opentype.js (parse only)

This fork contains a light-weight version of opentype.js that only parses OpenType/TrueType/WOFF font buffers and returns metadata. There are no drawing helpers, glyph constructors, or layout utilities—parse() is the entire public API.

Installation

npm install @lvcabral/opentype.js

Usage

import { readFileSync } from 'fs';
import { parse } from '@lvcabral/opentype.js';

const data = readFileSync('./test/fonts/Roboto-Black.ttf');
const font = parse(data);

console.log(font.unitsPerEm);           // 2048
console.log(font.ascender, font.descender);
console.log(font.tables.head.macStyle);
console.log(font.names.fontFamily.en);

The returned Font object exposes:

• unitsPerEm, ascender, descender
• tables.head and tables.hhea objects exactly as they appear in the font tables
• names, keyed by name ID (e.g. font.names.fullName) with locale entries (BCP-47 tags when available, otherwise the raw 0x#### language ID).

Unsupported table data is ignored. If a required table (head or hhea) is missing the parser throws.

Formats

• TrueType and OpenType fonts (\x00\x01\x00\x00, true, typ1, OTTO)
• WOFF containers (tables are decompressed automatically)
• Format 0/1 name tables encoded in UTF-16

Development

• npm run build – bundles src/opentype.mjs into dist/opentype.module.js (ESM) and dist/opentype.js with sourcemaps for local debugging
• npm run dist – produces the minified distributables dist/opentype.module.min.js and dist/opentype.min.js (with sourcemaps)
• npm test – runs the minimal Mocha suite that loads sample fonts and asserts metadata
• npm run lint – ESLint over the src/ directory

The parser lives in src/opentype.mjs and only depends on:

• src/parse.mjs for DataView helpers
• src/tables/{head,hhea,name}.mjs
• src/[email protected] for WOFF decompression

Test fonts are stored in test/fonts/. Published consumers load from the generated dist/ artifacts (main/module point there).

Versioning

We use SemVer for versioning.

License

MIT

Thanks

We would like to acknowledge the work of others without which opentype.js wouldn't be possible:

• pdf.js: for an awesome implementation of font parsing in the browser.
• FreeType: for the nitty-gritty details and filling in the gaps when the spec was incomplete.
• ttf.js: for hints about the TrueType parsing code.
• CFF-glyphlet-fonts: for a great explanation/implementation of CFF font writing.
• fontkit: for a great implementation of CFF2 parsing and variable font features
• tiny-inflate: for WOFF decompression.
• Microsoft Typography: the go-to reference for all things OpenType.
• Adobe Compact Font Format spec and the Adobe Type 2 Charstring spec: explains the data structures and commands for the CFF glyph format.
• All contributors.