修复箭头角度

Question

我怎样才能使小箭头指向正方向？

\documentclass[border=7pt]{standalone}
\usepackage{forest}
\usetikzlibrary{arrows.meta,
    chains,
    fit,
    positioning}
\usepackage{siunitx}
\tikzset{
    node distance = 2mm and 0mm,
    start chain = A going below,
    wbox/.style = {draw, text width=8*1.3 em, inner sep=1mm,
        on chain, node contents={}},
    gbox/.style = {draw, fill=lightgray, text width=1em, 
        inner xsep=0mm, inner ysep=1mm, 
        node contents={}},
    every label/.append style = {font=\footnotesize}
}
\begin{document}
    \begin{forest}
        for tree = {
            draw,
            minimum height=4ex,
            text depth=0.5ex,
            anchor=north,
            inner sep=1mm,
            tw/.style = {text width=#1*1.3 em},
            text centered,
            %
            s sep=1em,
            l sep=8ex,
            edge={-{Triangle[angle=60:2pt 3]}},
            edge path={
                \noexpand\path[\forestoption{edge}]
                (!u.south) -- (.north);
            },
        }
        [$\mathcal{D}_{blblblblbl}$  \SI{100}{\%}, tw=10,
        [$\mathcal{D}_{blblblblbl}$   \SI{80}{\%}, tw=8, name=DS]
        [$\mathcal{D}_{blblblb}$ \SI{20}{\%},tw=5]
        ] 
        \node [wbox, below=4.5mm of DS, label=left:1];    % A-1
        \foreach \i [count=\j from 2] in {2,3,4,k}
        {
            \ifnum\j=4
            \node [wbox, draw=none, label={[yshift=0.8ex]center:$\vdots$}]; % A-5
            \else
            \node [wbox, label=left:$\i$]; % A-2, ..., A-4
            \fi
        }
        \foreach \i [count=\j from 0]in {1,2,3,5}
        {
            \ifnum\i=5
            \node [gbox, left =of A-\i.east];
            \else
            \node [gbox, right=\j em of A-\i.west];
            \fi
        }    
        \node (n6)  [draw=black, rounded corners, dashed, 
        inner xsep=1em, xshift=-0.5em, 
        fit=(A-1) (A-5),
        label=right: Blalalalalalallalalalal] {};
        \draw[-{Triangle[angle=60:2pt 3]}] (DS) -- (n6);
    \end{forest}
\end{document}

Answer 1

只需将最后一行替换\end{forest}为

\draw[-{Triangle[angle=60:2pt 3]}] (DS.south) -- (DS.south|-n6.north);

这里，(DS.south|-n6.north)表示 的x分量DS.south，即箭头的起点， y分量表示n6.noerth。

\documentclass[border=7pt]{standalone}
\usepackage{forest}
\usetikzlibrary{arrows.meta,
    chains,
    fit,
    positioning}
\usepackage{siunitx}
\tikzset{
    node distance = 2mm and 0mm,
    start chain = A going below,
    wbox/.style = {draw, text width=8*1.3 em, inner sep=1mm,
        on chain, node contents={}},
    gbox/.style = {draw, fill=lightgray, text width=1em, 
        inner xsep=0mm, inner ysep=1mm, 
        node contents={}},
    every label/.append style = {font=\footnotesize}
}
\begin{document}
    \begin{forest}
        for tree = {
            draw,
            minimum height=4ex,
            text depth=0.5ex,
            anchor=north,
            inner sep=1mm,
            tw/.style = {text width=#1*1.3 em},
            text centered,
            %
            s sep=1em,
            l sep=8ex,
            edge={-{Triangle[angle=60:2pt 3]}},
            edge path={
                \noexpand\path[\forestoption{edge}]
                (!u.south) -- (.north);
            },
        }
        [$\mathcal{D}_{blblblblbl}$  \SI{100}{\%}, tw=10,
        [$\mathcal{D}_{blblblblbl}$   \SI{80}{\%}, tw=8, name=DS]
        [$\mathcal{D}_{blblblb}$ \SI{20}{\%},tw=5]
        ] 
        \node [wbox, below=4.5mm of DS, label=left:1];    % A-1
        \foreach \i [count=\j from 2] in {2,3,4,k}
        {
            \ifnum\j=4
            \node [wbox, draw=none, label={[yshift=0.8ex]center:$\vdots$}]; % A-5
            \else
            \node [wbox, label=left:$\i$]; % A-2, ..., A-4
            \fi
        }
        \foreach \i [count=\j from 0]in {1,2,3,5}
        {
            \ifnum\i=5
            \node [gbox, left =of A-\i.east];
            \else
            \node [gbox, right=\j em of A-\i.west];
            \fi
        }    
        \node (n6)  [draw=black, rounded corners, dashed, 
        inner xsep=1em, xshift=-0.5em, 
        fit=(A-1) (A-5),
        label=right: Blalalalalalallalalalal] {};
        \draw[-{Triangle[angle=60:2pt 3]}] (DS.south) -- (DS.south|-n6.north);
    \end{forest}
\end{document}

箭头一开始不垂直的原因是你添加了wbox节点左侧的数字。因此拟合的中心DS不重合。