UndoRightToLeftMirroring.swift

import SwiftUI

struct UndoRightToLeftMirroring: ViewModifier {
//    @Environment(\.layoutDirection) var layoutDirection

//    @ViewBuilder
    func body(content: Content) -> some View {
        content     // !!! Just do this undo the mirroring
//        VStack {
//            if layoutDirection == .leftToRight {
//                content
//            } else {
//                content
////                    .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))      // no effect here
//            }
//
//            Text("\(self.layoutDirection == .leftToRight ? ".leftToRight" : ".rightToLeft")")
//        }
    }
}

struct RIghtToLeftLayoutOddnessWidget: View {
    @Environment(\.layoutDirection) var layoutDirection

    var isHorizontal: Bool
    
    func horizontal() -> some View {
        HStack {
            ForEach(9...11, id: \.self) { index in
                VStack {
                    Text("\(index)")
//                        .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))    // work here
                        .modifier(UndoRightToLeftMirroring())                           // but not inside modifier
                    Color.green
                }
            }
        }
    }
    
    func vertical() -> some View {
        VStack {
            Color.blue
            Color.red
        }
    }
    
    @ViewBuilder
    var body: some View {
        VStack {
            if isHorizontal {
                horizontal()
            } else {
                vertical()
            }
            
            Text("\(self.layoutDirection == .leftToRight ? ".leftToRight" : ".rightToLeft")")
        }
    }
}

struct RIghtToLeftLayoutOddness: View {
    var body: some View {
        VStack {
            RIghtToLeftLayoutOddnessWidget(isHorizontal: true)
            RIghtToLeftLayoutOddnessWidget(isHorizontal: true)
                .environment(\.layoutDirection, .rightToLeft)
        }
    }
}

struct RIghtToLeftLayoutOddness_Previews: PreviewProvider {
    static var previews: some View {
        RIghtToLeftLayoutOddness()
    }
}