vyaz-monorepo / core/src / FontMetricsProvider

Class: FontMetricsProvider

Defined in: core/src/measure/FontMetricsProvider.ts:115

Font metrics provider — registers, resolves, and measures fonts.

Public API (stable):

• registerFont()
• getMetrics()
• getFont()
• setMode() / getMode()

Semi-stable (@beta — may change with notice):

• waitForPendingRegistrations()
• getRegisteredFamilies()
• getFamilyVariants()

Everything else is internal.

Implements

• IFontMetricsProvider

Constructors

Constructor

new FontMetricsProvider(): FontMetricsProvider

Returns

FontMetricsProvider

Methods

getFamilyVariants()

getFamilyVariants(family): string[]

Defined in: core/src/measure/FontMetricsProvider.ts:258

Beta

Get all variant keys registered for a given family. Returns empty array if family not found.

— may change with notice

Parameters

family

string

Returns

string[]

---

getFont()

getFont(family, weight?, style?): FontFace | undefined

Defined in: core/src/measure/FontMetricsProvider.ts:269

Get font engine FontFace for per-character calculations. Uses the same smart fallback logic as getMetrics().

Parameters

family

string

weight?

string = 'normal'

style?

string = 'normal'

Returns

FontFace | undefined

---

getMetrics()

getMetrics(fontFamily, fontSize, weight?, style?, mode?): FontMetrics

Defined in: core/src/measure/FontMetricsProvider.ts:362

Get pixel-scale metrics for a given font family, size, weight, and style.

Resolution order:

1. FontEngine (fontkit) from registry — with smart weight/style fallback
2. Canvas TextMetrics (browser fallback when fontkit unavailable)

Parameters

fontFamily

string

fontSize

number

weight?

string = 'normal'

style?

string = 'normal'

mode?

"browser" | "office"

Returns

FontMetrics

Throws

FontNotFoundError when font is neither registered nor available via Canvas

Implementation of

IFontMetricsProvider.getMetrics

---

getMode()

getMode(): "browser" | "office"

Defined in: core/src/measure/FontMetricsProvider.ts:164

Get current measurement mode.

Returns

"browser" | "office"

Implementation of

IFontMetricsProvider.getMode

---

getRegisteredFamilies()

getRegisteredFamilies(): string[]

Defined in: core/src/measure/FontMetricsProvider.ts:248

Beta

List all families registered in the provider.

— may change with notice

Returns

string[]

---

registerFont()

registerFont(family, options, source, sourcePath?): Promise<void>

Defined in: core/src/measure/FontMetricsProvider.ts:180

Register a binary font for use with fontkit.

In both Node.js and browser the font is loaded via FontEngine. In the browser the caller must provide font bytes (e.g. fetched via getFontBuffer() from ../utils/font.js).

Parameters

family

string

options

style?

string

variation?

Record<string, number>

weight?

string

source

string | ArrayBuffer | Uint8Array<ArrayBufferLike>

Font file bytes (ArrayBuffer / Uint8Array), or a URL string

sourcePath?

string

Optional filesystem path (used for @napi-rs/canvas in Node.js)

Returns

Promise<void>

Implementation of

IFontMetricsProvider.registerFont

---

setMode()

setMode(mode): void

Defined in: core/src/measure/FontMetricsProvider.ts:154

Set measurement mode.

• 'browser' — hhea.ascender/descender (default)
• 'office' — OS/2.usWinAscent/usWinDescent

Parameters

mode

"browser" | "office"

Returns

void

Implementation of

IFontMetricsProvider.setMode

---

waitForPendingRegistrations()

waitForPendingRegistrations(): Promise<void>

Defined in: core/src/measure/FontMetricsProvider.ts:237

Beta

Wait for all in-flight font registrations to complete. Useful after a batch of registerFont() calls before layout.

— may change with notice

Returns

Promise<void>