Struct FontManager 

pub struct FontManager { /* private fields */ }

Manages multiple fonts with fallback chain

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<Self>

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 0-3 are styled fonts, >3 are fallbacks Font indices: 0 = primary/regular, 1 = bold, 2 = italic, 3 = bold-italic, 4+ = fallbacks

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

Find the font index for a character in range fonts Returns None if the character is not in any range font

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

Get font reference by index

Arguments

• font_index - Font index: 0 = primary, 1 = bold, 2 = italic, 3 = bold-italic, 4..4+range_fonts.len() = range fonts, remaining = fallbacks

Returns

Reference to the font at the given index, or None if invalid index

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

Get the primary font reference

pub fn font_count(&self) -> usize

Get number of fonts loaded (including primary, styled fonts, range fonts, and fallbacks)

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

Get raw font data bytes for a font index

This is used by the text shaper to access the font data for shaping.

Arguments

• font_index - Font index: 0 = primary, 1 = bold, 2 = italic, 3 = bold-italic, 4..4+range_fonts.len() = range fonts, remaining = fallbacks

Returns

Reference to the raw font data bytes, or None if invalid index

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

Shape text using the appropriate font

This method uses HarfBuzz (via rustybuzz) to shape text with ligatures, kerning, and complex script support.

Arguments

• text - The text to shape
• bold - Whether the text is bold
• italic - Whether the text is italic
• options - Shaping options (ligatures, kerning, etc.)

Returns

A ShapedRun containing the shaped glyphs and metadata

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

This method allows you to shape text with a specific font, rather than using the styled font selection. This is useful for emoji and symbols that need to be shaped with their dedicated fonts.

Arguments

• text - The text to shape
• font_index - The specific font index to use
• options - Shaping options (ligatures, kerning, etc.)

Returns

A ShapedRun containing the shaped glyphs and metadata

pub fn clear_shape_cache(&mut self)

Clear the text shaping cache

This should be called when fonts are reloaded or changed.

pub fn shape_cache_size(&self) -> usize

Get the current size of the shape cache