Pure-Go, zero-dependency TrueType/OpenType text stack.
🌐 Website · 📚 Documentation
go-opentype is a family of pure-Go, CGO_ENABLED=0, standard-library-only
packages that together read a font file, resolve Unicode bidirectional and
complex-script text, and rasterise the result — with no
golang.org/x/* anywhere in the stack. It exists to functionally replace,
for a Go program that blits glyphs into a pixel buffer, the narrow slice of
golang.org/x/image/font a glyph-blitting UI needs, and
golang.org/x/text/unicode/bidi for mixed-direction text. The long-term aim
on the paths it covers is functional parity with the HarfBuzz + FreeType
pair.
| Repo | What it is |
|---|---|
| opentype | the engine — sfnt parsing (all cmap formats, glyf + CFF/CFF2 outlines), GSUB/GPOS/GDEF shaping, variable fonts, TrueType + CFF hinting, the OpenType MATH table, subsetting, and anti-aliased 4×4-supersampled rasterisation |
| bidi | the Unicode Bidirectional Algorithm (UAX #9), stdlib-only, no x/text |
| shape | a HarfBuzz-lite complex-text shaper: Arabic joining, Indic, the Universal Shaping Engine, Egyptian hieroglyphs, Hangul, vertical text, ligatures/marks/kerning — positioned glyphs in visual order |
| fonts | 46 bundled, legible, go:embedded font families — Latin, non-Latin scripts and CJK (Atkinson Hyperlegible default) |
| docs | this documentation site (MkDocs Material, versioned with mike) |
| brand | logo and brand assets |
- Pure Go, zero cgo, zero third-party dependencies. Cross-compiles and
embeds anywhere Go runs, including
GOOS=js GOARCH=wasm— no C toolchain, no vendored assets, no runtime fetch. - Honest about scope. Each repo's support matrix says plainly what's
implemented. CFF/CFF2 outlines, every GSUB/GPOS lookup type with GDEF and
lookup flags, TrueType + CFF hinting, vertical metrics, OpenType Variations
(variable fonts, incl.
HVAR/VVAR/MVAR), the OpenTypeMATHtable and font subsetting are all implemented today — on the paths it covers the engine aims at functional parity with HarfBuzz + FreeType. - Conformance-tested.
bidivalidates against the entire UnicodeBidiCharacterTest.txt;opentypeandshapesynthesise fonts in memory so their test suites never depend on an external.ttf. - 100% test coverage is the target, enforced as a CI gate, green across
6 arches plus
js/wasm,darwin/arm64andwindows/amd64.
opentype parses and rasterises TrueType glyf and CFF/CFF2 outlines with
every GSUB/GPOS lookup type, variable fonts, TrueType + CFF hinting, the
OpenType MATH table and subsetting; bidi implements UAX #9 through rule
L2 with full conformance-test coverage; shape composes both into Arabic,
Indic, Universal Shaping Engine, Egyptian hieroglyph, Hangul, vertical and
Latin/default complex-text shaping; fonts bundles 46 OFL/BSD-licensed
families across Latin, non-Latin scripts and CJK. 100% coverage, CI green
across 6 arches plus js/wasm, darwin/arm64 and windows/amd64.
BSD-3-Clause.