Struct TextLayoutEngine 

pub struct TextLayoutEngine { /* private fields */ }

Breaks TextRun sequences into LineBoxes that fit within a given width.

Uses real glyph-advance metrics from FontRegistry (rustybuzz + ttf-parser).

Implementations

impl TextLayoutEngine

pub fn new(fonts: &FontRegistry, style: &DocumentStyle) -> Self

pub fn measure_text_mm( &self, fonts: &FontRegistry, text: &str, font_size: f64, bold: bool, italic: bool, ) -> f64

Measures the rendered width of text in mm using real glyph metrics.

pub fn default_family_name(&self) -> &str

Returns the default font family name used for measurement.

pub fn set_default_family(&mut self, name: impl Into<String>)

Overrides the default font family used for measurement.

Used by Paragraph to apply a per-paragraph font family. Always restore with the previous value after the layout call.

pub fn line_height_mm(&self, fonts: &FontRegistry, font_size: f64) -> f64

Returns the line height in mm for font_size (pt).

pub fn layout_runs( &self, fonts: &FontRegistry, runs: &[TextRun], max_width_mm: f64, alignment: TextAlign, font_size: f64, tab_stops: &[TabStop], ) -> LayoutResult

Lays out runs into LineBoxes fitting max_width_mm.

tab_stops controls how \t characters inside runs are handled. Pass an empty slice when no tab stops are defined.

pub fn layout_plain( &self, fonts: &FontRegistry, text: &str, max_width_mm: f64, alignment: TextAlign, font_size: f64, style: AppliedStyle, ) -> LayoutResult

Convenience wrapper: lay out a plain string with a uniform style.

pub fn layout_runs_with_mode( &self, fonts: &FontRegistry, runs: &[TextRun], max_width_mm: f64, alignment: TextAlign, font_size: f64, tab_stops: &[TabStop], mode: LineBreakingMode, ) -> LayoutResult

Layout with explicit line-breaking mode.

When mode is LineBreakingMode::KnuthPlass and the optimal_wrap feature is compiled, uses the Knuth-Plass algorithm for better paragraph colour (inter-word spacing consistency). Falls back to greedy otherwise.

pub fn hyphenate_word(&self, word: &str) -> Vec<usize>

Returns hyphenation break points (byte indices) for a word.

Requires the hyphenation feature. Returns an empty Vec when the feature is disabled or the word has fewer than 5 characters.