qrious

v4.0.2

Published

2 years ago

Library for QR code generation using canvas

Downloads

215,414

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neocotic

qr code encode canvas image

 .d88888b.  8888888b.  d8b
d88P" "Y88b 888   Y88b Y8P
888     888 888    888
888     888 888   d88P 888  .d88b.  888  888 .d8888b
888     888 8888888P"  888 d88""88b 888  888 88K
888 Y8b 888 888 T88b   888 888  888 888  888 "Y8888b.
Y88b.Y8b88P 888  T88b  888 Y88..88P Y88b 888      X88
 "Y888888"  888   T88b 888  "Y88P"   "Y88888  88888P'
       Y8b

QRious is a pure JavaScript library for generating QR codes using HTML5 canvas.

Install

Install using the package manager for your desired environment(s):

$ npm install --save qrious
# OR:
$ bower install --save qrious

If you want to simply download the file to be used in the browser you can find them below:

Development Version (71kb - Source Map)
Production Version (18kb - Source Map)

Check out node-qrious if you want to install it for use within Node.js.

Examples

<!DOCTYPE html>
<html>
  <body>
    <canvas id="qr"></canvas>

    <script src="/path/to/qrious.js"></script>
    <script>
      (function() {
        var qr = new QRious({
          element: document.getElementById('qr'),
          value: 'https://github.com/neocotic/qrious'
        });
      })();
    </script>
  </body>
</html>

Open up demo.html in your browser to play around a bit.

API

Simply create an instance of QRious and you've done most of the work. You can control many aspects of the QR code using the following fields on your instance:

| Field | Type | Description | Default | Read Only | | --------------- | ------- | -------------------------------------------------- | ------------- | --------- | | background | String | Background color of the QR code | "white" | No | | backgroundAlpha | Number | Background alpha of the QR code | 1.0 | No | | element | Element | Element to render the QR code | <canvas> | Yes | | foreground | String | Foreground color of the QR code | "black" | No | | foregroundAlpha | Number | Foreground alpha of the QR code | 1.0 | No | | level | String | Error correction level of the QR code (L, M, Q, H) | "L" | No | | mime | String | MIME type used to render the image for the QR code | "image/png" | No | | padding | Number | Padding for the QR code (pixels) | null (auto) | No | | size | Number | Size of the QR code (pixels) | 100 | No | | value | String | Value encoded within the QR code | "" | No |

var qr = new QRious();
qr.background = 'green';
qr.backgroundAlpha = 0.8;
qr.foreground = 'blue';
qr.foregroundAlpha = 0.8;
qr.level = 'H';
qr.padding = 25;
qr.size = 500;
qr.value = 'https://github.com/neocotic/qrious';

The QR code will automatically update when you change one of these fields, so be wary when you plan on changing lots of fields at the same time. You probably want to make a single call to set(options) instead as it will only update the QR code once:

var qr = new QRious();
qr.set({
  background: 'green',
  backgroundAlpha: 0.8,
  foreground: 'blue',
  foregroundAlpha: 0.8,
  level: 'H',
  padding: 25,
  size: 500,
  value: 'https://github.com/neocotic/qrious'
});

These can also be passed as options to the constructor itself:

var qr = new QRious({
  background: 'green',
  backgroundAlpha: 0.8,
  foreground: 'blue',
  foregroundAlpha: 0.8,
  level: 'H',
  padding: 25,
  size: 500,
  value: 'https://github.com/neocotic/qrious'
});

You can also pass in an element option to the constructor which can be used to generate the QR code using an existing DOM element, which is the only time that you can specify read only options. element must either be a <canvas> element or an <img> element which can then be accessed via the canvas or image fields on the instance respectively. An element will be created for whichever one isn't provided or for both if no element is specified, which means that they can be appended to the document at a later time.

var qr = new QRious({
  element: document.querySelector('canvas'),
  value: 'https://github.com/neocotic/qrious'
});

qr.canvas.parentNode.appendChild(qr.image);

A reference to the QRious instance is also stored on both of the elements for convenience.

var canvas = document.querySelector('canvas');
var qr = new QRious({
  element: canvas,
  value: 'https://github.com/neocotic/qrious'
});

qr === canvas.qrious;
//=> true

`toDataURL([mime])`

Generates a base64 encoded data URI for the QR code. If you don't specify a MIME type, it will default to the one passed to the constructor as an option or the default value for the mime option.

var qr = new QRious({
  value: 'https://github.com/neocotic/qrious'
});

qr.toDataURL();
//=> "data:image/png;base64,iVBOR...AIpqDnseH86KAAAAAElFTkSuQmCC"
qr.toDataURL('image/jpeg');
//=> "data:image/jpeg;base64,/9j/...xqAqIqgKFAAAAAq3RRQAUUUUAf/Z"

Migrating from older versions

If you've been using an older major version and would like details on what's changed and information on how to migrate to the latest major release below:

https://github.com/neocotic/qrious/wiki/Migrating-from-older-versions

Bugs

If you have any problems with QRious or would like to see changes currently in development you can do so here. Core features and issues are maintained separately here.

Contributors

If you want to contribute, you're a legend! Information on how you can do so can be found in CONTRIBUTING.md. We want your suggestions and pull requests!

A list of QRious contributors can be found in AUTHORS.md.

License

See LICENSE.md for more information on our GPLv3 license.

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