Pixels to Lat, Lng - Miller projection Map

I have the following function function millerProjection(lat, lng, elem) { // Create sec() function function sec(value) { return 1/[login to view URL](value); } // Create fucntion to change degree to radians function toRadian(value) { return value * [login to view URL] / 180; } lng = toRadian(lng); lat = toRadian(lat); // Miller Projection var x = lng; var y = -1.25*[login to view URL]([login to view URL](Math.PI/4+0.4*(lat))); var width = [login to view URL](); var scale = width/[login to view URL]; x *= scale; y *= scale; x += width/2; y += width/2*0.7331989845 return [x,y]; } This converts lat, lng coordinates into pixel position on a miller projection map However we also need the reverse of that - convert pixel x,y to lat lng coordinates