I wonder, how I can create an arrowtail in the same size as here on the example page:
The left side has a nice little dot. But i fear that it is simply a small node and not an arrowtail. Am I right?
Unfortunately, arrowsize applies to both head & tail. Here is an enhancement request to create arrowheadsize and arrowtailsize.
It is possible to post-process a dot format output and have neato -n2 produce the result you want, but it is fiddley.
Here is a hand-edited dot output:
digraph aa {
graph [bb="0,0,216,252",
rankdir=LR,
ranksep=1.5
];
node [label="\N"];
edge [arrowhead=normal,
arrowtail=dot,
dir=both
];
a1 [height=0.5,
pos="27,18",
width=0.75];
b1 [height=0.5,
pos="189,18",
width=0.75];
a1 -> b1 [arrowsize=2,
pos="s,54.421,18 e,161.54,18 71.132,18 92.419,18 118.16,18 140.07,18"];
a2 [height=0.5,
pos="27,72",
width=0.75];
b2 [height=0.5,
pos="189,72",
width=0.75];
a2 -> b2 [arrowsize=1,
pos="s,54.421,72 e,161.54,72 63.208,72 88.932,72 123.77,72 150.1,72"];
a3 [height=0.5,
pos="27,126",
width=0.75];
b3 [height=0.5,
pos="189,126",
width=0.75];
a3 -> b3 [arrowsize=.5,
pos="s,54.421,126 e,161.54,126 59.073,126 86.78,126 127.2,126 155.37,126"];
a4 [height=0.5,
pos="27,180",
width=0.75];
b4 [height=0.5,
pos="189,180",
width=0.75];
a4 -> b4 [arrowsize=.25,
pos="s,54.421,180 e,161.54,180 57.252,180 85.757,180 128.9,180 157.74,180"];
A2 [height=0.5,
pos="27,234",
width=0.75];
B2 [height=0.5,
pos="189,234",
width=0.75];
A2 -> B2 [arrowsize=1,
dir=forward,
pos="e,161.54,234 54.421,234 80.476,234 120.57,234 150.03,234"];
// edited by hand
// started with "54.421,234" from A2->B2, then modified X coordinate a bit
XYZ [pos="55.1,234" shape=point width=.05 color=red]
}
And the result:
Thank you Steve!
I love that enhancement request!