Coloured call graphs!

Juha Jeronen has added some features to the Python call-graph generator (pyan) I’ve previously blogged about. With a single command line, I can now get pictures like this:

pyan.py -c backup.py journal.py journalcmd.py links.py --dot | dot -Tpng > backup-use-and-def.png

A bit of colour always shows a program’s structure in a better light. Green for the backup program, orange and blue for high-level and low-level journal manipulation, and yellow for link creation.

As well as automatic colouring by namespace, there are options to control whether use- and define- edges are shown, and whether nodes in each namespaces are grouped together. For instance, instead of drawing define-edges between namespaces and their members as above, we could omit those edges and instead group them. The “fdp” layout algorithm seems to render best for this graph:

pyan.py -n -g -c backup.py journal.py journalcmd.py links.py --dot | fdp -Tpng > backup-use-and-group.png

Juha’s colour and grouping enhancements are implemented for the GraphViz output. pyan also outputs .tgf files for yEd. But “trivial graph format” is just too trivial to support these options, so I may soon extend the program to write the more advanced .graphml format.