Hi list
I noticed this issue with a long-running application that displays
information from a variable number of sources by opening an embedded
window on a Text widget for each new source, and closing it when the
source is completed. To prevent increasing memory use, the widgets
inside the windows are "recycled", i.e. hidden using a tag and cached
when the window is closed, to be re-used when needed. New widgets are
only created when the cache is empty.
The code below demonstrates the issue by rapidly creating and hiding a
window containing the same Label widget. On my machine, each
create_window call initially takes < 1 ms, but a few minutes later
increases to several ms. After several hours, it takes a few seconds
for each operation.
If the commented line removing the tag is used instead of the
window_create call, there is no slowdown. Unfortunately this is not
useful in the real program, which requires that new windows open in a
specified position. AFAIK there is no way to move an embedded window on
a Text widget other than by re-calling window_create (but I'd be glad
to be wrong about that).
Any insights or suggestions?
-------------------------------
from time import time
from tkinter import *
root = Tk()
button = Button(root, text='Run')
text = Text(root)
text.tag_config('hide', elide=True)
label=Label(text, text='running')
def show_and_hide():
if button['text']=='Stop':
if text.tag_names(label):
t = time()
#this line gradually gets slower:
text.window_create(END, window=label)
#this line doesn't:
#text.tag_remove('hide', label)
print(round((time() - t) * 1000))
else:
text.tag_add('hide', label)
button.after(10, show_and_hide)
def run():
if button['text']=='Run':
button['text'] = 'Stop'
text.window_create(END, window=label)
show_and_hide()
else:
button['text'] = 'Run'
text.tag_add('hide', label)
button['command'] = run
button.pack()
text.pack()
mainloop()
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