tkinter виджет Frame

#!/usr/bin/python3.4
# -*- coding: utf-8 -*-

import tkinter as tk

num = 4
posx = [0, 960, 0, 960]
posy = [0, 0, 540, 540]
color = ['red','black','white','yellow']
sx = 960
sy = 540
 
class MainFrame(tk.Tk):
  def __init__ (self):
    tk.Tk.__init__(self)
    self.config(bg='blue')
    self.attributes('-fullscreen', True)
 
class WinFrame(tk.Frame):
  def __init__(self):
    tk.Frame.__init__(self, MainWindow)
    self.x = posx[i]
    self.y = posy[i]
    self.config(width=sx, height=sy, bg=color[i])
    self.place(x=self.x, y=self.y)
    self.bind('<Button-1>', self.on_screen)

  def on_screen(self, event):
    if self.winfo_width()==sx:
        self.config(width=1600, height=900)
        self.place(x=100, y=50)
        
    else:
        self.config(width=sx, height=sy)
        self.place(x=self.x, y=self.y)

    
if __name__ == '__main__':
  MainWindow= MainFrame()
  
  i = 0
  while i < num:
    WinCam = WinFrame()
    i=i+1

  MainWindow.mainloop()