Universal Color Converter for Avalonia

ColorConverter.cs

using System;
using System.Globalization;
using Avalonia;
using Avalonia.Data;
using Avalonia.Media;  

namespace Avalonia.Data.Converters;

public class ColorConverter : IValueConverter
{  
    public static object GetColor(object? value)
    {
        var x = value;
        if (x == null) return AvaloniaProperty.UnsetValue;
        if (x is Color r) return r;
        if (x is int t) return Color.FromUInt32(unchecked((uint)t));
        if (x is uint u) return Color.FromUInt32(u);
        if (x is SolidColorBrush scb) return scb.Color;
        if (x is Pen p && p.Brush is SolidColorBrush pscb) return pscb.Color;
        if (Color.TryParse(x.ToString(), out Color c))
        {
            return c;
        }
        return AvaloniaProperty.UnsetValue;
    }

    private static Dictionary<Color, SolidColorBrush> _solidBrushes = new(); 
    private static Dictionary<Color, Pen> _solidPens = new(); 
    static TValue GetOrCreate<TKey, TValue>(Dictionary<TKey, TValue> dictionary, TKey key,
        Func<TKey, TValue> factory) where TKey : notnull
    {
        if (dictionary.TryGetValue(key, out var rv))
            return rv;
        return dictionary[key] = factory(key); 
    }

    static Pen GetPen(Color c) => GetOrCreate(_solidPens, c, c => new Pen(GetBrush(c)));
    static Brush GetBrush(Color c) => GetOrCreate(_solidBrushes, c, c => new SolidColorBrush(c)); 
    public static object ConvertColor(Color color, Type targetType)
    {
        if (targetType == typeof(string)) return color.ToString();
        if (targetType == typeof(int)) return unchecked((int)color.ToUint32());
        if (targetType == typeof(uint)) return color.ToUint32();
        if (targetType == typeof(Color)) return color;
        if (targetType == typeof(Brush)) return GetBrush(color);
        if (targetType == typeof(Pen)) return GetPen(color);
        return AvaloniaProperty.UnsetValue;
    }
    public static object Convert(object? value, Type targetType)
    { 
        var colorVal = GetColor(value);
        if (!(colorVal is Color c))
            return new BindingNotification(
                new InvalidCastException($"{value} is not coercible to a valid color value"), 
                BindingErrorType.Error); 
        return ConvertColor(c, targetType); 
    }
    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
        => Convert(value, targetType);
    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
        => Convert(value, targetType);
}