pgflibraryshapes.dna.code.tex

%
% Copyright © 2021 by Timothy S. Jones
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
%
% The Current Maintainer of this work is Timothy S. Jones.
%
% This work consists of the files:
%
%   tikz-dna.dtx
%   tikz-dna.ins
%   tikzlibraryshapes.dna.code.tex
%   pgflibraryshapes.dna.code.tex
%
% and the derived file tikz-dna.sty.
%

\ProvidesFile{pgflibraryshapes.dna.code.tex}


% keys for shape single bent arrow
%
% /pgf/single bent arrow tip angle
% /pgf/single bent arrow head extend
% /pgf/single bent arrow head indent

\pgfkeys{/tikzdna/.cd,
    single bent arrow tip angle/.initial=90,
    single bent arrow head extend/.initial=.25cm,
    single bent arrow head indent/.initial=0cm,
}%

% Shape single bent arrow
%
%
\pgfdeclareshape{single bent arrow}{%
    \savedmacro\getsinglearrowpoints{%
        %
        % Get the outer sep.
        %
        \pgfmathsetlength\pgf@x{\pgfkeysvalueof{/pgf/outer xsep}}%
        \edef\xoutersep{\the\pgf@x}%
        \pgfmathsetlength\pgf@y{\pgfkeysvalueof{/pgf/outer ysep}}%
        \edef\youtersep{\the\pgf@y}%
        %
        % Get the node dimensions.
        %
        \pgfmathsetlength\pgf@xa{\pgfkeysvalueof{/pgf/inner xsep}}%
        \advance\pgf@xa.5\wd\pgfnodeparttextbox%
        \advance\pgf@xa.5\pgflinewidth%
        \pgfmathsetlength\pgf@ya{\pgfkeysvalueof{/pgf/inner ysep}}%
        \advance\pgf@ya.5\ht\pgfnodeparttextbox%
        \advance\pgf@ya.5\dp\pgfnodeparttextbox%
        \advance\pgf@ya.5\pgflinewidth%
        \ifpgfshapeborderusesincircle%
            \ifdim\pgf@xa<\pgf@ya%
                \pgf@xa\pgf@ya%
            \fi%
            \pgf@xa1.41421\pgf@xa%
            \pgf@ya\pgf@xa%
            \pgfmathsetmacro\rotate{\pgfkeysvalueof{/pgf/shape border rotate}}%
            \ifdim\xoutersep>\youtersep\relax%
                \let\youtersep\xoutersep%
            \else%
                \let\xoutersep\youtersep%
            \fi%
        \else%
            %
            % Round the rotation.
            %
            \pgfmathsetmacro\rotate{\pgfkeysvalueof{/pgf/shape border rotate}}%
            \pgfmathmod@{\rotate}{360}%
            \afterassignment\pgfmath@gobbletilpgfmath@%
            \expandafter\c@pgf@counta\pgfmathresult\relax\pgfmath@%
            \advance\c@pgf@counta45\relax%
            \divide\c@pgf@counta90\relax%
            \multiply\c@pgf@counta90\relax%
            \ifnum\c@pgf@counta<0\relax%
                \advance\c@pgf@counta360\relax%
            \fi%
            \edef\rotate{\the\c@pgf@counta}%
            %
            % Calculate the width and height of the node
            % contents, according to any border rotation.
            %
            \ifnum\c@pgf@counta=90\relax%
                \pgf@x\pgf@xa%
                \pgf@xa\pgf@ya%
                \pgf@ya\pgf@x%
                \let\pgfmathresult\xoutersep%
                \let\xoutersep\youtersep%
                \let\youtersep\pgfmathresult%
            \else%
                \ifnum\c@pgf@counta=270\relax%
                    \pgf@x\pgf@xa%
                    \pgf@xa\pgf@ya%
                    \pgf@ya\pgf@x%
                    \let\pgfmathresult\xoutersep%
                    \let\xoutersep\youtersep%
                    \let\youtersep\pgfmathresult%
                \fi%
            \fi%
        \fi%
        \addtosavedmacro\rotate%
        %
        % Get some useful trig stuff.
