test

tk-threading-error-example.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Fri Oct 18 10:27:51 2019

Incorrect example use of tkinter with Python threading 

@author: Benedict Wilkins AI
"""
import tkinter as tk
from threading import Thread 
import time

t = lambda: int(round(time.time() * 1000))

class Sleep:
    
    def __init__(self, wait):
        self.wait = wait
       
    def __enter__(self):
        self.start = t()
        self.finish = self.start + self.wait
    
    def __exit__(self, type, value, traceback):
        while t() < self.finish:
            time.sleep(1./1000.)
def quit():
    global finish
    finish = True
    root.destroy()
    print("DESTROYED")

def run():
    x = 0
    global finish
    while not finish:
        with Sleep(100):
            root.after(0, lambda : canvas.delete('all'))
            print("CLOSE NOW!")
            time.sleep(1)
            print("RUN AFTER")
            root.after(0, lambda : canvas.create_rectangle(x,0,x+200,200, fill='red'))
        x += 10
    print("CONTROL DONE")

root = tk.Tk()

root.title("My Title")
root.protocol("WM_DELETE_WINDOW", quit)

canvas = tk.Canvas(root, width=400, height=200, bd=0,
                            highlightthickness=0, bg='white')
canvas.pack()

global finish
finish = False

control_thread = Thread(target=run, daemon=True)
control_thread.start()

root.mainloop()
control_thread.join()