% Copyright 2026 by Qrrbrbirlbel
%
% This file may be distributed and/or modified
%
% 1. under the LaTeX Project Public License and/or
% 2. under the GNU Free Documentation License.
%
\unless\ifcsname tikzextset\endcsname
  \input tikzext-util.tex
\fi
\def\tikzext@arc@cw{%
  \ifdim\pgfkeysvalueof{/tikz/end angle}pt>\pgfkeysvalueof{/tikz/start angle}pt
    \pgfmathsubtract@{\pgfkeysvalueof{/tikz/end angle}}{360}%
    \pgfkeyssetevalue{/tikz/end angle}{+\pgfmathresult}%
  \fi
}
\def\tikzext@arc@ccw{%
  \ifdim\pgfkeysvalueof{/tikz/start angle}pt>\pgfkeysvalueof{/tikz/end angle}pt
    \pgfmathsubtract@{\pgfkeysvalueof{/tikz/start angle}}{360}%
    \pgfkeyssetevalue{/tikz/start angle}{+\pgfmathresult}%
  \fi
}
\def\tikzext@arc@auto{%
  \pgfmathanglebetweenpoints{\tikzext@arc@center}{\tikzext@arc@through}%
  \let\tikzext@arc@angle\pgfmathresult
  \pgfmathsubtract@{\tikzext@arc@angle}{\pgfkeysvalueof{/tikz/start angle}}%
  \pgfmathMod@{\pgfmathresult}{360}%
  \let\tikzext@temp\pgfmathresult
  \pgfmathsubtract@{\pgfkeysvalueof{/tikz/end angle}}{\tikzext@arc@angle}%
  \pgfmathMod@{\pgfmathresult}{360}%
  \pgfmathadd@{\pgfmathresult}{\tikzext@temp}%
  \ifdim\pgfmathresult pt<360pt % counter clockwise
    \tikzext@arc@ccw
  \else % clockwise
    \tikzext@arc@cw
  \fi
}

\tikzextset{
  every arc through/.code=,
  arc through/.unknown/.code=\pgfkeyssetevalue{/tikz/ext/arc through/through}{\pgfkeyscurrentname},
  arc through/through/.initial={(0,0)},
  arc through/center suffix/.initial=,
  arc through/clockwise/.code=\let\tikzext@arc@dir\tikzext@arc@cw,
  arc through/counter clockwise/.code=\let\tikzext@arc@dir\tikzext@arc@ccw,
  arc through/auto/.code=\let\tikzext@arc@dir\tikzext@arc@auto,
  arc through/clockwise/.value forbidden,
  arc through/counter clockwise/.value forbidden,
  arc through/counter clockwise,
  arc through/.code={%
    \tikzset{ext/every arc through}%
    \pgfqkeys{/tikz/ext/arc through}{#1}%
    \pgfkeysgetvalue{/tikz/ext/arc through/through}\tikz@temp
    \pgfextract@process\tikzext@arc@start{\tikz@scan@one@point\pgfutil@firstofone(\tikztostart)\relax}%
    \expandafter\pgfextract@process\expandafter\tikzext@arc@through\expandafter
      {\expandafter\tikz@scan@one@point\expandafter\pgfutil@firstofone\tikz@temp\relax}%
    \pgfextract@process\tikzext@arc@target{\tikz@scan@one@point\pgfutil@firstofone(\tikztotarget)\relax}%
    \pgfextract@process\tikzext@arc@midA{\pgfpointlineattime{.5}{\tikzext@arc@start}{\tikzext@arc@through}}%
    \pgfextract@process\tikzext@arc@midB{\pgfpointlineattime{.5}{\tikzext@arc@target}{\tikzext@arc@through}}%
    \pgfextract@process\tikzext@arc@center{%
      \pgfpointintersectionoflines
        {\tikzext@arc@midA}{\pgfmathrotatepointaround{\tikzext@arc@through}{\tikzext@arc@midA}{90}}%
        {\tikzext@arc@midB}{\pgfmathrotatepointaround{\tikzext@arc@through}{\tikzext@arc@midB}{90}}}%
    \pgfcoordinate{arc through center\pgfkeysvalueof{/tikz/ext/arc through/center suffix}}{\tikzext@arc@center}%
    \pgf@process{\pgfpointdiff{\tikzext@arc@center}{\tikzext@arc@start}}%
    \pgfmathveclen@{\pgfmath@tonumber\pgf@x}{\pgfmath@tonumber\pgf@y}%
    \pgfkeyssetevalue{/tikz/x radius}{+\pgfmathresult pt}%
    \pgfkeyssetevalue{/tikz/y radius}{+\pgfmathresult pt}%
    \pgfmathanglebetweenpoints{\tikzext@arc@center}{\tikzext@arc@start}%
    \pgfkeyssetevalue{/tikz/start angle}{+\pgfmathresult}%
    \pgfmathanglebetweenpoints{\tikzext@arc@center}{\tikzext@arc@target}%
    \pgfkeyssetevalue{/tikz/end angle}{+\pgfmathresult}%
    \tikzext@arc@dir
    \pgfkeyslet{/tikz/delta angle}\pgfutil@empty
    \def\tikz@to@path{arc[]\tikztonodes}%
  }%
}

%%% Compatibility
\tikzextset{
  /tikz-ext/compat/add library={topaths.arcthrough}{pre 0.6},
  compat/topaths.arcthrough/warn/.append code=%
    \tikzextutil@compatwarning@key{topaths.arcthrough}{pre 0.6}{/tikz/arc through}{/tikz/ext/arc through},
  compat/topaths.arcthrough/pre 0.6/.append code=%
    \pgfkeysdef{/tikz/arc through}{\pgfkeysvalueof{/tikz/ext/arc through/.@cmd}##1\pgfeov},
  compat/topaths.arcthrough/\pgfkeysvalueof{/tikz/ext/compat/topaths.arcthrough}%
}
\endinput