papnkukn / qrcode-svg

A simple QR Code generator in pure JavaScript / node.js library
MIT License
435 stars 93 forks source link

Introduction

This library has been written to generate a SVG image of QR Code in Node.js, goals:

Getting Started

Install the package:

npm install qrcode-svg

Inline example:

var QRCode = require("qrcode-svg");
var svg = new QRCode("Hello World!").svg();

More options:

var qrcode = new QRCode({
  content: "http://github.com/",
  padding: 4,
  width: 256,
  height: 256,
  color: "#000000",
  background: "#ffffff",
  ecl: "M",
});
qrcode.save("sample.svg", function(error) {
  if (error) throw error;
  console.log("Done!");
});

Options

List of options:

Container options:

SVG output

Editable squares

This mode is useful for designers to manipulate with particular squares. Thus, one can open the QR Code in an editor, select particular modules, move around, change color, etc. However, some old SVG viewers may generate minor gaps between the squares - the side effect when rendering an image at certain zoom level.

Default options

var qrcode = new QRCode({
  content: "Pretty Fox",
  join: false,
  predefined: false
});

Output with rect elements

<?xml version="1.0" standalone="yes"?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="256" height="256">
  <rect x="0" y="0" width="256" height="256" style="fill:#ffffff;shape-rendering:crispEdges;"/>
  <rect x="16" y="16" width="8" height="8" style="fill:#000000;shape-rendering:crispEdges;"/>
  <rect x="24" y="16" width="8" height="8" style="fill:#000000;shape-rendering:crispEdges;"/>
  <rect x="32" y="16" width="8" height="8" style="fill:#000000;shape-rendering:crispEdges;"/>
  ...
</svg>

Responsive web page

Squares joined into one path shape produce a compact file size, i.e. 4-5x reduced compared with rect elements. A single path element will result in an optimized rendering, thus not producing any minor gaps between the squares. Also using the container with viewBox attribute may contribute to the responsive scaling on the web.

Set join to true

var qrcode = new QRCode({
  content: "Pretty Fox",
  join: true,
  container: "svg-viewbox" //Useful but not required
});

Output with path element

<?xml version="1.0" standalone="yes"?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 256 256">
  <rect x="0" y="0" width="256" height="256" style="fill:beige;shape-rendering:crispEdges;"/>
  <path x="0" y="0" style="fill:blue;shape-rendering:crispEdges;" d="M35.31,35.31 V44.14 H44.14 V35.31 H35.31 Z..." />
</svg>

Predefined pattern

Algorithm defines the square pattern once before populating a canvas. Useful if you want to generate QR Code with candies. However, some SVG software and converters do not support defs or use elements.

Set predefined to true

var qrcode = new QRCode({
  content: "Pretty Fox",
  predefined: true
});

Output with defs and use elements

<?xml version="1.0" standalone="yes"?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="256" height="256">
  <defs><path id="qrmodule" d="M0 0 h8.827586206896552 v8.827586206896552 H0 z" style="fill:maroon;shape-rendering:crispEdges;" /></defs>
  <rect x="0" y="0" width="256" height="256" style="fill:beige;shape-rendering:crispEdges;"/>
  <use x="35.310344827586206" y="35.310344827586206" href="#qrmodule" />
  <use x="44.13793103448276" y="35.310344827586206" href="#qrmodule" />
  <use x="52.96551724137931" y="35.310344827586206" href="#qrmodule" />
  <use x="61.79310344827586" y="35.310344827586206" href="#qrmodule" />
  <use x="70.62068965517241" y="35.310344827586206" href="#qrmodule" />
  ...
</svg>

Command Line

Usage:
  qrcode-svg [options] <content>

Options:
  --help                 Print this message
  --version, -v          Print version number
  --padding , -p [value] Offset in number of modules
  --width, -w [px]       Image width in pixels
  --height, -h [px]      Image height in pixels
  --color, -fg [color]   Foreground color, hex or name
  --background [color]   Background color, hex or name
  --ecl [value]          Error correction level: L, M, H, Q
  --join                 Join modules into one SVG path, i.e. for crisp rendering
  --predefined           Use 'defs' and 'use' elements in SVG, i.e. for compact output
  --no-prettify          Avoid indenting and new lines in SVG, i.e. for compact output
  --viewbox              Use 'viewBox' instead of 'width' and 'height' attributes
  --swap-fix             Swap X and Y modules to fix issues with some QR readers
  --output, -o [file]    Output file name
  --force, -f            Force overwrite

Examples:
  qrcode-svg http://github.com
  qrcode-svg -f -o hello.svg "Hello World"
  qrcode-svg -p 4 -w 256 -h 256 --join --viewbox "Responsive..."
  qrcode-svg --padding 2 --width 120 --height 120 "Little fox..."
  qrcode-svg --color blue --background #ececec "...jumps over" 

Usage Scenarios

Convert to other formats

Using html-pdf to convert SVG to PDF (or PNG or JPEG)

var QRCode = require('qrcode-svg');
var svg = new QRCode('hello').svg();
...
var pdf = require('html-pdf');
pdf.create(svg, { border: 0, type: 'pdf' }).toFile('output.pdf', function(err, res) {
  ...
});

ASCII modules

QR Code in ASCII to output in a shell

var QRCode = require('qrcode-svg');

var hello = new QRCode("Hello World!");
var modules = hello.qrcode.modules;

var ascii = '';
var length = modules.length;
for (var y = 0; y < length; y++) {
  for (var x = 0; x < length; x++) {
    var module = modules[x][y];
    ascii += (module ? 'x' : ' ');
  }
  ascii += '\r\n';
}
console.log(ascii);

    xxxxxxx xx    x x xxxxxxx
    x     x  xxxx x x x     x
    x xxx x xx  xx  x x xxx x
    x xxx x       xx  x xxx x
    x xxx x  x   x  x x xxx x
    x     x  x  xx xx x     x
    xxxxxxx x x x x x xxxxxxx
            xx     xx        
    x x  xx    x x   xx   x x
       x x  xx x    xx x xx x
     x  x xx   x x x  xx   xx
     x xx  xxx xx x x  x  x x
     xx  xxxx       xxxx    x
    x x  x xx x xx xx x xx xx
    x    xx   xxxx    xxxx   
    xx xx   x  x  x x xx    x
       xxxx xxxx    xxxxxx  x
                    x   x x  
    xxxxxxx  x  xxx x x x   x
    x     x xxx  x xx   x  x 
    x xxx x        xxxxxxxxxx
    x xxx x  xxxxxxxxx  x xx 
    x xxx x xxx  xx  x    x x
    x     x    x    x     x  
    xxxxxxx xxx xxx   x   x x

Web browser

Use on a HTML page with JavaScript

<!DOCTYPE html>
<html>
<body>
<div id="container"></div>
<script src="https://github.com/papnkukn/qrcode-svg/raw/master/dist/qrcode.min.js"></script>
<script>
var qrcode = new QRCode({
  content: "Hello World!",
  container: "svg-viewbox", //Responsive use
  join: true //Crisp rendering and 4-5x reduced file size
});
var svg = qrcode.svg();
document.getElementById("container").innerHTML = svg;
</script>
</body>
</html>

Thanks

Thanks to davidshimjs for the base library.

Thanks to Kazuhiko Arase for the original QR Code in JavaScript algorithm.

Thanks to all contributors on the GitHub.

Legal notice

Licensed under the MIT license:
http://www.opensource.org/licenses/mit-license.php

The word "QR Code" is registered trademark of DENSO WAVE INCORPORATED
http://www.denso-wave.com/qrcode/faqpatent-e.html