I would like simply to plot labels not to the vertex of the graph but to the edge.
Simple enough case: Kamada Kawai layout for undirected graph.
I'm fantasizing about something like this:
visual_style["edge_label"] = g.es["weightthing"]
To try to justify my question as I was researching much but found only this:
The edge labels. They will be converted to character. Specify NA to omit edge labels.
Edge labels are omitted by default.
from here
I fail to understand the above quote. Sorry.
Unfortunately edge labels are not supported yet in the Python interface of igraph. (By the way, you were reading the documentation for the R interface).
Update: the development version of igraph (i.e. version 0.7) now supports edge labels.