OK. Collections was not added to my target.

Bindings in superview was defined inside body.

For now like this, in a simplest way struct ContentView: View { @ObservedObject var manager = Manager() var body: some View { ... VStack { ScrollView([.horizontal, .vertical]) { DotTestView(dots: $manager.dots) .frame(width: manager.size.width, height: manager.size.height) } HStack { Button(action: { Task { await manager.updateDots(in: manager.size) }}, label: {Text("start")}) Button(action: { print ("stop")}, label: {Text("How to Stop")}) } } ... } } Manager keeps all configuration data, has @Published var dots:[Dot]. Simple as that. And a problem is that Rainbow Wheel does not allow me to touch any Button. I suspect: @MainActor public struct DotGenerator {....} but I don't know how to make it different way in Swift6

Instead of using GeometryReader and SwiftUI structs for dot shape, I used Canvas and draw paths into its context

Those circles are defined in brown noise random positions and sizes, but generated PDF has visible grid, many circles are became elipses. Smallest circle in picture has size 1pt x 1pt.

I hope this is an ID: FB15716546