@liquid-js/qr-code-styling

QR Code Styling

JavaScript library for generating QR codes with customizable styling.

Try it here https://styled-qr.liquidjs.io/

Examples

Installation

npm install @liquid-js/qr-code-styling

API Documentation

https://liquid-js.github.io/qr-code-styling/

Usage

Browser

<!doctype html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <title>QR Code Styling</title>
</head>

<body>
    <div id="canvas"></div>
    <button type="button"
        id="dl">Download</button>
    <script type="module">
        import { QRCodeStyling, browserUtils } from 'https://unpkg.com/@liquid-js/qr-code-styling/lib/qr-code-styling.js'

        const qrCode = new QRCodeStyling({
            data: 'https://www.facebook.com/',
            image: 'https://upload.wikimedia.org/wikipedia/commons/5/51/Facebook_f_logo_%282019%29.svg',
            dotsOptions: {
                color: '#4267b2',
                type: 'rounded',
                size: 10
            },
            backgroundOptions: {
                color: '#e9ebee',
                margin: 1
            },
            imageOptions: {
                crossOrigin: 'anonymous',
                margin: 1,
                imageSize: 0.5
            }
        })

        qrCode.append(document.getElementById('canvas'))

        document.getElementById('dl').addEventListener('click', () => {
            browserUtils.download(qrCode, { extension: 'png' }, { width: 1200, height: 1200 })
        })
    </script>
</body>

</html>

Plugins

Version 5.0.0 of the library introduces plugin support to replace the now-deprecated QRCodeStyling.extension, with the ability to customize the shape of dots and corners. Existing extensions can still be applied as plugins: [{ postProcess: extensionFn }].

While the old API only supports a single extension, it is now possible to apply multiple plugins or even multiple instances of a single plugin. For example, to create a QR code with a complex border:

import { BorderPlugin } from '@liquid-js/qr-code-styling/border-plugin'

const qrCode = new QRCodeStyling({
    plugins: [
        new BorderPlugin({
            round: 1,
            size: 2,
            color: '#20c9dc'
        }),
        new BorderPlugin({
            round: 1,
            size: 60,
            color: '#4267b2',
            text: {
                font: 'sans-serif',
                color: '#e9ebee',
                size: 30,
                top: {
                    content: 'Scan the'.toUpperCase()
                },
                bottom: {
                    content: 'QR code'.toUpperCase()
                }
            }
        })
    ]
    // ...other options
})

Plugin development

A simple plugin example to customize QR code dots:

import { svgPath, DrawArgs } from '@liquid-js/qr-code-styling/plugin-utils'

const qrCode = new QRCodeStyling({
    plugins: [
        {
            drawDot: (args: DrawArgs): SVGElement | undefined => {
                const { size, x, y, document } = args

                const element = document.createElementNS('http://www.w3.org/2000/svg', 'path')                
                // Insert your own SVG path definition, or implement neighbour-aware logic through args.getNeighbor()
                element.setAttribute(
                    'd',
                    svgPath`M ${x} ${y + (size - size) / 2}
                  v ${size}
                  h ${size / 2}
                  a ${size / 2} ${size / 2} 0 0 0 0 ${-size}
                  z`
                )

                return element
            }
        },
    ]
    // ...other options
})

See Border plugin and figures for further reference.

Node

⚠️ Note: make sure to install peer dependencies when running on Node (not needed for browser environments)
npm install @liquid-js/qrcode-generator @xmldom/xmldom file-type sharp

import { QRCodeStyling } from '@liquid-js/qr-code-styling'
import { writeFile } from 'fs/promises'
import PDFDocument from 'pdfkit'
import SVGtoPDF from 'svg-to-pdfkit'

const qrCode = new QRCodeStyling({
    data: 'https://www.facebook.com/',
    image: 'https://upload.wikimedia.org/wikipedia/commons/5/51/Facebook_f_logo_%282019%29.svg',
    dotsOptions: {
        color: '#4267b2',
        type: 'rounded',
        size: 10
    },
    backgroundOptions: {
        color: '#e9ebee',
        margin: 1
    },
    imageOptions: {
        crossOrigin: 'anonymous',
        margin: 1,
        imageSize: 0.5
    }
})

const svgCode = await qrCode.serialize()

const { width, height } = qrCode.size
const buffers = []
const doc = new PDFDocument({ size: [width, height] })
doc.on('data', (v) => buffers.push(v))
const buffer = await new Promise((resolve) => {
    doc.on('end', () => {
        resolve(Buffer.concat(buffers))
    })
    SVGtoPDF(doc, svgCode, 0, 0, {
        width,
        height,
        assumePt: true
    })
    doc.end()
})
await writeFile('qr.pdf', buffer)

Kanji support

For Kanji mode to work, import stringToBytesFuncs from @liquid-js/qr-code-styling/kanji and inclue it with config.

import { stringToBytesFuncs } from '@liquid-js/qr-code-styling/kanji'

const qrCode = new QRCodeStyling({
    data: '漢字',
    qrOptions: {
        mode: Mode.kanji
    },
    stringToBytesFuncs
    // ...other options
})

License

MIT License