jabcode

JAB Code (experimental)

JAB Code (Just Another Barcode, ISO/IEC 23634:2022) is a full-colour 2D matrix barcode developed by Fraunhofer SIT: instead of black-and-white modules, each module carries one of several colours, so a symbol packs several bits per module rather than one. Like KarTrak, it needs a colour grid, not a BitMatrix, so it is documented, wired and tested separately.

This format is not reachable through encode(), decode(), listFormats() or the formats: allow-list, for the same reason as KarTrak: it produces/consumes a PolychromeMatrix, not a BitMatrix. See docs/COLOR_PIPELINE_NOTES.md for the shared colour infrastructure, and docs/JABCODE_NOTES.md for this format's own verification notes and honest limits — read that file before relying on this module for anything beyond its own round trip.

What is implemented, and what is not

This module implements one real, deliberately scoped configuration of the format — the reference encoder's own "default mode" fast path — not the full ISO specification.

Capability	Status
Single master symbol, 8 colours, ECC level 3 (default mode)	✅ Full
Byte-mode data encoding (any byte payload)	✅ Full
LDPC error correction (hard-decision decode)	✅ Full, self-consistency tested — see docs/JABCODE_NOTES.md for what "full" does not mean here
Decoding a PolychromeMatrix you already have	✅ Full
Decoding from a raw image, given known symbol corners	✅ Full — PerspectiveTransform + classifyGrid, the same known-geometry approach as KarTrak
Locating a symbol in an arbitrary photo	❌ Not implemented — no detector exists for this format yet
Text-mode compaction (upper/lower/numeric/punct/mixed/alphanumeric)	❌ Not implemented — byte mode alone can always encode any input (the reference's own comment), so this is a capacity/efficiency gap, not a correctness one
Metadata Part I/Part II, cascaded slave symbols, non-default colour counts or ECC levels, mask-pattern optimisation search	❌ Not implemented — all skipped by design along with default mode itself
Live palette calibration from a photographed symbol	❌ Not implemented — decoding classifies against the fixed default palette, like KarTrak
Verified interop with the real jabcode reference encoder/decoder	❌ Not done — no compiler or working reference build was available; see docs/JABCODE_NOTES.md

Writing

import { encodeJABCode } from '@sythos/js_barcode_universal/jabcode';

const matrix = encodeJABCode(new TextEncoder().encode('Hello, JAB Code!'));

console.log(matrix.jabcode);
// { version: 1, payloadLength: 16 }

matrix is a PolychromeMatrix, not a BitMatrix: a square grid whose side is 4 * version + 17 modules, version chosen automatically as the smallest side-version (1-32) whose net LDPC capacity fits the encoded payload. Render it with the colour renderer:

import { toColorImageData } from '@sythos/js_barcode_universal/jabcode';

const image = toColorImageData(matrix, { scale: 8, margin: 4 });
// { data: Uint8ClampedArray, width, height } — draw to a canvas as usual.

A single byte-mode segment tops out at 8207 bytes (encodeJABCode throws past that) — moot in practice, since no side-version's real capacity gets anywhere near that many bytes anyway (version 32's net capacity is around 4.2 KB).

Reading

import { decodeJABCode, decodeJABCodeMatrix } from '@sythos/js_barcode_universal/jabcode';

// Decode a PolychromeMatrix you already have (e.g. your own round trip).
const fromMatrix = decodeJABCodeMatrix(matrix);

// Decode a raw RGBA image, given the symbol's four corners and version —
// known geometry, like KarTrak; there is no detector for this format.
const fromImage = decodeJABCode(image, {
  topLeft: { x, y }, topRight: { x, y },
  bottomRight: { x, y }, bottomLeft: { x, y },
}, matrix.jabcode.version);

Both return the decoded payload as a Uint8Array.

Provenance

JAB Code's reference implementation (github.com/jabcode/jabcode) was consulted directly, read in full for the pieces this module implements, and used only to understand the format — no code from it is copied into this SDK. See licenses/jab-code.license for the license history and patent position, and docs/JABCODE_NOTES.md for exactly what was verified and how.