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Overview

CTk is the main application window class in CustomTkinter. It extends tkinter.Tk and provides automatic dark titlebar support on Windows and macOS, along with appearance mode and scaling capabilities.

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Inheritance

CTk(tkinter.Tk, CTkAppearanceModeBaseClass, CTkScalingBaseClass)
Inherits from:
  • tkinter.Tk - Base Tkinter window class
  • CTkAppearanceModeBaseClass - Provides appearance mode functionality
  • CTkScalingBaseClass - Provides scaling functionality

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Constructor

CTk(fg_color=None, **kwargs)
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fg_color
Optional[Union[str, Tuple[str, str]]]
default:"None"
Background color of the window. Can be a single color string or a tuple of (light_mode_color, dark_mode_color). If None, uses the theme default.
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**kwargs
dict
Additional arguments passed to tkinter.Tk constructor. Valid arguments include: screenName, baseName, className, useTk, sync, use.

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Methods

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configure

configure(**kwargs)
Configure the window properties.
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fg_color
Optional[Union[str, Tuple[str, str]]]
Background color of the window.
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**kwargs
dict
Additional tkinter.Tk configuration options including: bd, borderwidth, class, menu, relief, screen, use, container, cursor, height, highlightthickness, padx, pady, takefocus, visual, width.

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cget

cget(attribute_name: str) -> any
Get the value of a configuration attribute.
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attribute_name
str
required
Name of the attribute to retrieve. Can be “fg_color” or any valid tkinter.Tk attribute.
Returns: The value of the specified attribute.

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geometry

geometry(geometry_string: str = None)
Set or get the window geometry. Automatically applies window scaling.
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geometry_string
str
Geometry string in format “widthxheight+x+y” or “widthxheight”. If None, returns current geometry.
Returns: Current geometry string if geometry_string is None.

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minsize

minsize(width: int = None, height: int = None)
Set the minimum window size.
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width
int
Minimum width in pixels.
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height
int
Minimum height in pixels.

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maxsize

maxsize(width: int = None, height: int = None)
Set the maximum window size.
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width
int
Maximum width in pixels.
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height
int
Maximum height in pixels.

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resizable

resizable(width: bool = None, height: bool = None)
Set whether the window can be resized.
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width
bool
Whether the window can be resized horizontally.
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height
bool
Whether the window can be resized vertically.
Returns: Current resizable values as tuple.

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withdraw

withdraw()
Hide the window.

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iconify

iconify()
Minimize the window to an icon.

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deiconify

deiconify()
Restore a minimized or hidden window.

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mainloop

mainloop(*args, **kwargs)
Start the Tkinter event loop.
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*args
tuple
Arguments passed to tkinter.Tk.mainloop().
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**kwargs
dict
Keyword arguments passed to tkinter.Tk.mainloop().

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update

update()
Process all pending events and update the window.

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destroy

destroy()
Destroy the window and all its children.

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iconbitmap

iconbitmap(bitmap=None, default=None)
Set the window icon.
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bitmap
str
Path to the icon file (.ico on Windows).
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default
str
Default icon path.

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wm_iconbitmap

wm_iconbitmap(bitmap=None, default=None)
Alias for iconbitmap() method.
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bitmap
str
Path to the icon file (.ico on Windows).
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default
str
Default icon path.

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Usage Example

import customtkinter as ctk

# Create the main window
app = ctk.CTk()
app.title("My Application")
app.geometry("800x600")

# Configure window properties
app.configure(fg_color=("white", "#1a1a1a"))
app.minsize(400, 300)
app.resizable(True, True)

# Add widgets
label = ctk.CTkLabel(app, text="Hello, CustomTkinter!")
label.pack(pady=20)

button = ctk.CTkButton(app, text="Click Me")
button.pack(pady=10)

# Start the event loop
app.mainloop()

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Advanced Example

import customtkinter as ctk

class App(ctk.CTk):
    def __init__(self):
        super().__init__()
        
        # Configure window
        self.title("Advanced CTk Window")
        self.geometry("900x650")
        self.minsize(600, 400)
        
        # Set appearance mode and color theme
        ctk.set_appearance_mode("dark")
        ctk.set_default_color_theme("blue")
        
        # Configure grid
        self.grid_columnconfigure(0, weight=1)
        self.grid_rowconfigure(0, weight=1)
        
        # Create main frame
        self.main_frame = ctk.CTkFrame(self)
        self.main_frame.grid(row=0, column=0, sticky="nsew", padx=20, pady=20)
        
if __name__ == "__main__":
    app = App()
    app.mainloop()

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Notes

  • The window automatically applies dark titlebar styling on Windows and macOS
  • Initial window size is 600x500 pixels (before any scaling)
  • Default title is “CTk”
  • On Windows, a default CustomTkinter icon is set automatically
  • All size-related methods (geometry, minsize, maxsize) automatically handle scaling
  • The window inherits all standard tkinter.Tk methods and properties

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