Source code for CodeSlicing episode exploring overlay / background modifiers vs ZStack - demo-01

OverlayVsZStackDemo01.swift

//
//  OverlayVsZStackDemo01.swift
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do so,
//  subject to the following conditions:
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
//  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
//  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
//  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
//  AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
//  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//  Copyright © 2021 Adam Fordyce. All rights reserved.
//

import SwiftUI
import PureSwiftUI

private func Square(_ color: Color, _ sideLength: CGFloat = 100) -> some View {
    Rectangle()
        .fill(color)
        .frame(sideLength)
}

struct OverlayVsZStackDemo01: View {
    
    var body: some View {
        
        let offset: CGFloat = 20
        
        let blueSquare = Square(.blue)
        let whiteSquare = Square(.white).offset(offset, offset)
        let yellowSquare = Square(.yellow).offset(offset, -offset)
        let greenSquare = Square(.green).offset(-offset, -offset)
        let redSquare = Square(.red).offset(-offset, offset)
        
        VStack(spacing: 0) {
            blueSquare
                .overlay(whiteSquare)
                .background(yellowSquare)
                .background(greenSquare)
                .overlay(redSquare)
        
            ZStack {
                greenSquare
                yellowSquare
                blueSquare
                whiteSquare
                redSquare
            }
        }
    }
}

struct OverlayVsZStackDemo01_Previews: PreviewProvider {
    struct OverlayVsZStackDemo01_Harness: View {

        var body: some View {
            OverlayVsZStackDemo01()
                .padding(100)
                .foregroundColor(.white)
                .backgroundColor(.white(0.1))
        }
    }

    static var previews: some View {
        OverlayVsZStackDemo01_Harness()
            .previewSizeThatFits()
    }
}