在两个森林子树之间绘制箭头

Question

我正在想象一棵树在两个不同时间点之间的变化，到目前为止已经得出了以下结论：

\documentclass[12pt,paper=a4]{scrartcl}
\usepackage{forest}

\begin{document}
\begin{forest}
  for tree={
    circle,
    draw,
    minimum size = 1pt
    % font=\tiny
  }
  [, phantom, for children={fit=band}, s sep'+=60pt
    [,
      [,
        [
          []
          []
        ]
        []
      ]
      [,
        []
        []
      ]
      [,
        []
        [,name=left
          []
          []
        ]
      ]
    ]
    [,
      [,
        [,name=right
          []
          []
        ]
        []
      ]
      [
          [,
            []
            []
          ]
          [,
            []
            [
              []
              []
            ]
          ]
        ]
    ]
  ]
  \draw[-latex,double] (left) to (right);
\end{forest}

\end{document}

输出结果如下：

这没问题，但我更希望它看起来更像这样：

到目前为止，添加额外节点的所有实验均未成功。添加outer sep节点看起来很奇怪，因为它还会向树的常规边缘添加填充。

无关，但也很有趣：我可以让树节点比现在更小吗？我知道minimum size，但会对或类似的东西感兴趣maximum size。

Answer 1

对于较短的箭头，最简单的解决方案是使用tikz的shorten键。

要使圆圈变小，请使用inner sep— 节点无论如何都是空的。您可能还想forest调整的l sep和。ls sep

（下面我也改成double了very thick。）

\documentclass[12pt,paper=a4]{scrartcl}
\usepackage{forest}

\begin{document}

\begin{forest}
  for tree={
    circle,
    draw,
    inner sep=1pt,
    l sep=5mm,
    l=5mm,
    s sep=2mm,
  }
  [, phantom, for children={fit=band}, s sep'+=60pt
    [,
      [,
        [
          []
          []
        ]
        []
      ]
      [,
        []
        []
      ]
      [,
        []
        [,name=left
          []
          []
        ]
      ]
    ]
    [,
      [,
        [,name=right
          []
          []
        ]
        []
      ]
      [
          [,
            []
            []
          ]
          [,
            []
            [
              []
              []
            ]
          ]
        ]
    ]
  ]
  \draw[-latex,very thick,shorten <=5mm,shorten >=5mm] (left) to (right);
\end{forest}

\end{document}

Answer 2

根据要求，这里有一个不影响根节点的方法phantom。使用baseline每个树中你想要与箭头对齐的节点。

\documentclass[border=10pt]{standalone}
\usepackage{forest}
\forestset{%
  my tree/.style={
    for tree={
      circle,
      draw,
      inner sep=1pt,
      l sep'=5mm,
      l'=5mm,
      s sep'=2mm,
    },
  }
}
\begin{document}
\begin{forest}
  my tree,
    [,
      [,
        [, baseline
          []
          []
        ]
        []
      ]
      [,
        []
        []
      ]
      [,
        []
        [
          []
          []
        ]
      ]
    ]
\end{forest}
\begin{tikzpicture}
  \draw [-latex,very thick] (0,0) -- +(60pt,0);
\end{tikzpicture}
\begin{forest}
  my tree
    [,
      [,
        [, baseline
          []
          []
        ]
        []
      ]
      [
          [,
            []
            []
          ]
          [,
            []
            [
              []
              []
            ]
          ]
        ]
    ]
\end{forest}
\end{document}