        %
        \pgfmathdivide{\pgfkeysvalueof{/pgf/single bent arrow tip angle}}{2}%
        \let\halftipangle\pgfmathresult%
        \pgfmathcosec@{\halftipangle}%
        \let\cosechalftipangle\pgfmathresult%
        \pgfmathcos@{\halftipangle}%
        \pgfutil@tempdima\pgfmathresult pt\relax%
        \pgfutil@tempdima\cosechalftipangle\pgfutil@tempdima%
        \edef\cothalftipangle{\pgfmath@tonumber{\pgfutil@tempdima}}%
        \pgfmathreciprocal@{\pgfmathresult}%
        \let\sechalftipangle\pgfmathresult%
        \pgfmathsin@{\halftipangle}%
        \pgfutil@tempdima\pgfmathresult pt\relax%
        \pgfutil@tempdima\sechalftipangle\pgfutil@tempdima%
        \edef\tanhalftipangle{\pgfmath@tonumber{\pgfutil@tempdima}}%
        %
        % Get the single arrow head extend, and adjust for minimum width.
        %
        \pgf@xb\pgf@ya%
        \pgf@xb\cothalftipangle\pgf@xb%
        \pgfmathsetlength\pgf@xc{\pgfkeysvalueof{/pgf/single bent arrow head extend}}%
        \pgf@yc\pgf@xc%
        \advance\pgf@xc\pgf@ya%
        \pgfmathsetlength\pgfutil@tempdimb{\pgfkeysvalueof{/pgf/minimum width}}%
        \ifdim\pgf@xc<.5\pgfutil@tempdimb%
            \pgfutil@tempdimb.5\pgfutil@tempdimb%
            \pgfmathdivide@{\pgfmath@tonumber{\pgfutil@tempdimb}}{\pgfmath@tonumber{\pgf@xc}}%
            \pgf@ya\pgfmathresult\pgf@ya%
            \pgf@xc\pgfmathresult\pgf@xc%
            \pgf@yc\pgfmathresult\pgf@yc%
            \pgf@xb\pgfmathresult\pgf@xb%
        \fi%
        %
        % Now calculate the height of the arrow and adjust for minimum height.
        %
        \advance\pgf@xc-\pgf@ya%
        \pgf@xc\cothalftipangle\pgf@xc%
        \pgf@xa2.0\pgf@xa%
        \advance\pgf@xa\pgf@xb%
        \pgfmathsetlength\pgfutil@tempdimb{\pgfkeysvalueof{/pgf/minimum height}}%
        \ifdim\pgf@xa<\pgfutil@tempdimb%
            \pgf@xa\pgfutil@tempdimb%
        \fi%
        \advance\pgf@xa-\pgf@xb%
        \pgf@xa.5\pgf@xa%
        \pgfmathsetlength\pgfutil@tempdima{\pgfkeysvalueof{/pgf/single bent arrow head indent}}%
        %
        % Now:
        %
        % xa - .5 * width of the node minus xb.
        % ya - .5 * height of the node contents.
        % xb - distance from the end of the node contents to the arrow tip.
        % xc - distance from the end of the node contents to the back end of the arrow head.
        % yc - distance from the top of the node contents to the top end of the arrow head.
        %
        \pgfsavepgf@process\centerpoint{%
            \pgf@x.5\wd\pgfnodeparttextbox%
            \pgf@y.5\ht\pgfnodeparttextbox%
            \advance\pgf@y-.5\dp\pgfnodeparttextbox%
        }%
        \pgfsavepgf@process\basepoint{%
            \pgf@x.5\wd\pgfnodeparttextbox%
            \pgf@y0pt%
        }%
        \pgfsavepgf@process\midpoint{%
            \pgf@x.5\wd\pgfnodeparttextbox%
            \pgfmathsetlength\pgf@y{+.5ex}%
        }%
        %
        % Should only need five points here...
