如何使用tkinter / ttk在Python 3中显示图像？

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 (ie 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()