Forest tree - how to draw nodes with double border?

I'm looking for something like this (finite automat). I want to draw a specific node as endnode, that means this node should have two circles as border. I'm using forest to draw my trees

Currently I'm having this code to generate a tree. There should be an "endnode" for "Jack", "Java", "Jim", "Ron" and "Ronny" (always at the last matching node)

\documentclass{beamer}
\usepackage{forest}
\begin{document}
\begin{forest}
for tree={
circle,
black,
draw,
minimum size = 2em,
font=\Large,
edge={->},
s sep = 30pt
}
[{}
[J, edge label={node[midway, left]{J}}
[a, edge label={node[midway, left]{a}}
[c,  edge label={node[midway, left]{c}}
[k,  edge label={node[midway, left]{k}}]]
[v,  edge label={node[midway, left]{v}}
[a,  edge label={node[midway, left]{a}}]]]
[i,  edge label={node[midway, left]{i}}
[m,  edge label={node[midway, left]{m}}]]]
[R,  edge label={node[midway, right]{R}}
[o,  edge label={node[midway, right]{o}}
[n,  edge label={node[midway, right]{n}}
[n,  edge label={node[midway, right]{n}}
[y,  edge label={node[midway, right]{y}}]]]]]]
\end{forest}
\end{document}

• welcome to tex.se! please show us what you try so far! – Zarko Dec 12 '17 at 9:22
• @Zarko updated post – Ian Fako Dec 12 '17 at 9:26
• Thanks for posting your code, but this is not a complete example. Please always post code we can copy-paste-compile. Is it just one node you want with double or several? If several, is there a pattern? – cfr Dec 12 '17 at 23:58
• @cfr Sorry, updated my code. There are several nodes, but there's not a real pattern. The tree stores names and each endnode should be a double bordered node ('Ron', 'Ronny'...) Currently solving this by the answer provided by Zarko – Ian Fako Dec 14 '17 at 14:45
• @IanFako In that case you can add where n children=0{double}{} to the tree's preamble and all the terminal nodes will be double-bordered. You can then just add double to any additional nodes which need it in the tree. This is a bit more flexible if, say, you change your mind about how to designate the terminal nodes or something, and a bit less error-prone. – cfr Dec 16 '17 at 4:55

meanwhile i found a simple example in my examples barn:

\documentclass[tikz,multi,border=5pt]{standalone}
\usepackage{forest}

\begin{document}
\begin{forest}
for tree={
draw=teal,
line width=0.4pt,
edge={draw=teal,very thin},
grow=east,
circle,
l sep=19mm,
%    anchor=children,
anchor=parent,
}
[A, double, outer sep=0.5pt,
[B]
[C]
]
\end{forest}
\end{document}


is this what you looking for?

• ah yes, thank you, double is the option I was searching for – Ian Fako Dec 12 '17 at 9:41

Here's a less labour-intensive way of getting the pattern of edge labels you want. This is entirely off-topic and doesn't even attempt to answer the actual question, which Zarko has already covered.

\documentclass[border=10pt]{standalone}
\usepackage{forest}
\begin{document}
\begin{forest}
for tree={
circle,
black,
draw,
minimum size = 2em,
font=\Large,
edge={->},
s sep = 30pt
},
delay={
for nodewalk={fake=r,1,descendants}{
if edge label={}{}{
edge label/.wrap value={ node [midway, left] {#1} }
}
},
for nodewalk={fake=r,l,descendants}{
if edge label={}{}{
edge label/.wrap value={ node [midway, right] {#1} }
}
}
}
[
[J, edge label=J
[a, edge label=a
[c,  edge label=c
[k,  edge label=k]]
[v,  edge label=v
[a,  edge label=a]]]
[i,  edge label=i
[m,  edge label=m]]]
[R,  edge label=R
[o,  edge label=o
[n,  edge label=n
[n,  edge label=n
[y,  edge label=y]]]]]]
\end{forest}
\end{document}


This is a bit trickier, perhaps, than the usual case in which people want all the labels for left-hand branches to go one way and all for right-hand branches to go the other. The pattern therefore seemed technically more interesting, though not necessarily aesthetically pleasing.

• a new example for mastering forest (+1). btw, in which time zone you live? here in gmt is time to slip :-) – Zarko Dec 13 '17 at 0:15
• @Zarko I'm horribly night-owl-ish ;). – cfr Dec 13 '17 at 1:12
• ah, very the same as me ..., but now will go to slip :-) – Zarko Dec 13 '17 at 1:14