tkinter/tk memory questions

[David LeBlanc]

Ed;

You didn't mention that the memory footprint drops drastically when a window
minimize/restore is done by the user.

David LeBlanc
Seattle, WA USA

> -----Original Message-----
> From: python-list-admin at python.org
> [mailto:python-list-admin at python.org]On Behalf Of Edward K. Ream
> Sent: Tuesday, December 03, 2002 18:07
> To: python-list at python.org
> Subject: tkinter/tk memory questions
>
>
> I am posting this to comp.lang.python and comp.lang.tcl because
> this posting
> concerns Python(tkinter) and tcl/tk.
>
> My Python/tkinter app creates an outline using Tk.Text widgets
> embedded in a
> Tk.Canvas, using the Idle tree code as a starting point.
>
> On XP, expanding and contracting the outline causes memory allocated to my
> app (as reported by the XP task manager) to increase significantly, say 4
> meg per expansion.  Contraction might be expected to recycle bindings
> (bindings are allocated only for visible nodes) but does not.
>
> I'm wondering whether this is something to be concerned about, and if so,
> what to do about it.  Note that expanding and contracting the
> outline is not
> undoable, and causes no memory to be allocated for undo/redo.
>
> Here is what I have done:
>
> 1. When expanding or contracting the outline (or for that matter, making
> _any_ change to outline) my app calls self.canvas.delete("all"), just as
> Idle does, before completely redrawing the canvas. I would naively think
> that this would "recycle" all the bindings made via bind and
> tag_bind in the
> canvas, except for a comment in the TreeNode.draw method in TreeWidget.py,
> viz.,
>
> # XXX This leaks bindings until canvas is deleted:
> self.canvas.tag_bind(id, "<1>", callback)
> self.canvas.tag_bind(id, "<Double-1>", lambda x: None)
>
> 2. Calling gc.collect() has no effect, regardless of what I do.  Moreover,
> gc.garbage (with gc tracing on) shows no garbage accumulating as
> the result
> of expanding or contracting outlines.
>
> It appears to me, therefore, that Tk (or tkinter?) is not immediately
> recycling the memory used for bindings.  I'm not sure that tcl is entitled
> to merely because I call self.canvas.delete("all"), but that is what I was
> hoping for :-)
>
> 3. In an effort to "encourage" Tk to do some recycling I tried to
> record all
> the bindings made while drawing the outline.  Something like this:
>
> # When creating bindings:
> self.canvas.tag_bind(id, "<1>", v.OnBoxClick)
> t.bind("<1>", v.OnHeadlineClick)
> if self.recycleBindings:
>   self.tagBindings.append((id,"<1>"),)
>   self.bindings.append((t,"<1>"),)
>
> # When redrawing the screen:
> self.deleteBindings()
> self.canvas.delete("all")
>
> def deleteBindings (self):
>  for id,binding in self.tagBindings:
>   self.canvas.tag_unbind(id,binding)
>  self.tagBindings = []
>  for t,binding in self.bindings:
>   t.bind(binding,"")
>  self.bindings = []
>
> But this has no apparent affect (for good or ill).  Note that
> 12,000 or more
> bindings may be unbound by deleteBindings when contracting a
> large outline.
>
> So my questions are:
>
> - Am I correct in my assumption that the memory being used is
> being used by
> tcl?
> - Is this a problem at all?  Will tcl eventually get around to freeing
> memory?  And how would I know?
> - Does tcl use a gc?  If so, is there a way to force to collect
> explicitly?
> And if so, is it a good idea to do so?
> - Are there any mechanisms in tkinter that might be helpful?
> - I'm pretty careful not to create any permanent references to bindings.
> Might tkinter be doing that?
> - Is there any way to force Tk to recycle memory used by bindings?
> - Is there anything clearly wrong about what I am doing?
> - Can anyone explain the comment in Idle about leaking bindings?
> - Is there anything else I should know or do?
>
> Thanks.
>
> Edward
> --------------------------------------------------------------------
> Edward K. Ream   email:  edream at tds.net
> Leo: Literate Editor with Outlines
> Leo: http://personalpages.tds.net/~edream/front.html
> --------------------------------------------------------------------
>
>
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