Кастомная кнопка в UserControl или UserControl со свойствами кнопки

        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            double width, height;
            if
            (
                values?.Length == 2
                && double.TryParse(values[0]?.ToString(), out width)
                && double.TryParse(values[1]?.ToString(), out height))
                return new PointCollection(new Point[] { new Point(0, 0), new Point(width, 0), new Point(0.5 * width, height) });
            return null;
        }

namespace ButtonTriangleWPF
{
    /// <summary>Делегат функции возвращающей коллекцию вершин фигуры вписанной в заданную область</summary>
    /// <param name="width">Ширина области</param>
    /// <param name="height">Высота области</param>
    /// <returns>PointCollection - коллекцию вершин фигуры</returns>
    public delegate PointCollection InscribedPolygonHandler(double width, double height);
    /// <summary>
    /// Логика взаимодействия для ButtonTriangle.xaml
    /// </summary>
    public partial class ButtonTriangle : Button
    {
        public ButtonTriangle()
        {
            InitializeComponent();
        }
 
        static readonly BrushConverter brushConverter = new BrushConverter();
 
 
 
        public InscribedPolygonHandler InscribedPolygonDelegate
        {
            get { return (InscribedPolygonHandler)GetValue(InscribedPolygonDelegateProperty); }
            set { SetValue(InscribedPolygonDelegateProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for InscribedPolygonDelegate.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty InscribedPolygonDelegateProperty =
            DependencyProperty.Register("InscribedPolygonDelegate", typeof(InscribedPolygonHandler), typeof(ButtonTriangle), new PropertyMetadata((InscribedPolygonHandler)InscribedPolygonMetod));
 
 
 
        protected static readonly DependencyPropertyKey PointsKey =
            DependencyProperty.RegisterReadOnly(nameof(Points), typeof(PointCollection), typeof(ButtonTriangle), new PropertyMetadata(null));
 
        public PointCollection Points
        {
            get { return (PointCollection)GetValue(PointsProperty); }
            protected set { SetValue(PointsKey, value); }
        }
 
        // Using a DependencyProperty as the backing store for Points.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty PointsProperty = PointsKey.DependencyProperty;
        //DependencyProperty.Register(nameof(Points), typeof(PointCollection), typeof(ButtonTriangle), new PropertyMetadata(null));
 
        private void PART_Grid_SizeChanged(object sender, SizeChangedEventArgs e)
            => Points = InscribedPolygonDelegate?.Invoke(e.NewSize.Width, e.NewSize.Height); /*new PointCollection(new Point[] { new Point(0, 0), new Point(e.NewSize.Width, 0), new Point(0.5 * e.NewSize.Width, e.NewSize.Height) });*/
 
        static protected PointCollection InscribedPolygonMetod(double width, double height)
            => new PointCollection(new Point[] { new Point(0, 0), new Point(width, 0), new Point(0.5 * width, height) });
 
        public double StrokeThickness
        {
            get { return (double)GetValue(StrokeThicknessProperty); }
            set { SetValue(StrokeThicknessProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for StrokeThickness.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty StrokeThicknessProperty =
            DependencyProperty.Register(nameof(StrokeThickness), typeof(double), typeof(ButtonTriangle), new PropertyMetadata(1.0));
 
 
 
        public Brush MouseOverBackground
        {
            get { return (Brush)GetValue(MouseOverBackgroundProperty); }
            set { SetValue(MouseOverBackgroundProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for MouseOverBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverBackgroundProperty =
            DependencyProperty.Register(nameof(MouseOverBackground), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FFBEE6FD")));
 
 
 
        public Brush MouseOverBorder
        {
            get { return (Brush)GetValue(MouseOverBorderProperty); }
            set { SetValue(MouseOverBorderProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for MouseOverBorder.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverBorderProperty =
            DependencyProperty.Register(nameof(MouseOverBorder), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FF3C7FB1")));
 
 
 
        public Brush PressedBackground
        {
            get { return (Brush)GetValue(PressedBackgroundProperty); }
            set { SetValue(PressedBackgroundProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for PressedBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty PressedBackgroundProperty =
            DependencyProperty.Register(nameof(PressedBackground), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FFC4E5F6")));
 
 
 
        public Brush PressedBorder
        {
            get { return (Brush)GetValue(PressedBorderProperty); }
            set { SetValue(PressedBorderProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for PressedBorder.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty PressedBorderProperty =
            DependencyProperty.Register(nameof(PressedBorder), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FF2C628B")));
 
 
 
        public Brush DisabledBackground
        {
            get { return (Brush)GetValue(DisabledBackgroundProperty); }
            set { SetValue(DisabledBackgroundProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for DisabledBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledBackgroundProperty =
            DependencyProperty.Register(nameof(DisabledBackground), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FFF4F4F4")));
 
 
 
 
        public Brush DisabledBorder
        {
            get { return (Brush)GetValue(DisabledBorderProperty); }
            set { SetValue(DisabledBorderProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for DisabledBorder.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledBorderProperty =
            DependencyProperty.Register(nameof(DisabledBorder), typeof(Brush), typeof(ButtonTriangle), new PropertyMetadata(brushConverter.ConvertFrom("#FFADB2B5")));
 
    }
}

namespace ButtonTriangleWPF
{
    /// <summary>Статический класс с делегатами создающими списки вершин
    /// различных фигур в заданной области</summary>
    public static class InscribedPolygonClass
    {
        /// <summary>Делегат метода возвращающего коллекцию вершин ромба
        /// вписанного в заданную область</summary>
        public static InscribedPolygonHandler InscribedRhombusDelegate { get; } = (width, height) =>
            new PointCollection
            {
                new Point(0.5 * width, 0),
                new Point(width, 0.5 * height),
                new Point(0.5 * width, height),
                new Point(0, 0.5 * height)
            };
 
        /// <summary>Делегат метода возвращающего коллекцию вершин шестиугольника
        /// вписанного в заданную область</summary>
        public static InscribedPolygonHandler InscribedHexagonDelegate { get; } = (width, height) =>
            new PointCollection
            {
                new Point(0.25 * width, 0),
                new Point(0.75 * width, 0),
                new Point(width, 0.5 * height),
                new Point(0.75 * width, height),
                new Point(0.25 * width, height),
                new Point(0, 0.5 * height)
            };
 
        /// <summary>Делегат метода возвращающего коллекцию вершин "галочки"
        /// вписанной в заданную область</summary>
        public static InscribedPolygonHandler InscribedMarkItemDelegate { get; } = (width, height) =>
            new PointCollection
            {
                new Point( 0, 0),
                new Point(0.5 * width, 0.5 * height),
                new Point(width, 0),
                new Point(0.5 *width, height)
            };
    }
}

        public Brush MouseOverBackground
        {
            get { return (Brush)GetValue(MouseOverBackgroundProperty); }
            set { SetValue(MouseOverBackgroundProperty, value); }
        }
 
        // Using a DependencyProperty as the backing store for MouseOverBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverBackgroundProperty =
            DependencyProperty.Register(nameof(MouseOverBackground), typeof(Brush), typeof(ButtonTriangle), 
                     new PropertyMetadata(brushConverter.ConvertFrom("#FFBEE6FD")));
        /// #FFBEE6FD - это цвет по умолчанию.

    public partial class ButtonTriangle : Button
    {
        public ButtonTriangle()
        {
            InitializeComponent();
 
           // Здесь можно записать жёсткие значения свойств.
        }