshift=2cm]
            \filldraw (0,0) circle (1pt);
            \draw (0,0) rectangle (4,2);
            \node [anchor=base west] (n) {n};
        \end{scope}
        \draw [->,red] (scope1.east) -- (scope2.west);
    \end{tikzpicture}
    
\end{document}

输出：