With iOS 18 beta which recently came out, I was curious in how to use the new .presentationSizing. Does it completely change the size of the sheet or is this only a notable feature for mac apps? Also are there any new features which make it so the .sheet can be presented above the tab bar like in the apple FindMy app.

I tried something like this but it did not work.

import SwiftUI

@available(iOS 18.0, *)
struct Test: View {
    @State private var isPresented = false
    
    var body: some View {
        Button("Show Modal") {
            isPresented.toggle()
        }
        .sheet(isPresented: $isPresented) {
            ModalContentView()
                .presentationSizing(SquareSizing())
        }
    }
}

struct ModalContentView: View {
    var body: some View {
        Text("This is a modal view.")
            .padding()
            .background(Color.blue)
            .foregroundColor(.white)
    }
}

@available(iOS 18.0, *)
struct SquareSizing: PresentationSizing {
    func proposedSize(for subview: PresentationSizingRoot, context: PresentationSizingContext) -> ProposedViewSize {
        let size = CGSize(width: 400, height: 400)
        return ProposedViewSize(size)
    }
}


#Preview{
    if #available(iOS 18.0, *) {
        Test()
    } else {
        // Fallback on earlier versions
    }
}