private void AddCropToElement(FrameworkElement fel)
        {
            if (_felCur != null)
            {
                return;
            }
            var rcInterior = new Rect(
                0,
                0,
                fel.ActualWidth,
                fel.ActualHeight);
            var adornerLayer = AdornerLayer.GetAdornerLayer(fel);
            _clp = new CroppingAdorner(fel, rcInterior);
            _felCur = fel;
            var color = Colors.Black;
            color.A = 180;
            _clp.Fill = new SolidColorBrush(color);
            adornerLayer.Add(_clp);
            adornerLayer.UpdateLayout();

            var dx = 1d / _clp.ClippingRectangle.Width * _imageWidth;
            var dy = 1d / _clp.ClippingRectangle.Height * _imageHeight;
            _clp.SetClippingRectangle(new Rect(
                Configuration.Configuration.Instance.Settings.ClippingRectangle.X / dx,
                Configuration.Configuration.Instance.Settings.ClippingRectangle.Y / dy,
                Configuration.Configuration.Instance.Settings.ClippingRectangle.Width / dx,
                Configuration.Configuration.Instance.Settings.ClippingRectangle.Height / dy
                ));

            UpdateClippingRectangle();
            _clp.CropChanged += (sender, args) =>
            {
                UpdateClippingRectangle();
            };
            Image.SizeChanged += ImageSizeChanged;
        }