René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"RuntimeError: Cannot get window extent w/o renderer","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nMatplotlib 2.2.0 seems to introduce regression regarding the use of `Agg` renderer. In specific cases, get_window_extent() does raise `RuntimeError: Cannot get window extent w/o renderer`.\r\n\r\n**Code for reproduction**\r\n\r\n```python\r\n#!/usr/bin/env python3\r\nimport matplotlib\r\nmatplotlib.use('Agg')\r\nimport matplotlib.pyplot as plt\r\n\r\nfig = plt.figure()\r\nax = fig.add_subplot(111, frameon=True)\r\nax.plot()\r\n\r\n# If the call to draw() below is removed, everything works\r\n# However, this line cases xtick and ytick get_window_extent()\r\n# to raise 'RuntimeError: Cannot get window extent w/o renderer'\r\n# on matplotlib 2.2.0 (tested also on 2.2.2)\r\n#\r\n# Moreover, this works just fine with and without the call to\r\n# draw() below, with matplotlib 2.1.2\r\nplt.get_current_fig_manager().canvas.draw()\r\n\r\nax.set_xlabel(ax.get_xlabel()).get_window_extent()\r\nax.set_ylabel(ax.get_ylabel()).get_window_extent()\r\nfor xtick in ax.get_xticklabels():\r\n    xtick.get_window_extent()\r\nfor ytick in ax.get_yticklabels():\r\n    ytick.get_window_extent()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n```$ python matplotlib-bug.py\r\nTraceback (most recent call last):\r\n  File \"matplotlib-bug.py\", line 22, in \u003cmodule\u003e\r\n    xtick.get_window_extent()\r\n  File \"/usr/lib/python3.6/site-packages/matplotlib/text.py\", line 920, in get_window_extent\r\n    raise RuntimeError('Cannot get window extent w/o renderer')\r\nRuntimeError: Cannot get window extent w/o renderer\r\n```\r\n\r\n**Expected outcome**\r\n\r\nNo exception should be raised. No exception is raised when the code is used with matplotlib 2.1.2.\r\n\r\n**Matplotlib version**\r\n  * Operating system: Arch Linux\r\n  * Matplotlib version: 2.2.2\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): agg\r\n  * Python version: 3.6.4\r\n\r\nInstalled with `pacman -S python python-matplotlib`. Tested against older version of matplotlib by installing them in virtualenv using pip.","author":{"url":"https://github.com/desowin","@type":"Person","name":"desowin"},"datePublished":"2018-03-24T18:45:36.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/10874/matplotlib/issues/10874"}