wraps the mod result to avoid negative results.

   
 

//http://isotopescreencapture.codeplex.com/
//The MIT License (MIT)
namespace Isotope.Math
{
    public static class MathUtil
    {
        /// <summary>
        /// This is a variant of mod that wraps the mod result to avoid negative results. this is what Python&#039;s mod operator does
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        private static double mod_wrap_angle(double x, double y)
        {
            if (y == 0)
            {
                throw new System.DivideByZeroException();
            }

            double r = x%y;
            if (r > 0 &amp;&amp; y < 0)
            {
                r = r + y;
            }
            else if (r < 0 &amp;&amp; y > 0)
            {
                r = r + y;
            }
            return r;
        }

        /// <summary>
        /// wraps a number around so that it always fits between 0.0 and 1.0. negative numbers will wrap around to the correct positive number
        /// </summary>
        /// <remarks>
        /// if the input number is already in the range, no change will occur
        /// </remarks>
        /// <param name="v">input value </param>
        /// <returns>the wrapped number</returns>
        public static double WrapAngle_0_1(double v)
        {
            const double min = 0.0;
            const double max = 1.0;
            if (IsInRange(v, min, max))
            {
                // the number is already in the range so do nothing
                return v;
            }
            return mod_wrap_angle(v, max);
        }
        /// <summary>
        /// Checks if a value is in a range (inclusive)
        /// </summary>
        /// <param name="val"></param>
        /// <param name="min"></param>
        /// <param name="max"></param>
        /// <returns></returns>
        public static bool IsInRange(double val, double min, double max)
        {
            return ((min <= val) &amp;&amp; (val <= max));
        }

        /// <summary>
        /// Checks if a value is in the range 0.0 to 1.0 inclusive
        /// </summary>
        /// <param name="val"></param>
        /// <returns></returns>
        public static bool IsInRange_0_1(double val)
        {
            return IsInRange(val, 0.0, 1.0);
        }        
   }
}