=koder=

QR/bar code scanner for the Browser


:bulb: Demo

https://qr.maslick.tech

🚀 Features

* QR/barcode module implemented in WebAssembly
* Barcode support (UPC-A, UPC-E, EAN-8, EAN-13, I25, CODE-128, CODE-39, CODE-93, CODABAR, DATABAR)
* Uses Zbar C++ library (version 0.23.90)
* Packaged as PWA (caching files with Service Worker, Add to Home Screen)
* Mobile first (can be used on a Laptop as well)
* Multiplatform (iOS, Android, Desktop)
* QR/bar code recognition logic is performed off the browser's Main thread (i.e. Web Worker)
koder* React component supports a jsqr based Web Worker (see jsQrWorker.js)
* Emscripten-zbar-sdk Docker image based on emscripten/emsdk, Dockerfile
* ReactJS component
* Vanilla JS example
* :new: Turn on/off the beep sound
* :new: Support for UPN QR (Slovenia only)
* :new: EU Digital Covid Certificate validator (vaccination, test), works in `offline mode!
* :new: Emscripten v3.1.1
* :new: npm package

⚡ Usage

$3

`shell
npm install --global yarn
yarn install --frozen-lockfile
`

$3

`shell
npm run start
open https://locahost:8080
`

$3

`shell
npm run build # -> build React app into ./public
npm run prod # -> serve static web app on port 8082
open http://localhost:8082
`

⚡ NPM module

`
npm install @maslick/koder
`

`javascript
// CommonJS
const Koder = require('@maslick/koder');

// ES6 modules
import Koder from '@maslick/koder';
`

`javascript
const Koder = require('@maslick/koder');
const {loadImage, createCanvas} = require("canvas");

const getImageData = async (src) => {
const img = await loadImage(src);
const canvas = createCanvas(img.width, img.height);
const ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0);
return {
data: ctx.getImageData(0, 0, img.width, img.height).data,
width: img.width,
height: img.height
};
};

(async () => {
const url = 'https://raw.githubusercontent.com/maslick/koder/master/screenshots/app_1.png';
const koder = await new Koder().initialized;
const {data, width, height} = await getImageData(url);

const t0 = new Date().getTime();
const res = koder.decode(data, width, height);
const t1 = new Date().getTime();

console.log(Scanned in ${t1-t0} ms); // Scanned in 7 ms
console.log(res); // http://en.m.wikipedia.org
})();
`

:spades: Development

$3


`shell
docker pull maslick/emscripten-zbar-sdk
docker build -t maslick/emscripten-zbar-sdk -f docker/Dockerfile docker
`

$3

`shell

React app

docker run \
-e INPUT_FILE=zbar/qr.cpp \
-e OUTPUT_FILE=zbar \
-e OUTPUT_DIR=public/wasm \
-v $(pwd):/app \
maslick/emscripten-zbar-sdk make -B
`

$3

`shell

React app

OUTPUT_DIR=public/wasm OUTPUT_FILE=zbar make clean
``

🔭 References

* WebAssembly at Ebay
* Barcode Scanner WebAssembly
* zbar.wasm