Summary

from:#23995 (comment)

tricontour[f] documents and accepts parametersorigin andextent, but interestingly, they are not used 😲. They are only used incontour[f], where one can leave out X and Y, in which caseorigin andextent define where to place the data in the Axes. When one thinks about it, this concept does obviously does not apply to triangular grids. One always has to specify x and y, either directly or via a `Triangulation.

It's a bit hard to see thatorigin andextent are unused, because they are passed through multiple levels of kwargs and are added as attributes toContourSet, which is the common base class ofTriContourSet andQuadContourSet. ButTriContourSet does not use them. One can also check this by removing the validation checks on these values and then passing in nonsense values: The plot does not care. It seems this docstring part was copied fromcontour[f] without thinking about it.

Proposed fix

Goal: Removeorigin andextents parameters fromtricontour[f]()

Things to do:

• Find out the how to properly handleorigin andextent in theContourSet class hierarchy. Likely move toQuadContourSet. But it might be that we have leave it inContourSet but warn/error when used inTriContourSet.
• Based on that determine the proper place to deprecate them.
• Change thetricontour[f] docstring accordingly (deprecation statement and mention that they don't have any effect).
• When the deprecation expires, clean up.

Note: Nobody has complained that these parameters don't have any effect, so I assume nobody uses them intentionally. But since they are documented, I think we still have to jump the deprecation hoops.