Source code for Quick Tips episode: Power-Up Your Previews

PowerUpYourPreviews.swift

//
//  PowerUpYourPreviews.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.
//
//  Created by Adam Fordyce on 08/07/2021.
//  Copyright © 2021 Adam Fordyce. All rights reserved.
//

import SwiftUI
import PureSwiftUI

struct IncrementControl: View {
    
    @Binding var counter: Int
    
    var min = Int.min
    var max = Int.max
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            HStack {
                IncrementButton(sfSymbolName: .minus) {
                    if counter > min {
                        counter -= 1
                    }
                }
                .frame(geo.height)

                Text("\(counter)")
                    .greedyWidth()

                IncrementButton(sfSymbolName: .plus) {
                    if counter < max {
                        counter += 1
                    }
                }
                .frame(geo.height)
            }
            .font(.system(size: geo.heightScaled(0.4)))
        }
    }
}

private let buttonGradient = LinearGradient([.orange, .red], to: .trailing)

private struct IncrementButton: View {
    
    let sfSymbolName: SFSymbolName
    let handler: () -> ()
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            Button {
                handler()
            } label: {
                SFSymbol(sfSymbolName)
                    .greedyFrame()
                    .clipRoundedRectangleWithStroke(geo.widthScaled(0.15), Color.white,
                                                    lineWidth: geo.widthScaled(0.05), fill: buttonGradient)
            }
        }
    }
}

struct IncrementControl_Previews: PreviewProvider {
    struct IncrementControl_Harness: View {

        @State private var counter = 2
        @State private var counterWithMin = 2
        @State private var counterWithMax = 2
        @State private var counterWithMinMax = 2

        var body: some View {
            VStack(spacing: 20) {
                Group {
                    IncrementControl(counter: $counter)
                    IncrementControl(counter: $counterWithMin, min: 0)
                    IncrementControl(counter: $counterWithMax, max: 4)
                    IncrementControl(counter: $counterWithMinMax, min: 0, max: 4)
                }
                .frame(250, 60)
            }
            .greedyFrame()
            .foregroundColor(.white)
            .backgroundColor(.white(0.1))
            .ignoresSafeArea()
        }
    }
    
    static var previews: some View {
        IncrementControl_Harness()
            .previewDevice(.iPhone_12_Pro_Max)
    }
}