[Tutor] Displaying image in scrolled canvas

[Michael P. Reilly]

kromag@nsacom.net wrote
> 
> I am attempting to place a large .gif file into a scrolled canvas. I am 
> working from the examples in programming python (in case the code looked 
> slightly familiar :-)
> 
> To wit:

Try these changes :

> from Tkinter import * 
> class ScrolledCanvas(Frame):
>     def __init__(self, parent=None, color='white'):
>         Frame.__init__(self, parent)
>         self.pack(expand=YES, fill=BOTH)                  
>         photo=PhotoImage(file='\windows\desktop\wacky3.gif')
          self.photo=PhotoImage(file='\\window\\desktop\\wacky3.gif')

>         canv = Canvas(self, bg=color, relief=SUNKEN)
>         canv.config(width=1010, height=745)                
>         canv.config(scrollregion=(0,0,300, 1000))         
>         canv.create_image(10,10, image=photo, anchor=NW)
          canv.create_image(10,10, image=self.photo, anchor=NW)

>         sbar = Scrollbar(self)
>         sbar.config(command=canv.yview)                   
>         canv.config(yscrollcommand=sbar.set)              
>         sbar.pack(side=RIGHT, fill=Y)                     
>         canv.pack(side=LEFT, expand=YES, fill=BOTH)      
> if __name__ == '__main__': ScrolledCanvas().mainloop()
> 
> results in the properly-sized frame and scrollbar, but for some reason the 
> image does not pop to life. What am I missing here?

Image objects in Tkinter need to have the reference kept.  Because of a
interaction between Tk and Tkinter, when the actual object is destroyed
the Tk image is destroyed as well.

  -Arcege

-- 
+----------------------------------+-----------------------------------+
| Michael P. Reilly                | arcege@speakeasy.net              |