tkinter: loading file before entering mainloop

[Peter Billam]

Peter Billam wrote:
>> They're multiplied up from
>>   canvas_height = self.canvas.winfo_height()
>> so I guess mainloop already think it's idle, while grid is still
>> taking 10ms to work out what goes where.
 
On 2009-03-15, John McMonagle <jmcmonagle at NO.SPAM.velseis.com.au> wrote:
> You need to query the requested width and height for windows which
> are not yet realised.
> canvas_height = self.canvas.winfo_reqheight()

Good suggestion: it didn't work for me, perhaps because I just ask for
an overall window geometry, then leave it to grid to assign as much
as possible to the canvas?    This does the job:

num_retries = 0
  ...
    canvas_height = self.canvas.winfo_height()
    global num_retries
    if canvas_height < 5:  # is 1 in the 10ms it takes for grid to work
        if num_retries > 4:
            print("loadFile: can't get canvas height",file=sys.stderr)
            num_retries = 0
            return
        application.after(50, self.loadFile, sys.argv[1])
        num_retries += 1
        return

though I'm not quite sure how :-) because
application = tkinter.Tk()
at the top level, and I haven't had to declare
    global application
within loadFile...
I am a python newbie, so things mysterious to me do happen.

Regards,  Peter

-- 
Peter Billam       www.pjb.com.au    www.pjb.com.au/comp/contact.html