Adjusting Edge Paths in TikZ to Avoid Overlapping Nodes and Other Edges

Question

The following code

\begin{tikzpicture}[auto,node distance=2cm,>=latex]
% Posizionamento manuale dei vertici
  \node[circle,draw] (A) at (1,2) {A};
  \node[circle,draw] (B) at (3,2) {B};
  \node[circle,draw] (C) at (5,2) {C};
  \node[circle,draw] (D) at (4,0) {D};
  \node[circle,draw] (E) at (0,-1) {E};
  \node[circle,draw] (F) at (2,0) {F};
  \node[circle,draw] (S) at (-0.5,1) {S};
% Disegno degli archi con pesi
  \draw (A) -- node {$2$} (B);
  \draw (A) -- node {$2$} (S);
  \draw (S) to[out=90,in=120] node[above] {$3$} (B);
  \draw (S) -- node {$1$} (F);
  \draw (S) -- node {$4$} (E);
  \draw (E) -- node {$5$} (F);
  \draw (E) to[out=0,in=220] node[above] {$2$} (D);
  \draw (F) -- node {$3$} (D);
  \draw (C) -- node {$3$} (D);
  \draw (C) -- node {$3$} (B);
  \draw (B) -- node {$6$} (D);
  \draw (B) to[out=90,in=120] node[above] {$1$} (E);
\end{tikzpicture}

produces the following graph:

Upon closer inspection, it is apparent that the edge from B to E overlaps with other edges and the node A. I am seeking guidance on how to reroute this particular edge to the left of nodes S and A, preventing overlap with other edges and nodes. Any assistance on achieving this would be greatly appreciated.

duplicate -- https://tex.stackexchange.com/questions/617538/make-tikz-arrow-curvier/617540#617540 — js bibra, Dec 28 '23 at 04:31

score 4 · Accepted Answer · answered Dec 27 '23 at 13:51

A solution is to use the key looseness=2 for the \draw command. Also the keys out and in are changed. The option overlay is added so that the bounding box does not become too large.

\documentclass[border=6pt]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[auto,node distance=2cm,>=latex]
% Posizionamento manuale dei vertici
  \node[circle,draw] (A) at (1,2) {A};
  \node[circle,draw] (B) at (3,2) {B};
  \node[circle,draw] (C) at (5,2) {C};
  \node[circle,draw] (D) at (4,0) {D};
  \node[circle,draw] (E) at (0,-1) {E};
  \node[circle,draw] (F) at (2,0) {F};
  \node[circle,draw] (S) at (-0.5,1) {S};
% Disegno degli archi con pesi
  \draw (A) -- node {$2$} (B);
  \draw (A) -- node {$2$} (S);
  \draw (S) to[out=90,in=120] node[above] {$3$} (B);
  \draw (S) -- node {$1$} (F);
  \draw (S) -- node {$4$} (E);
  \draw (E) -- node {$5$} (F);
  \draw (E) to[out=0,in=220] node[above] {$2$} (D);
  \draw (F) -- node {$3$} (D);
  \draw (C) -- node {$3$} (D);
  \draw (C) -- node {$3$} (B);
  \draw (B) -- node {$6$} (D);
  \draw[looseness=2,overlay] (B) to[out=110,in=130] node[above] {$1$} (E);
\end{tikzpicture}
\end{document}

Zarko · Answer 2 · 2023-12-27T18:16:00.527

By use of the bbox and quotes libraries the image code is a bit shorter, more clear and resulted image is much nicer (without extra white space around it):

\documentclass[margin=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{bbox,
                quotes}
\begin{document}
    \begin{tikzpicture}[bezier bounding box,
                C/.style = {circle, draw, inner sep=2pt},
every edge quotes/.style = {auto, font=\footnotesize, inner sep=2pt},
                        ]
% Posizionamento manuale dei vertici
    \begin{scope}[nodes=C]
\node (A) at (1, 2) {A};
\node (B) at (3, 2) {B};
\node (C) at (5, 2) {C};
\node (D) at (4, 0) {D};
\node (E) at (0,-1) {E};
\node (F) at (2, 0) {F};
\node (S) at (-.5,1){S};
    \end{scope}
% Disegno degli archi con pesi
\draw   (A) edge["$2$"] (S) 
        (A) edge["$2$"] (B)
        (S) edge[bend left=60,"$3$"] (B) 
        (S) edge["$1$"] (F) 
        (S) edge["$4$"] (E) 
        (E) edge["$5$"] (F)
        (E) edge[bend right,"$2$"] (D)
        (E) edge[bend left=90, looseness=2, "$1$"] (B) 
        (F) edge["$3$"] (D) 
        (C) edge["$3$"] (D) 
        (C) edge["$3$"] (B) 
        (B) edge["$6$"] (D);
\end{tikzpicture}
\end{document}

BTW, in your code fragment you define arrows head which than is not used in the picture. So it is a bit unclear, is your graph is directed (edges have arrows heads) or not. MY MWE consider the latter case:

Adjusting Edge Paths in TikZ to Avoid Overlapping Nodes and Other Edges

2 Answers2