Backward.cs

using System.Threading.Tasks;
using SkiaSharp;
 
namespace Waher.Layout.Layout2D.Model.Figures.SegmentNodes
{
    public class Backward : Distance, ISegment, IDirectedElement
    {
        public Backward(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public override string LocalName => "Backward";
 
        public override ILayoutElement Create(Layout2DDocument Document, ILayoutElement Parent)
        {
            return new Backward(Document, Parent);
        }
 
        public Task Measure(DrawingState State, PathState PathState)
        {
            if (this.defined)
                PathState.Backward(this.dist);
        
            return Task.CompletedTask;
        }
 
        public virtual Task Draw(DrawingState State, PathState PathState, SKPath Path)
        {
            if (this.defined)
            {
                this.P1 = Path.LastPoint;
                Path.LineTo(this.P2 = PathState.Backward(this.dist));
            }
    
            return Task.CompletedTask;
        }
 
        protected SKPoint P1;
 
        protected SKPoint P2;
 
        public bool TryGetStart(out float X, out float Y, out float Direction)
        {
            X = this.P1.X;
            Y = this.P1.Y;
            Direction = CalcDirection(this.P1, this.P2);
 
            return this.defined;
        }
 
        public bool TryGetEnd(out float X, out float Y, out float Direction)
        {
            X = this.P2.X;
            Y = this.P2.Y;
            Direction = CalcDirection(this.P1, this.P2);
 
            return this.defined;
        }
 
    }
}