如何自动调整节点周围的形状大小

Question

我正在使用维恩图来说明两个有限集之间的函数关系。根据集合中的元素数量，我使用的椭圆可能不包含所有元素（及其标签）。如何调整以下代码以使椭圆自动调整大小以包含所有节点及其标签？

\documentclass{article}
\usepackage{pgf,tikz}
\usetikzlibrary{positioning,shapes,fit}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}
\begin{document}
            \begin{tikzpicture}[
              every node/.style={on grid},
              setA/.style={fill=blue,circle,inner sep=2pt},
              setB/.style={fill=red,circle,inner sep=2pt},
              every fit/.style={draw,fill=blue!15,ellipse,text width=30pt},
              >=latex
            ]

            % set A
            \node[setA,label=left:$x$] (x) {};
            \node [setA,below = of x,label=left:$y$] (y) {};
            \node [setA,below = of y,label=left:$z$] (z) {};
            \node[above=of x,anchor=south] {$A$};

            % set B
            \node[setB,label=right:$10$,right=3cm of x] (10) {};
            \node[setB,label=right:$20$, below = of 10] (20) {};
            \node[setB,label=right:$30$,below = of 20] (30) {};
            \node[setB,label=right:$40$,below = of 30] (40) {};
            \node[above=of 10,anchor=south] {$B$};

            % the arrows
            \draw[->,shorten >= 3pt] (x) -- node[label=above:$f$] {} (10);
            \draw[->,shorten >= 3pt] (y) -- node[] {} (10);
            \draw[->,shorten >= 3pt] (z) -- node[] {} (30);

            % the boxes around the sets
            \begin{pgfonlayer}{background}
            \node[fit= (x)  (z) ] {};
            \node[fit= (10) (30) ] {};
            \end{pgfonlayer}
            \end{tikzpicture}
\end{document}

Answer 1

您必须命名标签并将其添加到“fit”中

\documentclass{article}
\usepackage{pgf,tikz}
\usetikzlibrary{positioning,shapes,fit}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}
\begin{document}
            \begin{tikzpicture}[
              every node/.style={on grid},
              setA/.style={fill=blue,circle,inner sep=2pt},
              setB/.style={fill=red,circle,inner sep=2pt},
              every fit/.style={draw,fill=blue!15,ellipse,text width=30pt},
              >=latex
            ]

            % set A
            \node[setA,label=left:$x$] (x) {};
            \node [setA,below = of x,label=left:$y$] (y) {};
            \node [setA,below = of y,label=left:$z$] (z) {};
            \node[above=of x,anchor=south,name=A] {$A$};

            % set B
            \node[setB,label=right:$10$,right=3cm of x] (10) {};
            \node[setB,label=right:$20$, below = of 10] (20) {};
            \node[setB,label=right:$30$,below = of 20] (30) {};
            \node[setB,label=right:$40$,below = of 30] (40) {};
            \node[above=of 10,anchor=south] {$B$};

            % the arrows
            \draw[->,shorten >= 3pt] (x) -- node[label=above:$f$] {} (10);
            \draw[->,shorten >= 3pt] (y) -- node[] {} (10);
            \draw[->,shorten >= 3pt] (z) -- node[] {} (30);

            % the boxes around the sets
            \begin{pgfonlayer}{background}
            \node[fit= (x)  (z)  (A)] {};
            \node[fit= (10) (30) ] {};
            \end{pgfonlayer}
            \end{tikzpicture}
\end{document}

看如何使用“fit”来框住节点和标签