tkInter scoping problem ?

[Fredrik Lundh]

bernard <bh at cellware.de> wrote:
> To display an image on a canvas I tried
> 
> PhotoImage(name=name, file="./" + name + ".gif")
> c.create_image(x, y, anchor=NW, image=name)
> 
> which works fine.

now that's an interesting way to abuse Tkinter objects :-)

> However when I use this code in the __init__ method of a class
> 
> class TeleTubby:
>    def __init__(self, c, name, x, y):
>       PhotoImage(name=name, file="./" + name + ".gif")
>       c.create_image(x, y, anchor=NW, image=name)
>       ...
> 
> I get the error 
>       tcl Error: image "tinky" doesn't exist

if you don't hold on to the PhotoImage object, it's
garbage collected by Python before the call to
create_image.

(if you run the same code in the interpreter, the magic
"_" (last result) variable keeps a reference to the image,
for a short while -- when "_" is used for the next result,
the image object is garbage collected, and the image
shown on the canvas is blanked...)

> Then trying
> 
>       self.pic = PhotoImage(file="./" + name + ".gif")
>       c.create_image(x, y, anchor=NW, self.pic)
>       
> this time I get no error but no image.

try this:

       self.pic = PhotoImage(file="./" + name + ".gif")
       c.create_image(x, y, anchor=NW, image=self.pic)

</F>