feat: Ellipse shape

joezearing · Mar 14, 2021 · c8d261d · c8d261d
1 parent 3c96748
commit c8d261d
Show file tree

Hide file tree

Showing 4 changed files with 72 additions and 6 deletions.
diff --git a/samples/SharedDemo/Demos/Simple.razor.cs b/samples/SharedDemo/Demos/Simple.razor.cs
@@ -16,12 +16,6 @@ protected override void OnInitialized()
             var node1 = NewNode(50, 50);
             var node2 = NewNode(300, 300);
             diagram.Links.Add(new LinkModel(node1.GetPort(PortAlignment.Right), node2.GetPort(PortAlignment.Left)));
-            diagram.Links.Add(new LinkModel(node1, node2)
-            {
-                SourceMarker = LinkMarker.Arrow,
-                TargetMarker = LinkMarker.Arrow,
-                Segmentable = true
-            });
             diagram.Nodes.Add(new[] { node1, node2, NewNode(300, 50) });
         }
 

diff --git a/src/Blazor.Diagrams.Core/Geometry/Ellipse.cs b/src/Blazor.Diagrams.Core/Geometry/Ellipse.cs
@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+
+namespace Blazor.Diagrams.Core.Geometry
+{
+    public class Ellipse : IShape
+    {
+        public Ellipse(double x, double y, double rx, double ry)
+        {
+            X = x;
+            Y = y;
+            Rx = rx;
+            Ry = ry;
+        }
+
+        public double X { get; }
+        public double Y { get; }
+        public double Rx { get; }
+        public double Ry { get; }
+
+        public IEnumerable<Point> GetIntersectionsWithLine(Line line)
+        {
+            var a1 = line.Start;
+            var a2 = line.End;
+            var dir = new Point(line.End.X - line.Start.X, line.End.Y - line.Start.Y);
+            var diff = a1.Substract(X, Y);
+            var mDir = new Point(dir.X / (Rx * Rx), dir.Y / (Ry * Ry));
+            var mDiff = new Point(diff.X / (Rx * Rx), diff.Y / (Ry * Ry));
+
+            var a = dir.Dot(mDir);
+            var b = dir.Dot(mDiff);
+            var c = diff.Dot(mDiff) - 1.0;
+            var d = b * b - a * c;
+
+            if (d > 0)
+            {
+                var root = Math.Sqrt(d);
+                var ta = (-b - root) / a;
+                var tb = (-b + root) / a;
+
+                if (ta >= 0 && 1 >= ta || tb >= 0 && 1 >= tb)
+                {
+                    if (0 <= ta && ta <= 1)
+                        yield return a1.Lerp(a2, ta);
+
+                    if (0 <= tb && tb <= 1)
+                        yield return a1.Lerp(a2, tb);
+                }
+            }
+            else
+            {
+                var t = -b / a;
+                if (0 <= t && t <= 1)
+                {
+                    yield return a1.Lerp(a2, t);
+                }
+            }
+        }
+    }
+}
diff --git a/src/Blazor.Diagrams.Core/Geometry/Point.cs b/src/Blazor.Diagrams.Core/Geometry/Point.cs
@@ -15,6 +15,10 @@ public Point(double x, double y)
         public double X { get; }
         public double Y { get; }
 
+        public double Dot(Point other) => X * other.X + Y * other.Y;
+        public Point Lerp(Point other, double t)
+            => new Point(X * (1.0 - t) + other.X * t, Y * (1.0 - t) + other.Y * t);
+
         // Maybe just make Points mutable?
         public Point Add(double value) => new Point(X + value, Y + value);
         public Point Add(double x, double y) => new Point(X + x, Y + y);

diff --git a/src/Blazor.Diagrams.Core/Geometry/Shapes.cs b/src/Blazor.Diagrams.Core/Geometry/Shapes.cs
@@ -7,5 +7,13 @@ namespace Blazor.Diagrams.Core.Geometry
     public static class Shapes
     {
         public static IShape Rectangle(NodeModel node) => new Rectangle(node.Position, node.Size!);
+
+        public static IShape Circle(NodeModel node)
+        {
+            var halfWidth = node.Size!.Width / 2;
+            var centerX = node.Position.X + halfWidth;
+            var centerY = node.Position.Y + node.Size!.Height / 2;
+            return new Ellipse(centerX, centerY, halfWidth, halfWidth);
+        }
     }
 }