Fake large title navigation bar

FakeLagetTitleNavigationBar.swift

import SwiftUI

@available(iOS 18.0, *)
struct FakeNavigationBarView: View {

    @State var point: CGPoint = .zero

    let titleFullHeight: CGFloat = 100
    let titleMinHeight: CGFloat = 44

    var progress: CGFloat {
        if point.y < 0 {
            return 0
        } else {
            return min(1, point.y / (titleFullHeight - titleMinHeight))
        }
    }

    var titleHeight: CGFloat {
        titleMinHeight + (titleFullHeight - titleMinHeight) * (1 - progress)
    }

    let colors: [Color] = [.red, .green, .blue, .orange, .yellow, .purple]

    var body: some View {
        NavigationStack {
            VStack(spacing: 0) {
                ZStack {
                    if progress > 0.8 {
                        Text("Collection")
                            .font(.system(size: 17, weight: .bold))
                    } else {
                        Text("Collection")
                            .font(.system(size: 34, weight: .bold))
                            .frame(maxWidth: .infinity, alignment: .leading)
                    }
                }
                .padding(.horizontal, 16)
                .frame(maxWidth: .infinity)
                .frame(height: titleHeight)
                .background(.regularMaterial)
                .zIndex(1)

                ScrollView {
                    LazyVStack {
                        ForEach(0..<100) { i in
                            Rectangle()
                                .fill(colors[i % colors.count])
                                .frame(height: 56)
                        }
                    }
                }
                .scrollClipDisabled()
                .onScrollGeometryChange(for: CGPoint.self) { proxy in
                    proxy.contentOffset
                } action: { _, newValue in
                    point = newValue
                }
            }
        }
    }

}

@available(iOS 18.0, *)
#Preview {
    FakeNavigationBarView()
}

2025-03-16.17.10.17.mov