How can I display an image in Python 3 using tkinter/ttk? - image

Question

The nub of the matter is, what am I doing wrong in the following code snippet?
from tkinter import *
from tkinter.ttk import *
root = Tk()
myButton = Button(root)
myImage = PhotoImage(myButton, file='myPicture.gif')
myButton.image = myImage
myButton.configure(image=myImage)
root.mainloop()
The error message I get from idle3 is as follows:
>>>
Traceback (most recent call last):
File "/home/bob/Documents/Python/tkImageTest.py", line 9, in <module>
myButton.configure(image=myImage)
File "/usr/lib/python3.2/tkinter/__init__.py", line 1196, in configure
return self._configure('configure', cnf, kw)
File "/usr/lib/python3.2/tkinter/__init__.py", line 1187, in _configure
self.tk.call(_flatten((self._w, cmd)) + self._options(cnf))
TypeError: __str__ returned non-string (type Button)
>>>
This error message has me stumped, I simply don't understand what it is trying to say. Any ideas?
I would also appreciate suggestions for changes...

Answer 1

The error seems to point to the myButton argument passed to PhotoImage. As you noted in your comment, PhotoImage was treating the widget object as a string (there are several options of type string; see a list of PhotoImage options here).
Your code will work if you implement that line without referencing the myButton object:
myImage = PhotoImage(file='myPicture.gif')
I'm not certain you need to alter the PhotoImage constructor. Look at the PhotoImage docs to determine the valid options (i.e. resource names) for that class. Quoting the help file:
Help on class PhotoImage in module tkinter:
class PhotoImage(Image)
| Widget which can display colored images in GIF, PPM/PGM format.
|
| Method resolution order:
| PhotoImage
| Image
| builtins.object
|
| Methods defined here:
|
| __getitem__(self, key)
| # XXX config
|
| __init__(self, name=None, cnf={}, master=None, **kw)
| Create an image with NAME.
|
| Valid resource names: data, format, file, gamma, height, palette,
| width.
FYI: The easiest way to get to the docs from Python at the command line or from IDLE:
from tkinter import PhotoImage
help(PhotoImage)
And lastly, another useful link about this class is at http://tkinter.unpythonic.net/wiki/PhotoImage.

Answer 2

I tested the example with python 2.7.9, 3.2.5, 3.3.5, 3.4.3 in 32bit and 64bit.
(Win 8.1 64bit)
The code works.
( in python 3.4.3 64bit I had first an error message.
I've completely uninstalled 3.4.3 and then reinstalled.
Now, the example works also with 3.4.3 64 bit )
# basic code from >>
# http://tkinter.unpythonic.net/wiki/PhotoImage
# extra code -------------------------------------------------------------------------
from __future__ import print_function
try:
import tkinter as tk
except:
import Tkinter as tk
import sys
import platform
print ()
print ('python ', sys.version)
print ('tkinter ', tk.TkVersion)
print ()
print (platform.platform(),' ',platform.machine())
print ()
# basic code -------------------------------------------------------------------------
root = tk.Tk()
def create_button_with_scoped_image():
# "w6.gif" >>
# http://www.inf-schule.de/content/software/gui/entwicklung_tkinter/bilder/w6.gif
img = tk.PhotoImage(file="w6.gif") # reference PhotoImage in local variable
button = tk.Button(root, image=img)
# button.img = img # store a reference to the image as an attribute of the widget
button.image = img # store a reference to the image as an attribute of the widget
button.grid()
create_button_with_scoped_image()
tk.mainloop()