René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Multicolor errorbars cannot have caps","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nBringing https://stackoverflow.com/questions/56490293/why-do-i-get-an-invalid-rgba-argument-valueerror-when-defining-capsize-to-my-e to the issue tracker.\r\n\r\nMulticolored errorbars cannot have caps. Settings `capsize` for a bar plot with multiple colors results in a ValueError.\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug.\r\nPlease make sure to minimize the number of dependencies required, and provide\r\nany necessary plotted data.\r\nAvoid using threads, as Matplotlib is (explicitly) not thread-safe.--\u003e\r\n\r\n```\r\nimport matplotlib.pyplot as plt\r\nplt.rcParams[\"errorbar.capsize\"] = 2\r\n\r\nfig, ax = plt.subplots( figsize=(3,3))\r\n\r\ncolors=['crimson', 'limegreen', 'indigo']\r\n\r\nax.bar( [0,1,2], \r\n        [5,3,4],\r\n        linewidth=2,\r\n        color=\"papayawhip\",\r\n        edgecolor=colors,\r\n        ecolor=colors,\r\n        yerr=[1.5, 1, 1.5], \r\n        error_kw = {\r\n            'elinewidth': 2, }\r\n        )\r\n\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n\u003c!--The output produced by the above code, which may be a screenshot, console output, etc.--\u003e\r\n\r\n```\r\nTraceback (most recent call last):\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\backends\\backend_qt5.py\", line 501, in _draw_idle\r\n    self.draw()\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\backends\\backend_agg.py\", line 388, in draw\r\n    self.figure.draw(self.renderer)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\artist.py\", line 38, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\figure.py\", line 1709, in draw\r\n    renderer, self, artists, self.suppressComposite)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\image.py\", line 135, in _draw_list_compositing_images\r\n    a.draw(renderer)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\artist.py\", line 38, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\axes\\_base.py\", line 2645, in draw\r\n    mimage._draw_list_compositing_images(renderer, self, artists)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\image.py\", line 135, in _draw_list_compositing_images\r\n    a.draw(renderer)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\artist.py\", line 38, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\lines.py\", line 812, in draw\r\n    self.get_markeredgecolor(), self._alpha)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\colors.py\", line 177, in to_rgba\r\n    rgba = _to_rgba_no_colorcycle(c, alpha)\r\n  File \"D:\\***\\lib\\site-packages\\matplotlib\\colors.py\", line 238, in _to_rgba_no_colorcycle\r\n    raise ValueError(\"Invalid RGBA argument: {!r}\".format(orig_c))\r\nValueError: Invalid RGBA argument: ['crimson', 'limegreen', 'indigo']\r\n```\r\n\r\n**Expected outcome**\r\n\r\nExpected outcome would be the same as with\r\n\r\n    plt.rcParams[\"errorbar.capsize\"] = 0\r\n\r\n![image](https://user-images.githubusercontent.com/23121882/59093295-defcbc80-8913-11e9-8d4b-7d77a6032a2a.png)\r\n\r\n\r\n***but with caps on the errorbars:***\r\n\r\n![image](https://user-images.githubusercontent.com/23121882/59097946-318fa600-891f-11e9-8043-fd0eea9572a9.png)\r\n\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: Win8\r\n  * Matplotlib version: current\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): any\r\n  * Python version: 3.6.6\r\n","author":{"url":"https://github.com/ImportanceOfBeingErnest","@type":"Person","name":"ImportanceOfBeingErnest"},"datePublished":"2019-06-07T09:05:12.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/14480/matplotlib/issues/14480"}