[FIXED] Changing Background Colour with a While Loop in Python

Issue

I am trying to configure a label in my window with the result of an iteration that produces the range of hexadecimal colour codes from #000000 to #FFFFFF so that the label’s background colour fades through all the possible colors between #000000 and #FFFFFF with a fraction of a second interval but it doesn’t seem to complete the loop before stating at #000000 again.

I have used the the print method to display the colour code being deployed with every loop and it doesn’t seem to be restarting as the display does.

from time import *
from time import sleep
from tkinter import *


def changing_color():
    global color
    while True:
        for i in range(0, 2**24):
            r = format(i, "02x")
            for j in range(0, 255):
                g = format(j, "02x")
                for k in range(0, 255):
                    b = format(k, "02x")
                    color = "#"+r+g+b
                    print(color)
                    date_label.config(bg=color)
                    day_label.config(bg=color)
                    window.update()
                    sleep(0.01)


def update_frame1():

    day_string = strftime("%A")
    day_label.config(text=day_string)

    date_string = strftime("%d, %B %Y")
    date_label.config(text=date_string)

    frame1.after(1000, update_frame1)

def update_frame2():

    time_string = strftime("%I:%M:%S:%p")
    time_label.config(text=time_string)

    frame2.after(1000, update_frame2)


window = Tk()
window.title("RO'Clock")

color = ""


frame1 = Frame(window)
frame1.pack(expand=True, fill="both")

frame2 = Frame(window)
frame2.pack(expand=True, fill="both")

date_label = Label(frame1, font=("Ink Free", 20))
date_label.pack(expand=True, fill="both")

day_label = Label(frame1, font=("Ink Free", 15))
day_label.pack(expand=True, fill="both")

time_label = Label(frame2, font=("Consolas", 30), fg="#00FF00", bg="black")
time_label.pack(expand=True, fill="both")


update_frame2()

update_frame1()

changing_color()


window.mainloop()

Solution

I cleaned your imports and translated it into an OOP approach for better readability and also to get rid of global variables. Your endless loop is now a recursive function using after and incrementing the color values each cycle.

from tkinter import Tk, Frame, Label
from time import strftime


class RoClock(Tk):
    def __init__(self):
        super().__init__()
        self.title("RO'Clock")
        self.color = ""

        self.frame1 = Frame(self)
        self.frame1.pack(expand=True, fill="both")

        self.frame2 = Frame(self)
        self.frame2.pack(expand=True, fill="both")

        self.date_label = Label(self.frame1, font=("Ink Free", 20))
        self.date_label.pack(expand=True, fill="both")

        self.day_label = Label(self.frame1, font=("Ink Free", 15))
        self.day_label.pack(expand=True, fill="both")

        self.time_label = Label(self.frame2, font=("Consolas", 30), fg="#00FF00", bg="black")
        self.time_label.pack(expand=True, fill="both")

        self.update_frame2()

        self.update_frame1()

        self.changing_color(0, 0, 0)  # passing starting values

    def changing_color(self, k, j, i):  # new recursive function using after instead of endless while loop
        if k == 256:
            k = 0
            j += 1
        if j == 256:
            j = 0
            i += 1
        if i == 256:
            i = 0

        r = format(i, "02x")
        g = format(j, "02x")
        b = format(k, "02x")
        color = "#"+r+g+b
        print(color)
        self.date_label.config(bg=color)
        self.day_label.config(bg=color)
        self.after(1, self.changing_color, k+1, j, i)

    def update_frame1(self):
        day_string = strftime("%A")
        self.day_label.config(text=day_string)

        date_string = strftime("%d, %B %Y")
        self.date_label.config(text=date_string)

        self.frame1.after(1000, self.update_frame1)

    def update_frame2(self):
        time_string = strftime("%I:%M:%S:%p")
        self.time_label.config(text=time_string)

        self.frame2.after(1000, self.update_frame2)

r = RoClock()
r.mainloop()

While this is working it is not pretty! To get rid of the flickering you have to rethink how you calculate your colors to get colors of equal brightness!

Answered By - Jan_B