Placement of tokens in tikz/petri

Question

Is there some easy trick to make \node[place,tokens=3]{} place 3 tokens in a row (and not in a triangle)?

Answer 1

In the file tikzlibrarypetri.code.tex you would find the needed macros. There are commands \tikz@def@grow@tokens{number of tokens}{number of the token}{x shift}{y shift} as in Grigorys comment) that can be analyzed and modified.

Here's the modification for number of tokens= 3 and number of the token= 1, 2, 3 - just place this code in your preamble:

\makeatletter
\tikz@def@grow@tokens{3}{1}{-1}{0}
\tikz@def@grow@tokens{3}{2}{0}{0}
\tikz@def@grow@tokens{3}{3}{1}{0}
\makeatother

Sample output of the modified manual Petri-net example:

Note the three tokens in a row in the middle of the image.