Struct TextEngine 

pub struct TextEngine { /* private fields */ }

The sole owner of font discovery and app-registered fonts. Parley owns the actual font collection and resolves scripts, bidi direction and fallback.

Implementations

impl TextEngine

pub fn layout_paragraphs( &mut self, text: &str, style: &TextStyle, options: TextLayoutOptions, ) -> Arc<TextDocumentLayout>

Lays out text paragraph by paragraph; see TextDocumentLayout.

Paragraphs are laid out with options and visible overflow: max_lines and overflow apply to whole-text layouts only.

impl TextEngine

pub fn new() -> Self

pub fn with_shared<R>(f: impl FnOnce(&mut Self) -> R) -> R

Runs f with this thread’s shared measuring engine.

Application code that measures text while building or inside a LayoutBuilder should use this instead of TextEngine::new(): a new engine starts with an empty cache and reshapes every string on every rebuild, while the shared engine keeps layouts across frames. A nested call from inside f gets a temporary engine rather than panicking.

pub const fn diagnostics(&self) -> TextDiagnostics

pub const fn cache_byte_budget(&self) -> usize

Approximate bytes the layout pools may retain together. Defaults to 32 MiB.

pub fn set_cache_byte_budget(&mut self, bytes: usize)

Bounds the approximate bytes retained by the layout pools, evicting least recently used layouts beyond it. Half goes to finished layouts and a quarter each to width-independent lines and shaped wrapping paragraphs. The paragraphs of a document being composed are exempt, so a long file is never reshaped on each edit.

pub const fn cache_bytes(&self) -> usize

Approximate bytes the layout pools retain now. Layouts shared between pools are counted by each, so this is an upper bound.

pub fn has_pending_application_fonts(&self) -> bool

Whether fonts were registered with register_application_font since this engine last laid out text. Retained layouts measured with the older fonts are stale.

pub fn sync_application_fonts(&mut self) -> bool

Registers thread application fonts added since this engine last laid out text, returning whether there were any.

pub const fn font_database_generation(&self) -> u64

pub fn register_font_bytes(&mut self, bytes: impl Into<Vec<u8>>)

Registers all faces in a TrueType/OpenType byte buffer with Parley’s Fontique collection. Invalid buffers are harmless: Fontique ignores them, while the generation still invalidates stale cached layouts.

pub fn layout( &mut self, text: &str, style: &TextStyle, max_width: Option<f32>, align: TextAlign, ) -> Arc<TextLayout>

pub fn layout_with_options( &mut self, text: &str, style: &TextStyle, options: TextLayoutOptions, ) -> Arc<TextLayout>

Shapes a paragraph with retained wrapping and overflow policy.

Trait Implementations

impl Default for TextEngine

fn default() -> Self

Returns the “default value” for a type.