Struct TextShaper 

pub struct TextShaper { /* private fields */ }

Text shaper using HarfBuzz via rustybuzz

Implementations

impl TextShaper

pub fn new() -> Self

Create a new text shaper with default settings

pub fn with_cache_size(max_cache_size: usize) -> Self

Create a new text shaper with a specific cache size

pub fn detect_grapheme_clusters<'a>( &self, text: &'a str, ) -> Vec<(usize, &'a str)>

Detect grapheme clusters in the input text

This is crucial for:

• Regional indicator pairs (flag emoji like 🇺🇸)
• ZWJ sequences (emoji like 👨‍👩‍👧‍👦)
• Combining characters (diacritics like é)
• Emoji with skin tone modifiers (👋🏽)

pub fn is_regional_indicator_pair(&self, grapheme: &str) -> bool

Detect regional indicator pairs (flag emoji)

Regional indicators are pairs of characters U+1F1E6-U+1F1FF that combine to form flag emoji (e.g., 🇺🇸 = U+1F1FA + U+1F1F8)

pub fn contains_zwj(&self, grapheme: &str) -> bool

Check if a grapheme contains a Zero Width Joiner (ZWJ)

ZWJ sequences are used for complex emoji like family emoji (👨‍👩‍👧‍👦)

pub fn shape_text( &mut self, text: &str, font_data: &[u8], font_index: usize, options: ShapingOptions, ) -> Arc<ShapedRun>

Shape a text run using rustybuzz

This performs the actual text shaping, applying OpenType features like ligatures, kerning, and contextual alternates.

Arguments

• text - The text to shape
• font_data - The font data (TrueType/OpenType)
• font_index - Font index for cache key
• options - Shaping options

Returns

A ShapedRun containing the shaped glyphs and metadata

pub fn clear_cache(&mut self)

Clear the shape cache

pub fn cache_size(&self) -> usize

Get the current cache size

Trait Implementations

impl Default for TextShaper

fn default() -> Self

Returns the “default value” for a type.