Tkinter - getting canvas window size

[Rick Pasotto]

Why do the print statements in the following program show zero?
How can I figure out the size of the frame?

from Tkinter import *

w = Tk()
cnv = Canvas(w,bg='white',relief=SUNKEN)
cnv.config(width=400,height=200)
cnv.pack(side=LEFT,expand=YES,fill=BOTH)

f = Frame(cnv,relief=GROOVE,borderwidth=2)
for j in range(5):
        l = Label(f,text='label: %2d' % (j),
                relief=GROOVE,borderwidth=2,padx=5)
        l.pack(side=LEFT,expand=YES,fill=X,padx=5,pady=2)
f.pack()
cw = cnv.create_window(20,20,window=f,anchor=NW)

print f.cget('height'),f.cget('width')
print cnv.itemcget(cw,'height'), cnv.itemcget(cw,'width')

w.mainloop()



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    Rick Pasotto    rickp at telocity.com    http://www.niof.net