Scaling Functions

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set_widget_scaling()

import customtkinter as ctk

# Make all widgets 50% larger
ctk.set_widget_scaling(1.5)

# Make all widgets smaller
ctk.set_widget_scaling(0.8)

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Parameters

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Behavior

• Affects all CustomTkinter widgets globally
• Changes apply immediately to all existing and new widgets
• Multiplies with automatic DPI scaling (if enabled)
• Does not affect window dimensions (use set_window_scaling() for that)

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set_window_scaling()

import customtkinter as ctk

# Make all windows 25% larger
ctk.set_window_scaling(1.25)

# Make all windows smaller
ctk.set_window_scaling(0.9)

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Parameters

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Behavior

• Affects all CustomTkinter windows (CTk, CTkToplevel) globally
• Changes apply immediately to all existing and new windows
• Multiplies with automatic DPI scaling (if enabled)
• Does not affect widget dimensions (use set_widget_scaling() for that)

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deactivate_automatic_dpi_awareness()

import customtkinter as ctk

# Must be called before creating any windows
ctk.deactivate_automatic_dpi_awareness()

root = ctk.CTk()

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Parameters

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Behavior

• Must be called before creating any CTk or CTkToplevel windows
• Disables automatic DPI scaling detection on Windows
• On Windows, prevents the call to SetProcessDpiAwareness(2)
• After calling this, only the manual scaling factors from set_widget_scaling() and set_window_scaling() are applied
• On macOS, DPI scaling works automatically and cannot be disabled
• On Linux, DPI awareness is not implemented

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Use Cases

• When you need full manual control over scaling
• If automatic DPI detection causes issues with your application
• When developing cross-platform applications that need consistent sizing

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Example: Combined Usage

import customtkinter as ctk

# Disable automatic DPI scaling
ctk.deactivate_automatic_dpi_awareness()

# Set custom scaling factors
ctk.set_widget_scaling(1.2)  # Widgets 20% larger
ctk.set_window_scaling(1.0)  # Windows at normal size

root = ctk.CTk()
root.geometry("400x300")

# Create some widgets
button = ctk.CTkButton(root, text="Large Button")
button.pack(pady=20)

label = ctk.CTkLabel(root, text="Large Label")
label.pack(pady=20)

root.mainloop()

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Example: Dynamic Scaling

import customtkinter as ctk

root = ctk.CTk()

def increase_scale():
    # Get current scale and increase it
    ctk.set_widget_scaling(1.5)

def decrease_scale():
    ctk.set_widget_scaling(0.8)

def reset_scale():
    ctk.set_widget_scaling(1.0)

frame = ctk.CTkFrame(root)
frame.pack(pady=20, padx=20, fill="both", expand=True)

ctk.CTkButton(frame, text="Increase Scale", command=increase_scale).pack(pady=10)
ctk.CTkButton(frame, text="Decrease Scale", command=decrease_scale).pack(pady=10)
ctk.CTkButton(frame, text="Reset Scale", command=reset_scale).pack(pady=10)

root.mainloop()

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Notes

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Platform Differences

• Windows: Full DPI awareness support. CustomTkinter calls SetProcessDpiAwareness(2) for per-monitor DPI awareness
• macOS: DPI scaling works automatically at the OS level
• Linux: DPI awareness not currently implemented

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Scaling Calculation

final_widget_scaling = system_dpi_scaling × widget_scaling_value
final_window_scaling = system_dpi_scaling × window_scaling_value

final_widget_scaling = widget_scaling_value
final_window_scaling = window_scaling_value

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Best Practices

• Call scaling functions before creating widgets for consistent appearance
• Use deactivate_automatic_dpi_awareness() only when necessary
• Test your application on different DPI settings and displays
• Keep widget and window scaling separate for fine-grained control
• Values below 0.4 are clamped to 0.4 to maintain usability