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@searsuite/sear-render-metrics

Platform-neutral text shaping and glyph measurement contracts.

Text shaping engines

classRenderContextTextShaper: class RenderContextTextShaper extends TextShaper

Portable fallback backed by the host's render-neutral text measurements.

constructorRenderContextTextShaper(context: RenderContext): RenderContextTextShaper

Inherited members 3

Inherited from TextShaper.

symbol

clearCache

shape
classTextMeasurementManager: Owns reusable semantic text measurements for one editor runtime.

constructorTextMeasurementManager(textShaper: TextShaper): TextMeasurementManager

propertyreadonly symbol: typeof symbolstatic

DI token for resolving the editor-local text measurement manager.

methodclear(): void

Clears semantic measurements without taking ownership of the text shaper.

methodmeasureSpace(font: string): TextShapeResult

Measures one space for a font and reuses the editor-local result.
classTextShaper: Abstract adapter boundary for HarfBuzz, Skia, browser-native, or platform text-shaping implementations.

Concrete adapters translate the normalized request to their shaping library and return engine-neutral glyph/cluster data.

constructorTextShaper(): TextShaper

propertyreadonly symbol: symbolstatic

DI token for resolving the editor-local text-shaper provider.

methodclearCache(): void

Clears all cached shaping results owned by this adapter.

methodshape(input: TextShapeInput): TextShapeResult

Shapes one homogeneous text run, reusing an identical cached request.
classWebTextShaper: class WebTextShaper extends TextShaper

Browser-native TextShaper backed by Canvas2D.

Canvas2D preserves the browser's native shaping for complete text runs but does not expose glyph ids or glyph ranges. Results therefore contain grapheme clusters and caret measurements while leaving glyphs empty. Call clearCache() after an asynchronously loaded font becomes available.

constructorWebTextShaper(context: WebTextShaperContext): WebTextShaper

Creates a Web text shaper over a host-owned Canvas2D context.

Inherited members 3

Inherited from TextShaper.

symbol

clearCache

shape
classWebTextShaperError: class WebTextShaperError extends SearError

Error raised when a Web text-shaping request cannot be represented by Canvas2D.

constructorWebTextShaperError(message: string, details?: SearErrorDetails): WebTextShaperError

Creates a Web text-shaper error with stable diagnostics.

propertyreadonly code: "WEB_TEXT_SHAPER_ERROR"

Stable machine-readable identifier for this error category.

Inherited members 9

Inherited from SearError.

cause

details

message

name

stack

stackTraceLimit

report

captureStackTrace

prepareStackTrace
interfaceWebTextShaperContext: Native text settings and operations required by the Web adapter.

propertydirection: CanvasDirection

propertyfont: string

propertyfontKerning?: CanvasFontKerning

methodmeasureText(text: string): TextMetrics

methodrestore(): void

methodsave(): void
functioncreateWebTextShaperContext: createWebTextShaperContext(renderContext: RenderContext): WebTextShaperContext

Adapts the shared render context to the Web shaper contract.

Shape and font values

interfaceFontDescriptorInput: Structured font values supplied by editor configuration and host contexts.

propertyreadonly fontFamily: string

propertyreadonly fontSize: number
interfaceShapedCaretStop: A logical caret boundary produced by the shaping implementation.

propertyreadonly textOffset: number

UTF-16 source-text offset for this caret boundary.

propertyreadonly x: number

Advance position in the shaped run's logical direction.
interfaceShapedGlyph: One positioned glyph returned by a text-shaping implementation.

propertyreadonly cluster: number

UTF-16 offset of the source text cluster represented by this glyph.

propertyreadonly glyphId: number

propertyreadonly xAdvance: number

propertyreadonly xOffset: number

propertyreadonly yAdvance: number

propertyreadonly yOffset: number
interfaceShapedTextCluster: Mapping between source text and the glyph range generated for it.

propertyreadonly glyphEnd: number

propertyreadonly glyphStart: number

propertyreadonly textEnd: number

propertyreadonly textStart: number
interfaceTextShapeInput: Input passed to a text-shaper implementation. Offsets are UTF-16 offsets.

propertyreadonly direction?: TextShapeDirection

propertyreadonly features?: Readonly<Record<string, TextShapeFeatureValue>>

Explicit OpenType feature settings, for example { liga: true, kern: true }.

propertyreadonly font: string

Font descriptor understood by the selected shaping implementation.

propertyreadonly language?: string

ISO/BCP language tag, when known.

propertyreadonly script?: string

OpenType script tag, when known.

propertyreadonly text: string

propertyreadonly variations?: Readonly<Record<string, number>>

Variation-axis values for variable fonts, keyed by four-character axis tag.
interfaceTextShapeResult: Engine-neutral result of shaping one homogeneous text run.

propertyreadonly caretStops: readonly ShapedCaretStop[]

propertyreadonly clusters: readonly ShapedTextCluster[]

propertyreadonly fontAscent?: number

propertyreadonly fontDescent?: number

propertyreadonly fontLineGap?: number

propertyreadonly glyphs: readonly ShapedGlyph[]

propertyreadonly height: number

Total vertical advance, normally zero for horizontal text.

propertyreadonly width: number

Total horizontal advance of the shaped run.
typeTextShapeDirection: type TextShapeDirection = "ltr" | "rtl"

Direction of a shaped text run in logical document order.
typeTextShapeFeatureValue: type TextShapeFeatureValue = boolean | number

OpenType feature value accepted by a text-shaper adapter.
functioncreateFontDescriptor: createFontDescriptor(input: FontDescriptorInput): string

Creates the low-level font descriptor consumed by text shaping and rendering.