Display flow arrows when selecting a path

PamhagenSysCtrl/Helpers/Pipeline/Inlet.cs

@@ -11,11 +11,14 @@ namespace PamhagenSysCtrl.Helpers.Pipeline {
         public bool IsTwoWay => false;
         public bool Orientation { get; set; }
         public Brush? Highlight { get; set; }
+        public (bool TowardEnd, double PathOffset)? Flow { get; set; }
+        public double FlowLength => _flowArrow?.Length ?? 0;
 
         private Line? _outer1;
         private Line? _outer2;
         private Line? _inner1;
         private Line? _inner2;
+        private FlowArrow? _flowArrow;
 
         public Inlet(INode start, ISink end, bool orientation = false) {
             Start = start;
@@ -74,11 +77,13 @@ namespace PamhagenSysCtrl.Helpers.Pipeline {
             canvas.Children.Add(_outer2);
             canvas.Children.Add(_inner1);
             canvas.Children.Add(_inner2);
+            _flowArrow = FlowArrow.Create(canvas, _inner1!, _inner2!);
         }
 
         public void Update() {
             _inner1?.Stroke = Highlight ?? Brushes.DarkGray;
             _inner2?.Stroke = Highlight ?? Brushes.DarkGray;
+            _flowArrow?.Update(Highlight == PamhagenBrushes.Green ? Flow : null);
         }
     }
 }