[Tkinter] How do I change an image dynamically

[Tkinter] How do I change an image dynamically - Printable Version

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How do I change an image dynamically - LeeMadeux - Jan-25-2018

I am trying to dynamically change a displayed picture to another picture on a GUI.
I have tried various suggested ways seen on websites and none have worked this far.
What am I doing wrong?

from tkinter import *
from tkinter import ttk

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label=ttk.Label(root, image=stgImg)
    label.image = stgImg
    return

root = Tk()

root.geometry('1010x740+200+200')

stgImg = PhotoImage(file="Stage0.gif")
label=ttk.Label(root, image=stgImg)
label.place(x=400, y=400)

testBtn=ttk.Button(root, text="TEST", command=TestLogic)
testBtn.place(x=400, y=200)
root.mainloop()

The first image is displayed just fine. When I press the button, nothing happens.

Thanks...

RE: How do I change an image dynamically - Barrowman - Jan-25-2018

(Jan-25-2018, 08:49 PM)LeeMadeux Wrote: I am trying to dynamically change a displayed picture to another picture on a GUI.
I have tried various suggested ways seen on websites and none have worked this far.
What am I doing wrong?
def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label=ttk.Label(root, image=stgImg)
    label.image = stgImg
    return

Perhaps this little change might help

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label=ttk.Label(root, image=stgImg)
    label.image = stgImg
    root.update_idletasks()
    return

RE: How do I change an image dynamically - haha001 - Feb-01-2018

(Jan-25-2018, 08:49 PM)LeeMadeux Wrote: I am trying to dynamically change a displayed picture to another picture on a GUI. I have tried various suggested ways seen on websites and none have worked this far. What am I doing wrong?
 from tkinter import * from tkinter import ttk def TestLogic(): stgImg = PhotoImage(file="Stage1.gif") label=ttk.Label(root, image=stgImg) label.image = stgImg return root = Tk() root.geometry('1010x740+200+200') stgImg = PhotoImage(file="Stage0.gif") label=ttk.Label(root, image=stgImg) label.place(x=400, y=400) testBtn=ttk.Button(root, text="TEST", command=TestLogic) testBtn.place(x=400, y=200) root.mainloop() 
The first image is displayed just fine. When I press the button, nothing happens. Thanks...

You might consider using Thread. To unblock the mainloop.

RE: How do I change an image dynamically - selmansem - May-28-2020

Try this...

from tkinter import *
from tkinter import ttk

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label.configure(image=stgImg)
    label.image = stgImg

root = Tk()

root.geometry('1010x740+200+200')
 
stgImg = PhotoImage(file="Stage0.gif")
label=ttk.Label(root, image=stgImg)
label.place(x=400, y=400)
 
testBtn=ttk.Button(root, text="TEST", command=TestLogic)
testBtn.place(x=400, y=200)
root.mainloop()

RE: How do I change an image dynamically - menator01 - May-28-2020

#! /usr/bin/env python3

from tkinter import *
from tkinter import ttk

class Picture:
    def __init__(self, parent):
        self.parent = parent
        img = PhotoImage(file='img1.png')
        self.label = ttk.Label(self.parent)
        self.label['image'] = img
        img.image = img
        self.label.pack()

        btn = Button(self.parent, command=self.update, text='Test').pack(side='bottom', pady=50)

    def update(self):
        img = PhotoImage(file='img2.png')
        self.label['image'] = img
        img.image = img

def main():
    root = Tk()
    root.geometry('400x400+50+50')
    Picture(root)
    root.mainloop()

main()

RE: How do I change an image dynamically - deanhystad - May-28-2020

Images in tkinter are odd. If you don't protect the image from garbage collection you will not see the image change.

RE: How do I change an image dynamically - moorthypnt - Jun-04-2020

(May-28-2020, 08:50 PM)selmansem Wrote: Try this...

from tkinter import *
from tkinter import ttk

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label.configure(image=stgImg)
    label.image = stgImg

root = Tk()

root.geometry('1010x740+200+200')
 
stgImg = PhotoImage(file="Stage0.gif")
label=ttk.Label(root, image=stgImg)
label.place(x=400, y=400)
 
testBtn=ttk.Button(root, text="TEST", command=TestLogic)
testBtn.place(x=400, y=200)
root.mainloop()

It is working.

But what is the logic behind
"label.image = stgImg " this command.

Only this command makes it work. It is completely new addition when compared with text update.

RE: How do I change an image dynamically - deanhystad - Jun-04-2020

That command tells sets the image reference count to 1. Python cannot delete the image and reuse the memory.

This is what I mean by "Images in tkinter are odd". I would think that setting an image to be used in a button or a label should save that image from garbage collection. I could see if it is just stamping something on a canvas, but python treats all images this way. You need a non-local variable to keep hold of the image handle, preventing the image reference counter from going to zero, for the image to stick around.