Dashboard/Dashboard.Common/Drawing/Brush.cs

using System.Collections.Specialized;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.CompilerServices;

namespace Dashboard.Drawing
{
    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 sealed class SolidColorBrush(Color color) : Brush
    {
        public Color Color { get; } = color;
    }

    public class ImageBrush(Image image) : Brush
    {
        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 => 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));
        }
    }
}