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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Docs: default backend is not always `\"agg\"` (e.g., if X11 is working)","articleBody":"### Problem\r\n\r\nOne may get the impression that `\"agg\"` is the default backend from reading\r\n\u003e There are three ways to configure your backend:\r\n\u003e 1. The `rcParams[\"backend\"]` (default: `'agg'`) parameter in your `matplotlibrc` file\r\n\u003e 2. The `MPLBACKEND` environment variable\r\n\u003e 3. The function `matplotlib.use()`\r\n\r\nhttps://matplotlib.org/stable/tutorials/introductory/usage.html#selecting-a-backend\r\n\r\nSo, not having a `matplotlibrc` nor `MPLBACKEND`, I would expect that `\"agg\"` is default. However, with `DISPLAY` set and an X11 server running, I get\r\n```\r\nuser@host:~/cia\u003e xeyes; echo $?; python -c \"import matplotlib as mpl; print(mpl.get_backend())\"\r\n0\r\nTkAgg\r\n```\r\n\r\nOnly after closing the X11 server, everything is as expected:\r\n```\r\nuser@host:~/cia\u003e xeyes; echo $?; python -c \"import matplotlib as mpl; print(mpl.get_backend())\"\r\nError: Can't open display: localhost:12.0\r\n1\r\nagg\r\n```\r\n\r\n### Suggested Improvement\r\n\r\n- Explain that an interactive backend is selected by default if available.\r\n- Make sure people find this information when searching for \"TkAgg\" (in case someone looks for this when trying to understand why they get what I observe).\r\n- Remove  \"(default: `'agg'`)\" from `rcParams[\"backend\"]` (because it's not always correct)\r\n","author":{"url":"https://github.com/bersbersbers","@type":"Person","name":"bersbersbers"},"datePublished":"2021-03-29T21:03:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/19813/matplotlib/issues/19813"}