ManualInlinView.swift

import SwiftUI

struct ManualInlinView: View {
    @State private var isInline = false
    private let clearHeight = 200.0  // 이 부분을 수정 가능

    var body: some View {
        ScrollView {
            VStack {
                Color.blue
                    .frame(height: 300)
                    .background(
                        Color.clear
                            .frame(height: clearHeight)
                            .onVisibilityChange { isVisible in
                                isInline = !isVisible
                            }
                    )
                    .overlay {
                        Text("This area is a image")
                            .font(.title)
                    }

                HStack {
                    Text("제목")
                        .font(.title)

                    Spacer()
                }
                .padding()

                HStack {
                    Text("얄라리얄랴리얄라셩얄라리얄라얄라리얄랴리얄라셩얄라리얄라얄라리얄랴리얄라셩얄라리얄라얄라리얄랴리얄라셩얄라리얄라얄라리얄랴리얄라셩얄라리얄라")
                }
                .padding(.horizontal)



                Color.gray
                    .frame(height: 400)
                    .overlay {
                        Text("This area is description")
                            .font(.title)
                            .foregroundStyle(.white)
                    }

                Color.gray
                    .frame(height: 400)
                    .overlay {
                        Text("This area is description")
                            .font(.title)
                            .foregroundStyle(.white)
                    }

                Color.gray
                    .frame(height: 400)
                    .overlay {
                        Text("This area is description")
                            .font(.title)
                            .foregroundStyle(.white)
                    }
            }
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button {
                        isInline.toggle()
                    } label: {
                        Image(systemName: "chevron.left")
                    }
                }

                ToolbarItem(placement: .principal) {
                    if isInline {
                        Text("제목")
                            .bold()
                    }
                }
            }
            .toolbarBackground(.tintColor, for: .navigationBar)
            .toolbarBackground(
                isInline ? .visible : .hidden,
                for: .navigationBar
            )
        }
        .ignoresSafeArea()
    }
}

#Preview {
    NavigationStack {
        ManualInlinView()
    }
}

struct ViewVisibilityModifier: ViewModifier {
    let onChange: (Bool) -> Void

    func body(content: Content) -> some View {
        content
            .background(
                GeometryReader { geometry in
                    let minY = geometry.frame(in: .global).minY

                    Color.clear
                        .onChange(of: minY) { _ in
                            let isVisible = UIScreen.main.bounds.intersects(geometry.frame(in: .global))
                            onChange(isVisible)
                        }
                }
            )
    }
}

extension View {
    func onVisibilityChange(_ onChange: @escaping (Bool) -> Void) -> some View {
        self.modifier(ViewVisibilityModifier(onChange: onChange))
    }
}