MinifyJpegAsync

To minify JPEG images with or without loosing jpeg image quality or EXIF data.

Demo

Copy this project on desktop and open example.html

Environment

TESTED(24/01/2013): FireFox, GoogleChrome, IE10, Opera.
PhantomJS

Function

minify(image, sideLength, quality, keepExif, callback) - Resizes jpeg image propotionally. If desired size is bigger than input, 'minify' doesn't resize image.
    image - jpeg data(DataURL string or binary string)
    sideLength - int value of new image's long side length
    quality A float between 0 and 1 depending of the picture quality you want. 1 is the best quality available from source.
    keepExif true if you want to keep exif data
    callback - callback function will be done with resized jpeg data(binary string) as argument.

How to Use

<input type="file" id="files" name="files[]" multiple />
<script source="/js/MinifyJpegAsync.js" />
<script>
function post(data) {
    var array = [];
    for (var p=0; p<data.length; p++) {
        array[p] = data.charCodeAt(p);
    }
    var u8array = new Uint8Array(array);

    var req = new XMLHttpRequest();
    req.open("POST", "/resize", false);
    req.setRequestHeader('Content-Type', 'image/jpeg');
    req.send(u8array.buffer);
}

function handleFileSelect(evt) {
    var files = evt.target.files;

    for (var i = 0, f; f = files[i]; i++){
        var reader = new FileReader();
        reader.onloadend = function(e){
            MinifyJpegAsync.minify(e.target.result, 1280, 1/*Max quality*/, true /*keepExif*/, post);
        };
        reader.readAsDataURL(f);
    }
}

document.getElementById('files').addEventListener('change', handleFileSelect, false);
</script>

Testing

From the root project directory, run the following command:

user@ubuntu:~/projects/MinifyJpegAsync$ phantomjs phestum.js MinifyJpegAsync.js

License

This software is released under the MIT License, see LICENSE.txt.