SkiaSharp is a 2D graphics system for .NET powered by the open-source Skia graphics engine that is used extensively in Google products. You can use SkiaSharp in your Xamarin.Forms applications to draw 2D vector graphics, bitmaps, and text.
printfn "touch event at (%f, %f)" args.Location.X args.Location.Y
By default, the view will not be redrawn when the model changes. You should set invalidate to true when you know that a redraw is needed. Set it back to false when done, otherwise it will be redrawn at each update.