帮助 Tikz 圆圈

Question

我正在使用 TikZ 绘制分支限界树，需要一些帮助。

这是我的代码：

\documentclass[
    12pt,           
    oneside,                
    a4paper,            
    english,        
    french,     
    spanish,            
    brazil              
    ]{abntex2}
\usepackage{graphicx}
\usepackage{float}
\usepackage{tikz}
\usetikzlibrary{calc, shapes}

\begin{document}

\begin{figure}[H]
\centering
\tikzset{thick,
         tree node/.style = {align=center, inner sep=0pt, font = \scriptsize},
every label/.append style = {font=\scriptsize},
                 S/.style = {draw, circle, minimum size = 20mm, inner sep=0pt,
                             top color=white, bottom color=blue!20},
               ENL/.style = {% edge node left
                             font=\footnotesize, left=1pt},
               ENR/.style = {% edge node right
                             font=\footnotesize, right=1pt},
                     grow = down,
         sibling distance = 2.8cm,
           level distance = 3cm
           }
\begin{tikzpicture}
\node [S, label= 2:Some text here] {$PL0$}
    child{node [S] {$PL1$}
            child{node [S] {$PL3$}
            edge from parent node[ENL] {$x2 \leq 2$}}
            child{node [S] {$PL4$}
                 child{node [S] {$PL5$}
                     child{node [S] {$PL7$}
                     edge from parent node[ENL] {$x2 \leq 3$}}
                     child{node [S, label = 2:More text here] {$PL8$}
                     edge from parent node[ENR] {$x2 \geq 4$}}
          edge from parent node[ENL] {$x1 \leq 3$}}
          child{node [S, label = 2:Another text here] {$PL6$}
          edge from parent node[ENR] {$x1 \geq 4$}}
            edge from parent node[ENR] {$x2 \geq 3$}}
    edge from parent node[ENL] {$x1 \leq 4$}}
    child{node [S, label = 2:Last text here] {$PL2$}
    edge from parent node[ENR] {$x1 \geq 5$}};
\end{tikzpicture}
        \caption{My Figure.}
\end{figure}

\end{document}

结果你应该得到这个数字：

好吧，这里有两件事我需要帮助：

1. 即使使用该\centering命令，图形也不会居中。我这里遗漏了什么？

2. 我需要在这些圆圈内写入更多信息。例如，在第一个圆圈（PL0）中，它应该包含以下附加信息：

我尝试了很多方法，但无法使这些信息适合圆圈。

Answer 1

1. 图是居中。为了验证这一点，我在文本区域周围添加了框架tikzpicture。
2. 如果希望圆圈中的内容更多，则需要将其添加到节点内容中。如果希望允许多行文本，则需要添加适当的对齐（或text width）键，例如align=center。

\documentclass[
    12pt,           
    oneside,                
    a4paper,            
    english,        
    french,     
    spanish,            
    brazil              
    ]{abntex2}
\usepackage[showframe]{geometry}
\usepackage{float}
\usepackage{tikz}
\usetikzlibrary{calc, shapes}

\begin{document}

\begin{figure}[H]
\centering
\tikzset{thick,
         tree node/.style = {align=center, inner sep=0pt, font = \scriptsize},
every label/.append style = {font=\scriptsize},
                 S/.style = {draw, circle, minimum size = 20mm, inner sep=0pt,
                             top color=white, bottom color=blue!20,
                             align=center}, %<-
               ENL/.style = {% edge node left
                             font=\footnotesize, left=1pt},
               ENR/.style = {% edge node right
                             font=\footnotesize, right=1pt},
                     grow = down,
         sibling distance = 2.8cm,
           level distance = 3cm
           }
\begin{tikzpicture}
\node [S, label= 2:Some text here] {$PL0$}
    child{node [S] {$PL0$\\ $x_1 = 4,333$ e\\ $x_2 = 2$ \\ $f = 42$}
            child{node [S] {$PL3$}
            edge from parent node[ENL] {$x2 \leq 2$}}
            child{node [S] {$PL4$}
                 child{node [S] {$PL5$}
                     child{node [S] {$PL7$}
                     edge from parent node[ENL] {$x2 \leq 3$}}
                     child{node [S, label = 2:More text here] {$PL8$}
                     edge from parent node[ENR] {$x2 \geq 4$}}
          edge from parent node[ENL] {$x1 \leq 3$}}
          child{node [S, label = 2:Another text here] {$PL6$}
          edge from parent node[ENR] {$x1 \geq 4$}}
            edge from parent node[ENR] {$x2 \geq 3$}}
    edge from parent node[ENL] {$x1 \leq 4$}}
    child{node [S, label = 2:Last text here] {$PL2$}
    edge from parent node[ENR] {$x1 \geq 5$}};
\draw (current bounding box.south west) rectangle (current bounding box.north east);    
\end{tikzpicture}
        \caption{My Figure.}
\end{figure}

\end{document}

我还建议看一下forest包装。