glqr

gleam add glqr

Display QR Code

import gleam/io
import glqr as qr

pub fn main() -> Nil {
  let assert Ok(code) =
    qr.new("HELLO WORLD")
    |> qr.generate()

  code
  |> qr.to_printable()
  |> io.println() // YOU CANT USE ECHO AS IT PRESERVES THE NEWLINE
}

Config Options

• Error Correction Level

  • L (Low, 7% of damage to image be restored)
  • M (Medium, 15% of damage to image be restored)
  • Q (Quartile, 25% of damage to image be restored)
  • H (High, 30% of damage to image be restored)

• Minimum Version (1-40, default is 1)

  • Version 1: 21x21 matrix
  • Version 40: 177x177 matrix

import gleam/io
import glqr as qr

pub fn main() -> Nil {
  let assert Ok(code) =
    qr.new("HELLO WORLD")
    |> qr.error_correction(qr.L)
    |> qr.min_version(10)
    |> qr.generate()

  code
  |> qr.to_printable()
  |> io.println() // YOU CANT USE ECHO AS IT PRESERVES THE NEWLINE
}

Save SVG

import glqr as qr
import simplifile

pub fn main() -> Nil {
  let assert Ok(code) =
    qr.new("HELLO WORLD")
    |> qr.generate()

  let svg =
    code
    |> qr.to_svg()

  let assert Ok(_) = simplifile.write("output.svg", svg)
  Nil
}

Simple Lustre Example

import gleam/int
import glqr
import lustre
import lustre/attribute
import lustre/element

fn render_qr(value: String, size: Int) {
  let assert Ok(matrix) =
    glqr.new(value)
    |> glqr.generate()

  let svg = glqr.to_svg(matrix)

  lustre.element(element.unsafe_raw_html(
    "",
    "div",
    [attribute.style("max-width", int.to_string(size) <> "px")],
    svg,
  ))
}

pub fn main() {
  let app = render_qr("https://github.com/lustre-labs/lustre", 150)
  let assert Ok(_) = lustre.start(app, "#app", Nil)

  Nil
}

Further documentation can be found at https://hexdocs.pm/glqr.

Development

gleam run   # Run the project
gleam test  # Run the tests

TODO

• Import as local module
• Data Analysis
  • Numeric
  • Alphanumeric
  • Byte
  • Kanji
• Data Encoding
  • Mode Indicator
  • Character Count Indicator
  • Data Bits
  • Terminator
  • Pad Bits
• Error correction
• QR Code Structure
• Draw Matrix
• Add Snapshot Testing
• Add more Snapshot testing
• Add Lustre example
• Use matrix with custom QrCode type with bitarray instead of list of lists
• Add to_bits feature

References

Thonky’s QR Code Tutorial

IODevs elixir qr code library

SiliconJungles elixir qr code library

Nayuki QR Code Step by Step

Gears BitArray Blog Post