/// <summary>
        /// Synchronizes the properties.
        /// </summary>
        public override void SynchronizeProperties()
        {
            base.SynchronizeProperties();
            var a = (Annotations.TextAnnotation)InternalAnnotation;

            a.TextHorizontalAlignment = HorizontalAlignment.ToHorizontalAlignment();
            a.Background = Background.ToOxyColor();

            a.Offset = Offset.ToScreenVector();
            a.TextVerticalAlignment = VerticalAlignment.ToVerticalAlignment();
            a.Padding = Padding.ToOxyThickness();

            a.Stroke          = Stroke.ToOxyColor();
            a.StrokeThickness = StrokeThickness;
        }