import pyglet
from tkinter.messagebox import showinfo
window = pyglet.window.Window()
label = pyglet.text.Label('Hello, world',
    font_name='Times New Roman',
    font_size=36,
    x=window.width//2, y=window.height//2,
    anchor_x='center', 
    anchor_y='center'
)
@window.event
def on_draw():
    window.clear()
    showinfo('Hello', 'Hello, World')
label.draw()
pyglet.app.run()