Double-edged nodes with different colours

Help
#1

I’m looking to produce a doublecircle where the outer circle is coloured black, and the inner circle is coloured blue. If I use the following DOT code,

digraph {
    1 [color=blue shape=doublecircle]
}

and render it with dot, I get the following,

dotfile.gv
dotfile.gv1200×1200 55.6 KB

Is there any way of producing a doublecircle where the inner and outer circles are set to two different colours? Any help would be greatly appreciated - thank you in advance.

#2

I wonder if color=“blue:black” would work. Haven’t tried it.

Saw a similar example at
http://www.graphviz.org/doc/info/attrs.html#d:color

#3

I liked the two-tone color idea, but it doesn’t seem to work.
You can run your graph (with one circle) through dot -Tdot and then (programmatically or manually) edit the output to add a second node, slightly smaller, on top of the original node, producing something like this:

digraph {
	graph [bb="0,0,44,44"];
	node [label="\N"];
	1	[color=blue,
		height=0.61111,
		pos="22,22",
		shape=circle,
		width=0.61111];
    // added manually - cut/paste & edit		
	_inside1  [color=red, // changed color
		height=0.5,   // smaller
		pos="22,22",  // same center
		shape=circle,
		label=""      // no label
		width=0.5];   // smaller
}

doubleCircle1

A kludge, but it works.

p.s. I wonder how hard it would be to add this multi-color feature to any node with peripheries.

#4

This is a kludge, but a super neat kludge - exactly what I was looking for, thank you!

@mark, I did try your suggestion, but the output was the same as the graph I posted in my original post. Thank you anyway for your answer.