Dashboard/Dashboard.Drawing/Brush.cs

using System;
using System.Drawing;

namespace Dashboard.Drawing
{
    public class BrushExtension : DrawExtension
    {
        private BrushExtension() : base("DB_Brush") { }

        public static readonly BrushExtension Instance = new BrushExtension();
    }

    public interface IBrush : IDrawResource
    {
    }

    public readonly struct SolidBrush(Color color) : IBrush
    {
        public IDrawExtension Kind { get; } = SolidBrushExtension.Instance;
        public Color Color { get; } = color;

        public override int GetHashCode()
        {
            return HashCode.Combine(Kind, Color);
        }
    }

    public readonly struct GradientBrush(Gradient gradient) : IBrush
    {
        public IDrawExtension Kind { get; } = GradientBrushExtension.Instance;
        public Gradient Gradient { get; } = gradient;

        public override int GetHashCode()
        {
            return HashCode.Combine(Kind, Gradient);
        }
    }

    public class SolidBrushExtension : DrawExtension
    {
        private SolidBrushExtension() : base("DB_Brush_solid", new[] { BrushExtension.Instance }) { }

        public static readonly SolidBrushExtension Instance = new SolidBrushExtension();
    }

    public class GradientBrushExtension : DrawExtension
    {
        private GradientBrushExtension() : base("DB_Brush_gradient", new[] { BrushExtension.Instance }) { }

        public static readonly GradientBrushExtension Instance = new GradientBrushExtension();
    }
}