Tikz Wheelchart - 防止标签重叠

Question 1

在这里我定义了强调垂直极点值的乘数：

    \pgfmathsetmacro\labelmag{
      1 + .9*(abs(1/sin(\midangle)))^1 - .03*(abs(1/sin(\midangle)))^2}

然后我绘制这样的数据标签：

    \draw  [*-,thin] node [append after command={(\midangle:\midradius pt) -- 
     (\midangle:\outerradius + \labelmag ex) -- (\tikzlastnode)}] at
     (\midangle:\outerradius + \labelmag ex)

我显然必须调整.9和的-.03值\labelmag。

我认为，如果标签恰好位于垂直方向的 0 度或 180 度处，它就会中断（溢出）。

妇女权利委员会：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows}
\usepackage{filecontents}
\usepackage{pgfplots}
\usepackage{pgfplotstable}

\begin{filecontents}{testdata.csv}
    Name,   Quantity
    "Blueberries",  56
    "Pears",    35
    "Bananas",  24
    "Grapes",   22
    "Peaches", 17
    "Mangoes", 12
    "Strawberries", 3
    "Raspberries", 3
    "Kiwis", 3
\end{filecontents}

\begin{document}

\pgfplotstableread[ignore chars=",col sep=comma]{testdata.csv}\datatable

\pgfplotstableread{
    clr
    blue!70
    green!80
    green!10!orange!90!
    yellow!50!orange!50!
    pink!30!red!60!
    purple!80
    green!60!black!40!
    black!50
    pink!30!red!60!
    blue!70
    green!10!orange!90!
    yellow!50!orange!50!
    pink!30!red!60!
}\MyColors

% Adjusts the size of the wheel:
\def\innerradius{2.8cm}
\def\outerradius{3.2cm}

\newcommand\LabelName{}
\newcommand\LabelValue{}

% The main macro
\newcommand{\wheelchart}[1]{
    % Calculate total
    \pgfmathsetmacro{\totalnum}{0}
    % get number of rows in table
    \pgfplotstablegetrowsof{#1}
    % minus 1 because indexing starts as zero
    \pgfmathsetmacro{\RowsInTable}{\pgfplotsretval-1}
    \foreach \i in {0,...,\RowsInTable} {
        \pgfplotstablegetelem{\i}{Quantity}\of{#1}
        \pgfmathparse{\pgfplotsretval+\totalnum}
        \global\let\totalnum=\pgfmathresult
    }
    \begin{center}
        \begin{tikzpicture}

        % Calculate the thickness and the middle line of the wheel
        \pgfmathsetmacro{\wheelwidth}{\outerradius-\innerradius}
        \pgfmathsetmacro{\midradius}{(\outerradius+\innerradius)/2}

        % Rotate so we start from the top
        \begin{scope}[rotate=90]

        % Loop through each value set. \cumnum keeps track of where we are in the wheel
        \pgfmathsetmacro{\cumnum}{0}


        \foreach \i in {0,...,\RowsInTable} {
            % get values from table
            \pgfplotstablegetelem{\i}{Name}\of{#1}\global\let\LabelName=\pgfplotsretval
            \pgfplotstablegetelem{\i}{Quantity}\of{#1}\renewcommand\LabelValue{\pgfplotsretval}

            \pgfmathsetmacro{\newcumnum}{\cumnum + \LabelValue/\totalnum*360}


            % Calculate the percent value
            \pgfmathsetmacro{\percentage}{\LabelValue}
            % Calculate the mid angle of the colour segments to place the labels
            \pgfmathsetmacro{\midangle}{-(\cumnum+\newcumnum)/2}


            % This is necessary for the labels to align nicely
            \pgfmathparse{
                (-\midangle<180?"west":"east")
            } \edef\textanchor{\pgfmathresult}
            \pgfmathsetmacro\labelshiftdir{ifthenelse(\RowsInTable==0,-1,1)*(1-2*(-\midangle>180))}

            % Draw the color segments. Somehow, the \midrow units got lost, so we add 'pt' at the end. Not nice...
            \pgfplotstablegetelem{\i}{clr}\of{\MyColors}
            \fill[color=\pgfplotsretval] (-\cumnum:\outerradius) arc (-\cumnum:-(\newcumnum):\outerradius) --
            (-\newcumnum:\innerradius) arc (-\newcumnum:-(\cumnum):\innerradius) -- cycle;

            % Draw the data labels
            \pgfmathsetmacro\labelmag{
              1 + .9*(abs(1/sin(\midangle)))^1 - .03*(abs(1/sin(\midangle)))^2}
            \draw  [*-,thin] node [append after command={(\midangle:\midradius pt) -- 
             (\midangle:\outerradius + \labelmag ex) -- (\tikzlastnode)}] at
             (\midangle:\outerradius + \labelmag ex) 
             [xshift=\labelshiftdir*0.5cm,inner sep=0pt, outer sep=0pt, ,anchor=\textanchor]{\LabelName: \pgfmathprintnumber{\percentage}};

            % Set the old cumulated angle to the new value
            \global\let\cumnum=\newcumnum
        }

        \end{scope}
        %      \draw[gray] (0,0) circle (\outerradius) circle (\innerradius);
        \end{tikzpicture}
    \end{center}
}

% This is where the CSV should be added instead of hard-coded data entries.
\wheelchart{\datatable}

\end{document}

跟进

上面选择的函数\labelmag代表了（对于此数据集）所需的函数。但是，它可以设置为在垂直极点处增长的任何函数（当\midangle接近 0 或 pi/2 时）。例如，这里有一个不会在极点处爆炸的替代函数，这是通过向值添加一个小的偏移量abs(sin())来防止分母为零来实现的：

        \def\offsetmag{.1}
        \pgfmathsetmacro\labelmag{
          1 + 1.4*(1/(\offsetmag+abs(sin(\midangle))))^1 
            -.04*(1/(\offsetmag+abs(sin(\midangle))))^2}

请注意，如果我将 Kiwis 设置得非常小，例如，将其从 3 更改为 1，这实际上将 Kiwi 辐条放置在与垂直方向成 1.04 度的位置，它仍然可以使用此修改后的函数正常工作：

这里的教训是，人们可以努力改进该\labelmag函数，使其更加灵活并且能够容忍极坐标数。

Answer