matplotlib-devel Mailing List for matplotlib

--- On Sat, 6/12/10, Eric Firing <ef...@ha...> wrote:
> > With TkAgg on Mac OS X, the first call to show()
> > blocks, and returns when all figures are closed by the user.
> > However, subsequent calls to show() return immediately.
> 
> This is anomalous, then; on linux, no call to show blocks
> with tkagg. 
> Puzzling difference.
If I remove the _needmain stuff in the show() function in the TkAgg backend, then each call to show() blocks on Mac OS X with the TkAgg backend, which (in my understanding) is the desired behavior. I don't know the purpose of _needmain in the show() function, other than to disallow multiple calls to show().
--Michiel.
 

On 06/11/2010 10:02 PM, Michiel de Hoon wrote:
>> I agree that the difference in blocking behavior is still a
>> problem. I think that what we should do for now, *if* multiple
>> calls to show work on the Mac (which I can't easily test), is
>> change the documentation to correspond to the present situation,
>> highlighting the real problem of different blocking behavior.
>
> On Mac OS X, the MacOSX native backend supports multiple calls to show(). Each call to show() blocks, and show() returns when all figures are closed by the user.
>
OK, so this sounds like the standard blocking behavior, just like gtk*, 
wx*, and qt* on Linux.
> With TkAgg on Mac OS X, the first call to show() blocks, and returns when all figures are closed by the user. However, subsequent calls to show() return immediately.
>
This is anomalous, then; on linux, no call to show blocks with tkagg. 
Puzzling difference.
> With GtkCairo on Mac OS X, each call to show() blocks, so show() can be called repeatedly. However, after closing all windows, show() does not return unless the user presses ctrl-c. This may not be so difficult to fix though. Basically, we need to keep track of how many windows are open at any given point, and tell the GTK main loop to exit when the number of windows reaches zero (this is how the MacOSX native backend does it).
>
I wasn't even aware of this backend; but sure enough, I have it on 
linux, and it works the same as gtkagg et al.
Why would it behave differently on OS X, with the need for the ctrl-C?
If you have TkAgg and GtkCairo, does it mean you also have GtkAgg? If 
so, I would expect it to behave like GtkCairo.
Thanks for the testing.
Eric
> --Michiel.
>
>
>

> I agree that the difference in blocking behavior is still a
> problem. I think that what we should do for now, *if* multiple
> calls to show work on the Mac (which I can't easily test), is
> change the documentation to correspond to the present situation,
> highlighting the real problem of different blocking behavior.
On Mac OS X, the MacOSX native backend supports multiple calls to show(). Each call to show() blocks, and show() returns when all figures are closed by the user.
With TkAgg on Mac OS X, the first call to show() blocks, and returns when all figures are closed by the user. However, subsequent calls to show() return immediately.
With GtkCairo on Mac OS X, each call to show() blocks, so show() can be called repeatedly. However, after closing all windows, show() does not return unless the user presses ctrl-c. This may not be so difficult to fix though. Basically, we need to keep track of how many windows are open at any given point, and tell the GTK main loop to exit when the number of windows reaches zero (this is how the MacOSX native backend does it).
--Michiel.