在 tikz 中使用 \foreach

Question

我是 tikz 的新手，正在尝试理解该\foreach函数。这是我的代码：

\documentclass[border=10pt]{standalone}
\usepackage{tikz}\usetikzlibrary{calc,shapes,positioning,arrows,positioning,shapes.geometric,fit,trees}
\begin{document}

\tikzstyle{block} = [diamond, draw, text width=6em, text badly centered, node distance=3cm, inner sep=0pt] 

\begin{tikzpicture}[subs/.style={grow=down,xshift=1em,anchor=west,edge from parent path={(\tikzparentnode.south) |- (\tikzchildnode.west)}},
blk/.style={rectangle,draw},
first/.style={level distance=6ex},second/.style={level distance=12ex},third/.style={level distance=18ex},
fourth/.style={level distance=24ex},fifth/.style={level distance=30ex},sixth/.style={level distance=36ex},
seventh/.style={level distance=42ex},eigth/.style={level distance=48ex},ninth/.style={level distance=54ex},
level 1/.style={sibling distance=20em}]
%UAS
    \coordinate
    node[blk]{UAS}
    [edge from parent fork down]
%UAV
    child{node[blk] {UAV}
    child[subs,first] {node[blk]{Power}}
    child[subs,second] {node[blk]{Flight computer}}
    child[subs,third] {node[blk] {Landing gear}}
    child[subs,fourth]{node[blk]{Flight controls}}
    child[subs,fifth]{node[blk]{Airframe}}
    child[subs,sixth]{node[blk]{Engine (propulsion/fuel)}}
    child[subs,seventh]{node[blk]{Communication/navigation}}
    child[subs,eigth]{node[blk]{Electrical/hydraulics/environmental}}
    child[subs,ninth]{node[blk]{Environmental control}}
    }
\end{tikzpicture}
\end{document}

如您所见，我创建了九种样式来移动页面上的每个子项。这似乎非常不切实际且笨重。我曾考虑使用该\foreach功能根据子项数量自动执行此移动过程，但无法正常工作。有人能帮忙吗？

Answer 1

嗯，这比想象的要困难。我想我做到了……

完整代码：

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc,shapes,positioning,arrows,positioning,shapes.geometric,fit,trees}
\begin{document}

\tikzstyle{block} = [diamond, draw, text width=6em, text badly centered, node distance=3cm, inner sep=0pt] 

\begin{tikzpicture}[%
     subs/.style={grow=down,xshift=1em,anchor=west,edge from parent path={(\tikzparentnode.south) |- (\tikzchildnode.west)}},
     blk/.style={rectangle,draw},
     level 1/.style={sibling distance=20em}
]

\coordinate
node[blk]{UAS}
[edge from parent fork down]
child { node[blk] {UAV}
    child [subs,style={level distance=6 ex}]
    foreach [count=\i,
             evaluate={\j=6*(\i-1);}] \p in 
        {Power,computer,Landing gear,Flight controls,Airframe,Engine (propulsion/fuel),Communication/navigation,Electrical/hydraulics/environmental,Environmental control}
        {child[subs,style={level distance=\j ex}] {node[blk]{\p}}}
    };
\end{tikzpicture}
\end{document}

结果：