Pchp.Library.PhpMath.atan2 C# (CSharp) Method

        public static double atan2(double y, double x)
        {
            double rv = Math.Atan(y / x);
            if (x < 0)
            {
                return ((rv > 0) ? -Math.PI : Math.PI) + rv;
            }
            else return rv;
        }