PathSpline.cs

using System.Collections.Generic;
using SkiaSharp;
 
namespace Waher.Layout.Layout2D.Model.Figures.SegmentNodes
{
    public class PathSpline : IDirectedElement
    {
        private readonly List<SKPoint> vertices;
 
        public PathSpline(float X0, float Y0)
        {
            this.vertices = new List<SKPoint>() { new SKPoint(X0, Y0) };
        }
 
        public void Add(float X, float Y)
        {
            this.vertices.Add(new SKPoint(X, Y));
        }
 
        public SKPoint[] ToArray()
        {
            return this.vertices.ToArray();
        }
 
        public bool TryGetStart(out float X, out float Y, out float Direction)
        {
            int c = this.vertices.Count;
            if (c<2)
            {
                X = Y = Direction = 0;
                return false;
            }
 
            SKPoint P0 = this.vertices[0];
            SKPoint P1 = this.vertices[1];
            float dx = P1.X - P0.X;
            float dy = P1.Y - P0.Y;
 
            X = P0.X;
            Y = P0.Y;
            Direction = LayoutElement.CalcDirection(dx, dy);
 
            return true;
        }
 
        public bool TryGetEnd(out float X, out float Y, out float Direction)
        {
            int c = this.vertices.Count;
            if (c < 2)
            {
                X = Y = Direction = 0;
                return false;
            }
 
            SKPoint P0 = this.vertices[c - 2];
            SKPoint P1 = this.vertices[c - 1];
            float dx = P1.X - P0.X;
            float dy = P1.Y - P0.Y;
 
            X = P1.X;
            Y = P1.Y;
            Direction = LayoutElement.CalcDirection(dx, dy);
 
            return true;
        }
    }
}