        %
        \pgfsavepgf@process\arrowtip{%
            \pgf@x\pgf@xa%
            \advance\pgf@x\pgf@xb%
            \pgf@y0pt\relax%
        }%
        \pgfsavepgf@process\beforearrowtip{%
            \pgf@x\pgf@xa%
            \advance\pgf@x-\pgf@xc%
            \pgf@y\pgf@ya%
            \advance\pgf@y\pgf@yc%
        }%
        \pgfsavepgf@process\beforearrowhead{%
            \pgf@x\pgf@xa%
            \advance\pgf@x-\pgf@xc%
            \advance\pgf@x\pgfutil@tempdima%
            \pgf@y\pgf@ya%
        }%
        \pgfsavepgf@process\beforearrowbend{%
            \pgf@x-\pgf@xa%
            \pgf@y\pgf@ya%
        }%
        \pgfsavepgf@process\afterarrowbend{%
            \pgf@x-\pgf@xa%
            \advance\pgf@x2\pgf@ya
            \pgf@y-\pgf@ya%
        }%
        \pgfsavepgf@process\afterarrowtail{%
            \pgf@x-\pgf@xa%
            \pgf@y\pgf@ya%
            \advance\pgf@y-2\pgf@xa%
        }%
        \pgfsavepgf@process\beforearrowtail{%
            \pgf@x-\pgf@xa%
            \advance\pgf@x2\pgf@ya
            \pgf@y\pgf@ya%
            \advance\pgf@y-2\pgf@xa%
        }%
        %
        % Calculate the anchor point at the arrow tip...
        %
        \pgfsavepgf@process\arrowtipanchor{%
            \pgfpointadd{\centerpoint}{\arrowtip}%
            \pgf@xa\xoutersep\relax%
            \advance\pgf@x\cosechalftipangle\pgf@xa%
        }%
        \advance\pgf@x.5\wd\pgfnodeparttextbox%
        \edef\externalradius{\the\pgf@x}%
        \addtosavedmacro\externalradius%
        %
        % ...and the rest of the points.
        %
        \pgfmathanglebetweenlines{\beforearrowtip}{\beforearrowhead}{\beforearrowtip}{\arrowtip}%
        \pgf@xa\xoutersep\relax%
        \pgfutil@tempdima\pgfmathresult pt\relax%
        \pgfutil@tempdima.5\pgfutil@tempdima%
        \pgfmathcosec@{\pgfmath@tonumber{\pgfutil@tempdima}}%
        \pgf@xa\pgfmathresult\pgf@xa%
        \pgfutil@tempdima-\pgfutil@tempdima%
        \advance\pgfutil@tempdima180pt\relax%
        \advance\pgfutil@tempdima-\halftipangle pt\relax%
        %
        \pgfsavepgf@process\beforearrowtipanchor{%
            \pgfqpointpolar{\pgfmath@tonumber{\pgfutil@tempdima}}{\the\pgf@xa}%
            \pgf@xb\pgf@x%
            \pgf@yb\pgf@y%
            \pgf@process{\pgfpointadd{\centerpoint}{\beforearrowtip}}%
            \advance\pgf@x\pgf@xb%
            \advance\pgf@y\pgf@yb%
        }%
        \pgfmathanglebetweenpoints{\beforearrowhead}{\beforearrowtip}%
        \pgfutil@tempdima-\pgfmathresult pt\relax%
        \advance\pgfutil@tempdima180pt\relax%
        \pgfutil@tempdima.5\pgfutil@tempdima%
        \pgfmathcosec@{\pgfmath@tonumber{\pgfutil@tempdima}}%
        \pgf@xa\xoutersep\relax%
        \pgf@xa\pgfmathresult\pgf@xa%
        \pgfutil@tempdima-\pgfutil@tempdima%
        \advance\pgfutil@tempdima180pt\relax%
        \pgfsavepgf@process\beforearrowheadanchor{%
            \pgfqpointpolar{\pgfmath@tonumber{\pgfutil@tempdima}}{\the\pgf@xa}%
            \pgf@xb\pgf@x%
            \pgf@yb\pgf@y%
            \pgf@process{\pgfpointadd{\centerpoint}{\beforearrowhead}}%
            \advance\pgf@x\pgf@xb%
            \advance\pgf@y\pgf@yb%
        }%
        \pgfsavepgf@process\beforearrowbendanchor{%
            \pgfpointadd{\centerpoint}{\beforearrowbend}%
            \advance\pgf@x-\xoutersep\relax%
            \advance\pgf@y\youtersep\relax%
        }%
        \pgfsavepgf@process\afterarrowbendanchor{%
            \pgfpointadd{\centerpoint}{\afterarrowbend}%
            \advance\pgf@x\xoutersep\relax%
            \advance\pgf@y-\youtersep\relax%
        }%
        \pgfsavepgf@process\afterarrowtailanchor{%
            \pgfpointadd{\centerpoint}{\afterarrowtail}%
            \advance\pgf@x-\xoutersep\relax%
            \advance\pgf@y-\youtersep\relax%
