[Tex/LaTex] Tikz new shape : how to access/define anchors

tikz-pgf

I would like to create some new shape in order to use it with tiKz. The problem I'm front facing is how to access edged of the newly created shapes.

So far I got this :

\documentclass[paper=a4,11pt,parskip=half,twoside]{scrartcl}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[french]{babel}
\usepackage[pdftex]{graphicx}

\usepackage{tikz}
\usepackage{circuitikz}
\usepackage{pgfplots}

\def\convEl{%
    ++(-.5,-.5) -- ++(1,0) -- ++(0,1) -- ++(-1,0) -- cycle
}

\def\convEm{%
    ++(0,0) circle (.5)
}

\def\convMe{%
    ++(-.5,-.5) -- ++(.5,1) -- ++(.5,-1) -- cycle
}

\def\accEn{%
    ++(-.5,-.5) -- ++(.5,0) -- ++(0,1) -- ++(-.5,0) -- cycle ++(0,-1) -- ++(.5,1)
}

\begin{document}

\begin{tikzpicture}
    \filldraw[draw=red,ultra thick,fill=orange] (0,0) \convEl node (a) {};
    \filldraw[draw=red,ultra thick,fill=orange] (2,0) \convEm node (b) {};
    \filldraw[draw=red,ultra thick,fill=orange] (4,0) \convMe;
    \filldraw[draw=red,ultra thick,fill=orange] (6,0) \accEn;
\end{tikzpicture}

\end{document}

Well maybe I should precise some more in comparison to the code provided. I want to access specific positions of my shapes, like bottom center and +30°/-30° on each side to connect arrows. Here is a little scheme of the behaviour expected. This is why I need to create / access some more anchors. If i draw a simple rectangle, I can do it, but with new/special shapes like the one I need…

Arrows connection

Best Answer

Using Spike's approach is for sure a possibility, but the shape to be defined is quite simple, so I think there's a simplest way. Credit should go to Jake's answer How to have a cross out rectangle in tikz?, because here I just adapted things.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}

\tikzset{
        orange square/.style={draw=red,ultra thick, fill=orange,%
        minimum width=1cm, minimum height=1cm},%
        orange circle/.style={circle,draw=red,ultra thick, fill=orange,minimum width=1cm},%
        orange triangle/.style={regular polygon, regular polygon sides=3,%
        draw=red,ultra thick, fill=orange,minimum height=1cm},%
        orange rectangle/.style={rectangle,draw=red,ultra thick,%
        fill=orange,minimum height=1cm,minimum width=0.5cm,append after command={                       
            (\tikzlastnode.north east) edge[draw=red,ultra thick,shorten >=1.75\pgflinewidth,
                shorten <=1.75\pgflinewidth,](\tikzlastnode.south west)
            }
        },%
}

\begin{document}
\begin{tikzpicture}[scale=1.75,transform shape]
\node[orange square] (a) at (0,0){};
\node[orange circle] (b) at (2,0){};
\node[orange triangle] (c) at (4,0){};
\node[orange rectangle] (d) at (6,0){};
\draw[->,>=stealth] (a.south) -- (b.west) (b.north) -- (c.north)-- (d.center);
\end{tikzpicture}
\end{document}

Result:

enter image description here

The edit of the question was very useful to better understand the request. In this case perhaps it is better to define a new shape, but that's Spike's domain: I provide you an alternative. Ok, it could be an alternative if one is used to the calc library.

The basic hint is that regular polygons define also corner anchors so, by taking them as reference, it is possible to access every position without defining a new shape.

The revised example:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric,calc}

\tikzset{
        orange square/.style={regular polygon, regular polygon sides=4,%
        draw=red,ultra thick, fill=orange,minimum width=1.5cm},%
        orange triangle/.style={regular polygon, regular polygon sides=3,%
        draw=red,ultra thick, fill=orange,minimum height=1.5cm},%
        }

\begin{document}

\begin{tikzpicture}[scale=1.75,transform shape]
\node[orange square,] (e) at (0,-2){};
\node[orange triangle] (f) at (4,-2.165){};

% Display the anchors
\foreach \anchor/\placement in {corner 1/above, corner 2/above, corner 3/below, corner 4/below}
\draw[shift=(e.\anchor)] plot[mark=x] coordinates{(0,0)}node[\placement] {\tiny\texttt{(e.\anchor)}};

\foreach \anchor/\placement in {corner 1/above, corner 2/below, corner 3/below}
\draw[shift=(f.\anchor)] plot[mark=x] coordinates{(0,0)}node[\placement] {\tiny\texttt{(f.\anchor)}};

% Drawing the arrows    
\draw[-latex] ($(e.corner 3)!0.5!(e.corner 4)-(0,1)$)--($(e.corner 3)!0.5!(e.corner 4)$);
\draw[-latex] ($(e.corner 1)!0.2!(e.corner 4)$)--($(f.corner 1)!0.25!(f.corner 2)$);
\draw[-latex] ($(e.corner 1)!0.5!(e.corner 4)$)--($(f.corner 1)!0.525!(f.corner 2)$);
\draw[-latex] ($(e.corner 1)!0.8!(e.corner 4)$)--($(f.corner 1)!0.8!(f.corner 2)$);
\end{tikzpicture}
\end{document}

Result:

enter image description here

Related Solutions

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

A solution which allows to draw intersection segments of any two intersections is available as tikz library fillbetween.

This library works as general purpose tikz library, but it is shipped with pgfplots and you need to load pgfplots in order to make it work:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}];

\end{tikzpicture}

\end{document}

enter image description here

The key intersection segments is described in all detail in the pgfplots reference manual section "5.6.6 Intersection Segment Recombination"; the key idea in this case is to

create a temporary path temp1 which is the first intersection segment of red and blue, more precisely, it is the first intersection segment in the Left argument in red and blue : red. This path is drawn as thin black path. Substitute its \draw statement by \path to make it invisible.
Compute the desired intersection segment by intersecting temp1 and green and use the correct intersection segment. By trial and error I figured that it is the third segment of path temp1 which is written as L3 (L = left argument in temp1 and green and 3 means third segment of that path).

The argument involves some trial and error because fillbetween is unaware of the fact that end and startpoint are connected -- and we as end users do not see start and end point.

Note that you can connect these path segments with other paths. If such an intersection segment should be the continuation of another path, use -- as before the first argument in sequence. This allows to fill paths segments:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,fill=blue,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}]  
    [intersection segments={of=temp1 and green, sequence={--R2}}]
;

\end{tikzpicture}

\end{document}

enter image description here

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(45:3);

Use ++ before each new incremental coordinate to make it relative to the last one and put the pencil there.

Here's a complete example:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(30:3) {[rounded corners=10pt]-- ++(5,0) -- ++(0,-6)} -- ++(-7,0) -- cycle;
\end{document}

Of course, combining this with the -| or |- path operators can simplify the code even further; the following two pieces of code produce the same result:

\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(3,0) -- ++(0,1) -- ++(1,0) -- ++(0,-3) -- ++(2,0);\par\bigskip

and

\tikz\draw (20,12) -| ++(2,2) -| ++(3,1) -- ++(1,0) |- ++(2,-3);

I don't think that defining commands in this case adds anything; in fact, I think it reduces the functionality of the existing syntax (which is already simple). The example demonstrates that you can use, for example, polar coordinates and modify (up to TikZ limitations) the path attributes midways; even if the current question doesn't require this, it's a good thing to have the possibility to do those kind of modification if they are required.

Best Answer

Related Solutions

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

Related Question