[igraph] Horizontal gap (hgap) not taken into account when creating a Sugiyama layout with the Python binding

[Antonin Lenfant]

Hello,

I am trying to represent a layered graph, so I want to use the Sugiyama layout generator included in igraph.

However, it seems that it doesn't take into account the hgap property, which should set the "minimum horizontal gap between vertices in the same layer", according to the documentation.

I tried with multiple hgaps (0.1, 10, 100...) and plot target sizes (plot's bbox property), but nothing changed.

Here is the relevant part of my code :

layout = g.layout_sugiyama(layers=layout_node_layer, maxiter=1000, hgap=10)

igraph.plot(g, "graph.pdf", layout=layout, vertex_label=None, bbox=(20000,160000))

It also seems that the weights property ("edge weights to be used") wasn't taken into account when I tried it, passing a list with the weight for each layer.

If anybody has an idea about what is causing this, it definitely would help me a lot!

Thanks in advance,

Antonin Lenfant