Struct ShapingFallback 

pub struct ShapingFallback<S: TextShaper = NoopShaper> { /* private fields */ }

Transparent shaping with guaranteed fallback.

Wraps an optional primary shaper and a NoopShaper fallback. Always produces a valid ShapedLineLayout regardless of whether the primary shaper is available or succeeds.

The output layout has identical API surface for both paths, so downstream code (cursor, selection, copy, rendering) does not need to branch on which shaping path was used.

Implementations

impl ShapingFallback<NoopShaper>

pub fn terminal() -> Self

Create a terminal-mode fallback (always uses NoopShaper).

impl<S: TextShaper> ShapingFallback<S>

pub fn with_shaper(shaper: S, capabilities: RuntimeCapability) -> Self

Create a fallback with a primary shaper.

pub fn set_features(&mut self, features: FontFeatures)

Set the font features used for shaping.

pub fn set_shaping_tier(&mut self, tier: LayoutTier)

Set the minimum tier for shaping.

pub fn set_capabilities(&mut self, caps: RuntimeCapability)

Update runtime capabilities (e.g., after font load/unload).

pub fn set_validate_output(&mut self, validate: bool)

Enable or disable output validation.

pub fn shape_line( &self, text: &str, script: Script, direction: RunDirection, ) -> (ShapedLineLayout, FallbackEvent)

Shape a line of text with automatic fallback.

Returns the layout and a diagnostic event describing which path was taken. The layout is guaranteed to be valid and non-empty for non-empty input.

pub fn shape_lines( &self, lines: &[&str], script: Script, direction: RunDirection, ) -> (Vec<ShapedLineLayout>, FallbackStats)

Shape multiple lines with fallback, collecting stats.

Returns layouts and accumulated statistics.