Tikzpicture edge over graph

Question

I've got the image attached, obtained from code

    \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

  \node (S) {};
  \node[main node] (0) [node distance=1.1cm,below of=S] {$s$};
  \node[main node] (3) [node distance=2.2cm,below of=0] {3};
  \node[main node] (2) [node distance=2.2cm,left of=3] {2};
  \node[main node] (1) [node distance=2.2cm,left of=2] {1};
  \node[main node] (4) [node distance=2.2cm,right of=3] {4};
  \node[main node] (5) [node distance=2.2cm,right of=4] {5};
  \node (6) [node distance=1.1cm,below of=1] {};
  \node (7) [node distance=1.1cm,below of=2] {};
  \node (8) [node distance=1.4cm,below left of=3] {};
  \node (9) [node distance=1.1cm,below of=4] {};
  \node (10) [node distance=1.1cm,below of=5] {};
  \node[main node] (T) [node distance=2.75cm,below of=3] {$t$};

  \path[every node/.style={font=\sffamily\small}]
    (S) edge node [right] {} (0)
    (0) edge node [left] {} (1)
        edge node [left] {} (2)
        edge node [right] {} (3)
        edge node [left] {} (4)
        edge node [right] {} (5)
    (1) edge node [above] {} (2)
            edge node [left] {} (6)
            edge node [left] {} (T)
    (2) edge node [above] {} (3)
        edge node [left] {} (7)
        edge node [left] {} (T)
    (3) edge node [above] {} (4)
            edge node [left] {} (8)
            edge node [left] {} (T)
    (4) edge node [above] {} (5)
        edge node [right] {} (9)
        edge node [right] {} (T)
    (5) edge node [right] {} (10)
        edge node [right] {} (T)
    ;
    \end{tikzpicture}

and I would like to know how I could draw the "red" edges using TIKZ package.

Thanks.

graph

Welcome to TeX.SX! Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. — , Mar 14 '14 at 17:35

Gonzalo Medina · Accepted Answer · 2014-03-18T00:30:47.637

There are a number of possibilities. One of them is to use the

to[out=<angle>,in=<angle>,looseness=<value>]

syntax for \draw:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows}

\begin{document}

    \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

  \node (S) {};
  \node[main node] (0) [node distance=1.1cm,below of=S] {$s$};
  \node[main node] (3) [node distance=2.2cm,below of=0] {3};
  \node[main node] (2) [node distance=2.2cm,left of=3] {2};
  \node[main node] (1) [node distance=2.2cm,left of=2] {1};
  \node[main node] (4) [node distance=2.2cm,right of=3] {4};
  \node[main node] (5) [node distance=2.2cm,right of=4] {5};
  \node (6) [node distance=1.1cm,below of=1] {};
  \node (7) [node distance=1.1cm,below of=2] {};
  \node (8) [node distance=1.4cm,below left of=3] {};
  \node (9) [node distance=1.1cm,below of=4] {};
  \node (10) [node distance=1.1cm,below of=5] {};
  \node[main node] (T) [node distance=2.75cm,below of=3] {$t$};

\draw (T) to[out=180,in=180,looseness=4] (0);
\draw (5) to[out=-20,in=0,looseness=2] (T);

  \path[every node/.style={font=\sffamily\small}]
    (S) edge node [right] {} (0)
    (0) edge node [left] {} (1)
        edge node [left] {} (2)
        edge node [right] {} (3)
        edge node [left] {} (4)
        edge node [right] {} (5)
    (1) edge node [above] {} (2)
            edge node [left] {} (6)
            edge node [left] {} (T)
    (2) edge node [above] {} (3)
        edge node [left] {} (7)
        edge node [left] {} (T)
    (3) edge node [above] {} (4)
            edge node [left] {} (8)
            edge node [left] {} (T)
    (4) edge node [above] {} (5)
        edge node [right] {} (9)
        edge node [right] {} (T)
    (5) edge node [right] {} (10)
        edge node [right] {} (T)
    ;
    \end{tikzpicture}
\end{document}

enter image description here

Another one using .. controls .. and the calc library:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,arrows}

\begin{document}

    \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

  \node (S) {};
  \node[main node] (0) [node distance=1.1cm,below of=S] {$s$};
  \node[main node] (3) [node distance=2.2cm,below of=0] {3};
  \node[main node] (2) [node distance=2.2cm,left of=3] {2};
  \node[main node] (1) [node distance=2.2cm,left of=2] {1};
  \node[main node] (4) [node distance=2.2cm,right of=3] {4};
  \node[main node] (5) [node distance=2.2cm,right of=4] {5};
  \node (6) [node distance=1.1cm,below of=1] {};
  \node (7) [node distance=1.1cm,below of=2] {};
  \node (8) [node distance=1.4cm,below left of=3] {};
  \node (9) [node distance=1.1cm,below of=4] {};
  \node (10) [node distance=1.1cm,below of=5] {};
  \node[main node] (T) [node distance=2.75cm,below of=3] {$t$};

\draw let \p1=(T), \p2=(0) in
  (T) .. controls ([xshift=-8cm]\x1,.5*\y1+.5*\y2) .. (0);
\draw let \p1=(5), \p2=(T) in
  (5) .. controls ([xshift=2cm]\x1,.5*\y1+.5*\y2) .. (T);

