# escpos

[![Package Version](https://img.shields.io/hexpm/v/escpos)](https://hex.pm/packages/escpos)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/escpos/)

ESC/POS library for Gleam.

Implements a subset of ESC/POS commands for controlling receipt printers.

[ESC/POS Specification](https://download4.epson.biz/sec_pubs/pos/reference_en/escpos/commands.html)

```sh
gleam add escpos@1
```

## Usage

### Declarative API

The `escpos/document` module provides a high-level declarative API:

```gleam
import escpos/document.{bold, cut, justify, line, styled, text, Center}
import escpos/printer

pub fn main() {
  let assert Ok(printer) = printer.device("/dev/usb/lp0")

  document.render([
    styled([justify(Center), bold()], [
      line([text("Receipt")]),
    ]),
    line([text("Item 1 ... $5.00")]),
    line([text("Item 2 ... $3.50")]),
    cut(),
  ])
  |> printer.print(printer)
}
```

### Imperative API

The `escpos` module provides a lower-level builder-style API:

```gleam
import escpos.{Center, Left}
import escpos/printer

pub fn main() {
  let assert Ok(printer) = printer.device("/dev/usb/lp0")

  escpos.new()
  |> escpos.reset()
  |> escpos.align(Center)
  |> escpos.bold(True)
  |> escpos.writeln("Receipt")
  |> escpos.bold(False)
  |> escpos.align(Left)
  |> escpos.writeln("Item 1 ... $5.00")
  |> escpos.writeln("Item 2 ... $3.50")
  |> escpos.line_feed(3)
  |> escpos.cut()
  |> printer.print(printer)
}
```

Further documentation can be found at <https://hexdocs.pm/escpos>.

## Development

```sh
gleam run   # Run the project
gleam dev   # Experiment with a printer
gleam test  # Run the tests
```

## Todo

- Some way to justify between text, work in `justify-between` branch