        }%
        \pgfsavepgf@process\beforearrowtailanchor{%
            \pgfpointadd{\centerpoint}{\beforearrowtail}%
            \advance\pgf@x\xoutersep\relax%
            \advance\pgf@y-\youtersep\relax%
        }%
        %
        \pgfmathanglebetweenpoints{\centerpoint}{\beforearrowtipanchor}%
        \let\center@angle@beforearrowtip\pgfmathresult%
        \pgfmathanglebetweenpoints{\centerpoint}{\beforearrowheadanchor}%
        \let\center@angle@beforearrowhead\pgfmathresult%
        \pgfmathanglebetweenpoints{\centerpoint}{\beforearrowbendanchor}%
        \let\center@angle@beforearrowbend\pgfmathresult%
        \addtosavedmacro\center@angle@beforearrowtip%
        \addtosavedmacro\center@angle@beforearrowhead%
        \addtosavedmacro\center@angle@beforearrowbend%
        %
        \pgfmathanglebetweenpoints{\midpoint}{\beforearrowtipanchor}%
        \let\mid@angle@beforearrowtip\pgfmathresult%
        \pgfmathanglebetweenpoints{\midpoint}{\beforearrowheadanchor}%
        \let\mid@angle@beforearrowhead\pgfmathresult%
        \pgfmathanglebetweenpoints{\midpoint}{\beforearrowbendanchor}%
        \let\mid@angle@beforearrowbend\pgfmathresult%
        \addtosavedmacro\mid@angle@beforearrowtip%
        \addtosavedmacro\mid@angle@beforearrowhead%
        \addtosavedmacro\mid@angle@beforearrowbend%
        %
        \pgfmathanglebetweenpoints{\basepoint}{\beforearrowtipanchor}%
        \let\base@angle@beforearrowtip\pgfmathresult%
        \pgfmathanglebetweenpoints{\basepoint}{\beforearrowheadanchor}%
        \let\base@angle@beforearrowhead\pgfmathresult%
        \pgfmathanglebetweenpoints{\basepoint}{\beforearrowbendanchor}%
        \let\base@angle@beforearrowbend\pgfmathresult%
        \addtosavedmacro\base@angle@beforearrowtip%
        \addtosavedmacro\base@angle@beforearrowhead%
        \addtosavedmacro\base@angle@beforearrowbend%
        %
        \addtosavedmacro\arrowtipanchor%
        \addtosavedmacro\beforearrowtipanchor%
        \addtosavedmacro\beforearrowheadanchor%
        \addtosavedmacro\beforearrowbendanchor%
        \addtosavedmacro\afterarrowbendanchor%
        \addtosavedmacro\afterarrowtailanchor%
        \addtosavedmacro\beforearrowtailanchor%
    }%
    \savedanchor\centerpoint{%
        \pgf@x.5\wd\pgfnodeparttextbox%
        \pgf@y.5\ht\pgfnodeparttextbox%
        \advance\pgf@y-.5\dp\pgfnodeparttextbox%
    }%
    \savedanchor\midpoint{%
        \pgf@x.5\wd\pgfnodeparttextbox%
        \pgfmathsetlength\pgf@y{+0.5ex}%
    }%
    \savedanchor\basepoint{%
        \pgf@x.5\wd\pgfnodeparttextbox%
        \pgf@y0pt%
    }%
    \anchor{center}{\centerpoint}%
    \anchor{mid}{\midpoint}%
    \anchor{mid east}{%
        \getsinglearrowpoints%
        \let\pgf@singlearrow@referencepoint\midpoint%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{\externalradius}{0pt}}%
    }%
    \anchor{mid west}{%
        \getsinglearrowpoints%
        \let\pgf@singlearrow@referencepoint\midpoint%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{-\externalradius}{0pt}}%
    }%
    \anchor{base}{\basepoint}%
    \anchor{base east}{%
        \getsinglearrowpoints%
        \let\pgf@singlearrow@referencepoint\basepoint%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{\externalradius}{0pt}}%
    }%
    \anchor{base west}{%
        \getsinglearrowpoints%
        \let\pgf@singlearrow@referencepoint\basepoint%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{-\externalradius}{0pt}}%
    }%
    \anchor{north}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{0pt}{\externalradius}}%
    }%
    \anchor{south}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{0pt}{-\externalradius}}%
    }%
    \anchor{east}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{\externalradius}{0pt}}%
    }%
