# ex_bardecode

Unofficial Elixir NIF for [Softek Barcode Reader Toolkit](http://www.bardecode.com/en1/app/linux/).

## Installation

If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `bardecode` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:ex_bardecode, "~> 0.8.0"}
  ]
end
```

Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at [https://hexdocs.pm/ex_bardecode](https://hexdocs.pm/ex_bardecode).

## Usage

Bardecode exposes three functions for reading barcodes from different sources.

* `read_barcode` reads from the specified image file (JPEG or TIFF)
* `read_barcode_from_bitmap` decodes JPEG data from an in-memory binary
* `read_barcode_from_data_url` performs base64 decoding from a data_url formatted string and then decodes JPEG data.

```elixir
Bardecode.read_barcode(
  "barcode.jpg",
  %{
    license: "license key", 
    type: [:pdf417, :code128],
    multiple: true
  }
)
```

The options map is the same for all three functions.

* `license` string for SoftTek (optional). If no license is specified, the last three characters of barcodes will be replaced with ???. A 30 day license can be obtained from sales@bardecode.com.
* `type` is a list of barcodes to look for. By default it looks for all types, but this is slower than specifying specific types. Valid types are [:codabar, :code39, :code128, :code25, :ean13, :ean8, :upca, :upce, :pdf417, :datamatrix].
* `multiple` will wait to find multiple barcodes if `true`. By default (`false`) it returns as soon as one barcode of any type is found.
* `max_threads` can be used to limit the number of threads used. The default (0) determines the number based on the number of CPU cores available.
* `timeout` is the maximum time in milliseconds, the default is 5000 (more of a suggestion).
* `noise_reduction` increases the chances of finding a barcode in a poor quality image but also increases the time taken to process an image, default is 0 (off).
* `despeckle` increases the chances of finding a barcode in a poor quality image but also increases the time taken to process an image, default is 0 (off).

## Resources

* Softek Barcode Toolkit documentation included in [the download](http://www.bardecode.com/en1/app/linux/)
* [Erlang Native Implemented Functions](http://erlang.org/doc/man/erl_nif.html) (NIF)
* [Using C from Elixir with NIFs](https://andrealeopardi.com/posts/using-c-from-elixir-with-nifs/)
* [libjpeg](http://ijg.org) download contains an example.c