René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"wx backend assertion error with fig.canvas.timer.start()","articleBody":"\r\n\r\nwx assertion error when starting canvas timer instance.\r\n\r\n\r\n**Code for reproduction**\r\n```\r\nimport matplotlib\r\nmatplotlib.use('WXAgg')\r\nimport matplotlib.pyplot as plt\r\nimport numpy as np\r\nfrom datetime import datetime\r\n\r\ndef update_title(axes):\r\n    axes.set_title(datetime.now())\r\n    axes.figure.canvas.draw()\r\nfig, ax = plt.subplots()\r\nx = np.linspace(-3, 3)\r\nax.plot(x, x ** 2)\r\ntimer = fig.canvas.new_timer(interval=100)\r\ntimer.add_callback(update_title, ax)\r\ntimer.start()\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n```\r\nTraceback (most recent call last):\r\n  File \"timer_debug.py\", line 18, in \u003cmodule\u003e\r\n    timer = fig.canvas.new_timer(interval=100)\r\n  File \"/Users/ewthornton/opt/anaconda3/envs/grid_gen3/lib/python3.7/site-packages/matplotlib/backend_bases.py\", line 2374, in new_timer\r\n    return self._timer_cls(interval=interval, callbacks=callbacks)\r\n  File \"/Users/ewthornton/opt/anaconda3/envs/grid_gen3/lib/python3.7/site-packages/matplotlib/backends/backend_wx.py\", line 78, in __init__\r\n    TimerBase.__init__(self, *args, **kwargs)\r\n  File \"/Users/ewthornton/opt/anaconda3/envs/grid_gen3/lib/python3.7/site-packages/matplotlib/backend_bases.py\", line 1094, in __init__\r\n    self.single_shot = False\r\n  File \"/Users/ewthornton/opt/anaconda3/envs/grid_gen3/lib/python3.7/site-packages/matplotlib/backend_bases.py\", line 1145, in single_shot\r\n    self._timer_set_single_shot()\r\n  File \"/Users/ewthornton/opt/anaconda3/envs/grid_gen3/lib/python3.7/site-packages/matplotlib/backends/backend_wx.py\", line 91, in _timer_set_single_shot\r\n    self._timer.Start()\r\nwx._core.wxAssertionError: C++ assertion \"m_milli \u003e 0\" failed at /opt/concourse/worker/volumes/live/3ef8f33f-8e5b-442f-6716-948fc4646a36/volume/wxpython_1547931203930/work/ext/wxWidgets/src/osx/core/timer.cpp(69) in Start(): invalid value for timer timeout\r\n```\r\n\r\n\r\n**Expected outcome**\r\nShould produce output like this example.\r\nhttps://matplotlib.org/3.1.1/gallery/event_handling/timers.html\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: OSX 10.15.6\r\n  * Matplotlib version: 3.3.2 (bug not present in 3.2.2)\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): wxAgg\r\n  * Python version: 3.7.8\r\n  * Jupyter version (if applicable):\r\n  * Other libraries: wxpython 4.0.4 (also tried 4.0.7-post2)\r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\nconda\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\nConda-forge\r\n\r\n","author":{"url":"https://github.com/gonesurfing","@type":"Person","name":"gonesurfing"},"datePublished":"2020-10-01T04:54:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/18620/matplotlib/issues/18620"}