"Based on the solution provided at TikZ: How to draw a pattern at the border of a tikz path I was able to do all the graphics in my thesis, except for one shape. As you can see in the graphic" ( ;-) Filling rule and for pattern at border)
I would like to draw an open pat, where the beginning and end are not connected, as shown in case c) just that I want to decorate it with a pattern, as can be seen in case a) and b).
Currently I try to help my self by hiding a part of the path with a white rectangle.
The problem is that I can only apply the pattern to closed paths. As soon as I remove the cycle at the end of a path that has the style EDR or EDO I get the error: Package tikz Error: Cannot parse this coordinate.
How can I decorate an open path with a pattern? As shown in this figure (modified with inkscape.)
The MWE:
\documentclass[tikz]{standalone}
\usepackage{tikz}
\usetikzlibrary{patterns}
\usetikzlibrary{decorations,backgrounds}
% BEGIN from https://tex.stackexchange.com/a/419558/11820
\newcounter{tmp}
%\tikzstyle{D}=[draw=blue,line width=1pt,preaction={clip, postaction={draw=blue,opacity=0.5,line width=12pt}}]
%<- note that tikzstyle is deprecated
\tikzset{D/.style={
preaction={draw=blue,line width=1pt},
preaction={decoration={contour lineto closed, contour distance=6pt},
decorate,
},
postaction={
insert path={%
\pgfextra{%
\pgfinterruptpath
\begin{scope}[opacity=0.5, transparency group]
\path[fill=blue,even odd rule]
\mySecondList \myList
;
\end{scope}
\endpgfinterruptpath}
}},
}}
\tikzset{EDR/.style={
preaction={draw=red,line width=1pt},
preaction={decoration={contour lineto closed, contour distance=6pt},
decorate,
},
postaction={
insert path={%
\pgfextra{%
\pgfinterruptpath
\path[pattern=north west lines, pattern color=red,even odd rule]
\mySecondList \myList
;
\endpgfinterruptpath}
}},
}}
\makeatletter
\def\pgfdecoratedcontourdistance{0pt}
\pgfset{
decoration/contour distance/.code=%
\pgfmathsetlengthmacro\pgfdecoratedcontourdistance{#1}}
\pgfdeclaredecoration{contour lineto closed}{start}{%
\state{start}[
next state=draw,
width=0pt,
persistent precomputation=\let\pgf@decorate@firstsegmentangle\pgfdecoratedangle]{%
\pgfextra{\xdef\myList{}\xdef\mySecondList{}}
\pgfextra{\setcounter{tmp}{0}}
\pgfpathmoveto{\pgfpointlineattime{.5}
{\pgfqpoint{0pt}{\pgfdecoratedcontourdistance}}
{\pgfqpoint{\pgfdecoratedinputsegmentlength}{\pgfdecoratedcontourdistance}}}%
}%
\state{draw}[next state=draw, width=\pgfdecoratedinputsegmentlength]{%
\ifpgf@decorate@is@closepath@%
\pgfmathsetmacro\pgfdecoratedangletonextinputsegment{%
-\pgfdecoratedangle+\pgf@decorate@firstsegmentangle}%
\fi
\pgfmathsetlengthmacro\pgf@decoration@contour@shorten{%
-\pgfdecoratedcontourdistance*cot(-\pgfdecoratedangletonextinputsegment/2+90)}%
\pgfpathlineto
{\pgfpoint{\pgfdecoratedinputsegmentlength+\pgf@decoration@contour@shorten}
{\pgfdecoratedcontourdistance}}%
\stepcounter{tmp}
\pgfcoordinate{muemmel\thetmp}{\pgfpoint{\pgfdecoratedinputsegmentlength+\pgf@decoration@contour@shorten}
{\pgfdecoratedcontourdistance}}
\pgfcoordinate{feep\thetmp}{\pgfpoint{\pgfdecoratedinputsegmentlength}{0pt}}
\pgfextra{\xdef\myList{\myList (muemmel\thetmp) -- }%
\xdef\mySecondList{\mySecondList (feep\thetmp) -- }}
\ifpgf@decorate@is@closepath@%
\pgfpathclose
\pgfextra{\xdef\myList{\myList cycle}%
\xdef\mySecondList{\mySecondList cycle}}
\fi
}%
\state{final}{\pgfextra{%\typeout{\myList,\mySecondList}
}}%
}
\makeatother
\tikzset{
contour/.style={
decoration={
name=contour lineto closed,
contour distance=#1
},
decorate}}
% END from https://tex.stackexchange.com/a/419558/11820
\tikzset{EDO/.style={
preaction={draw=orange,line width=1pt},
preaction={decoration={contour lineto closed, contour distance=6pt},
decorate,
},
postaction={
insert path={%
\pgfextra{%
\pgfinterruptpath
\path[pattern=north east lines, pattern color=orange,even odd rule]
\mySecondList \myList
;
\endpgfinterruptpath}
}},
}}
\begin{document}
\begin{tikzpicture}[]
\node at (-.5,0) {a)};
\path [EDO] (2.875,0) -- ++(0,.75) -- ++(-2.875,0) -- ++(0,-.75) -- cycle;
\path [EDR] (0,0) -- ++(0,-1) -- ++(6,0) -- ++(0,1) -- ++(-3.125,0) -- cycle ;
\fill [white] (.21,.3) rectangle (2.655,-.3);
\begin{scope}[yshift=-2cm]
\node at (-.5,0) {b)};
\path [EDO] (2.875,0) -- ++(0,.75) -- ++(-2.875,0) -- ++(0,-.75) -- cycle;
\path [EDR] (0,0) -- ++(0,-1) -- ++(6,0) -- ++(0,1) -- ++(-3.125,0) -- cycle ;
\end{scope}
\begin{scope}[yshift=-4cm]
\node at (-.5,0) {c)};
\path [draw, orange, line width=1pt] (2.875,0) -- ++(0,.75) -- ++(-2.875,0) -- ++(0,-.75);
\path [draw, red, line width=1pt] (0,0) -- ++(0,-1) -- ++(6,0) -- ++(0,1) -- ++(-3.125,0);
\end{scope}
\end{tikzpicture}
\end{document}
