Mailman 3 December 2019 - Tkinter-discuss

wait_window exception
by Vasilis Vlachoudis Jan. 6, 2020

Jan. 6, 2020

What is the correct way to open a dialog and wait for the window Typically I am doing the following on a class subclassed of Toplevel # ---------------------------------------------------------------------- def __init__(self, title=None, master=None, **kw): super().__init__(master, class_="FileDialog") self.transient(master) self.title(title) self.protocol("WM_DELETE_WINDOW", self.close) # ... all initialization.... etc... def show(self): self.focus_set() try: self.deiconify() self.wait_visibility() self.update_idletasks() self.grab_set() except tk.TclError: pass self.wait_window() Unfortunately, several times when the system is not very responsive I get a traceback report from my users like ... File \"/usr/local/flair/lib/bFileDialog.py\", line 361, in show self.wait_window() File \"/usr/lib64/python3.7/tkinter/__init__.py\", line 642, in wait_window self.tk.call(\'tkwait\', \'window\', window._w) _tkinter.TclError: bad window path name \".!flair.!configdialog3.!opendialog\" Is there the possibility that the user clicks on the "Ok" or "Cancel" button before the code execution arrives to the wait_window(), so when it is there it gives the error message. Or can be something else that I am missing. Thanks in advance Vasilis

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The Async delete problem....
by Mike Barnett Dec. 15, 2019

Dec. 15, 2019

I've been fighting this error for a couple of years now and just when I think I've got it understood and "Fixed", it bites me again. Here's the error: Exception ignored in: <function Variable.__del__ at 0x0000016CA840C9D0> Traceback (most recent call last): File "X:\Python\python3.8\lib\tkinter\__init__.py", line 351, in __del__ if self._tk.getboolean(self._tk.call("info", "exists", self._name)): RuntimeError: main thread is not in main loop Exception ignored in: <function Variable.__del__ at 0x0000016CA840C9D0> Traceback (most recent call last): File "X:\Python\python3.8\lib\tkinter\__init__.py", line 351, in __del__ if self._tk.getboolean(self._tk.call("info", "exists", self._name)): RuntimeError: main thread is not in main loop Exception ignored in: <function Variable.__del__ at 0x0000016CA840C9D0> Traceback (most recent call last): File "X:\Python\python3.8\lib\tkinter\__init__.py", line 351, in __del__ if self._tk.getboolean(self._tk.call("info", "exists", self._name)): RuntimeError: main thread is not in main loop Exception ignored in: <function Image.__del__ at 0x0000016CA8446310> Traceback (most recent call last): File "X:\Python\python3.8\lib\tkinter\__init__.py", line 4014, in __del__ self.tk.call('image', 'delete', self.name) RuntimeError: main thread is not in main loop Tcl_AsyncDelete: async handler deleted by the wrong thread It happens in programs that are multi-threaded. The threads do NOT make any tkinter calls and do not touch any variable that has anything to do with tkinter. What appears to be happening is that tkinter objects are marked to be deleted and then when Python's garbage collect runs and actually does the deletes, it is happening in the context of the thread, not the main thread. My way around this at the moment is to keep the widgets around for the duration of the program rather than deleting them in any way. I would really like to get this solved though as other people using my code run into this and don't know what to do. Any ideas on how to dispose of widgets / windows in a way that immediately calls these delete methods? Or is it possible to tell tkinter that despite the deletes being called from another thread it's OK because the thread isn't actually changing anything at the same time as the main thread? Thank you -mike

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Lines around Tk Widgets on Linux but not Windows
by Mike Barnett Dec. 14, 2019

Dec. 14, 2019

I've had this problem for a very long time and have not been able to fix it regardless of what I've tried. My tk widgets all have a white border, despite setting the border width to zero. I don't have this problem on the Scale widget and on ttk widgets. The buttons you see along the bottom of the attached screenshot are TK Buttons except for one of them which is a TTK Button. The ttk one doesn't have a border. Any clues as to what I need to configure to remove these? They show up on Linux (including the Pi) and online on Trinket. Thank you for any kind of clues at all for me to investigate! -mike

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How to handle any Windows message (eg. WM_GETOBJECT)?
by Aivar Annamaa Dec. 10, 2019

Dec. 10, 2019

Hi! It looks like accessibility support in Tk won't happen (https://core.tcl-lang.org/tk/tktview/deb6cddecf55c6921281f8f855b6b366aed646…). I'm wondering is it somehow possible to bolt on some accessibility support at least on Windows. It looks like the starting point is that the app should be able to provide customized responses to WM_GETOBJECT messages. I didn't find such name in Tk source code. Does it mean Tk event loop simply drops these? Is it somehow possible to install an extra WM event handler to catch these? Best regards, Aivar

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tkinter.PhotoImage to PIL.Image
by Vasilis Vlachoudis Dec. 6, 2019

Dec. 6, 2019

Hi all, I have several images loaded as tkinter.PhotoImage, I want some to resize them The PhotoImage zoom accepts only integer values and the result is not that great. While if load them with PIL resize them and then convert to PIL.ImageTk it is much better. I found several references on how to convert from PIL to tkinter but I cannot find how to do the opposite so I can use the PIL resizing with the existing tkinter images. Many thanks Vasilis

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