    \anchor{west}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{-\externalradius}{0pt}}%
    }%
    \anchor{north east}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{\externalradius}{\externalradius}}%
    }%
    \anchor{south east}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{\externalradius}{-\externalradius}}%
    }%
    \anchor{south west}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{-\externalradius}{-\externalradius}}%
    }%
    \anchor{north west}{%
        \getsinglearrowpoints%
        \csname pgf@anchor@single bent arrow@border\endcsname{\pgfqpoint{-\externalradius}{\externalradius}}%
    }%
    \anchor{before head}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\beforearrowheadanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{before tip}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\beforearrowtipanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{tip}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\arrowtipanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{after tip}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{%
            \pgfpointadd{%
                \pgfpointdiff{\centerpoint}{\beforearrowtipanchor}%
                \pgf@y-\pgf@y%
            }{\centerpoint}}%
        {\centerpoint}{\rotate}%
    }%
    \anchor{after head}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{%
            \pgfpointadd{%
                \pgfpointdiff{\centerpoint}{\beforearrowheadanchor}%
                \pgf@y-\pgf@y%
            }{\centerpoint}}%
        {\centerpoint}{\rotate}%
    }%
    \anchor{before tail}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\beforearrowtailanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{before bend}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\beforearrowbendanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{after bend}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\afterarrowbendanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{after tail}{%
        \getsinglearrowpoints%
        \pgfmathrotatepointaround{\afterarrowtailanchor}{\centerpoint}{\rotate}%
    }%
    \anchor{tail}{%
        \getsinglearrowpoints%
        \pgfpointlineattime{0.5}{%
            \pgfmathrotatepointaround{\beforearrowbendanchor}{\centerpoint}{\rotate}%
        }%
        {%
            \pgfmathrotatepointaround{%
            \pgfpointadd{%
                \pgfpointdiff{\centerpoint}{\beforearrowbendanchor}%
                \pgf@y-\pgf@y%
            }{\centerpoint}}%
            {\centerpoint}{\rotate}%
        }%
    }%
    \backgroundpath{%
        {%
            \pgftransformshift{\centerpoint}%
            \pgftransformrotate{\rotate}%
            \pgfpathmoveto{\arrowtip}%
            \pgfpathlineto{\beforearrowtip}%
            \pgfpathlineto{\beforearrowhead}%
            \pgfpathlineto{\beforearrowbend}%
            \pgfpathlineto{\afterarrowtail}%
            \pgfpathlineto{\beforearrowtail}%
            \pgfpathlineto{\afterarrowbend}%
            \pgfpathlineto{\beforearrowhead\pgf@y-\pgf@y}%
            \pgfpathlineto{\beforearrowtip\pgf@y-\pgf@y}%           
        }%
        \pgfpathclose%
    }%
    \anchorborder{%
        \pgfsavepgf@process\externalpoint{}%            
        \getsinglearrowpoints%
        \pgfutil@ifundefined{pgf@singlearrow@referencepoint}{\let\referencepoint\centerpoint}%
            {\let\referencepoint\pgf@singlearrow@referencepoint}%
        \pgfsavepgf@process\externalpoint{%
            \externalpoint%
            \pgf@xa\pgf@x%
            \pgf@ya\pgf@y%
            \referencepoint%
            \advance\pgf@x\pgf@xa%
            \advance\pgf@y\pgf@ya}% 
        \pgfmathanglebetweenpoints{\centerpoint}{\externalpoint}%
        \pgfmathsubtract@{\pgfmathresult}{\rotate}%
