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