René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: TclError raised by _set_image_for_button() when _update_window_dpi() runs","articleBody":"### Bug summary\r\n\r\nI was trying to debug #22822 and an unrelated error pops up in `_set_image_for_button` when moving a window between monitors of different DPIs. It is a Tcl error that pops up during the `_update_window_dpi` callback and is therefore printed without ending the program.\r\n\r\n### Code for reproduction\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nimport matplotlib\r\nmatplotlib.use('tkagg')\r\n\r\nfig, ax = plt.subplots(1,1)\r\nplt.show()\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\n```\r\nException in Tkinter callback\r\nTraceback (most recent call last):\r\n  File \"C:\\Users\\richa\\miniconda3\\envs\\mpl-dev\\lib\\tkinter\\__init__.py\", line 1921, in __call__\r\n    return self.func(*args)\r\n  File \"c:\\users\\richa\\documents\\github\\matplotlib\\lib\\matplotlib\\backends\\_backend_tk.py\", line 438, in _update_window_dpi\r\n    self.toolbar._rescale()\r\n  File \"c:\\users\\richa\\documents\\github\\matplotlib\\lib\\matplotlib\\backends\\_backend_tk.py\", line 574, in _rescale\r\n    NavigationToolbar2Tk._set_image_for_button(self, widget)\r\n  File \"c:\\users\\richa\\documents\\github\\matplotlib\\lib\\matplotlib\\backends\\_backend_tk.py\", line 674, in _set_image_for_button\r\n    button.configure(image=image)\r\n  File \"C:\\Users\\richa\\miniconda3\\envs\\mpl-dev\\lib\\tkinter\\__init__.py\", line 1675, in configure\r\n    return self._configure('configure', cnf, kw)\r\n  File \"C:\\Users\\richa\\miniconda3\\envs\\mpl-dev\\lib\\tkinter\\__init__.py\", line 1665, in _configure\r\n    self.tk.call(_flatten((self._w, cmd)) + self._options(cnf))\r\n_tkinter.TclError: image \"pyimage10\" doesn't exist\r\n```\r\n\r\nAlso because the callback is interrupted, some widgets are not rescaled.\r\n\r\n### Expected outcome\r\n\r\nno traceback and properly scaled widgets\r\n\r\n### Additional information\r\n\r\nThis code was introduced in #22163 to improve the Tk toolbar buttons in dark mode situations.  I don't immediately see the cause, but it seems very easy for me to trigger so I'm surprised nobody noticed? attn: @daniilS \r\n\r\n### Operating system\r\n\r\nWindows\r\n\r\n### Matplotlib Version\r\n\r\nmain back to ff60b28 (bisected)\r\n\r\n### Matplotlib Backend\r\n\r\ntkagg\r\n\r\n### Python version\r\n\r\n3.10.4\r\n\r\n### Jupyter version\r\n\r\n_No response_\r\n\r\n### Installation\r\n\r\ngit checkout","author":{"url":"https://github.com/richardsheridan","@type":"Person","name":"richardsheridan"},"datePublished":"2022-04-13T01:34:04.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/22836/matplotlib/issues/22836"}