This code makes a window with the conditions that the user cannot change the dimensions of the Tk()
window, and also disables the maximise button.
import tkinter as tk
root = tk.Tk()
root.resizable(width=False, height=False)
root.mainloop()
Within the program you can change the window dimensions with @Carpetsmoker’s answer, or by doing this:
root.geometry('{}x{}'.format(<widthpixels>, <heightpixels>))
It should be fairly easy for you to implement that into your code. 🙂