A tkinter window that fades in and out at specified intervals

fading_window.py

"""
Window that fades in an out at a specified time interval and increment
Author: Israel Dryer
Modified: March 29, 2021
"""

from tkinter import ttk
import tkinter


def fade_out(widget, increment):
    alpha = widget.attributes('-alpha')
    if (alpha - increment) >= 0:
        widget.attributes('-alpha', alpha - increment)
        widget.after(100, fade_out, widget, increment)
        return
    widget.after(100, fade_in, widget, increment)

def fade_in(widget, increment):
    alpha = widget.attributes('-alpha')
    if (alpha + increment) <= 1:
        widget.attributes('-alpha', alpha + increment)
        widget.after(100, fade_in, widget, increment)
        return
    widget.after(100, fade_out, widget, increment)


root = tkinter.Tk()
root.geometry('400x400')
root.eval('tk::PlaceWindow . center')

root.option_add('*font', 'Helvetica 24')
ttk.Scale(root, from_=1, to=100, value=25).pack(fill='x', padx=10, pady=10)
ttk.Label(root, text="Hello world!", anchor='center').pack(fill='x', pady=10)

root.after(100, fade_out, root, 0.05)
root.mainloop()