// Image clone 
function imgGrayScale(element) {
    var obj = element;

    // clone image
    $(obj).each(function () {
        var el = $(this);
        el.css({ "position": "absolute" }).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({ "position": "absolute", "z-index": "998", "opacity": "0" }).insertBefore(el).queue(function () {
            var el = $(this);
            el.parent().css({ "width": this.width, "height": this.height });
            el.dequeue();
        });
        if ($.browser.msie) {
            grayscaleImageIE(this);
        } else {
            this.src = grayscaleImage(this.src);
        }

        //this.src = grayscale(this.src);
    });

    // Fade image 
    // $(obj).mouseover(function(){
    // 	$(this).parent().find('img:first').stop().animate({opacity:1}, 300);
    // });

    // $('.img_grayscale').mouseout(function(){
    // 	$(this).stop().animate({opacity:0}, 300);
    // });		

}

function grayscaleImageIE(imgObj) {
    imgObj.style.filter = 'progid:DXImageTransform.Microsoft.BasicImage(grayScale=1)';
}

function grayscaleImage(src) {
    var canvas = document.createElement('canvas');
    var canvasContext = canvas.getContext('2d');

    var imgObj = new Image();
    imgObj.src = src;

    var imgW = imgObj.width;
    var imgH = imgObj.height;

    canvas.width = imgW;
    canvas.height = imgH;

    canvasContext.drawImage(imgObj, 0, 0);
    var imgPixels = canvasContext.getImageData(0, 0, imgW, imgH);

    for (var y = 0; y < imgPixels.height; y++) {
        for (var x = 0; x < imgPixels.width; x++) {
            var i = (y * 4) * imgPixels.width + x * 4;
            var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
            imgPixels.data[i] = avg;
            imgPixels.data[i + 1] = avg;
            imgPixels.data[i + 2] = avg;
        }
    }


    canvasContext.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
    return canvas.toDataURL();
}