Does this address #9265 and the reasons we reverted the original fix?

This is effectively the same as #8539 (which was reverted), though perhaps a bit better, but it still breaks the radar axes example.

With the slightly cleaner implementation, maybe the radar example could override add_patch to not do interpolation.

May I know what's the expected output for radar chart?

@MeowsterEric See the expected outcome in #9261 :)

Thanks. I will take a look.
Btw, how do I properly set up the image comparison test?
Seems like the expected and actual image has RMS diff of 35.0

What's the preferred image comparison tolerance value?

The preferred image tolerance is 0. Make sure you have build Matplotlib correctly for image comparison tests and then you can copy the result of the test as the expected image.

Please also add style='mpl20' to the image_comparison decorator so you get a new-style image.

Given that this breaks an example, and that this plus a proposed fix are in #10561, I am closing this as redundant. It is still available and linked, so the comments can be reviewed as part of the history when considering #10561.