EX9.18.py

# 9.18 (Display flashing text) Write a program that displays the flashing text “Welcome,”
# as shown in Figure 9.30a–b. (Hint: To make the text flash, you need to repeatedly
# draw it on the canvas or alternately delete it. Use a Boolean variable to control the
# alternation.)

from tkinter import *  # Import tkinter

width = 200
height = 100


class MainGUI:
    def __init__(self):
        window = Tk()  # Create a window
        window.title("Flashing Text")  # Set a title

        sleepTime = 100
        canvas = Canvas(window, bg="white", width=width, height=height)
        canvas.pack()

        on = True
        while True:
            if on:
                canvas.create_text(width / 2, height / 2, text="Welcome", tags="text")
            else:
                canvas.delete("text")

            on = not on
            canvas.after(sleepTime)  # Sleep for 100 milliseconds
            canvas.update()

        window.mainloop()  # Create an event loop


MainGUI()