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如何将文本定位在图表的节点内？

tag-icon • tag-icon tikz-pgf graphs
如何将文本定位在图表的节点内？

我想创建一个可视化的Bellman-Ford 算法。为此，我需要将权重（数字或 $\infty$）和前任（字母）的信息添加到每个节点中。这应该看起来像这样（使用 Gimp 完成）：

在此处输入图片描述

我怎样才能用 LaTeX (Tikz) 来实现这个效果？

我目前正在创建我的图表：

\documentclass{beamer}
\usepackage{tikz}
\usepackage{verbatim}
\usetikzlibrary{arrows,shapes}

\begin{document}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}

\begin{frame}
\tikzstyle{vertex}=[circle,fill=black!25,minimum size=20pt,inner sep=0pt]

    \begin{figure}
        \begin{tikzpicture}[scale=2.5, auto,swap]
            % First we draw the vertices
            \foreach \pos/\name in {{(0,2)/a}, {(1,2)/b}, {(2,2)/c},
                                    {(0,1)/d}, {(1,1)/e}, {(2,1)/f}, 
                                    {(0,0)/g}, {(1,0)/h}, {(2,0)/i}}
                \node[vertex] (\name) at \pos {$\name$};
            % Connect vertices with edges and draw weights
            \foreach \source/ \dest /\weight/\style in {a/b/0/, b/c/1/, a/d/2/, e/d/5/,
                                                b/e/3/bend right, e/b/-1/bend right, b/f/4/above, f/i/3/,
                                                i/e/1/, g/h/1/}
                \path (\source) edge[->,\style, thick] node {$\weight$} (\dest);
        \end{tikzpicture}
        \end{figure}
    \end{frame}
\end{document}

答案1

您可以使用 放置文本label={[<options>]center:<text>}，其中 center 将标签放在“主机”节点的中间，因此您必须使用标签的xshift=..., yshift=...来移动它。<options>

\documentclass{beamer}
\usepackage{tikz}
\usepackage{verbatim}
\usetikzlibrary{arrows,shapes}

\begin{document}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}

\begin{frame}
\tikzset{
    vertex/.style={
        circle,
        fill=black!25,
        minimum size=20pt,
        inner sep=0pt,
        text height=1ex,
        text depth=1ex,
        label={[weight label]center:\weight},
        label={[pred label]center:\pred}
    },
    pred label/.style={
        font=\tiny,
        xshift=0.3em,
        yshift=-0.8ex,
        text height=1ex,
        text depth=0pt
    },
    weight label/.style={
        font=\tiny,
        xshift=-0.3em,
        yshift=-0.8ex,
        text height=1ex,
        text depth=0pt
    }
}


    \begin{figure}
        \begin{tikzpicture}[scale=2.5, auto,swap]
            % First we draw the vertices
            \foreach \pos/\name/\weight/\pred in {%
                {(0,2)/a/0/g},%
                {(1,2)/b/$\infty$/a}%
            }
                \node[vertex] (\name) at \pos {$\name$};
            % Connect vertices with edges and draw weights
            \foreach \source/ \dest /\weight/\style in {a/b/0/}
                \path (\source) edge[->,\style, thick] node {$\weight$} (\dest);
        \end{tikzpicture}
        \end{figure}
    \end{frame}
\end{document}

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