swaps EllipseF to use a struct, as well as implementing IEquatable, and IShapeF - this resolves #703

src/dotnet/MonoGame.Extended/Math/EllipseF.cs

@@ -1,20 +1,29 @@
 using System;
+using System.Runtime.Serialization;
 using Microsoft.Xna.Framework;
 
 namespace MonoGame.Extended
 {
-    public class EllipseF
+    [DataContract]
+    public struct EllipseF : IEquatable<EllipseF>, IEquatableByRef<EllipseF>, IShapeF
     {
+        [DataMember] public Vector2 Center { get; set; }
+        [DataMember] public float RadiusX { get; set; }
+        [DataMember] public float RadiusY { get; set; }
+
+        public Point2 Position
+        {
+            get => Center;
+            set => Center = value;
+        }
+
         public EllipseF(Vector2 center, float radiusX, float radiusY)
         {
             Center = center;
             RadiusX = radiusX;
             RadiusY = radiusY;
         }
-
-        public Vector2 Center { get; set; }
-        public float RadiusX { get; set; }
-        public float RadiusY { get; set; }
+    
         public float Left => Center.X - RadiusX;
         public float Top => Center.Y - RadiusY;
         public float Right => Center.X + RadiusX;
@@ -44,5 +53,28 @@ namespace MonoGame.Extended
         {
             return Contains(point.X, point.Y);
         }
+
+        public bool Equals(EllipseF ellispse)
+        {
+            return Equals(ref ellispse);
+        }
+
+        public bool Equals(ref EllipseF ellispse)
+        {
+            // ReSharper disable once CompareOfFloatsByEqualityOperator
+            return ellispse.Center == Center 
+                   && ellispse.RadiusX == RadiusX 
+                   && ellispse.RadiusY == RadiusY;
+        }
+
+        public static bool operator ==(EllipseF first, EllipseF second)
+        {
+            return first.Equals(ref second);
+        }
+
+        public static bool operator !=(EllipseF first, EllipseF second)
+        {
+            return !(first == second);
+        }
     }
 }