Description

timhoffm

opened on May 31, 2026

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Summary

ContourLabeler is a mixin designed to add labeling functionality to ContourSet. It is only used there and due to heavy dependence on ContourSet API unlikely to be usable anywhere else.

Having this part of the ContourSet functionality split up makes documentation more complex (two classes) and makes tools complain about unresolvable attributes when we rely on ContourSet attributes from within ContourLabeler.

Proposed fix

I propose to inline all ContourLabeler functions into ContourSet and remove ContourLabler.

While this is technically a breaking change, I don't think there is anybody relying on ContourLabeler explicitly. It's too special to be usable anywhere else and search also did not indicate any usage
https://github.com/search?q=%2F%5CbContourLabeler%5Cb%2F+language%3APython+NOT+is%3Afork+NOT+path%3A**%2Fmatplotlib%2F**+NOT+path%3A**%2Fsite-packages%2F**+NOT+path%3Acontour.py&type=code

Reacted by Ruth Comer

Activity

1. timhoffm

   added

   Maintenance

   status: needs comment/discussionneeds consensus on next stepneeds consensus on next step

   on May 31, 2026
2. sahilmathur254 commented on Nov 4, 2026

   

   sahilmathur254

   on Nov 4, 2026

   Contributor

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   I’d be interested in taking this on. I’d move the labelling methods into ContourSet, update the affected references and documentation, and run the contour-labeling tests to check that behaviour is preserved.

   Before starting, could we confirm the compatibility approach? Are you comfortable removing ContourLabeler directly as proposed, or would you prefer a compatibility path through the usual deprecation process? I’ll keep the change focused on this consolidation.

   Reacted by Tim Hoffmann
3. timhoffm commented on Nov 5, 2026

   

   timhoffm

   on Nov 5, 2026

   MemberAuthor

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   I think we can dare to remove ContourLabeler directly.
4. sahilmathur254 commented on Nov 5, 2026

   

   sahilmathur254

   on Nov 5, 2026

   Contributor

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   Thanks @timhoffm, that clarifies it. I’ll move the labelling methods into ContourSet and remove ContourLabeler, update the affected documentation and references, and run the contour-labeling tests to check that behaviour is preserved

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