time.sleep() and Tkinter after()?
Davy
I have used Tkinter after() to do loop update GUI in my previous post.
See http://groups.google.com/group/comp.lang.python/browse_thread/thread/6b616abc236c345b/7df7684d33c969c5#7df7684d33c969c5
And I tried to change after() to time.sleep(), but it seems doesn't
work at all, the Queue send and receive data properly, but the GUI
didn't even appear?
//-----code changed-----
def draw_canvas_loop(canvas_b):
while (True):
board = data_queue.get(block = True, timeout=2)
print 'get', data_queue.qsize()
draw_canvas(board, canvas_b, x, y, block_width, block_height)
time.sleep(0.3)
##canvas_b.after(300, lambda:draw_canvas_loop(canvas_b))
//--------------------------------
So, can I use time.sleep() in GUI application? Or Tkinter scheduler
just ignore the sleep() function?
And if I use after(), will the code form a recursive function call,
and the memory usage will boost as the program goes (I have watched
the task manager in WinXP and find the python.exe eat more and more
memory...).
//------code-----------
def draw_canvas_loop(canvas_b):
board = data_queue.get(block = True, timeout=1)
print 'get', data_queue.qsize()
draw_canvas(board, canvas_b, x, y, block_width, block_height)
canvas_b.after(300, lambda:draw_canvas_loop(canvas_b))
//-------------------------
Best regards,
Davy
Hendrik van Rooyen
> I have used Tkinter after() to do loop update GUI in my previous post.
> And I tried to change after() to time.sleep(), but it seems doesn't
> work at all, the Queue send and receive data properly, but the GUI
> didn't even appear?
>
> //-----code changed-----
> def draw_canvas_loop(canvas_b):
> while (True):
> board = data_queue.get(block = True, timeout=2)
Do you want it to block, or do you want it to time out?
> print 'get', data_queue.qsize()
> draw_canvas(board, canvas_b, x, y, block_width, block_height)
> time.sleep(0.3)
this will make the gui unresponsive for the time
> ##canvas_b.after(300, lambda:draw_canvas_loop(canvas_b))
and then the control runs off the end of the function.
> So, can I use time.sleep() in GUI application? Or Tkinter scheduler
> just ignore the sleep() function?
time.sleep(sleep_time) will effectively suspend the gui mainloop
(if it is in the mainloop) for the sleep_time, making the gui unresponsive
for that time. Eschew it here. Use it in other, non GUI helper threads.
>
> And if I use after(), will the code form a recursive function call,
only if it is coded that way - yours does not look recursive to me
> and the memory usage will boost as the program goes (I have watched
> the task manager in WinXP and find the python.exe eat more and more
> memory...).
> def draw_canvas_loop(canvas_b):
> board = data_queue.get(block = True, timeout=1)
> print 'get', data_queue.qsize()
> draw_canvas(board, canvas_b, x, y, block_width, block_height)
Here you draw a new canvas object - what has happened to the
previous one? Is it possibly still hanging around? Should you
do something about it?
- Hendrik
Davy
> "Davy" <zh...@gmail.com> wrote:
> > I have used Tkinter after() to do loop update GUI in my previous post.
> > And I tried to change after() to time.sleep(), but it seems doesn't
> > work at all, the Queue send and receive data properly, but the GUI
> > didn't even appear?
>
> > //-----code changed-----
> > def draw_canvas_loop(canvas_b):
> > while (True):
> > board = data_queue.get(block = True, timeout=2)
>
> Do you want it to block, or do you want it to time out?
Hi Hendrik, nice comments :-)
Do you think block and time out are contradict to each other?
>
> > print 'get', data_queue.qsize()
> > draw_canvas(board, canvas_b, x, y, block_width, block_height)
> > time.sleep(0.3)
>
> this will make the gui unresponsive for the time
>
> > ##canvas_b.after(300, lambda:draw_canvas_loop(canvas_b))
>
> and then the control runs off the end of the function.
>
> > So, can I use time.sleep() in GUI application? Or Tkinter scheduler
> > just ignore the sleep() function?
>
> time.sleep(sleep_time) will effectively suspend the gui mainloop
> (if it is in the mainloop) for the sleep_time, making the gui unresponsive
> for that time. Eschew it here. Use it in other, non GUI helper threads.
Although I don't understand your explaination very well(I guess
maybe .after() re-schedule is better than .sleep unresponsive in GUI
application?)I will take it as a golden rule.
>
>
>
> > And if I use after(), will the code form a recursive function call,
>
> only if it is coded that way - yours does not look recursive to me
>
> > and the memory usage will boost as the program goes (I have watched
> > the task manager in WinXP and find the python.exe eat more and more
> > memory...).
> > def draw_canvas_loop(canvas_b):
> > board = data_queue.get(block = True, timeout=1)
> > print 'get', data_queue.qsize()
> > draw_canvas(board, canvas_b, x, y, block_width, block_height)
>
> Here you draw a new canvas object - what has happened to the
> previous one? Is it possibly still hanging around? Should you
> do something about it?
Yeah, I forgot to *delete* the rectangle object I generate before.
One more question, besides create/delete method, can I just create two
rectangles (one black/one white), and assign two tags to these two
rectangles, and place rectangle by just using tags(that is, can I
place one object on several places of the canvas)?
>
> - Hendrik
Hendrik van Rooyen
"Davy" <zhli...@gmail.com> wrote:
>Although I don't understand your explanation very well(I guess
>maybe .after() re-schedule is better than .sleep unresponsive in GUI
>application?)I will take it as a golden rule.
I did not in fact try to explain it - I was trying to get you to
think a bit wider, as that way you would get more benefit
than just being given a solution.
As for taking what I say as a golden rule:-
If you hang around this group for long enough, you will learn to
never take what I say as gospel - I often pull the piss - be warned!
8<-----------------------------------
>Yeah, I forgot to *delete* the rectangle object I generate before.
>One more question, besides create/delete method, can I just create two
>rectangles (one black/one white), and assign two tags to these two
>rectangles, and place rectangle by just using tags(that is, can I
>place one object on several places of the canvas)?
You can redraw it to make it look different and position it on
another place, but I have never seen one thing in two places
before. If it is possible I don't know how to do it.
Now if it were a class, you could have multiple instances,
but I have only ever seen one thing, one picture...
- Hendrik