I'm trying to get the midpoint of children views. I have a Triangle shape like this

struct Triangle: Shape {
    func path(in rect: CGRect) -> Path {
        var path = Path()

        path.move(to: CGPoint(x: rect.midX, y: rect.minY))
        path.addLine(to: CGPoint(x: rect.minX, y: rect.maxY))
        path.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY))
        path.addLine(to: CGPoint(x: rect.midX, y: rect.minY))

        return path
    }
}

Then I have a view like this

    var body: some View {
        ZStack {
            ForEach(items) { item in
                Triangle()
            }
         }

In this view I would like to store the midpoint of every Triangle view. In other words, how to pass info from a children view to a parent view in SwiftUI?