awaforge

tableGdef

AGPL-3.0-onlyRelease 2L4

Table GDEF — Glyph Definition (OT §7.5).

Module tableGdef | Source packages/front/office/fonts/src/table/gdef.js | Deps fontErrors, fontReader, layoutClassDefinitions | Worker-safe yes

Glyph-class metadata for GSUB/GPOS: Base (1), Ligature (2), Mark (3), Component (4). Includes attachList, ligCaretList, markAttachClassDef and — depending on version — markGlyphSetsDef, itemVarStore.

Exports

Symbol Type Description
GDEF_CLASS const Frozen enum { BASE:1, LIGATURE:2, MARK:3, COMPONENT:4 }.
parseGdef function (bytes) => { majorVersion, minorVersion, glyphClassDef, markAttachClassDef, attachListOffset, ligCaretListOffset, markGlyphSetsDefOffset, itemVarStoreOffset }.
tableGdef factory Factory.

Usage

import fw from '@awacloud/fw';
import { fw_require, modules } from '@awacloud/fonts';

for (const m of [...fw_require, ...modules]) fw.runtime.register(m);
const { parseGdef, GDEF_CLASS } = fw.runtime.resolve('tableGdef');
const gdef = parseGdef(sfnt.tables.GDEF.bytes);
const isMark = gdef.glyphClassDef?.lookup(gid) === GDEF_CLASS.MARK;

Notes

  • Versions 1.0 / 1.2 / 1.3 supported (markGlyphSets / itemVarStore offsets are 0 when absent, not undefined).
  • glyphClassDef is the result of parseClassDef (with .lookup).

See also