根据值列表计算标签角度

Question

作为 tex 和 tikz 的初学者，我坚持使用 foreach 进行数组处理。我想沿圆周绘制两个带有文本的圆圈。

\documentclass[tikz]{standalone}
\usepackage[utf8]{inputenx}
\usetikzlibrary{decorations.text}
\begin{document}
\sffamily
\begin{tikzpicture}[
    black,
    ultra thick,
    planet/.style = {draw,fill,circle,inner sep=#1},
    circle label/.style = {
    postaction={
        decoration={
        text along path,
        text = {#1},
        text align=center,
        text color=black,
        reverse path,
        },
    decorate,
    }
    }
]
\filldraw[white] (-8,-8) rectangle (9,10);
    \path[circle label={|\large|Circle one}] (0,-8-.2) arc (-90:360-90:8+.2);
    \draw[color=black,fill=gray!15] (0,0) circle (8);
    \path[circle label={|\large|Inner Circle}] (0,-4-.2) arc (-90:360-90:4+.2);
    \draw[color=black,fill=black!20] (0,0) circle (4);

% Values
\pgfkeys{/90/.code=Point A,
    /0/.code=Point B,
    /180/.code=Point C,
    /270/.code=Point D}

\foreach \angle in {0,90,180,270}
\draw (\angle:2.75) -- (\angle:2.75cm) node {\pgfkeys{\angle}};

\end{tikzpicture}
\end{document}

我知道如何以正确的角度绘制标签。但我想创建一个包含其点的列表，然后自动执行其余操作。

举个例子： 我在 pgfkeys 上添加了一个额外的点（没有角度），并将 360 除以项目数。对于每个循环，下一个项目都会从列表中删除并沿着路径放置。

Answer 1

下一段代码展示了一个解决方案foreach。该命令placetext有两个参数，第一个是要分发的列表labels，第二个是圆radius。第一个foreach计算项目总数，第二个沿圆绘制它们。

\documentclass[tikz]{standalone}
\usepackage[utf8]{inputenx}
\usetikzlibrary{decorations.text}

\newcommand{\placetext}[2]{
\foreach \item [count=\totalitems] in {#1};
\foreach \item [count=\numitem, evaluate=\numitem as \angle using {(\numitem-1)*360/\totalitems}] in {#1}
    \draw (\angle:#2) node {\item};
}


\begin{document}
\sffamily
\begin{tikzpicture}[
    black,
    ultra thick,
    planet/.style = {draw,fill,circle,inner sep=#1},
    circle label/.style = {
    postaction={
        decoration={
        text along path,
        text = {#1},
        text align=center,
        text color=black,
        reverse path,
        },
    decorate,
    }
    }
]
\filldraw[white] (-8,-8) rectangle (9,10);
    \path[circle label={|\large|Circle one}] (0,-8-.2) arc (-90:360-90:8+.2);
    \draw[color=black,fill=gray!15] (0,0) circle (8);
    \path[circle label={|\large|Inner Circle}] (0,-4-.2) arc (-90:360-90:4+.2);
    \draw[color=black,fill=black!20] (0,0) circle (4);

% Values
%\pgfkeys{/90/.code=Point A,
%    /0/.code=Point B,
%    /180/.code=Point C,
%    /270/.code=Point D}
%
%\foreach \angle in {0,90,180,270}
%\draw (\angle:2.75) -- (\angle:2.75cm) node {\pgfkeys{\angle}};

\placetext{Point A, Point B, Point C, Point D, Point E}{2.75}
\placetext{Point A, Point B, Point C}{6.75}

\end{tikzpicture}
\end{document}