如何在乳胶中画一棵树？

Question

我想在乳胶中画这棵树，但我不知道怎么做，有人能帮我在乳胶中画这棵树吗？我不熟悉它。谢谢

Answer 1

虽然从技术上讲这是一棵树，但它在视觉上像矩阵一样组织，这就是为什么我建议TikZ-CD对于它使用TikZ 矩阵内部。

TikZ 矩阵的工作方式类似于tabular或array环境，其中每个单元格由 分隔&，每行由 分隔\\。

但是，TikZ-CD 添加了\arrow（或更短：）\ar宏，指定在单元格之间画一条线。

通常，人们会写类似的东西来指定指向右的\ar[r]箭头r，类似地，l和u存在d（左，上，下）。TikZ-CD 还为这些提供了“快捷方式”：\rar，，，，。\lar\uar\dar

对于小注释，我定义了键from above、from below和from left，from right它们放置一个箭头，从该方向指向该单元格中的节点。箭头开头的文本可以在引号内给出。

代码

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows.meta, cd, quotes}
\tikzcdset{
  from direction/.style={
    leftarrow, at end, to path={--++(#1:1em)\tikztonodes}},
  /utils/temp/.style args={#1:#2:#3}{
    from #1/.style={start anchor=#2, from direction=#3, #1}},
  /utils/temp/.list={
    below:south:down, above:north:up, left:west:left, right:east:right},
  math mode with extras/.style 2 args={
    math mode=false,
    /tikz/matrix of nodes/.append style={
      execute at begin node={$#1}, execute at end node={#2$}}}}
\begin{document}
\begin{tikzcd}[
  math mode with extras = \{\},
  arrow style=tikz, sep=1em,
  labels={auto=false, font=\footnotesize},
  arrows={dash, thick},
  cells={nodes={
    circle, draw=red, inner sep=+.2em,
    text width={width("$\{b, c, e\}$")}, align=center}},
  ]
      b, g    \rar \ar[from above, "Root"]
  &   b       \dar                                 \\
  &   b, c    \dar                                 \\
      b, c, e \dar
  &   b, c, e \lar \rar \ar[from below, "Join"]
  &   b, c, e \dar                                 \\
      b, e    \dar
  & & b, e    \dar \ar[from left, "Introduce $b$"] \\
      b       \dar
  & & e       \dar \ar[from left, "Forget $(f)$"]  \\
      a, b    \dar \ar[from right, "Node $i$"]
  & & e, f    \dar                                 \\
      d, a, b \dar
  & & f       \ar[from left, "Leaf"]               \\
      b, d    \rar
  &   d
\end{tikzcd}
\end{document}

输出

Answer 2

使用该库的解决方案chains：

\documentclass[border=10pt]{standalone}
\usepackage{mathpazo}
\usepackage{tikz}
\usetikzlibrary{chains, scopes}

\begin{document}
\begin{tikzpicture}[
        thick,
        node distance=5mm,
        every join/.style={
            shorten >=1pt,
            shorten <=1pt,
        },
        every pin/.style={
            font=\small,
            pin edge={
                thick,
                black,
                shorten <=2pt,
                <-
            }
        },
        every on chain/.style={
            join,
            every join/.style=->,
            circle, 
            draw=red, 
            inner sep=3.5pt,
            text width=3.5em, 
            align=center,
            execute at begin node={\(\{},
            execute at end node={\}\)}
        }
    ]
    { [start chain=going right]
        \node[on chain, pin={above:Root}] {b,g};
        \node[on chain] {b};
        \node[on chain, continue chain=going below] {b,c};
        \node[on chain, pin={below:Join}] {b,c,e};
        { [start branch=A going left]
            \node[on chain] {b,c,e};
            \node[on chain, continue chain=going below] {b,e};
            \node[on chain] {b};
            \node[on chain, pin={right:Node $i$}] {a,b};
            \node[on chain] {d,a,b};
            \node[on chain] {b,d};
            \node[on chain, continue chain=going right] {d};
        }
        { [start branch=B going right]
            \node[on chain] {b,c,e};
            \node[on chain, continue chain=going below, pin={left:Introduce $(b)$}] {b,e};
            \node[on chain, pin={left:Forget $(f)$}] {e};
            \node[on chain] {e,f};
            \node[on chain, pin={left:Leaf}] {f};
        }
    }
\end{tikzpicture}
\end{document}