awaforge

fontCompositeResolve

AGPL-3.0-onlyRelease 2L4

Recursive flattening of a composite glyph into a single Path.

Module fontCompositeResolve | Source packages/front/office/fonts/src/glyph/compositeResolve.js | Deps fontErrors, fontPath | Worker-safe yes

Follows OT spec §glyf composite description: each component references a glyph by index, applies a 2×2 F2Dot14 transform + XY offset (ARGS_ARE_XY_VALUES mode) to it, and concatenates its commands onto the result path. The point-to-point (anchor) mode falls back to a (0, 0) offset — rarely used in practice.

Resolve

const { resolveGlyphPath, MAX_DEPTH } = runtime.resolve('fontCompositeResolve');

API

Method Signature Returns
resolveGlyphPath (glyphs: Array, index: number, visited?: Set, depth?: number) => Path Flattened path, ready to render.
MAX_DEPTH number 16 — nesting cap beyond which RenderError is thrown.

Behavior

  • null glyph ⇒ empty Path.
  • kind === 'simple' ⇒ delegates to pathFromSimpleGlyph.
  • kind === 'composite' ⇒ iterates components, applies transform + offset, concatenates.
  • Unknown kind ⇒ RenderError('fonts/composite-bad-kind').
  • Cycle detected ⇒ RenderError('fonts/composite-cycle').
  • Depth > 16 ⇒ RenderError('fonts/composite-depth').

Examples

const { resolveGlyphPath } = runtime.resolve('fontCompositeResolve');
const path = resolveGlyphPath(glyphTable, 42);
console.log(path.toSvgPath());

Notes

  • The OT spec mandates ≤ 4 nesting levels, but real-world fonts occasionally exceed it — this module accepts up to 16 to stay pragmatic.
  • Flattening is lazy per call: font.getGlyphByIndex triggers it on every access, no memoization.
  • Out-of-range index or non-array input throws ContractError.

See also