Circumvent error arising from calling GUI function outside of GUI thread

[zacsimile]

The update_event thread makes GUI calls outside of main Tk loop, This results in

Traceback (most recent call last):
  File "C:\Users\DeanLab\.conda\envs\ASLM\lib\threading.py", line 973, in _bootstrap_inner
    self.run()
  File "C:\Users\DeanLab\.conda\envs\ASLM\lib\threading.py", line 910, in run
    self._target(*self._args, **self._kwargs)
  File "c:\users\deanlab\desktop\github\aslm\src\aslm\controller\controller.py", line 953, in update_event
    self.update_stage_controller_silent(value)
  File "c:\users\deanlab\desktop\github\aslm\src\aslm\controller\controller.py", line 918, in update_stage_controller_silent
    self.stage_controller.set_position_silent(stage_gui_dict)
  File "c:\users\deanlab\desktop\github\aslm\src\aslm\controller\sub_controllers\stage_controller.py", line 306, in set_position_silent
    self.unbind_position_callbacks()
  File "c:\users\deanlab\desktop\github\aslm\src\aslm\controller\sub_controllers\stage_controller.py", line 250, in unbind_position_callbacks
    self.widget_vals[axis].trace_remove("write", cbname)
  File "C:\Users\DeanLab\.conda\envs\ASLM\lib\tkinter\__init__.py", line 424, in trace_remove
    self._tk.call('trace', 'remove', 'variable',
RuntimeError: main thread is not in main loop

from time to time. The right solution is to move all GUI calls out of external threads. The solution I propose here works around the threading so we have to change less code.

[AdvancedImagingUTSW]

“ # ZM: I am so sorry for this.”
😂

[codecov]

Codecov Report

Merging #491 (6450a5a) into develop (7c97070) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           develop     #491      +/-   ##
===========================================
- Coverage    47.00%   46.98%   -0.03%     
===========================================
  Files          155      155              
  Lines        14335    14342       +7     
===========================================
  Hits          6738     6738              
- Misses        7597     7604       +7     

Flag	Coverage Δ
unittests	46.98% <0.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/aslm/controller/controller.py	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

[AdvancedImagingUTSW]

What would happen in the case that it tries to update the stage controller silently 10 times, and it throws a RuntimeError each time?

[zacsimile]

The stage controller wouldn't update. So we'd have a mismatch between true stage position and what is reported in the program.