get direction of mouse

direction.js

var getDirection = function (ev, obj) {
    var w = obj.offsetWidth,
        h = obj.offsetHeight,
        x = (ev.pageX - obj.offsetLeft - (w / 2) * (w > h ? (h / w) : 1)),
        y = (ev.pageY - obj.offsetTop - (h / 2) * (h > w ? (w / h) : 1)),
        d = Math.round( Math.atan2(y, x) / 1.57079633 + 5 ) % 4;
  
    return d;
};