On 3/1/2016 9:35 PM, jf...@ms4.hinet.net wrote:
Recently I was puzzled by a tkinter problem. The codes below (from a book) can
display the picture correctly.
gifdir = "../gifs/"
from tkinter import *
win = Tk()
photo = PhotoImage(file=gifdir + "ora-pp.gif")
Button(win, image=photo).pack()
win.mainloop()
Since photo is a global name, the binding remain until you explicitly
delete it or exit the app.
And the codes below (from another book) will also work.
class DrumMachine:
....
....
def create_play_bar(self):
....
....
photo = PhotoImage(file='images/signature.gif')
label = Label(playbar_frame, image=photo)
label.image = photo
label.grid(row=start_row, column=50, padx=1, sticky='w')
....
....
Here photo is a local name and the binding disappears when the function
exits. I would rewrite it to follow pattern 1.
self.photo = PhotoImage(file='images/signature.gif')
label = Label(playbar_frame, image=self.photo)
To me, saving an attribute reference is not worth the extra line.
In the second example, I noticed that the "photo" was referenced two times
and I think it might be a redundancy so I remove the line "label.image =
photo". But it fails then.
On another question, I made the same suggestion. Oops.
--
Terry Jan Reedy
--
https://mail.python.org/mailman/listinfo/python-list
