Program hangs after closing GUI

[jhossbach]

I noticed that the script doesn't end after closing the GUI using the keyboard. Without looking in detail I think this could be because keyboard events are not caught in this line, only using the mouse buttons works: https://github.com/Wazzaps/fingerpaint/blob/ff7090b4a5a0b999dc75ef687911e8c04299f3f4/fingerpaint/fingerpaint.py#L189-L191

[Wazzaps]

That's really weird, it works fine on my end. Are you on X11 or Wayland? What key are you pressing? Handling key codes in that codepath won't work because it's only for events in the touchpad. I have a hunch, try pressing a key then moving your finger over the touchpad (without pressing), if that works it's because I'm not giving tkinter time to handle keypresses.

[jhossbach]

Yeah, that works.

[Wazzaps]

Seems like my touchpad sends periodic updates ("no one's pressing me"), which make the window close. Your's probably doesn't so event = touchpad.read_one() never returns. I'll see if it has an option for a timeout

[Wazzaps]

Could you test the attached version? It should give the tkinter runtime every 0.1 seconds fingerpaint.zip

[jhossbach]

Unfortunately doesn't fix it, let me try to see where the program hangs

[jhossbach]

I am having a hard time debugging because of the event polling, but so far using python -m trace --trace /usr/bin/fingerpaint -o test.png I found that seems to stay loop in the while loop instead of getting stuck in touchpad.read_one():

 --- modulename: __init__, funcname: update_idletasks
__init__.py(1349):         self.tk.call('update', 'idletasks')
fingerpaint.py(109):                 top.update()
 --- modulename: __init__, funcname: update
__init__.py(1343):         self.tk.call('update')
fingerpaint.py(82):             while True:
fingerpaint.py(83):                 lines = next(events)
 --- modulename: fingerpaint, funcname: handler_loop
fingerpaint.py(178):         while True:
fingerpaint.py(179):             event = touchpad.read_one()
 --- modulename: eventio, funcname: read_one
eventio.py(58):         event = _input.device_read(self.fd)
eventio.py(60):         if event:
fingerpaint.py(180):             if event:
fingerpaint.py(195):             if last_pos != curr_pos:
fingerpaint.py(205):                 yield []
fingerpaint.py(84):                 for line in lines:
fingerpaint.py(108):                 top.update_idletasks()

[Wazzaps]

Hmm, try this version: fingerpaint.zip It should:

1. print every time it handles events
2. steal focus at start (though that's unlikely to be the problem because painting after pressing a key works for you)

[jhossbach]

No change unfortunately. I don't have a lot of time to dig into this problem, but fortunately enough it is more of a convenience issue rather than an actual bug