        \ifdim\pgfmathresult pt<0pt\relax%
            \pgfmathadd@{\pgfmathresult}{360}%
        \fi%
        \let\externalangle\pgfmathresult%
        \pgf@x\externalangle pt\relax%
        \ifx\referencepoint\midpoint%
            \pgf@xa\mid@angle@beforearrowtip pt\relax%
            \pgf@xb\mid@angle@beforearrowhead pt\relax%
            \pgf@xc\mid@angle@beforearrowbend pt\relax%
        \else%
            \ifx\referencepoint\basepoint%
                \pgf@xa\base@angle@beforearrowtip pt\relax%
                \pgf@xb\base@angle@beforearrowhead pt\relax%
                \pgf@xc\base@angle@beforearrowbend pt\relax%
            \else%
                \pgf@xa\center@angle@beforearrowtip pt\relax%
                \pgf@xb\center@angle@beforearrowhead pt\relax%
                \pgf@xc\center@angle@beforearrowbend pt\relax%
            \fi%
        \fi%
        \ifdim\pgf@x<\pgf@xa%
            \let\firstpoint\arrowtipanchor%
            \let\secondpoint\beforearrowtipanchor%
        \else%
            \ifdim\pgf@x<\pgf@xb%
                \ifdim\pgf@xb<\pgf@xa%
                    \let\firstpoint\arrowtipanchor%
                    \let\secondpoint\beforearrowtipanchor%
                \else%
                    \let\firstpoint\beforearrowheadanchor%
                    \let\secondpoint\beforearrowtipanchor%
                \fi%
            \else%
                \ifdim\pgf@x<\pgf@xc%
                    \let\firstpoint\beforearrowheadanchor%
                    \let\secondpoint\beforearrowbendanchor%
                \else%
                    \pgf@xc-\pgf@xc%
                    \advance\pgf@xc360pt\relax%
                    \ifdim\pgf@x<\pgf@xc%
                        \let\firstpoint\beforearrowbendanchor%
                        \pgfsavepgf@process\secondpoint{%
                            \pgfpointadd{%
                                \pgfpointdiff{\centerpoint}{\beforearrowbendanchor}%
                                \pgf@y-\pgf@y%
                            }{\centerpoint}%
                        }%
                    \else%
                        \pgf@xa-\pgf@xa%
                        \advance\pgf@xa360pt\relax%
                        \pgf@xb-\pgf@xb%
                        \advance\pgf@xb360pt\relax%
                        \ifdim\pgf@x<\pgf@xa%
                            \ifdim\pgf@x<\pgf@xb%
                                \pgfsavepgf@process\firstpoint{%
                                    \pgfpointadd{%
                                            \pgfpointdiff{\centerpoint}{\beforearrowbendanchor}%
                                            \pgf@y-\pgf@y%
                                    }{\centerpoint}%
                                }%
                                \pgfsavepgf@process\secondpoint{%
                                    \pgfpointadd{%
                                        \pgfpointdiff{\centerpoint}{\beforearrowheadanchor}%
                                        \pgf@y-\pgf@y%
                                    }{\centerpoint}%
                                }%
                            \else%
                                \ifdim\pgf@xb<\pgf@xa%
                                    \pgfsavepgf@process\firstpoint{%
                                        \pgfpointadd{%
                                                \pgfpointdiff{\centerpoint}{\beforearrowheadanchor}%
                                                \pgf@y-\pgf@y%
                                        }{\centerpoint}%
                                    }%
                                \else%
                                    \pgfsavepgf@process\firstpoint{%
                                        \pgfpointadd{%
                                                \pgfpointdiff{\centerpoint}{\arrowtipanchor}%
