tikz 中图形的自定义节点

Question

我找到了以下雪花的图片：

\begin{tikzpicture}[decoration=Koch snowflake]
    \draw decorate{decorate{decorate{decorate{(0,0) -- (3,0)}}}};
    \draw decorate{decorate{decorate{decorate{(3,0) -- (1.5,-3)}}}};
    \draw decorate{decorate{decorate{decorate{(1.5,-3) -- (0,0)}}}};
\end{tikzpicture}

我可以用它来替换在 tikz 中绘制的图形的圆圈（节点）吗？这是我的图表：

\begin{tikzpicture}
  [scale=.6,auto=right,every node/.style={circle,fill=yellow!70}]
  \node (n6) at (31,20) {6};
  \node (n4) at (34,18)  {4};
  \node (n5) at (38,19)  {5};
  \node (n1) at (41,18) {1};
  \node (n2) at (39,16)  {2};
  \node (n3) at (35,15)  {3};

  \foreach \from/\to in {n6/n4,n4/n5,n5/n1,n1/n2,n2/n5,n2/n3,n3/n4}
    \draw (\from) -- (\to);

\end{tikzpicture}

Answer 1

根据我的发现，实现此目标最直接的方法可能是采用pics。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{decorations.fractals} 
\tikzset{pics/.cd,
snowflake/.style n args={2}{code={%
\begin{scope}[decoration=Koch snowflake]
    \draw[#1] decorate{decorate{decorate{decorate{(-1.5,1) -- (1.5,1)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(1.5,1) -- (0,-2)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(0,-2) -- (-1.5,1)}}}};
    \path[#1] (-1.5,1) -- (1.5,1) -- (0,-2);
    \node at (0,0) {#2};
    \end{scope}}}}
\begin{document}
\begin{tikzpicture}[scale=.6,auto=right]
  \pic[local bounding box=n6,scale=0.3] at (31,20) {snowflake={fill=yellow}{6}};
  \pic[local bounding box=n4,scale=0.3] at (34,18)  {snowflake={fill=yellow}{4}};
  \pic[local bounding box=n5,scale=0.3] at (38,19)  {snowflake={fill=yellow}{5}};
  \pic[local bounding box=n1,scale=0.3] at (41,18) {snowflake={fill=yellow}{1}};
  \pic[local bounding box=n2,scale=0.3] at (39,16)  {snowflake={fill=yellow}{2}};
  \pic[local bounding box=n3,scale=0.3] at (35,15)  {snowflake={fill=yellow}{3}};

  \foreach \from/\to in {n6/n4,n4/n5,n5/n1,n1/n2,n2/n5,n2/n3,n3/n4}
    \draw (\from) -- (\to);

\end{tikzpicture}   
\end{document}

最简洁的方法可能是定义一个新形状。考虑到形状的复杂性，这可能并不简单，但可以想象这并非不可能。另一种选择是使用节点的路径图片，但就像pic上面的 s 一样，这“仅”会导致背景图片，特别是不会定义节点的边界，这意味着连接雪花的线条之间的间隙将与上面的类似。（如果将节点基于圆形，它们可能会变得稍微小一些，但路径图片有其他微妙之处，这就是我删除之前答案的这部分的原因。）

请注意，如果您担心连接节点的线之间的间隙，有一个简单的解决方法。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{decorations.fractals,backgrounds} 
\tikzset{pics/.cd,
snowflake/.style n args={2}{code={%
\begin{scope}[decoration=Koch snowflake]
    \draw[#1] decorate{decorate{decorate{decorate{(-1.5,1) -- (1.5,1)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(1.5,1) -- (0,-2)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(0,-2) -- (-1.5,1)}}}};
    \path[#1] (-1.5,1) -- (1.5,1) -- (0,-2);
    \node at (0,0) {#2};
    \end{scope}}}}
\begin{document}
\begin{tikzpicture}[scale=.6,auto=right]
  \pic[local bounding box=n6,scale=0.3] at (31,20) {snowflake={fill=yellow}{6}};
  \pic[local bounding box=n4,scale=0.3] at (34,18)  {snowflake={fill=yellow}{4}};
  \pic[local bounding box=n5,scale=0.3] at (38,19)  {snowflake={fill=yellow}{5}};
  \pic[local bounding box=n1,scale=0.3] at (41,18) {snowflake={fill=yellow}{1}};
  \pic[local bounding box=n2,scale=0.3] at (39,16)  {snowflake={fill=yellow}{2}};
  \pic[local bounding box=n3,scale=0.3] at (35,15)  {snowflake={fill=yellow}{3}};
  \begin{scope}[on background layer]
  \foreach \from/\to in {n6/n4,n4/n5,n5/n1,n1/n2,n2/n5,n2/n3,n3/n4}
    \draw (\from.center) -- (\to.center);
  \end{scope}
\end{tikzpicture}   
\end{document}

当然，我并不是说这些线会以同样的方式精确地击中“节点” \pgfpointshapeborder，但由于这些雪花是球形的，所以它几乎可以起作用。

附录：根据评论的要求，一个具有 3 个参数的版本，其中第 3 个参数是节点选项，例如颜色、字体等。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{decorations.fractals,backgrounds} 
\tikzset{pics/.cd,
snowflake/.style n args={3}{code={%
\begin{scope}[decoration=Koch snowflake]
    \draw[#1] decorate{decorate{decorate{decorate{(-1.5,1) -- (1.5,1)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(1.5,1) -- (0,-2)}}}};
    \draw[#1] decorate{decorate{decorate{decorate{(0,-2) -- (-1.5,1)}}}};
    \path[#1] (-1.5,1) -- (1.5,1) -- (0,-2);
    \node[#3] at (0,0) {#2};
    \end{scope}}}}
\begin{document}
\begin{tikzpicture}[scale=.6,auto=right]
  \pic[local bounding box=n6,scale=0.3] at (31,20) {snowflake={fill=yellow}{6}{text=red}};
  \pic[local bounding box=n4,scale=0.3] at (34,18) {snowflake={fill=yellow}{4}{font=\sffamily,text=blue}};
  \pic[local bounding box=n5,scale=0.3] at (38,19) {snowflake={fill=yellow}{5}{rotate=45}};
  \pic[local bounding box=n1,scale=0.3] at (41,18) {snowflake={fill=yellow}{1}{}};
  \pic[local bounding box=n2,scale=0.3] at (39,16) {snowflake={fill=yellow}{2}{}};
  \pic[local bounding box=n3,scale=0.3] at (35,15) {snowflake={fill=yellow}{3}{}};
  \begin{scope}[on background layer]
  \foreach \from/\to in {n6/n4,n4/n5,n5/n1,n1/n2,n2/n5,n2/n3,n3/n4}
    \draw (\from.center) -- (\to.center);
  \end{scope}
\end{tikzpicture}   
\end{document}