Struct FontManager 

pub struct FontManager { /* private fields */ }

Manages multiple fonts with fallback chain.

Font indices are assigned as follows:

• 0: Primary/regular font
• 1: Bold font (if available)
• 2: Italic font (if available)
• 3: Bold-italic font (if available)
• 4..4+N: Unicode range fonts (N = number of range fonts)
• 4+N..: Fallback fonts

Implementations

impl FontManager

pub fn new( primary_family: Option<&str>, bold_family: Option<&str>, italic_family: Option<&str>, bold_italic_family: Option<&str>, font_ranges: &[FontRange], ) -> Result<FontManager, Error>

Create a new FontManager with primary font and system fallbacks.

Arguments

• primary_family - Regular/normal weight font family name
• bold_family - Bold weight font family name (optional)
• italic_family - Italic font family name (optional)
• bold_italic_family - Bold italic font family name (optional)
• font_ranges - Unicode range-specific font mappings

pub fn find_glyph( &self, character: char, bold: bool, italic: bool, ) -> Option<(usize, u16)>

Find a glyph for a character across the font fallback chain.

Arguments

• character - Character to find glyph for
• bold - Whether text should be bold
• italic - Whether text should be italic

Returns

(font_index, glyph_id) where font_index identifies which font contains the glyph.

pub fn find_range_font_index(&self, char_code: u32) -> Option<(usize, u16)>

Find the font index for a character in range fonts.

pub fn get_font(&self, font_index: usize) -> Option<&FontRef<'static>>

Get font reference by index.

Arguments

• font_index - Font index (see struct documentation for layout)

pub fn primary_font(&self) -> &FontRef<'static>

Get the primary font reference.

pub fn font_count(&self) -> usize

Get number of fonts loaded (primary + styled + range + fallbacks).

pub fn get_font_data(&self, font_index: usize) -> Option<&[u8]>

Get raw font data bytes for a font index.

pub fn shape_text( &mut self, text: &str, bold: bool, italic: bool, options: ShapingOptions, ) -> Arc<ShapedRun>

Shape text using the appropriate font.

Uses HarfBuzz (via rustybuzz) for ligatures, kerning, and complex script support.

pub fn shape_text_with_font_index( &mut self, text: &str, font_index: usize, options: ShapingOptions, ) -> Arc<ShapedRun>

Shape text using a specific font index.

pub fn clear_shape_cache(&mut self)

Clear the text shaping cache.

pub fn shape_cache_size(&self) -> usize

Get the current size of the shape cache.

pub fn find_grapheme_glyph( &mut self, grapheme: &str, bold: bool, italic: bool, ) -> Option<(usize, u16)>

Find glyph(s) for an entire grapheme cluster.

This is essential for rendering multi-character sequences like:

• Flag emoji (🇺🇸) - regional indicator pairs
• ZWJ sequences (👨‍👩‍👧‍👦) - family emoji
• Skin tone modifiers (👋🏽)
• Combining characters (é = e + acute accent)

Arguments

• grapheme - The grapheme cluster string (may be multiple Unicode codepoints)
• bold - Whether text should be bold
• italic - Whether text should be italic

Returns

Some((font_index, glyph_id)) for the primary glyph representing the grapheme, or None if no suitable glyph was found.