drag and drop on divs using border radius

drag and drop on divs using border radius

I am making divs look like circles using border radius, however, I think jQuery thinks they are still square, I got around most of the bugs using simple trig to calculate where the drop is, however for things like hoverClass I am not sure how to get around this. The only thing I can think of is to use SVG graphics instead of divs.

any ideas?