Implement INotifyPropertyChanged for brushes.

Dashboard.Common/Drawing/Brush.cs

@@ -1,27 +1,111 @@
+using System.Collections.Specialized;
+using System.ComponentModel;
 using System.Drawing;
-using System.Numerics;
+using System.Runtime.CompilerServices;
 
 namespace Dashboard.Drawing
 {
-    public abstract class Brush
+    public abstract class Brush : INotifyPropertyChanged, ICloneable
     {
+        public event PropertyChangedEventHandler? PropertyChanged;
+
+        public virtual object Clone()
+        {
+            return MemberwiseClone();
+        }
+
+        protected void SetField<T>(ref T field, T value, [CallerMemberName] string property = "")
+        {
+            field = value;
+            OnPropertyChanged(property);
+        }
+
+        protected virtual void OnPropertyChanged(string property)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
+        }
     }
 
-    public class SolidColorBrush(Color color) : Brush
+    public sealed class SolidColorBrush(Color color) : Brush
     {
         public Color Color { get; } = color;
     }
 
     public class ImageBrush(Image image) : Brush
     {
-        public Image Image { get; set; } = image;
-        public Box2d TextureCoordinates { get; set; } = new Box2d(0, 0, 1, 1);
+        public Image Image 
+        {
+            get;
+            set => SetField(ref field, value);
+        } = image;
+
+        public Box2d TextureCoordinates
+        {
+            get;
+            set => SetField(ref field, value);
+        } = new Box2d(0, 0, 1, 1);
     }
 
     public class NinePatchImageBrush(Image image) : Brush
     {
-        public Image Image { get; set; } = image;
-        public Box2d CenterCoordinates { get; set; } = new Box2d(0, 0, 1, 1);
-        public Vector4 Extents { get; set; } = Vector4.Zero;
+        public Image Image
+        { 
+            get;
+            set => SetField(ref field, value);
+        } = image;
+
+        public Box2d CenterCoordinates
+        {
+            get;
+            set => SetField(ref field, value);
+        } = new Box2d(0, 0, 1, 1);
+
+        public Extents Extents
+        {
+            get;
+            set => SetField(ref field, value);
+        } = Extents.None;
+    }
+
+    public class GradientBrush : Brush
+    {
+        public Gradient Gradient 
+        {
+            get;
+            set
+            {
+                Unsubscribe(field);
+                Subscribe(value);
+
+                SetField(ref field, value);
+            }
+        }
+
+        public GradientBrush(Gradient gradient)
+        {
+            Gradient = gradient;
+        }
+
+        private void Subscribe(Gradient gradient)
+        {
+            gradient.PropertyChanged   += GradientPropertyChanged;
+            gradient.CollectionChanged += GradientCollectionChanged;
+        }
+
+        private void Unsubscribe(Gradient? gradient)
+        {
+            gradient?.PropertyChanged   -= GradientPropertyChanged;
+            gradient?.CollectionChanged -= GradientCollectionChanged;
+        }
+
+        private void GradientCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
+        {
+            OnPropertyChanged(nameof(Gradient));
+        }
+
+        private void GradientPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            OnPropertyChanged(nameof(Gradient));
+        }
     }
 }