react-qr-reader-rokl

Introduction

A React component for reading QR codes from the webcam. It uses the WebRTC standards for reading webcam data and zxing-js is used for detecting QR codes in that data. To optimise the speed and experience, a web-worker is used to offload the heavy QR code algorithm on a separate process. The web worker is inlined and loaded on creation of the component.

Known Issues

• Server side rendering won't work so only require the component when rendering in a browser environment.
• Due to browser implementations the camera can only be accessed over https or localhost.
• In Firefox a prompt will be shown to the user asking which camera to use, so facingMode will not affect it.
• On IOS 11 it is only supported on Safari and not on Chrome or Firefox due to Apple making the API not available to 3rd party browsers.

Install

npm install --save roklenarcic-reader

Example

import React, { Component } from 'react'
import QrReader from 'roklenarcic-reader'

class Test extends Component {
  state = {
    result: 'No result'
  }

  handleScan = data => {
    if (data) {
      this.setState({
        result: data
      })
    }
  }
  handleError = err => {
    console.error(err)
  }
  render() {
    return (
      <div>
        <QrReader
          delay={300}
          onError={this.handleError}
          onScan={this.handleScan}
          style={{ width: '100%' }}
        />
        <p>{this.state.result}</p>
      </div>
    )
  }
}

Props

Events

Prop	Argument	Description
onScan	result,binary	Scan event handler. Called every scan with the decoded text and decoded bytes or null if no QR code was found.
onError	Error	Called when an error occurs.
onLoad	object	Called when the component is ready for use. Object properties are mirrorVideo: boolean, streamLabel: string
onImageLoad	img onLoad event	Called when the image in legacyMode is loaded.

Options

Prop	Type	Default	Description
delay	number or false	500	The delay between scans in milliseconds. To disable the interval pass in false.
facingMode	user or environment	environment	Specify which camera should be used (if available).
resolution	number	600	The resolution of the video (or image in legacyMode). Larger resolution will increase the accuracy but it will also slow down the processing time.
style	a valid React style	none	Styling for the container element. Warning The preview will always keep its 1:1 aspect ratio.
className	string	none	ClassName for the container element.
showViewFinder	boolean	true	Show or hide the build in view finder. See demo
constraints	object	null	Use custom camera constraints that the override default behavior. MediaTrackConstraints
legacyMode	boolean	false	If the device does not allow camera access (e.g. IOS Browsers, Safari) you can enable legacyMode to allow the user to take a picture (On a mobile device) or use an existing one. To trigger the image dialog just call the method openImageDialog from the parent component. Warning You must call the method from a user action (eg. click event on some element).
characterSet	string	none	Specify character set of the code, like "ISO-8859-2"

Dev

Install dependencies

npm install

Build

npm run build

Demo

npm run storybook

Linting

npm run lint

Tested platforms

• Chrome macOs & Android
• Firefox macOs & Android
• Safari macOs & IOS

License

Copyright (c) 2020 Rok Lenarčič

This file is free software: you may copy, redistribute and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

This file is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see https://www.gnu.org/licenses/.

This project incorporates work covered by the following copyright and
permission notice:

The MIT License (MIT)

Copyright (c) 2018 Thomas Billiet

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

and notice:

The MIT License (MIT)

Copyright (c) 2019 Paulo Cesar

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.