René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"wide mathtext accents are mis-centered","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\nAll's in the title.\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```python\r\nfrom pylab import *\r\n\r\nfigtext(.5, .5, r\"$\\widebar{abc} \\qquad \\mathrm{\\widebar{abc}}$\")\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![test](https://user-images.githubusercontent.com/1322974/104620564-6b926380-568f-11eb-9ab3-d6f85d982e00.png)\r\n\r\n**Expected outcome**\r\n\r\nThe bar should be correctly centered.  (The italic version is still ok-ish, but the roman one is far too offset.)\r\n  Likewise for `\\widehat` and `\\widetilde`.\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: linux\r\n  * Matplotlib version (`import matplotlib; print(matplotlib.__version__)`): HEAD (3.3+)\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): qt5agg\r\n  * Python version: 3.9\r\n  * Jupyter version (if applicable):\r\n  * Other libraries: \r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\n\r\n-----\r\n\r\nFrom a quick look, this is due to the `sym.width/4` horizontal correction added to an HCentered box in `accent()`.  Indeed replacing `centered` by just `accent_box` appears to fix the issue... but now the italic correction is lost when using italics.\r\n\r\nI think the correct solution likely implies doing an exegesis of node 12 of the TeXbook's appendix G (p442), or any of the articles linked at https://github.com/matplotlib/matplotlib/pull/18916#issuecomment-751506966.\r\n","author":{"url":"https://github.com/anntzer","@type":"Person","name":"anntzer"},"datePublished":"2021-01-14T16:40:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/19299/matplotlib/issues/19299"}