tikz-pin-anchors.tex

% Author: Julien Cubizolles
% Public domain

\newcommand*\ifStrInTF[2]{%
  \edef\tikz@temp{{#1}{#2}}%
  \expandafter\pgfutil@in@\tikz@temp
  \ifpgfutil@in@\expandafter\pgfutil@firstoftwo\else\expandafter\pgfutil@secondoftwo\fi}
\newcommand*\ifStrEmptyTF[1]{%
  \def\tikz@temp{#1}\ifx\tikz@temp\pgfutil@empty
    \expandafter\pgfutil@firstoftwo\else\expandafter\pgfutil@secondoftwo\fi}

\def\tikz@swapanchor#1.#2\tikz@stop#3#4{#1#4#3}
\newcommand*\tikzAddAnchor[2]{%
  \ifStrInTF{.}{#1}{%
    \ifStrEmptyTF{#2}
      {\edef#1{\expandafter\tikz@swapanchor#1\tikz@stop{}{}}}
      {\edef#1{\expandafter\tikz@swapanchor#1\tikz@stop{#2}{.}}}%
  }{%
    \ifStrEmptyTF{#2}{}% no true
      {\edef#1{#1.#2}}%
  }}
\tikzset{
  pin anchor/.style={tikz@pin@post/.append style={anchor=#1}},
  label anchor/.style={tikz@label@post/.append style={anchor=#1}},
  pin edge pin anchor/.style={
    append after command={\pgfextra\tikzAddAnchor{\tikzlastnode}{#1}\endpgfextra}%
  },
  pin edge parent anchor/.style={
    append after command={\pgfextra\tikzAddAnchor{\tikz@save@last@node}{#1}\endpgfextra}%
  }
}