HandyControl/Net40/HandyControl_Net40/Expression/Drawing/MarchLocation.cs

using System.Collections.Generic;
using System.Windows;

namespace HandyControl.Expression.Drawing
{
    internal class MarchLocation
    {
        public double After { get; private set; }

        public double Before { get; private set; }

        public int Index { get; private set; }

        public double Ratio { get; private set; }

        public MarchStopReason Reason { get; private set; }

        public double Remain { get; private set; }

        public static MarchLocation Create(MarchStopReason reason, int index, double before, double after,
            double remain)
        {
            var num = before + after;
            return new MarchLocation
            {
                Reason = reason,
                Index = index,
                Remain = remain,
                Before = MathHelper.EnsureRange(before, 0.0, num),
                After = MathHelper.EnsureRange(after, 0.0, num),
                Ratio = MathHelper.EnsureRange(MathHelper.SafeDivide(before, num, 0.0), 0.0, 1.0)
            };
        }

        public double GetArcLength(IList<double> accumulatedLengths)
        {
            return MathHelper.Lerp(accumulatedLengths[Index], accumulatedLengths[Index + 1], Ratio);
        }

        public Vector GetNormal(PolylineData polyline, double cornerRadius = 0.0)
        {
            return polyline.SmoothNormal(Index, Ratio, cornerRadius);
        }

        public Point GetPoint(IList<Point> points)
        {
            return GeometryHelper.Lerp(points[Index], points[Index + 1], Ratio);
        }
    }
}