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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Backend related issues with matplotlib 3.0.0rc1","articleBody":"I noticed three backend related issues with matplotlib 3.0.0rc1 on Windows:\r\n\r\n1) Setting `backend = TkAgg` in `setup.cfg` before building wheels, TkAgg does not get enabled as the default backend in the `mpl-data/matplotlibrc` file. That option has been removed in https://github.com/matplotlib/matplotlib/commit/56acb0f691f3447f7f15b257b164e0bc431760eb#diff-2eeaed663bd0d25b7e608891384b7298. I am aware this is (sort of) mentioned in the `whats_new` document. TkAgg has always been the default backend in the official binaries for Windows. IMO, this default has been more predictable, reliable (e.g. see issue 2), and faster loading than other backends.\r\n\r\n2) At least on my system with PyQt4 installed, the default backend is unusable:\r\n```Python\r\n\u003e\u003e\u003e from matplotlib import pyplot\r\n\u003e\u003e\u003e pyplot.plot()\r\n[]\r\n\u003e\u003e\u003e pyplot.show()\r\nTraceback (most recent call last):\r\n  File \"X:\\Python37\\lib\\site-packages\\matplotlib\\backends\\backend_qt5agg.py\", line 57, in paintEvent\r\n    buf, buf.shape[1], buf.shape[0], QtGui.QImage.Format_RGBA8888)\r\nAttributeError: type object 'QImage' has no attribute 'Format_RGBA8888' \r\n```\r\nA window opens but no plot is rendered.\r\n\r\n3) I am unable to print the default backend:\r\n```Python\r\n\u003e\u003e\u003e import matplotlib\r\n\u003e\u003e\u003e print(matplotlib.get_backend())\r\n\u003cobject object at 0x000002928A3FE7A0\u003e \r\n```\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: Windows 10 Pro WS 1803\r\n  * Matplotlib version: 3.0.0rc1\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): \u003cobject object at 0x000001F814B0E7A0\u003e\r\n  * Python version: Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32\r\n  * Jupyter version (if applicable):\r\n  * Other libraries: \r\n\r\nInstalled from source matplotlib-3.0.0rc1.zip\r\n\r\n","author":{"url":"https://github.com/cgohlke","@type":"Person","name":"cgohlke"},"datePublished":"2018-08-12T06:13:05.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":21},"url":"https://github.com/11844/matplotlib/issues/11844"}