Tkinter Pillow Resize Image Looks Choppy While Resizing

[AaronCatolico1]

I have a frame that stores a label which stores a background image. When I resize the form and the frame resizes, the background image of the label looks really choppy while it's being resized by the function. I was thinking about putting the function on a separate thread because I believe the image might look choppy because of it being on the main thread.

Here's what I've tried:

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from tkinter import Tk, Button, Label, Frame from tkinter import ttk, PhotoImage import threading import time from PIL import Image, ImageTk   class MainWindow(Tk):     def __init__(self):         super().__init__()   #create groupbox1 background image for modern look framing     self.gb1_img = Image.open('imgs/groupbox-1.png')     self.gb1_img = self.gb1_img.resize((260, 490), Image.Resampling.LANCZOS)     self.gb1_img = ImageTk.PhotoImage(self.gb1_img)       self.gb1_container = Frame(self, bg='#333333', width=280)     self.gb1_container.pack(side='left', fill='y', padx=20, pady=(120, 20))     self.gb1_container.bind('<Configure>', self.start_resize_gb1)       self.gb1 = Label(self.gb1_container, image=self.gb1_img, bg='#333333')     self.gb1.place(x=0, y=0)     def start_resize_gb1(self, e):     t = threading.Thread(target=self.resize_gb1, args=(e,), daemon=1)     t.start()     #resize groupbox1 frame image     def resize_gb1(self, e):         self.gb1_img1 = Image.open('imgs/groupbox-1.png')         self.gb1_img1 = self.gb1_img1.resize((e.width, e.height), Image.Resampling.LANCZOS)         self.gb1_img1 = ImageTk.PhotoImage(self.gb1_img1)         self.gb1.configure(image=self.gb1_img1)     if __name__ == '__main__':     app = MainWindow()     app.title('Main Window')     app.configure(bg='#333333')       #center the Main Window:     w = 1000  # Width     h = 620  # Height       app.geometry('%dx%d+%d+%d' % (w, h, x, y))     app.mainloop()

Is there a way that I can bind the function on it's own thread so that it doesn't look so choppy while resizing?

The error that I keep getting is:

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Exception in thread Thread-57 (resize_gb1): Traceback (most recent call last):   File "C:\Users\Aaron\AppData\Local\Programs\Python\Python310\lib\threading.py", line 1016, in _bootstrap_inner     self.run()   File "C:\Users\Aaron\AppData\Local\Programs\Python\Python310\lib\threading.py", line 953, in run     self._target(*self._args, **self._kwargs)   File "C:\Users\Aaron\Documents\Python\Project1\testing\MAIN.py", line 92, in resize_gb1     self.gb1_img1 = ImageTk.PhotoImage(self.gb1_img1)   File "C:\Users\Aaron\AppData\Roaming\Python\Python310\site-packages\PIL\ImageTk.py", line 143, in __init__     self.paste(image)   File "C:\Users\Aaron\AppData\Roaming\Python\Python310\site-packages\PIL\ImageTk.py", line 195, in paste     im.load()   File "C:\Users\Aaron\AppData\Roaming\Python\Python310\site-packages\PIL\ImageFile.py", line 268, in load     self.load_end()   File "C:\Users\Aaron\AppData\Roaming\Python\Python310\site-packages\PIL\PngImagePlugin.py", line 962, in load_end     self.fp.read(4)  # CRC AttributeError: 'NoneType' object has no attribute 'read'

[deanhystad]

I don't have your image, but I made a fairly large image (800x800) and resizing is not choppy at all. Even when I opened the file each time, which is wasteful. I included my code if you want to look at it.

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import tkinter as tk from PIL import Image, ImageTk   class MainWindow(tk.Tk):     def __init__(self):         super().__init__()         self.geometry('360x300')         frame = tk.Frame(self)         frame.pack(padx=10, pady=10, expand=True, fill=tk.BOTH)         frame.bind('<Configure>', self.resize_label)         self.raw_image = Image.open('test.png')         self.image = self.raw_image.resize((200, 200), Image.Resampling.LANCZOS)         self.image = ImageTk.PhotoImage(self.image)         self.label = tk.Label(frame, image=self.image)         self.label.place(x=0, y=0)       def resize_label(self, e):         size = (e.width, e.height)         self.image = self.raw_image.resize(size, Image.Resampling.LANCZOS)         self.image = ImageTk.PhotoImage(self.image)         self.label["image"] = self.image   if __name__ == '__main__':     MainWindow().mainloop()

I was able to use a thread to resize the image. This just made drawing the image choppy because the code that resizes the image is no longer synchronized with the window update. You can see that in this version.

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import tkinter as tk from PIL import Image, ImageTk from threading import Thread   class MainWindow(tk.Tk):     def __init__(self):         super().__init__()         self.geometry('360x300')         self.frame = tk.Frame(self)         self.frame.pack(padx=10, pady=10, expand=True, fill=tk.BOTH)         self.frame.bind('<Configure>', self.resize_label)         self.raw_image = Image.open('test.png')         self.image = self.raw_image.resize((200, 200), Image.Resampling.LANCZOS)         self.image = ImageTk.PhotoImage(self.image)         self.label = tk.Label(self.frame, image=self.image)         self.label.place(x=0, y=0)       def resize_label(self, e):         Thread(target=self.resize_image, args=(e.width, e.height)).start()       def resize_image(self, wide, high):         self.image = self.raw_image.resize((wide, high), Image.Resampling.LANCZOS)         self.image = ImageTk.PhotoImage(self.image)         self.label["image"] = self.image   if __name__ == '__main__':     MainWindow().mainloop()

I'm not sure what problem you had using threads. The code you posted has errors that prevent it from running, even without resizing the window. Also, your error message does not match anything in the posted code. If you are going to post code and an error message, please post the code that generated the message.

I am also confused by this: "the background image of the label'. A label can have an image, but it cannot have a "background" image. As far as I know there is no way to place other widgets on top of the label's image. Do you know something I don't?

[AaronCatolico1]

Thanks for your help. I thought that the code I posted was related to the issue. Long day yesterday .
Also, I meant to say that the label enabled me to create a background image for the frame by packing the label into the frame after loading an image into the label.