                                                \pgf@y-\pgf@y%
                                        }{\centerpoint}%
                                    }%
                                \fi%
                                \pgfsavepgf@process\secondpoint{%
                                        \pgfpointadd{%
                                            \pgfpointdiff{\centerpoint}{\beforearrowtipanchor}%
                                            \pgf@y-\pgf@y%
                                        }{\centerpoint}%
                                    }%
                            \fi%
                        \else%
                            \pgfsavepgf@process\firstpoint{%
                                \pgfpointadd{%
                                    \pgfpointdiff{\centerpoint}{\beforearrowtipanchor}%
                                    \pgf@y-\pgf@y%
                                }{\centerpoint}%
                            }%
                            \let\secondpoint\arrowtipanchor%
                        \fi%
                    \fi%
                \fi%
            \fi%
        \fi%
        \pgfsavepgf@process\firstpoint{%
            \pgfmathrotatepointaround{\firstpoint}{\centerpoint}{\rotate}%
        }%
        \pgfsavepgf@process\secondpoint{%
            \pgfmathrotatepointaround{\secondpoint}{\centerpoint}{\rotate}%
        }%
        \pgfpointintersectionoflines{\referencepoint}{\externalpoint}%
            {\firstpoint}{\secondpoint}%
    }%
}%

% keys for shape promoter
%
% /pgf/promoter arrow

\pgfkeys{/tikzdna/.cd,
    promoter arrow/.initial=Triangle,
}%

% Shape promoter
%
%
\pgfdeclareshape{promoter}{%
  \inheritsavedanchors[from=rectangle] % this is nearly a rectangle
  \inheritanchorborder[from=rectangle]%
  \inheritanchor[from=rectangle]{center}%
  \inheritanchor[from=rectangle]{north}%
  \inheritanchor[from=rectangle]{north west}%
  \inheritanchor[from=rectangle]{north east}%
  \inheritanchor[from=rectangle]{south}%
  \inheritanchor[from=rectangle]{south west}%
  \inheritanchor[from=rectangle]{south east}%
  \inheritanchor[from=rectangle]{west}%
  \inheritanchor[from=rectangle]{east}%
  \anchor{crown}{%
    \pgf@process{\southwest}%
    \pgf@xa=\pgf@x%
    \pgf@process{\northeast}%
    \advance\pgf@x by \pgf@xa%
    \advance\pgf@y by 3pt%
  }%
  \backgroundpath{% this is new
    % store lower right in xa/ya and upper right in xb/yb
    \southwest \pgf@xa=\pgf@x \pgf@ya=\pgf@y%
    \northeast \pgf@xb=\pgf@x \pgf@yb=\pgf@y%
    % construct main path
    \pgfpathmoveto{\pgfpoint{\pgf@xa}{\pgf@ya}}%
    \pgfpathlineto{\pgfpoint{\pgf@xa}{\pgf@yb}}%
    \pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@yb}}%
    \pgfsetarrowsend{\pgfkeysvalueof{/pgf/promoter arrow}}%
  }%
}%


% Shape terminator
%
%
\pgfdeclareshape{terminator}{%
  \inheritsavedanchors[from=rectangle] % this is nearly a rectangle
  \inheritanchorborder[from=rectangle]%
  \inheritanchor[from=rectangle]{center}%
  \inheritanchor[from=rectangle]{north}%
  \inheritanchor[from=rectangle]{north west}%
  \inheritanchor[from=rectangle]{north east}%
  \inheritanchor[from=rectangle]{south}%
  \inheritanchor[from=rectangle]{south west}%
  \inheritanchor[from=rectangle]{south east}%
  \inheritanchor[from=rectangle]{west}%
  \inheritanchor[from=rectangle]{east}%
  \backgroundpath{
    % store lower right in xa/ya and upper right in xb/yb
    \southwest \pgf@xa=\pgf@x \pgf@ya=\pgf@y%
    \northeast \pgf@xb=\pgf@x \pgf@yb=\pgf@y%
    \advance\pgf@x by \pgf@xa%
    \pgf@xc=\pgf@x%
    % construct main path
    \pgfpathmoveto{\pgfpoint{\pgf@xc}{\pgf@ya}}%
    \pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yb}}%
    \pgfpathmoveto{\pgfpoint{\pgf@xb}{\pgf@yb}}%
    \pgfpathlineto{\pgfpoint{\pgf@xa}{\pgf@yb}}%
  }%
}%




\endinput