JS: Animation for a hover with 'mouse direction'

gistfile1.js

$(".overlayLink").bind("mouseenter mouseleave",function(e){

/** the width and height of the current div **/
var w = $(this).width();
var h = $(this).height();

/** calculate the x and y to get an angle to the center of the div from that x and y. **/
/** gets the x value relative to the center of the DIV and "normalize" it **/
var x = (e.pageX - this.offsetLeft - (w/2)) * ( w > h ? (h/w) : 1 );
var y = (e.pageY - this.offsetTop  - (h/2)) * ( h > w ? (w/h) : 1 );

/** the angle and the direction from where the mouse came in/went out clockwise (TRBL=0123);**/
/** first calculate the angle of the point, 
 add 180 deg to get rid of the negative values
 divide by 90 to get the quadrant
 add 3 and do a modulo by 4  to shift the quadrants to a proper clockwise TRBL (top/right/bottom/left) **/
var direction = Math.round((((Math.atan2(y, x) * (180 / Math.PI)) + 180 ) / 90 ) + 3 )  % 4;


/** do your animations here **/ 
switch(direction) {
 case 0:
  /** animations from the TOP **/
 break;
 case 1:
  /** animations from the RIGHT **/
 break;
 case 2:
  /** animations from the BOTTOM **/
 break;
 case 3:
  /** animations from the LEFT **/
 break;
}});