import tkinter as tk
import random

def generate_qr_code(canvas, size=21, square_size=10):
    canvas.delete("all")
    for _ in range(size * size // 2):
        x = random.randint(0, size - 1)
        y = random.randint(0, size - 1)
        canvas.create_rectangle(x * square_size, y * square_size, 
                                (x + 1) * square_size, (y + 1) * square_size, 
                                fill="black")

def main():
    root = tk.Tk()
    root.title("QR Kód")
    
    canvas_size = 210  # 21 * 10
    canvas = tk.Canvas(root, width=canvas_size, height=canvas_size, bg="white")
    canvas.pack()
    
    generate_button = tk.Button(root, text="Vygenerovat QR kód", 
                                command=lambda: generate_qr_code(canvas))
    generate_button.pack()
    
    root.mainloop()

if __name__ == "__main__":
    main()