Question

I’m trying to achieve this effect with jQuery.

I wrote some of the code, but it’s buggy (move to the bottom-right corder and you’ll see).
check it out

Basically, if there’s an already-built jQuery plugin that you know of that does this, I’d be very happy using it, if not, any help with my formula would be appreciated. This is what I get for not paying attention in Maths classes 🙂

Thanks in advance.

Maikel

Answer 1

Overall I think this is what you’re looking for:

$.fn.sexyImageHover = function() { 
    var p = this, // parent
        i = this.children('img'); // image

    i.load(function(){
        // get image and parent width/height info
        var pw = p.width(),
            ph = p.height(),
            w = i.width(),
            h = i.height();

        // check if the image is actually larger than the parent
        if (w > pw || h > ph) {
            var w_offset = w - pw,
                h_offset = h - ph;

            // center the image in the view by default
            i.css({ 'margin-top':(h_offset / 2) * -1, 'margin-left':(w_offset / 2) * -1 });

            p.mousemove(function(e){
                var new_x = 0 - w_offset * e.offsetX / w,
                    new_y = 0 - h_offset * e.offsetY / h;

                i.css({ 'margin-top':new_y, 'margin-left':new_x });
            });
        }
    });
}

You can test it here.

Notable changes:

• new_x and new_y should be divided by the images height/width, not the container’s height/width, which is wider.
• this is already a jQuery object in a $.fn.plugin function, no need to wrap it.
  • i and p were also jQuery objects, no need to keep wrapping them
• no need to bind mousemove on mouseenter (which rebinds) the mousemove will only occur when you’re inside anyway.