HStack-VStack-dynamic-switching.swift

import SwiftUI

struct ContentView: View {
  @State var horizontal: Bool = true
  @Namespace var namespace

  var body: some View {
    VStack(spacing: 40) {
      if horizontal {
        HStack { items }
      } else {
        VStack { items }
      }
      Button("Toggle") {
        withAnimation { horizontal.toggle() }
      }
    }
    .padding()
  }

  @ViewBuilder var items: some View {
    Ellipse().fill(Color.red)
      .matchedGeometryEffect(id: "circle", in: namespace)
    Capsule().fill(Color.green)
      .matchedGeometryEffect(id: "capsule", in: namespace)
    Rectangle().fill(Color.blue)
      .matchedGeometryEffect(id: "rectangle", in: namespace)
  }
}

struct ContentView_Previews: PreviewProvider {
  static var previews: some View {
    ContentView()
  }
}

This is the code accompanying this tweet: https://twitter.com/olebegemann/status/1464946888768208900