How to read QR code using iPad camera on website?

J888 picture J888 · May 29, 2013 · Viewed 8.4k times · Source

I am using the following code to access the camera but aim is to read QR codes using camera. Using the following code I can only take the picture and save it then using my backend read the QR code from the saved file.

How can I modify the code to process the picture while the camera is reading. Or something like sending the streams to the back-end and once the QR code is detected it notifies the user.

I need to work with a tablet.

I can use the following to record videos as well but how to send the streams to back-end

 <input type="file" capture="camera" accept="video/*">

My code to take pictures

<!DOCTYPE HTML>
<html>
    <head>
    <meta name="viewport" content="width=320; user-scalable=no" />
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title>ColorThief Demo</title>

    <script type="text/javascript" charset="utf-8" src="jquery-2.0.0.min.js"></script>
    <script type="text/javascript" charset="utf-8" src="quantize.js"></script>
    <script type="text/javascript" charset="utf-8" src="color-thief.js"></script>

    <style>
    #yourimage {
        width:100%; 
    }

    #swatches {
        width: 100%;
        height: 50px;   
    }

    .swatch {
        width:18%;
        height: 50px;
        border-style:solid;
        border-width:thin;  
        float: left;
        margin-right: 3px;  
    }
    </style>
    </head>

    <body>

        <input type="file" capture="camera" accept="image/*" id="takePictureField">
        <img id="yourimage">

        <div id="swatches">
            <div id="swatch0" class="swatch"></div>
            <div id="swatch1" class="swatch"></div>
            <div id="swatch2" class="swatch"></div>
            <div id="swatch3" class="swatch"></div>
            <div id="swatch4" class="swatch"></div>
        </div>

    <script>
    var desiredWidth;

    $(document).ready(function() {
        console.log('onReady');
        $("#takePictureField").on("change",gotPic);
        $("#yourimage").load(getSwatches);
        desiredWidth = window.innerWidth;

        if(!("url" in window) && ("webkitURL" in window)) {
            window.URL = window.webkitURL;   
        }

    });

    function getSwatches(){
        var colorArr = createPalette($("#yourimage"), 5);
        for (var i = 0; i < Math.min(5, colorArr.length); i++) {
            $("#swatch"+i).css("background-color","rgb("+colorArr[i][0]+","+colorArr[i][1]+","+colorArr[i][2]+")");
            console.log($("#swatch"+i).css("background-color"));
        }
    }   

    //Credit: https://www.youtube.com/watch?v=EPYnGFEcis4&feature=youtube_gdata_player
    function gotPic(event) {
        if(event.target.files.length == 1 && 
           event.target.files[0].type.indexOf("image/") == 0) {
            $("#yourimage").attr("src",URL.createObjectURL(event.target.files[0]));
        }
    }



    </script>    
    </body>

</html>

Answer

mb21 picture mb21 · Jun 14, 2013

Capturing the video and sending it to the server will be prohibitively bandwidth-intensive on a mobile device. I would give jsqrcode a try and do it all client-side in JavaScript. Also, see this answer.