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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: rcParams[\"legend.labelcolor\"] treats \"none\" and \"None\" differently","articleBody":"### Bug summary\n\nThe \"standard\" matplotlib color semantics is that the strings `\"none\"` and `\"None\"` both mean fully transparent (as can be checked by mpl.colors.to_rgba); the object `None` can sometimes be used to mark a fallback.  Because the matplotlibrc format cannot distinguish between `None` and `\"None\"` (due the use of unquoted strings), it normally uses \"auto\" or \"inherit\" to mark a fallback.\r\nHowever, `rcParams[\"legend.labelcolor\"]` (a relatively recent introduction -- matplotlib 3.5) tries to use \"None\" as default, and as a result ends up having inconsistent behavior between `\"None\"` and `\"none\"`.\n\n### Code for reproduction\n\n```Python\nfrom pylab import *\r\n\r\nrcdefaults()\r\nprint(repr(rcParams[\"legend.labelcolor\"]))\r\n# default is the string \"None\"\r\n\r\nrcParams[\"legend.labelcolor\"] = \"None\"; plot([0, 1], label=\"foo\"); legend()\r\n# labels are black\r\n\r\nrcParams[\"legend.labelcolor\"] = \"none\"; plot([0, 1], label=\"foo\"); legend()\r\n# labels are transparent\r\n\r\nrcParams[\"legend.labelcolor\"] = None; plot([0, 1], label=\"foo\"); legend()\r\n# labels are black\n```\n\n\n### Actual outcome\n\nSee above.\n\n### Expected outcome\n\n\"None\" and \"none\" should mean the same (likely both should mean \"transparent\", not so much for usefulness but rather for consistency.\n\n### Additional information\n\nI suspect trying to support the object `None` as well here basically cannot be made to work (as long as matplotlibrc uses unquoted strings); the default should switch to be \"auto\" (or \"inherit\").\r\n\r\nAs a further point, the implementation of the rcParams validator `_validate_color_or_linecolor` seems wrong:\r\n```python\r\n    elif isinstance(s, str) and len(s) == 6 or len(s) == 8:  # (1)\r\n        stmp = '#' + s\r\n        if is_color_like(stmp):\r\n            return stmp\r\n        if s.lower() == 'none':  # (2)\r\n            return None\r\n```\r\nLikely parentheses are missing at (1); also (2) can never hold due to the len() check.\r\nAs a side point, 3 and 4-hex color codes (\"abc(d)\", meaning \"#abc(d)\", meaning \"#aabbcc(dd)\") are also not supported by rcParams (this is also the case for the more general _validate_color), even though the normal color machinery does support them.  At least this should be documented; I don't know if this can actually be supported without introducing an ambiguity with named colors.\n\n### Operating system\n\nmacos\n\n### Matplotlib Version\n\n3.9.0.dev1542+geb62d6951a\n\n### Matplotlib Backend\n\nany\n\n### Python version\n\n3.12\n\n### Jupyter version\n\nno\n\n### Installation\n\ngit checkout","author":{"url":"https://github.com/anntzer","@type":"Person","name":"anntzer"},"datePublished":"2024-04-30T14:19:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/28153/matplotlib/issues/28153"}