  \path[every node/.style={font=\sffamily\small}]
    (S) edge node [right] {} (0)
    (0) edge node [left] {} (1)
        edge node [left] {} (2)
        edge node [right] {} (3)
        edge node [left] {} (4)
        edge node [right] {} (5)
    (1) edge node [above] {} (2)
            edge node [left] {} (6)
            edge node [left] {} (T)
    (2) edge node [above] {} (3)
        edge node [left] {} (7)
        edge node [left] {} (T)
    (3) edge node [above] {} (4)
            edge node [left] {} (8)
            edge node [left] {} (T)
    (4) edge node [above] {} (5)
        edge node [right] {} (9)
        edge node [right] {} (T)
    (5) edge node [right] {} (10)
        edge node [right] {} (T)
    ;
    \end{tikzpicture}
\end{document}

enter image description here

You should condider loading the positioning library and using the = of syntax instead of the old and problematic of= syntax. Also, using the node distance=<length> and <lenght> option for tikzpicture you can avoid manually specifying distances for each node.

Here's the code for the first option using these suggestions:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning}

\begin{document}

    \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries},node distance=2.2cm and 1.1 cm]

  \node (S) {};
  \node[main node] (0) [below = 0.8cm of S] {$s$};
  \node[main node] (3) [below = of 0] {3};
  \node[main node] (2) [left = of 3] {2};
  \node[main node] (1) [left = of 2] {1};
  \node[main node] (4) [right = of 3] {4};
  \node[main node] (5) [right = of 4] {5};
  \node (6) [below = 0.8cm of 1] {};
  \node (7) [below = 0.8cm of 2] {};
  \node (8) [below left = 0.8cm of 3] {};
  \node (9) [below = 0.8cm of 4] {};
  \node (10) [below = 0.8cm of 5] {};
  \node[main node] (T) [below = of 3] {$t$};

\draw (T) to[out=180,in=180,looseness=3] (0);
\draw (5) to[out=-20,in=0,looseness=2] (T);

  \path[every node/.style={font=\sffamily\small}]
    (S) edge node [right] {} (0)
    (0) edge node [left] {} (1)
        edge node [left] {} (2)
        edge node [right] {} (3)
        edge node [left] {} (4)
        edge node [right] {} (5)
    (1) edge node [above] {} (2)
            edge node [left] {} (6)
            edge node [left] {} (T)
    (2) edge node [above] {} (3)
        edge node [left] {} (7)
        edge node [left] {} (T)
    (3) edge node [above] {} (4)
            edge node [left] {} (8)
            edge node [left] {} (T)
    (4) edge node [above] {} (5)
        edge node [right] {} (9)
        edge node [right] {} (T)
    (5) edge node [right] {} (10)
        edge node [right] {} (T)
    ;
    \end{tikzpicture}
\end{document}

enter image description here

Using pgfinterruptboundingbox you can temporarily interrupt the computation of the bounding box, so the new \draw commands don't add additional space:

\documentclass{article}
\usepackage{tikz}
\usepackage{showframe}
\usetikzlibrary{arrows,positioning}

\begin{document}

\begin{figure}
\centering
    \begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries},node distance=2.2cm and 1.1 cm]

  \node (S) {};
  \node[main node] (0) [below = 0.8cm of S] {$s$};
  \node[main node] (3) [below = of 0] {3};
  \node[main node] (2) [left = of 3] {2};
  \node[main node] (1) [left = of 2] {1};
  \node[main node] (4) [right = of 3] {4};
  \node[main node] (5) [right = of 4] {5};
  \node (6) [below = 0.8cm of 1] {};
  \node (7) [below = 0.8cm of 2] {};
  \node (8) [below left = 0.8cm of 3] {};
  \node (9) [below = 0.8cm of 4] {};
  \node (10) [below = 0.8cm of 5] {};
  \node[main node] (T) [below = of 3] {$t$};

  \begin{pgfinterruptboundingbox}
  \draw (T) to[out=180,in=180,looseness=3] (0);
  \draw (5) to[out=-20,in=0,looseness=2] (T);
  \end{pgfinterruptboundingbox}

  \path[every node/.style={font=\sffamily\small}]
    (S) edge node [right] {} (0)
    (0) edge node [left] {} (1)
        edge node [left] {} (2)
        edge node [right] {} (3)
        edge node [left] {} (4)
        edge node [right] {} (5)
    (1) edge node [above] {} (2)
            edge node [left] {} (6)
            edge node [left] {} (T)
    (2) edge node [above] {} (3)
        edge node [left] {} (7)
        edge node [left] {} (T)
    (3) edge node [above] {} (4)
            edge node [left] {} (8)
            edge node [left] {} (T)
    (4) edge node [above] {} (5)
        edge node [right] {} (9)
        edge node [right] {} (T)
    (5) edge node [right] {} (10)
        edge node [right] {} (T)
    ;
    \end{tikzpicture}
\caption[loftitle]{Graph}
\end{figure}

\end{document}

enter image description here

showframe was only used to have a visual guideline for the text area.

@GonzaloMedina: thank you very much for your complete, bright and various explanation! — Pippothedog, Mar 17 '14 at 21:40

Tikzpicture edge over graph

1 Answers1