+ let updateViewportPreview () =
+ for preview in stackPreviews.Children |> Seq.cast<Views.ImageSourcePreview> do
+ let srcImg = preview.Tag :?> SourceImage
+ if Some srcImg = state.CurrentImage then
+ preview.viewport.Visibility <- Visibility.Visible
+
+ let canvasWidth = canvasCurrentImage.ActualWidth * currentScale
+ let canvasHeight = canvasCurrentImage.ActualHeight * currentScale
+ let previewWidth = (preview.ActualWidth - preview.BorderThickness.Left - preview.BorderThickness.Right)
+ let previewHeight = (preview.ActualHeight - preview.BorderThickness.Top - preview.BorderThickness.Bottom)
+
+ let marginLeft = previewWidth * (scrollViewCurrentImage.HorizontalOffset - borderCurrentImage.BorderThickness.Left) / canvasWidth - 2.
+ let marginRight = previewWidth * (canvasWidth - (scrollViewCurrentImage.HorizontalOffset - borderCurrentImage.BorderThickness.Right) - scrollViewCurrentImage.ViewportWidth) / canvasWidth - 2.
+ let marginTop = previewHeight * (scrollViewCurrentImage.VerticalOffset - borderCurrentImage.BorderThickness.Top) / canvasHeight - 2.
+ let marginBottom = previewHeight * (canvasHeight - (scrollViewCurrentImage.VerticalOffset - borderCurrentImage.BorderThickness.Bottom) - scrollViewCurrentImage.ViewportHeight) / canvasHeight - 2.
+
+ preview.viewport.Margin <-
+ Thickness(
+ marginLeft,
+ marginTop,
+ marginRight,
+ marginBottom)
+ else
+ preview.viewport.Visibility <- Visibility.Hidden
+