I've been tooling around with PySimpleGUI for just a week now. I have not been able to decipher what DemoProgram(s) will help achieve my goal. Skills are novice/tinkerer.
Project: RasberryPi OpenCV workflow using:
- HDMI bridge, initiated with shell script when external image source is configured
- Capture shell script, grabbing frames from HDMI bridge into data folder
- Watcher.py script, watches data folder and processes new images via OpenCV script
- Dashboard, displayed using Chromium
Goal: GUI with button(s) to launch each step (1-4) of the process and give Real-time Output for the watcher.py script + ability to exit capture and watcher scripts which are long running
Attempted Solutions from https://github.com/PySimpleGUI/PySimpleGUI/tree/master/DemoPrograms
- Demo_Desktop_Floating_Toolbar.py
- Demo_Script_Launcher_Realtime_Output.py
- Demo_Multithreaded_Animated_Shell_Command.py
- Demo_Multithreaded_Multiple_Threads.py
- Demo_Multithreaded_Different_Threads.py
My attempts so far have yielded mixed results. I have been able to get individual steps to launch but I have not been able to put a combination of calls, triggers, and an event loop together that works.
My hunch is that using Demo_Multithreaded_Multiple_Threads.py is where I need to be building but trying to combine that with Demo_Script_Launcher_Realtime_Output.py for just the watcher.py script has led to hanging.
#!/usr/bin/python3
import subprocess
import threading
import time
import PySimpleGUI as sg
"""
You want to look for 3 points in this code, marked with comment "LOCATION X".
1. Where you put your call that takes a long time
2. Where the trigger to make the call takes place in the event loop
3. Where the completion of the call is indicated in the event loop
Demo on how to add a long-running item to your PySimpleGUI Event Loop
If you want to do something that takes a long time, and you do it in the
main event loop, you'll quickly begin to see messages from windows that your
program has hung, asking if you want to kill it.
The problem is not that your problem is hung, the problem is that you are
not calling Read or Refresh often enough.
One way through this, shown here, is to put your long work into a thread that
is spun off, allowed to work, and then gets back to the GUI when it's done working
on that task.
Every time you start up one of these long-running functions, you'll give it an "ID".
When the function completes, it will send to the GUI Event Loop a message with
the format:
work_id ::: done
This makes it easy to parse out your original work ID
You can hard code these IDs to make your code more readable. For example, maybe
you have a function named "update_user_list()". You can call the work ID "user list".
Then check for the message coming back later from the work task to see if it starts
with "user list". If so, then that long-running task is over.
"""
# ############################# User callable CPU intensive code #############################
# Put your long running code inside this "wrapper"
# NEVER make calls to PySimpleGUI from this thread (or any thread)!
# Create one of these functions for EVERY long-running call you want to make
def long_function_wrapper(work_id, window):
# LOCATION 1
# this is our "long running function call"
# sleep for a while as a simulation of a long-running computation
def process_thread():
global proc
proc = subprocess.Popen('python watcher.py data', shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
def main():
thread = threading.Thread(target=process_thread, daemon=True)
thread.start()
while True:
sg.popup_animated(sg.DEFAULT_BASE64_LOADING_GIF, 'Watcher is Running', time_between_frames=100)
thread.join(timeout=.1)
if not thread.is_alive():
break
sg.popup_animated(None)
output = proc.__str__().replace('\\r\\n', '\n')
sg.popup_scrolled(output, font='Courier 10')
if __name__ == '__main__':
main()
# at the end of the work, before exiting, send a message back to the GUI indicating end
window.write_event_value('-THREAD DONE-', work_id)
# at this point, the thread exits
return
############################# Begin GUI code #############################
def the_gui():
sg.theme('Light Brown 3')
layout = [[sg.Text('Multithreaded Work Example')],
[sg.Text('Click Go to start a long-running function call')],
[sg.Text(size=(25, 1), key='-OUTPUT-')],
[sg.Text(size=(25, 1), key='-OUTPUT2-')],
[sg.Text('?', text_color='blue', key=i, pad=(0,0), font='Default 14') for i in range(4)],
[sg.Button('Go'), sg.Button('Popup'), sg.Button('Exit')], ]
window = sg.Window('Multithreaded Window', layout)
# --------------------- EVENT LOOP ---------------------
work_id = 0
while True:
# wait for up to 100 ms for a GUI event
event, values = window.read()
if event in (sg.WIN_CLOSED, 'Exit'):
break
if event == 'Go': # clicking "Go" starts a long running work item by starting thread
window['-OUTPUT-'].update('Starting long work %s' % work_id)
window[work_id].update(text_color='red')
# LOCATION 2
# STARTING long run by starting a thread
thread_id = threading.Thread(
target=long_function_wrapper,
args=(work_id, window,),
daemon=True)
thread_id.start()
work_id = work_id+1 if work_id < 19 else 0
# if message received from queue, then some work was completed
if event == '-THREAD DONE-':
# LOCATION 3
# this is the place you would execute code at ENDING of long running task
# You can check the completed_work_id variable
# to see exactly which long-running function completed
completed_work_id = values[event]
window['-OUTPUT2-'].update(
'Complete Work ID "{}"'.format(completed_work_id))
window[completed_work_id].update(text_color='green')
if event == 'Popup':
sg.popup_non_blocking('This is a popup showing that the GUI is running', grab_anywhere=True)
# if user exits the window, then close the window and exit the GUI func
window.close()
############################# Main #############################
if __name__ == '__main__':
the_gui()
print('Exiting Program')
(cv) pi@raspberrypi:~/issgrab $ python GUIDE_GUI_master.py
*** Faking timeout ***
Exception in thread Thread-1:
Traceback (most recent call last):
File "/usr/lib/python3.5/threading.py", line 914, in _bootstrap_inner
self.run()
File "/usr/lib/python3.5/threading.py", line 862, in run
self._target(*self._args, **self._kwargs)
File "GUIDE_GUI_master.py", line 68, in long_function_wrapper
main()
File "GUIDE_GUI_master.py", line 57, in main
sg.popup_animated(sg.DEFAULT_BASE64_LOADING_GIF, 'Watcher is Running', time_between_frames=100)
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 15797, in PopupAnimated
transparent_color=transparent_color, finalize=True, element_justification='c', icon=icon)
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 6985, in __init__
self.Finalize()
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 7510, in Finalize
self.Read(timeout=1)
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 7325, in Read
results = self._read(timeout=timeout, timeout_key=timeout_key)
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 7365, in _read
self._Show()
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 7199, in _Show
StartupTK(self)
File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/PySimpleGUI/PySimpleGUI.py", line 12100, in StartupTK
my_flex_form.TKroot.mainloop()
File "/usr/lib/python3.5/tkinter/__init__.py", line 1143, in mainloop
self.tk.mainloop(n)
RuntimeError: Calling Tcl from different appartment
Exiting Program
