AztecEx

Pure Elixir library for encoding and decoding Aztec 2D barcodes per ISO/IEC 24778:2024.

No external dependencies or NIFs -- works everywhere Elixir runs.

Features

Encode arbitrary binary data into an Aztec symbol (compact or full-range)
Decode an Aztec symbol back to the original data
Reed-Solomon error correction (encode and decode) over GF(2^p)
SVG and text/Unicode renderers included
Supports all 5 encoding modes (Upper, Lower, Mixed, Punctuation, Digit) with optimal mode switching via dynamic programming
Configurable error correction level, symbol size, and render options

Installation

Add aztec_ex to your list of dependencies in mix.exs:

def deps do
  [
    {:aztec_ex, "~> 0.1.0"}
  ]
end

Quick Start

Encode

{:ok, code} = AztecEx.encode("Hello World")
# => %AztecEx.Code{compact: true, layers: 2, size: 19, ...}

Decode

{:ok, data} = AztecEx.decode(code.matrix)
# => "Hello World"

Render as SVG

svg = AztecEx.to_svg(code, module_size: 4, margin: 2)
File.write!("barcode.svg", svg)

Render as text (terminal)

IO.puts(AztecEx.to_text(code))

Options

Encoding

Option	Type	Default	Description
`:error_correction`	`float`	`0.23`	Minimum error correction ratio
`:min_layers`	`integer`	—	Minimum number of data layers
`:compact`	`boolean`	auto	Force compact (`true`) or full-range (`false`)

SVG Rendering

Option	Type	Default	Description
`:module_size`	`integer`	`4`	Pixel size of each module
`:margin`	`integer`	`1`	Quiet zone modules around symbol
`:dark_color`	`string`	`"#000000"`	Color for dark modules
`:light_color`	`string`	`"#FFFFFF"`	Color for light modules

Text Rendering

Option	Type	Default	Description
`:dark`	`string`	`"██"`	Character(s) for dark module
`:light`	`string`	`" "`	Character(s) for light module
`:newline`	`string`	`"\n"`	Line separator

Architecture

AztecEx.encode/2
  ├── HighLevelEncoder   (data → optimal bitstream)
  ├── BitStuffing        (stuff + pad to codeword boundary)
  ├── ReedSolomon.Encoder (generate check codewords)
  └── Encoder            (symbol layout → BitMatrix)

AztecEx.decode/1
  ├── Decoder            (detect finder, read mode/data)
  ├── ReedSolomon.Decoder (error correction)
  ├── BitStuffing        (unstuff)
  └── HighLevelDecoder   (bitstream → bytes)

License

MIT. See LICENSE for details.