如何制作具有分支矩形边并在分支前进行标记的图形？

Question

此图重复了标签，并且边缘既不是垂直的也不是水平的。我希望垂直边缘离开 A，标记为“x”，然后分成两个左右水平分支，这些分支将向节点 B 和 C 旋转 90 度。

\documentclass[]{standalone}
\usepackage{tikz}
\usetikzlibrary {graphs, graphdrawing, quotes}
\usegdlibrary{layered}

\begin{document}
    \begin{tikzpicture}
        \graph [
            layered layout,
            nodes = {draw, fill = white},
            edge quotes = {fill = white},
            level distance = 3 cm,
            sibling sep = 4 cm
        ]{
            A -> ["x", out = -90, in = 90] {
                B,
                C
           }
        };
    \end{tikzpicture}
\end{document}

Answer 1

除非你坚持使用\graph根据你的用例使用，否则你可以这样做：

\documentclass[tikz,border=1mm]{standalone}
\usetikzlibrary {positioning, calc}
    \begin{document}
        \begin{tikzpicture}[node distance = 2.5cm,>=stealth]
            \node[rectangle,inner sep=2pt,draw,align=center] (A) {A};
            \node[rectangle,inner sep=2pt,draw,align=center,below left = of A] (B) {B};
            \node[rectangle,inner sep=2pt,draw,align=center,below right = of A] (C) {C};
            \coordinate (D) at ($(A)!.7!(A |- B)$);
            \draw[thick,->] (A) -- (D) node[anchor=west,midway] {x} -| (B);
            \draw[thick,->] (D) -| (C);
        \end{tikzpicture}
    \end{document}

编辑：或者稍微简单一点的方法，例如：

\documentclass[tikz,border=1mm]{standalone}
\usetikzlibrary {positioning, calc}

\begin{document}
    \begin{tikzpicture}[node distance = 2.5cm,>=stealth]
        \node[rectangle,inner sep=2pt,draw,align=center] (A) {A};
        \node[rectangle,inner sep=2pt,draw,align=center,below left = of A] (B) {B};
        \node[rectangle,inner sep=2pt,draw,align=center,below right = of A] (C) {C};
        \draw[thick,->] (A) -- ($(B)!.5!(C)$) edge (C) node[anchor=west,midway] {x}  -- (B) ;
    \end{tikzpicture}
\end{document}

编辑2：所以，如果您想使用\graph，您可以使用这个，尽管标签有点尴尬：

\documentclass[tikz]{standalone}
\usetikzlibrary {graphs, graphdrawing, quotes}
\usegdlibrary{layered}

\begin{document}
    \begin{tikzpicture}[>=stealth,thick,
        connect/.style={to path={|- (\tikztotarget)}},
        connectwlabel/.style={to path={|- node[pos=0.25,anchor=west]{x} (\tikztotarget)}},
        ]
        \graph [
        layered layout,
        nodes = {draw, fill = white, minimum width=.5cm, minimum height=.5cm, thick},
        edge quotes = {fill = white},
        level distance = 3cm,
        sibling sep = 4cm,
        ]{
            A ->[connectwlabel] B;      
            A ->[connect] C;
        };
    \end{tikzpicture}
\end{document}

编辑3：事实证明，您实际上可以结合这些方法并执行以下操作：

\documentclass[tikz]{standalone}
\usetikzlibrary{graphs, graphdrawing, quotes,calc}
\usegdlibrary{layered}

\begin{document}
    \begin{tikzpicture}[>=stealth,thick,
        connect/.style={to path={(\tikztostart) -- ($(\tikztostart)!.7!(\tikztostart |- \tikztotarget)$) -| (\tikztotarget)}},
        connectwlabel/.style={to path={(\tikztostart) -- node[pos=0.5,anchor=west]{x} ($(\tikztostart)!.7!(\tikztostart |- \tikztotarget)$) -|  (\tikztotarget)}},
        ]
        \graph [
        layered layout,
        nodes = {draw, fill = white, minimum width=.5cm, minimum height=.5cm, thick},
        edge quotes = {fill = white},
        level distance = 2.5cm,
        sibling sep = 2cm,
        ]{
            A ->[connectwlabel] B;      
            A ->[connect] C;
        };
    \end{tikzpicture}
\end{document}

其 (对 和 进行了一些调整level distance)sibling sep如下所示：