How to add custom fonts in Kivy - Python?

Kivy allows developers to use custom fonts in their applications, providing a personalized touch to widgets like buttons, labels, and windows. Adding custom fonts involves two main steps: registering the font with Kivy using LabelBase.register() and applying it to widgets via the font_name property.

In this article, we will explore how to add custom fonts in Kivy applications, including font registration, widget application, and practical examples.

Installing Custom Fonts

Before using custom fonts in Kivy, you need to have the font files (.ttf or .otf format) available on your system or in your project directory ?

• Windows: Right-click the .ttf file and select "Install"
• macOS: Double-click the font file and select "Install Font"
• Linux: Copy the font file to ~/.local/share/fonts/ or /usr/share/fonts/

For Kivy applications, you can also place the font file directly in your project directory.

Registering Custom Fonts in Kivy

To use a custom font in Kivy, register it using LabelBase.register() from the kivy.core.text module ?

from kivy.core.text import LabelBase

# Register a custom font
LabelBase.register(name='MyCustomFont', fn_regular='path/to/font.ttf')

Example 1: Adding Custom Font to a Label

Here's a complete example showing how to create a Kivy app with a custom font applied to a label ?

import kivy
from kivy.app import App
from kivy.uix.label import Label
from kivy.core.text import LabelBase

class CustomFontApp(App):
    def build(self):
        # Register the custom font (assuming font_sample.ttf is in project directory)
        LabelBase.register(name='CustomFont', fn_regular='font_sample.ttf')
        
        # Create label with custom font
        label = Label(
            text='Welcome to TutorialsPoint!\nCustom Font Example',
            font_name='CustomFont',
            font_size='24sp',
            halign='center',
            text_size=(None, None)
        )
        return label

CustomFontApp().run()

Example 2: Adding Custom Font to a Button

Custom fonts can also be applied to buttons and other widgets ?

import kivy
from kivy.app import App
from kivy.uix.button import Button
from kivy.core.text import LabelBase

class CustomFontButtonApp(App):
    def build(self):
        # Register the custom font
        LabelBase.register(name='CustomFont', fn_regular='font_sample.ttf')
        
        # Create button with custom font
        button = Button(
            text='Click Me!',
            font_name='CustomFont',
            font_size='20sp',
            size_hint=(0.5, 0.2),
            pos_hint={'center_x': 0.5, 'center_y': 0.5}
        )
        return button

CustomFontButtonApp().run()

Advanced Font Configuration

You can register multiple font variants (regular, bold, italic) for more comprehensive font support ?

from kivy.core.text import LabelBase

# Register multiple font variants
LabelBase.register(
    name='MyFont',
    fn_regular='fonts/MyFont-Regular.ttf',
    fn_bold='fonts/MyFont-Bold.ttf',
    fn_italic='fonts/MyFont-Italic.ttf'
)

Font Properties

When applying custom fonts to widgets, you can customize several properties:

Troubleshooting Tips

• Ensure the font file path is correct relative to your Python script
• Use forward slashes (/) in file paths for cross-platform compatibility
• Verify the font file is not corrupted by testing it in other applications
• Check that the font name in LabelBase.register() matches what you use in font_name

Conclusion

Custom fonts in Kivy enhance the visual appeal of your applications. Register fonts using LabelBase.register() and apply them to widgets with the font_name property. This simple process allows you to create unique, branded user interfaces that stand out from default system fonts.