Tikz Edge Label Positioning mid anchor

Question

I would like to place labels below edges such that the letters don't wobble. I can place them on the edge using the mid anchor, but when I use below some other anchor is used to calculate the distance.

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\tikzstyle{vertex}=[circle, draw, inner sep=0.5ex]
\node [vertex] (0) {};
\foreach \n/\e in {1/a,2/b,3/c,4/d,5/e,6/f,7/g,8/h} {
  \pgfmathtruncatemacro{\left}{\n-1}
  \node [vertex] (\n) [right=of \left] {};
  \draw  (\left) -- node[anchor=mid] {\e} (\n); %on the edge, no wobble
  \draw (\left) -- node [below] {\e} (\n); % below the edge, wobble
};
\end{tikzpicture}
\end{document}

Please make sure that your example compiles -- the positioning library and \end{tikzpicture} was missing. — Torbjørn T., Aug 06 '13 at 09:19
Don't use numbers as node names. It will cause trouble if you refer to the angle anchors such as 4.90 — percusse, Aug 06 '13 at 09:47
I'd suggest using standalone instead of minimal. You can find some problems using minimal because, sometimes, it's too minimal. Look at What is the advantage of using minimal over article when creating a standalone graphic? — Ignasi, Aug 06 '13 at 09:47

score 3 · Accepted Answer · answered Aug 06 '13 at 09:38

node[below] means node[anchor=north] and labels wobble because they have different height. If you want all labels aligned you can choose base anchor which will align all labels to their baseline.

\documentclass[tikz,border=2mm]{standalone}
%\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}
\tikzstyle{vertex}=[circle, draw, inner sep=0.5ex]
\node [vertex] (0) {};
\foreach \n/\e in {1/a,2/b,3/c,4/d,5/e,6/f,7/g,8/h} {
  \pgfmathtruncatemacro{\left}{\n-1}
  \node [vertex] (\n) [right=of \left] {};
  \draw (\left) -- node [draw, below=5mm, anchor=base]  (\e) {\e} (\n); % below the edge, don't wobble
};
\draw[red] (a.base)--(h.base);

\begin{scope}[yshift=-1cm]
\node [vertex] (0) {};
\foreach \n/\e in {1/a,2/b,3/c,4/d,5/e,6/f,7/g,8/h} {
  \pgfmathtruncatemacro{\left}{\n-1}
  \node [vertex] (\n) [right=of \left] {};
  \draw (\left) -- node [draw, below]  (\e) {\e} (\n); % below the edge, wobble
};
\draw[red] (a.north)--(h.north);
\end{scope}
\end{tikzpicture}
\end{document}

enter image description here

Tikz Edge Label Positioning mid anchor

1 Answers1