sg552 at hotmail.co.uk
Fri Apr 23 07:58:03 EDT 2010
> On Apr 22, 5:55 pm, Rotwang <sg... at hotmail.co.uk> wrote:
> From my experience, mixing Tkinter with threads is a bad idea. As most
> GUI toolkits, it really doesn't like to be manipulated from different
> threads, so you might end up getting weird problems or even crashes.
> By the way, did you try to remove the line out.mainloop() from your
> 'draw' function?
I didn't. How do I get Python to display the draw window, other than by
> This is the line that blocks the IDLE GUI, since it
> initiates a secondary event loop that will only exit when you do a
> out.quit(), so that might be a solution.
>> BTW, another problem: whenever I call a widget.quit() method, the widget
>> in question crashes. IDLE carries on working but the widget window stays
>> there, not responding, and if I tell my OS to kill it then IDLE
>> restarts. Is this a bug? I'm using Windows 7 and Python 2.6.4.
> The 'quit' method just exits the mainloop. It doesn't destroy the
> widget. So if your application doesn't actually exit, the widget will
> just stay there. If you want to destroy the it too, you have to call
> explicitely widget.destroy().
That worked like a charm, thanks!
Here's another problem I've run into today: I've just added a bit of
code so that it's possible to resize the draw window and the contents
will be resized automatically. The method now looks something like this:
out = Tkinter.Tk()
slave = Tkinter.Canvas(out, width = wh, height = wh)
# I put the canvas widget inside a tk widget instead of just
# using the former because I want keypresses to do things, and
# it doesn't seem to be possible to bind keyboard events to a
# draw something
wh[:] = [b.width, b.height]
slave.config(width = wh, height = wh)
# resize the contents of slave
The trouble is, when I call the method the window it spawns slowly grows
larger, until I move or resize it myself by grabbing one of the edges;
after this everything works as intended. If I add the line "print wh"
after "wh[:] = [b.width, b.height]", the output looks like this (the
default value of wh is [640,480]:
My only guess as to why this is happening is that Tkinter is resizing
out to be 4 pixels wider and taller than slave, and the line
"slave.config(...)" consequently leads to resize being called again. But
this doesn't explain why it stops happening when I resize the window
intentionally, nor why the window apparently only gets larger every
third time resize is called. The problem goes away if I replace "wh[:] =
[b.width, b.height]" with
wh[:] = [b.width - 4, b.height - 4]
but this seems like a rather ad-hoc and ugly solution, and I'd rather
understand what's going on. Can anyone help?
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