<TextBlock RenderTransformOrigin=".5,.5" HorizontalAlignment="Center" VerticalAlignment="Center">
            <TextBlock.Triggers>
                <EventTrigger RoutedEvent="Loaded">
                    <EventTrigger.Actions>
                        <BeginStoryboard>
                            <Storyboard>
                                <DoubleAnimation Storyboard.TargetProperty="RenderTransform.(RotateTransform.Angle)"
                                                 From="0" To="180" RepeatBehavior="Forever"
                                                 Duration="0:0:1"/>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger.Actions>
                </EventTrigger>
            </TextBlock.Triggers>
            <TextBlock.Inlines>
                <Run Text="&#84;" FontFamily="Wingdings" FontSize="100"/>
            </TextBlock.Inlines>
            <TextBlock.RenderTransform>
                <RotateTransform/>
            </TextBlock.RenderTransform>
        </TextBlock>

    public class MyControl : Control
    {
        private readonly FontFamily _font;
        private readonly Brush _brush;
        private readonly Typeface _typeFace;
        private readonly FormattedText _text;

        public MyControl()
        {
           _font = new FontFamily("Wingdings");
           _brush = new SolidColorBrush(Colors.Black);
           _typeFace = new Typeface(_font, FontStyle, FontWeight, FontStretch);
           _text = new FormattedText("T", CultureInfo.CurrentCulture, FlowDirection, _typeFace, 100, _brush);
        }

        protected override void OnRender(DrawingContext drawingContext)
        {
            base.OnRender(drawingContext);
            drawingContext.DrawText(_text, new Point(10, 10));

        }
    }

    public class MyControl : Control
    {
        private readonly FontFamily _font;
        private readonly Brush _brush;
        private readonly Typeface _typeFace;
        private readonly FormattedText _text;

        public MyControl()
        {
           _font = new FontFamily("Wingdings");
           _brush = new SolidColorBrush(Colors.Black);
           _typeFace = new Typeface(_font, FontStyle, FontWeight, FontStretch);
           _text = new FormattedText("T", CultureInfo.CurrentCulture, FlowDirection, _typeFace, 100, _brush);
        }

        protected override void OnRender(DrawingContext drawingContext)
        {
            base.OnRender(drawingContext);
            drawingContext.DrawText(_text, new Point(10, 10));

        }
    }