node-quirc

    2.3.0 • Public • Published

    NPM Version Test

    node-quirc

    A Node.js Addon of the quirc library (QR decoder library - https://github.com/dlbeer/quirc).

    installation

    First, You need libpng and libjpeg (and their header files) installed. Then, simply

    % npm install node-quirc
    

    documentation

    node-quirc aim to be simple to use, the module exposes a decode() function and a constants object.

    decode(img[, callback])

    img must be either a Buffer of a PNG or JPEG encoded image file, or a decoded image in ImageData format with 1 (grayscale), 3 (RGB) or 4 (RGBA) channels.

    When callback is provided, it is expected to be a "classic" Node.js callback function, taking an error as first argument and the result as second argument. Because the provided image file may contains several QR Code, the result is always an array on success.

    When decode is called only with img as argument, a Promise is returned.

    const fs    = require("fs");
    const quirc = require("node-quirc");
    
    // load the image file
    const img = fs.readFileSync("./test/data/Hello+World.png");
    
    // callback version
    quirc.decode(img, (err, codes) => {
        if (err) {
            // handle err.
            console.error(`decode failed: ${err.message}`);
        } else {
            // do something with codes.
            console.dir(codes);
            console.log(codes.map((code) => code.data.toString('utf8')));
        }
    });
    
    // Promise version
    quirc.decode(img).then((codes) => {
        // do something with codes.
    }).catch((err) => {
        // handle err.
    });
    
    // alternatively, use an already-loaded ImageData, e.g. from the `canvas` library
    const context = canvas.getContext('2d');
    const imageData = context.getImageData(0, 0, 800, 600);
    quirc.decode(imageData).then((codes) => {
        // do something with codes.
        console.log(`codes read from ImageData (size=${
            imageData.data.length
        }, width=${imageData.width}, height=${
            imageData.height
        }):`, codes);
    }).catch((err) => {
        // handle err.
    });

    output:

    [
      {
        version: 1,
        ecc_level: 'H',
        mask: 1,
        mode: 'BYTE',
        eci: 'UTF_8',
        data: Buffer [Uint8Array] [ 72, 101, 108, 108, 111 ]
      },
      {
        version: 1,
        ecc_level: 'H',
        mask: 3,
        mode: 'BYTE',
        eci: 'UTF_8',
        data: Buffer [Uint8Array] [ 87, 111, 114, 108, 100 ]
      }
    ]
    [ 'Hello', 'World' ]
    

    constants

    see https://github.com/kAworu/node-quirc/blob/master/index.js#L26-L56

    testing

    Clone the repo and then simply

    % npm install && npm test
    

    license

    MIT, see LICENSE.

    Install

    npm i node-quirc

    DownloadsWeekly Downloads

    168

    Version

    2.3.0

    License

    MIT

    Unpacked Size

    2.25 MB

    Total Files

    43

    Last publish

    Collaborators

    • kaworu