[Edu-sig] re: Pygeo, platforms, wx and Tk

[Arthur]

>And I *do* face a crucial functional issue with TK, and only on Linux, as
>it happens, regarding threading.

>I may try to present the issue later, to try to get some feedback, and
>help determine whether the issue is inherent, a limitation of the
>developer, or a limitation of the particular toolkit.

Here goes:

So I have 2 windows - one is a Display for the VPython rendering and is
actually constructed as a class derived from the VPython display object
(native on Windows, GTK1 on linux) The other is a TK control panel.

The user can interact with either - pick and move points, for example, in
the Display, or reveal or hide construction levels from the control Panel.
So each must be in a loop, and the 2 windows need to be able to communicate
with to each other as to any user action.

On Windows, in the Display class I create the Panel, sending the Display as
one of the arguments, while saving a reference to the Panel as an attribute
of the Display class.  And start a thread that sets off the TK loop for the
Panel. The Display now has a reference to the Panel set on its creation, and
the Panel now has a reference to the Display, sent to it as an argument.
And the communication is bi-directional, via these references.

Same tact on Linux produces an error something to the effect:

"Attempt to start TK instance from a separate appartment" (definitely
spelled with 2 p's).

A search on this error message on python-list brings me to a post by Aahz,
resident threading expert, asking why one would want to multi-thread a TK
application. Implying, I think, that one can't.

I am not sure that I need to.  Or mean to. But nonetheless I can't find an
approach here that yields bi-directional messaging other than the one that
works on Windows.

This is sounding both esoteric, and not well described. But I am not so much
expecting as answer, as much as anyone's gut as to whether this is
answerable, and whether my problem is in any way TK specific.

Thanks.

Art