How to Diff two versions of a graph?

Question

I keep graphs under version control and I need a tool to help diffing the graph. Only the actual data should be diff'ed, not the layout, color, ...

The tool should display one of the graphs (probably with colors removed?) and highlight the differences to the new one. Normally, only new nodes should appear, or connections will be changed. New nodes/connections could be green, removed ones red, modified ones blue...

I could use text-diff tools and diff the GraphML format, but this would create the difference including the layout, colors, etc.

Do you know of such a tool? Maybe you need a new feature you could implement :-)

Answer 1

I can think of two approaches:

1. You could save your diagrams in TGF file format and text-diff the resulting files.
2. You could use XSLT to strip down the GraphML of your diagrams to leave only their structural information and then text-diff.