Briefcase run does not include Tkinter

[saroad2]

This is going to be quite long, hope It's Ok

I have a Briefcase project that shows matplotlib plots from a compact GUI.
I'm working on Windows with python3.7. When I run my program using briefcase dev it's working ok, but when trying to run it with breifcase run it fails.
I went down the rabbit hole and saw that on windows it runs the program using windows\src\FORMAL_NAME\python\pythonw.exe -m MY_PACKAGE_NAME. I tried to run it manually and saw that nothing is printed, not an error and not anything else.

I saw that in the same directory there is a python.exe file so I ran it with -m MY_PACKAGE_NAME and I got the following error:

Traceback (most recent call last):
  File "D:\obj\windows-release\37win32_Release\msi_python\zip_win32\runpy.py", line 193, in _run_module_as_main
  File "D:\obj\windows-release\37win32_Release\msi_python\zip_win32\runpy.py", line 85, in _run_code
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app\eddington_gui\__main__.py", line 1, in <module>
    from eddington_gui.app import main
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app\eddington_gui\app.py", line 6, in <module>
    from eddington import read_data_from_excel, InvalidDataFile, plot_fitting, plot_residuals, PlotConfiguration
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\eddington\__init__.py", line 18, in <module>
    from eddington.plot.residuals import plot_residuals
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\eddington\plot\residuals.py", line 1, in <module>
    from eddington.plot.util import title, label_axes, horizontal_line, plot_data, show_or_export
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\eddington\plot\util.py", line 1, in <module>
    import matplotlib.pyplot as plt
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\matplotlib\pyplot.py", line 2282, in <module>
    switch_backend(rcParams["backend"])
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\matplotlib\pyplot.py", line 221, in switch_backend
    backend_mod = importlib.import_module(backend_name)
  File "D:\obj\windows-release\37win32_Release\msi_python\zip_win32\__init__.py", line 127, in import_module
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\matplotlib\backends\backend_tkagg.py", line 1, in <module>
    from . import _backend_tk
  File "C:\Users\saroa\repositories\eddington_gui\windows\EddingtonGUI\src\\app_packages\matplotlib\backends\_backend_tk.py", line 6, in <module>
    import tkinter as tk
ModuleNotFoundError: No module named 'tkinter'

I looked at the windows\src\FORMAL_NAME\python\ and I saw that indeed Tkinter is not there.
Is that on purpose? how can I manually add Tkinter to there?

[freakboy3742]

Thanks for the report. So the issue here isn't briefcase specifically - it's the support package.

The support packages that Briefcase uses by default don't include tkinter (on purpose) - this is because getting a working tkinter build can be complicated. tkinter support requires external libraries that aren't always available, and they can't be obtained easily using purely Python tooling.

In the case of the Windows support package specifically, briefcase is actually using the Python-issued "embedded" distribution, which also doesn't include tkinter (on purpose, for the same reason).

It is entirely possible to support tkinter - however, you need to provide your own support package that includes tkinter and all it's additional dependencies.

If your requirement is around matplotlib specifically, you may have more luck using a different plotting backend. matplotlib has a pluggable rendering backend, and there are backends for widget toolkits other than tkinter (Qt, for example). Using one of those backends may be an easier option than trying to get tkinter support, as those widget kits have better Python installation support.

[freakboy3742]

One more note - at the very least, we should document that Tkinter isn't supported. Ideally, we'd be able to identify that the project won't work because of the support package - but programatically identifying that will be complex.

[saroad2]

Hey, replaced usage of Tkinter with WX and it works!

Thank you very much :)
Closing the issue.

[mocaccano]

Hi @freakboy3742, I'm facing the same issue at the moment and found this issue.
How can I explicitly add tkinter as a support package? Unable to figure this out, as by default, it just comes with python.
Like @saroad2 , briefcase dev works fine, but not briefcase run. Appreciate any help, thanks!

[freakboy3742]

@mocaccano It's not trivial, and I can't point you at an easy set of instructions to include it. While Tkinter is part of the standard library, it isn't part of the Windows embedded install - because it's not easy to redistribute. That's the same reason that we don't include it in the macOS support package that Briefcase uses.

[mocaccano]

Thanks for the reply. If I replace the part of the code which uses Tkinter by PySide6 which is one of the GUI options proposed by Briefcase, would it solve the problem of packaging?

[freakboy3742]

@mocaccano Yes, you can use Briefcase to package PySide packages. You can also use Toga, BeeWare's own GUI framework.

[jhi2]

Hey I think I have a copy of tkinter for python 3.12 from my install of it.
You can download it at my site at: https://internalfiles.johnnytech.net/githubfiles/briefcase-tkinter-issue/tkinter.zip.

[jhi2]

My tkinter support package is at https://internalfiles.johnnytech.net/githubfiles/briefcase-tkinter-issue/tkinter-support-package.tar

[freakboy3742]

@jhi2 Thanks for sharing that.

On this note; we're currently landing our iOS patches in CPython, which has required us to rework how CPython is built for iOS. This has had the unexpected side effect that with very few modifications, we're able to use the officially distributed CPython binary for macOS apps as the support package for macOS - which includes support for Tkinter.

It will likely still be a couple of months before this becomes "production ready", but you can see the work in progress here.

[jhi2]

@jhi2 Thanks for sharing that.

On this note; we're currently landing our iOS patches in CPython, which has required us to rework how CPython is built for iOS. This has had the unexpected side effect that with very few modifications, we're able to use the officially distributed CPython binary for macOS apps as the support package for macOS - which includes support for Tkinter.

It will likely still be a couple of months before this becomes "production ready", but you can see the work in progress here.

Well, I have Windows

[cylewis]

@jhi2 I'm in the process of making a GUI app which uses tkinter on python 3.10 that I want to work on windows and macOS. How do I use your support package to allow briefcase to work?

[freakboy3742]

@cylewis The short version is that you need to compile a version of the CPython support packages that include tkinter. This is not a simple task, as Tkinter isn't a simple thing to distribute - the official Windows embedded package (which is what Briefcase uses) doesn't include tkinter specifically because of the difficulties of packaging tkinter.

Honestly - my suggestion is that you need to have a very good reason to use tkinter in this day and age. There are much better GUI toolkits available these days, and they're not subject to the distribution issues that tkinter has.