Dynamic configuration of CTkLabel wraplength not working on dual monitor setup

[debicarroll]

I have a two-monitor setup and am having an issue with setting a CTkLabel wraplength dynamically when the window is resized on the smaller monitor (my laptop's monitor). On the smaller monitor, the initial window configuration looks correct but as soon as the window is resized, the label text extends off the edge of the window. The wraplength works correctly on the larger monitor no matter how I resize the window. Has anyone run into this and can I add anything to re-wrap correctly on both monitors?

Min reproduceable example:

import customtkinter as ctk

def watch_config_changes():
    window.bind('<Configure>', update_widths)
        
def update_widths(event):
    lbl_description.configure(wraplength=lbl_description.winfo_width())


window = ctk.CTk()
window.geometry(f"400x100")
window.grid_columnconfigure(0, weight=1)

lbl_description = ctk.CTkLabel(
    window, text=(
        "Long label text - one two three four five six seven eight "
        "nine ten eleven twelve thirteen fourteen "
        "fifteen sixteen seventeen eighteen nineteen twenty"
    ), bg_color="gray80", justify="left", anchor="w", wraplength=380   
)
lbl_description.grid(row=0, column=0, pady=10, padx=10, sticky="nsew")
lbl_description.grid_columnconfigure(0, weight=1)

window.after(1000, watch_config_changes)
window.mainloop()

Initial render on laptop monitor: Good

Resize slightly on laptop monitor: Cut Off

Drag to larger secondary monitor: Good

Resize on larger secondary monitor: Good

Edited to add:
My smaller monitor has a scale factor of 150% and larger 100%, and I think this is the problem. When I set ctk.deactivate_automatic_dpi_awareness() the wraplength works on both monitors. However, this also makes the text fuzzy. It seems like I need a way to detect the scale factor of the current monitor and recalculate the wraplength.

I tried ctypes.windll.shcore.GetScaleFactorForDevice(0) and window.tk.call('tk', 'scaling') but those both keep giving me 150 and 1.332 respectively when I move the CTk window to the larger 100% scaled monitor.

[dipeshSam]

Use .update() before accessing width.

...
lbl_description.update()
lbl_description.configure(wraplength=lbl_description.winfo_width())
...

Alternatively, you can directly access accurate width from event object.

...
lbl_description.configure(wraplength=event.width)
...

[debicarroll]

@dipeshSam That produces the same result; the text still extends out of window. And the width from the event returns the same value as winfo_width. And all the units of width and wraplength are pixel values. Everything matches except that the wraplength is wrapping at a different number of pixels than specified.

[dipeshSam]

@debicarroll Oops! You don't need to set wraplength actually. Use wrap="word" in your constructor initializer.

lbl_description = CTkTextbox(..., wrap="word", ...)

Regards.

[debicarroll]

@dipeshSam I think wrap="word" is only for a CTkTextbox, yes? It doesn't seem to work for CTkLabel. But I may switch the widget to a textbox if I can't resolve the issue for a label.

[dipeshSam]

@debicarroll You are right. The wrap="word" parameter is only supported in Text widget, not in Label. If you want responsive text area for the application then it is recommended to use Text widget instead of Label in tkinter or customtkinter. Although, I wrote a fully wrap-supportive label class for customtkinter. Here it is:

from customtkinter import (
    CTk,
    CTkFont,
    AppearanceModeTracker,
    ThemeManager
)
from tkinter import Event, Label


class WrappableLabel(Label):
    def __init__(self, 
        master=None, 
        text: str = "Sample Text",
        fg_color: str | tuple[str, str] = None,
        text_color: str | tuple[str, str] = None,
        font: CTkFont | tuple[str, str, int] = None,
        **kwargs):
        
        """Auto-wrap text in customtkinter. It wraps text in words based on window size."""
        
        self._font = CTkFont() if not font else font
        self._text = "Sample Text" if not text else text
        self._fg_color = master["bg"] if not fg_color else fg_color
        self._text_color = ThemeManager.theme["CTkLabel"]["text_color"] if not text_color else text_color

        super().__init__(master, text=text, foreground=self._get_color(self._text_color), font=self._font, bg=self._get_color(self._fg_color), **kwargs)
        self.master.bind("<Configure>", self._on_config, "+")
        AppearanceModeTracker.add(self._on_apprearance)
        

    def _on_config(self, event: Event):
        wrappable = event.width - self._font.measure(".")
        self.configure(wraplength=wrappable)
        
    def _get_color(self, color: str | tuple[str, str]) -> str:
        if isinstance(color, str):
            return color
        elif isinstance(color, (tuple, list)):
            return color[AppearanceModeTracker.get_mode()]
        
    def _on_apprearance(self, m=None):
        self.configure(bg=self._get_color(self.master.cget("bg")))
        self.configure(foreground=self._get_color(self._text_color))


if __name__ == "__main__":
    app = CTk()
    app.geometry("530x300")
    app.pack_propagate(False)

    lengthy_text = "One (1) Two (2) Three (3) Four (4) Five (5) Six (6) Seven (7) Eight (8) Nine (9) Ten (10)."
    
    lab = WrappableLabel(app, text=lengthy_text, anchor="w")
    lab.pack(side="left", padx=10, pady=10)


    app.mainloop()

Output:
https://github.com/user-attachments/assets/ab2a1b0c-4502-4142-82cd-8b674c607b8a

If the provided code does not work expectedly, let me know.
Regards.

[debicarroll]

Thank you @dipeshSam -- this looks to work well on both my monitors.

[dipeshSam]

@debicarroll You are most welcome.