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From: ChrisChia on 11 Aug 2010 19:50
Hi i have the following problem with Python Tkinter.
I switch to switch the image background (which i used Tkinter.Label
with image arg to display on the GUI).

How can I do that? the callback function which i have created doesn't
seem to work...
some advice?

below is my code:


import Tkinter as tk
from PIL import Image, ImageTk

root = tk.Tk()

# having problem with switching the image
def callback(event):
global root
root.panel1.pack_forget()
root.panel1.image = image2
root.panel1.pack()


def app():

root.title('FIT 2022 Assignment 1')

# pick an image file you have .bmp .jpg .gif. .png
# load the file and covert it to a Tkinter image object
imageFile = "c:\\test1.jpg"
image1 = ImageTk.PhotoImage(Image.open(imageFile))
imageFile2 = "c:\\test2.jpg"
image2 = ImageTk.PhotoImage(Image.open(imageFile2))


# get the image size
w = image1.width()
h = image1.height()


# position coordinates of root 'upper left corner'
x = 0
y = 0


# make the root window the size of the image
root.geometry("%dx%d+%d+%d" % (w, h, x, y))


# root has no image argument, so use a label as a panel
panel1 = tk.Label(root, image=image1)
panel1.pack(side='top', fill='both', expand='yes')
panel1.image = image1
panel1.bind("<Button-1>", callback)


panel1.pack()
root.mainloop()


app()
From: Eric Brunel on 12 Aug 2010 04:42
In article
<ecd3ebca-8192-445a-a60c-c688b18f4287(a)i4g2000prf.googlegroups.com>,
ChrisChia <chrischia82(a)gmail.com> wrote:

> Hi i have the following problem with Python Tkinter.
> I switch to switch the image background (which i used Tkinter.Label
> with image arg to display on the GUI).
>
> How can I do that? the callback function which i have created doesn't
> seem to work...

It is usually way better to post the actual error than just saying
"doesn't seem to work"� Here your problem is quite clear, but in most
circumstances, it would be quite difficult to figure out what's
happening.

> some advice?
>
> below is my code:
>
>
> import Tkinter as tk
> from PIL import Image, ImageTk
>
> root = tk.Tk()
>
> # having problem with switching the image
> def callback(event):
> global root
> root.panel1.pack_forget()
> root.panel1.image = image2

The variable image2 is not known in this context, so no wonder the
callback doesn't work. Let me guess: it says something like "NameError:
name 'image2' is not defined"?

> root.panel1.pack()
>
>
> def app():
>
> root.title('FIT 2022 Assignment 1')
>
> # pick an image file you have .bmp .jpg .gif. .png
> # load the file and covert it to a Tkinter image object
> imageFile = "c:\\test1.jpg"
> image1 = ImageTk.PhotoImage(Image.open(imageFile))
> imageFile2 = "c:\\test2.jpg"
> image2 = ImageTk.PhotoImage(Image.open(imageFile2))

Here, you create image2 as a local variable in function app. So the
variable name will not be known outside of app. If you want it to be
global, you have to add a line:
global image2
at the beginning of your app function. Then it should work correctly.

By the way, I usually find it better to organize a GUI into classes
rather than using functions. This way, you could store the images in
object attributes and define your callback as a method, and not as a
function.

> # get the image size
> w = image1.width()
> h = image1.height()
>
>
> # position coordinates of root 'upper left corner'
> x = 0
> y = 0
>
>
> # make the root window the size of the image
> root.geometry("%dx%d+%d+%d" % (w, h, x, y))
>
>
> # root has no image argument, so use a label as a panel
> panel1 = tk.Label(root, image=image1)
> panel1.pack(side='top', fill='both', expand='yes')
> panel1.image = image1
> panel1.bind("<Button-1>", callback)
>
>
> panel1.pack()
> root.mainloop()
>
>
> app()

HTH
- Eric -
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