enforce circular layout to be circular (and not elliptic)?

[maximelucas]

Right now, the circular layout may appear elliptic depending on the aspect ratio of the axis (see below). We enforce the aspect to be "equal". Do we want that? networkx does not apparently.

Modified from originally posted by @thomasrobiglio in #415 (comment)

[leotrs]

I'd suggest we do enforce it.

[maximelucas]

I'd tend to enforce it too. The user can still manually change the aspect ratio later if they want something specific.
A simple ax.set_aspect("equal") should suffice.

[maximelucas]

Actually, I don't think anything can be done inside xgi.circular_layout() because it only returns positions, but no axis.
The position values are correct. They end up being plotted as an ellipsis later when using xgi.draw() is used, an axis is created, and the aspect of the axis is determined. So it can be enforced externally like this:

fig, ax = plt.subplots()
pos = xgi.circular_layout(H)
xgi.draw(H, pos=pos, ax=ax)
ax.set_aspect("equal")

I'm not even sure we can enforce this automaticall inside xgi.draw() because that function is just passed pos but does not know about which layout it corresponds to. Am I missing anything?

[thomasrobiglio]

@maximelucas all you are saying is correct. What if we just point that out in the docs/tutorials and keep the function as it is?
The ax.set_aspect() could be enforced in the drawing functions in the case ax is None but I don't think that solves the issue, considering also that it would affect all the other layout + clash with the default aspect ratio of axes in matplotlib

[maximelucas]

Agreed, was also thinking we could mention this in the docs of xgi.circular_layout(H) and tutos.

Yea enforcing this in draw for ax is None does not seem optimal. The only way could be to actually check the positions of the nodes inside draw: if they are on a circle (output of circular_layout) then enforce aspect. Let me see how short that could be.

[maximelucas]

We've just discussed with Alice and Nicholas and decided to do the following:
Add an aspect argument to draw(), the value of which will be passed to ax.set_aspect(aspect, "datalim").
By default, we will set it to "equal" so that the the circular layout is a circle. This will also be the default for any other layout/pos.