from Tkinter import *
canvas = Canvas(width=300, height=300, bg='white')
canvas.pack(expand=YES, fill=BOTH)
canvas.create_arc(200, 200, 300, 100)
widget = Label(canvas, text='AAA', fg='white', bg='black')
widget.pack()
canvas.create_window(100, 100, window=widget)
mainloop()