% !TeX root = tikz-ext-manual.tex
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% Copyright 2022 by Qrrbrbirlbel
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% This file may be distributed and/or modified
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% 1. under the LaTeX Project Public License and/or
% 2. under the GNU Free Documentation License.
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\section{Arcs through Three Points}
\label{library:topaths.arcthrough}
\begin{tikzlibrary}{ext.topaths.arcthrough}
This library allows to use an arc defined by three points.
\end{tikzlibrary}
\begin{codeexample}[width=10cm,preamble=\usetikzlibrary{ext.topaths.arcthrough}]
\begin{tikzpicture}
\coordinate[label=above right:$A$] (A) at ( 3, 1);
\coordinate[label=above:$B$] (B) at ( 1, 2);
\coordinate[label=below left:$C$] (C) at (-2,-2);
\foreach \p in {A, B, C, arc through center}
\fill[red] (\p) circle[radius=2pt];
\end{tikzpicture}
\end{codeexample}
This can only by used for circles in the |canvas| coordinate system.
\begin{multicols}{2}
\begin{key}{/\tikzext/arc through/through=\meta{coordinate} (initially {(0,0)})}\keycompat{tikz/arc through}
The coordinate on the circle that defines~-- together with the
starting and target point~-- a circle.
\end{key}
\begin{key}{/\tikzext/arc through/center suffix=\meta{suffix} (initially {})}\keycompat{tikz/arc trough}
The |arc through| will define a coordinate named |arc through center|\meta{suffix}
so that it can be referenced later.
\end{key}
\begin{key}{/\tikzext/arc through/clockwise}\keycompat{tikz/arc trough}
The resulting arc will go clockwise from the starting point to the target point.
This will not necessarily go through the |through| point.
\end{key}
\begin{key}{/\tikzext/arc through/counter clockwise}\keycompat{tikz/arc trough}
The resulting arc will go counter clockwise from the starting point to the target point.
This will not necessarily go through the |through| point.
\end{key}
\begin{key}{/\tikzext/arc through=\meta{key-value}}\keycompat{tikz/arc trough}
This key should be used with |to|\indexPathOperationO{to} or |edge|\indexPathOperationO{edge}.
A parameter other than |center suffix|, |clockwise| or |counter clockwise| will
be assumed to be the |through| coordinate.
\end{key}
\end{multicols}
\endinput
