Exiting/killing a program with tkinter but leaving the graphic on the screen

[DeaD_EyE]

Something like this?
In this example I use just the stdout of the subprogramm, to set the label.
For demonstration, it's called after 5s.

gui.py

import sys
from tkinter import Tk, Button, Variable
from subprocess import check_output
from threading import Timer


def make_gui():
    root = Tk()
    text = Variable(root)
    text.set('Before')
    Button(root, textvariable=text).pack()
    Button(root, text='Exit', command=root.destroy).pack()
    return root, text


def main():
    root, text_var = make_gui()
    # with threadnig timer
    #timer = Timer(5, label, args=(text_var,))
    #timer.start()

    # root.after
    root.after(5000, label, text_var)
    root.mainloop()


def label(text_var):
    stdout = check_output([sys.executable, 'subprogram.py'], encoding='utf8')
    text_var.set(stdout)


if __name__ == '__main__':
    sys.exit(main())

subprogram.py

#!/usr/bin/env python3

print('Hello Label')