Microsoft.Xna.Framework.MathHelper.Clamp C# (CSharp) Method

        public static float Clamp(float value, float min, float max)
        {
            value = ((value > max) ? max : value);
            value = ((value < min) ? min : value);
            return value;
        }
        public static float Lerp(float value1, float value2, float amount)

        /// <summary>
        /// Processes an area and applies a gradient calculation to each part of the area.
        /// </summary>
        /// <param name="position">The center of the gradient.</param>
        /// <param name="strength">The width of the gradient spread.</param>
        /// <param name="angle">The angle to apply the gradient.</param>
        /// <param name="area">The area to calculate.</param>
        /// <param name="applyAction">The callback called for each part of the area.</param>
        public static void GradientFill(Point cellSize, Point position, int strength, int angle, Rectangle area, ColorGradient gradient, Action <int, int, Color> applyAction)
        {
            double radians = angle * Math.PI / 180; // = Math.Atan2(x1 - x2, y1 - y2);

            Vector2 angleVector = new Vector2((float)(Math.Sin(radians) * strength), (float)(Math.Cos(radians) * strength)) / 2;
            Vector2 location    = new Vector2(position.X, position.Y);

            if (cellSize.X > cellSize.Y)
            {
                angleVector.Y *= cellSize.X / cellSize.Y;
            }

            else if (cellSize.X < cellSize.Y)
            {
                angleVector.X *= cellSize.Y / cellSize.X;
            }

            Vector2 endingPoint   = location + angleVector;
            Vector2 startingPoint = location - angleVector;

            double x1 = (startingPoint.X / (double)area.Width) * 2.0f - 1.0f;
            double y1 = (startingPoint.Y / (double)area.Height) * 2.0f - 1.0f;
            double x2 = (endingPoint.X / (double)area.Width) * 2.0f - 1.0f;
            double y2 = (endingPoint.Y / (double)area.Height) * 2.0f - 1.0f;

            double start = x1 * angleVector.X + y1 * angleVector.Y;
            double end   = x2 * angleVector.X + y2 * angleVector.Y;

            for (int x = area.Left; x < area.Width; x++)
            {
                for (int y = area.Top; y < area.Height; y++)
                {
                    // but we need vectors from (-1, -1) to (1, 1)
                    // instead of pixels from (0, 0) to (width, height)
                    double u = (x / (double)area.Width) * 2.0f - 1.0f;
                    double v = (y / (double)area.Height) * 2.0f - 1.0f;

                    double here = u * angleVector.X + v * angleVector.Y;

                    double lerp = (start - here) / (start - end);

                    //lerp = Math.Abs((lerp - (int)lerp));

                    lerp = MyMathHelper.Clamp((float)lerp, 0f, 1.0f);

                    int counter;
                    for (counter = 0; counter < gradient.Stops.Length && gradient.Stops[counter].Stop < (float)lerp; counter++)
                    {
                        ;
                    }

                    counter--;
                    counter = (int)MyMathHelper.Clamp(counter, 0, gradient.Stops.Length - 2);

                    float newLerp = (gradient.Stops[counter].Stop - (float)lerp) / (gradient.Stops[counter].Stop - gradient.Stops[counter + 1].Stop);

                    applyAction(x, y, ColorHelper.Lerp(gradient.Stops[counter].Color, gradient.Stops[counter + 1].Color, newLerp));
                }
            }
        }