How to use winfo_width() (Tkinter)

Question

There are lot answer on stackoverflow
that say "to width of the widget one shoud use winfo_width()".

e.g. Get Tkinter Window Size

Could anybody point me to what I'm doing wrong?

My example code:

import Tkinter as tk


class App(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.pack()
        self._make_new_window()
        print 'self.winfo_width()', self.winfo_width()
        print 'self.text_window.winfo_width()', self.text_window.winfo_width()

    def _make_new_window(self):
        self.text_window = tk.Text(tk.Toplevel(self.master))
        self.text_window.pack()


root = tk.Tk()
app = App(master=root)
app.mainloop()

Actual result (printed on commandline):

self.winfo_width() 1
self.text_window.winfo_width() 1

This is strange because:

• self.text_window is definitely not the same size as self
• very strange measurement units

Expected result:

self.winfo_width() 30
self.text_window.winfo_width() 100

At least something allong these lines.

BTW.
This is on python 2.7.
Help info does not reveal anything usefull.

Help on method winfo_width in module Tkinter:

winfo_width(self) method of __main__.App instance
    Return the width of this widget.

EDIT - Solution:

• Size can be retrieved only after window is drawn; It's possible to use self.update()) (Get Tkinter Window Size)
• Need to use self.master.winfo_width() instead of self.winfo_width() for App (comment from fhdrsdg)

Fixed version looks like this:

import Tkinter as tk

help(tk.Frame)

class App(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.pack()
        self._make_new_window()
        self.update() # add update
        print 'self.master.winfo_width()', self.master.winfo_width() # use self.master
        print 'self.text_window.winfo_width()', self.text_window.winfo_width()

    def _make_new_window(self):
        self.text_window = tk.Text(tk.Toplevel(self.master))
        self.text_window.pack()


root = tk.Tk()
app = App(master=root)
app.mainloop()

Ouput is:

self.master.winfo_width() 108
self.text_window.winfo_width() 404