FontManager

FontManager

The FontManager struct manages font loading and provides access to the underlying cosmic_text::FontSystem. It lives in the aurora_text::font_manager module.

Feature gate

FontManager is part of the aurora_text crate and is available when the text feature is enabled on the main aurora crate.

Struct

pub struct FontManager {
    font_system: cosmic_text::FontSystem,
}

Constructor

FontManager::new()

Creates a new font manager with an empty font database. Equivalent to FontManager::default().

let mut font_manager = FontManager::new();

FontManager::new_with_locale(locale)

Creates a new font manager with a BCP 47 locale tag (e.g. "en-US", "ar-SA", "ja-JP"). The locale is passed to cosmic_text::FontSystem for locale-aware font fallback — for example, choosing Japanese vs Chinese variants of shared Han characters.

let mut fm = FontManager::new_with_locale("ja-JP");

FontManager::new_with_locale_and_system_db(locale)

Same as new_with_locale but also loads system fonts. Combines locale support with system font discovery.

let mut fm = FontManager::new_with_locale_and_system_db("ar-SA");

When using App::locale("ja-JP"), the platform automatically calls new_with_locale or new_with_locale_and_system_db based on the use_system_font setting.

Methods

load(path) -> Result<(), FontError>

Loads a font from a file path on disk. The path can be anything that implements AsRef<Path>.

font_manager.load("fonts/Roboto-Regular.ttf")?;

load_from_bytes(bytes) -> Option<String>

Loads a font from a byte slice. Returns the font family name on success, or None if the font could not be parsed.

This is the preferred method when embedding fonts with include_bytes!:

let family = font_manager.load_from_bytes(include_bytes!("Roboto-Regular.ttf"));
assert_eq!(family, Some("Roboto".to_string()));

font_system_mut() -> &mut cosmic_text::FontSystem

Returns a mutable reference to the underlying cosmic_text::FontSystem. Needed by TextLayout for shaping and rasterisation.

Usage with App

Fonts can be registered on the App builder using the font() method, which calls load_from_bytes internally:

App::new()
    .font(include_bytes!("Roboto-Regular.ttf"))
    .run(|window, _| { /* ... */ })
    .unwrap();

FontError

Errors returned by FontManager::load.

pub enum FontError {
    FailedToLoadFont(io::Error),
}

Variant	Cause
FailedToLoadFont	The file could not be read from disk

FontError implements Display and converts from io::Error.