This pull requestfails (mergedd636190 intocf7618c).

What do these magic numbers mean? Why is 20 of them better than 3 of them? (other than experimental evidence)
Perhaps these magic numbers could be dropped into the rcParams?

This change will need an entry in the api changelog.

Yes, so it's unclear. TheFancyArrow docstring is also not clear about what they are. The kwargwidth is the width of the arrow tail. Its default value is 0.001, but the docstring does not say what the units are. My first reaction was to say they in points, but I think thats too small. The kwarghead_width controls the width of the arrow head, its default is set to three times that ofwidth. This would mean the units are the same but, again, I don't know what they are.

Would we prefer anrcParam for this instead? I'm starting to think that would be a better approach...

Would we prefer an rcParam for this instead?

I'm not sure about this now. The scale factor is only used when a user hasn't specified an arrow width - if the user were looking to change this they should set the width directly rather than setting a scale factor indirectly inrcParams.

Personally I'd be happy to merge this if you wouldn't mind re-basing?

Done.

👍. Anybody else want to comment? If not, I'll merge in the next 48 hrs.

Cheers@dmcdougall

@pelson Want to go ahead with this?