Native Source code for CodeSlicing episode on Animated Weather Icons Part 4 - Element Composition

WeatherIconCloudSunRainDemoNative.swift

//
//  WeatherIconCloudSunRainDemoNative.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 08/05/2021.
//  Copyright © 2021 Adam Fordyce. All rights reserved.
//

import SwiftUI

private struct WeatherIconCloudSunRainDemoNative: View {

    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            ZStack {
                SunElement(showingRays: true)
                RainElement()
                CloudElement()
            }
            .padding()
            .background(RoundedRectangle(cornerRadius: geo.size.width * 0.07).fill(Color.white))
            .clipShape(RoundedRectangle(cornerRadius: geo.size.width * 0.07))
            .shadow(radius: geo.size.width * 0.02)
        }
    }
}

private struct CloudElement: View {
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            CloudView()
                .scaleEffect(0.7)
                .offset(x: geo.size.width * -0.15, y: geo.size.height * -0.03)
        }
    }
}

private struct SunElement: View {
    
    let showingRays: Bool
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            SunView(showingRays: showingRays)
                .scaleEffect(0.7)
                .offset(x: geo.size.width * 0.15, y: geo.size.height * -0.15)
        }
    }
}

private struct RainElement: View {
    
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            RainView()
                .scaleEffect(0.7)
                .rotationEffect(.degrees(30))
                .offset(x: geo.size.width * -0.2, y: geo.size.height * 0.26)
        }
    }
}

private struct CloudView: View {
    var body: some View {
        let debug = false
        CloudShape(debug: debug)
            .styling()
    }
}

private struct CloudShape: Shape {
    
    var debug = false
    
    func path(in rect: CGRect) -> Path {
        var path = Path()
        
        let startingPoint = CGPoint(x: rect.minX + rect.width * 0.17, y: rect.minY + rect.height * 0.833)
        
        path.move(to: startingPoint)
        
        let c1destination = CGPoint(x: rect.minX + rect.width * 0.141, y: rect.minY + rect.height * 0.465)
        let c1cp1 = CGPoint(x: rect.minX + rect.width * -0.05, y: rect.minY + rect.height * 0.81)
        let c1cp2 = CGPoint(x: rect.minX + rect.width * -0.05, y: rect.minY + rect.height * 0.5)

        let c2destination = CGPoint(x: rect.minX + rect.width * 0.737, y: rect.minY + rect.height * 0.35)
        let c2cp1 = CGPoint(x: rect.minX + rect.width * 0.17, y: rect.minY + rect.height * 0.13)
        let c2cp2 = CGPoint(x: rect.minX + rect.width * 0.6, y: rect.minY + rect.height * 0.06)

        let c3destination = CGPoint(x: rect.minX + rect.width * 0.773, y: rect.minY + rect.height * 0.833)
        let c3cp1 = CGPoint(x: rect.minX + rect.width * 1.08, y: rect.minY + rect.height * 0.35)
        let c3cp2 = CGPoint(x: rect.minX + rect.width * 1.08, y: rect.minY + rect.height * 0.8)

        path.addCurve(to: c1destination, control1: c1cp1, control2: c1cp2)
        path.addCurve(to: c2destination, control1: c2cp1, control2: c2cp2)
        path.addCurve(to: c3destination, control1: c3cp1, control2: c3cp2)

        path.closeSubpath()
        
        return path
    }
    
    @ViewBuilder func styling() -> some View {
        if debug {
            self.stroke(Color.black, style: .init(lineWidth: 2, lineCap: .round, lineJoin: .round))
        } else {
            self.fill(
                
                LinearGradient(
                        gradient: Gradient(colors: [Color(white: 0.7), Color(white: 0.3)]),
                        startPoint: .top,
                        endPoint: .bottom))
        }
    }
}

private struct SunView: View {

    let showingRays: Bool

    @State private var rotatingRays = false

    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            
            let rayWidth = geo.size.width * 0.08
            let rayHeight = geo.size.height * 0.2
            let rayOffset = geo.size.width * -0.4
            let sunDiameter = geo.size.width * 0.45
            ZStack {
                ForEach(0..<8) { rayIndex in
                    Capsule()
                        .fill(Color.yellow)
                        .frame(width: rayWidth, height: rayHeight)
                        .offset(y: showingRays ? rayOffset : 0)
                        .rotationEffect(.degrees(Double(45 * rayIndex)))
                }
                
                .rotationEffect(.degrees(rotatingRays ? 360 : 0))
                
                Circle()
                    .fill(Color.yellow)
                    .frame(width: sunDiameter, height: sunDiameter)
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
        }
        .onAppear {
            withAnimation(Animation.linear(duration: 8).repeatForever(autoreverses: false)) {
                rotatingRays = true
            }
        }
    }
}

private struct RainView: View {
    @State private var animating = false
    var body: some View {
        GeometryReader { (geo: GeometryProxy) in
            RainShape(animatableData: animating ? 1 : 0)
                .stroke(Color.blue, style: .init(lineWidth: geo.size.width * 0.07, lineCap: .round))
        }
        .onAppear {
            withAnimation(Animation.linear(duration: 1).repeatForever(autoreverses: false)) {
                animating = true
            }
        }
    }
}

private struct RainShape: Shape {
    
    var animatableData: CGFloat
    
    func path(in rect: CGRect) -> Path {
        var path = Path()
        
        let yOffset = rect.height * 0.35
        
        let animationOffset = yOffset * animatableData
        
        let col1X = rect.minX + rect.width * 0.3
        let col2X = rect.minX + rect.width * 0.5
        let col3X = rect.minX + rect.width * 0.7

        for row in 0...2 {
            let rowYOffset = CGFloat(row) * yOffset + animationOffset
            
            let drop1Start = CGPoint(x: col1X, y: rect.minY + rect.height * 0.15 + rowYOffset)
            let drop1End = CGPoint(x: col1X, y: rect.minY + rect.height * 0.28 + rowYOffset)
            
            path.move(to: drop1Start)
            path.addLine(to: drop1End)
            
            let drop2Start = CGPoint(x: col2X, y: rect.minY + rect.height * 0 + rowYOffset)
            let drop2End = CGPoint(x: col2X, y: rect.minY + rect.height * 0.13 + rowYOffset)
            
            path.move(to: drop2Start)
            path.addLine(to: drop2End)
            
            let drop3Start = CGPoint(x: col3X, y: rect.minY + rect.height * 0.08 + rowYOffset)
            let drop3End = CGPoint(x: col3X, y: rect.minY + rect.height * 0.2 + rowYOffset)
            
            path.move(to: drop3Start)
            path.addLine(to: drop3End)
        }
        
        return path
    }
}

struct WeatherIconCloudSunRainDemoNative_Previews: PreviewProvider {
    struct WeatherIconCloudSunRainDemoNative_Harness: View {
        
        var body: some View {
            WeatherIconCloudSunRainDemoNative()
                .frame(width: 300, height: 300)
                .frame(maxWidth: /*@START_MENU_TOKEN@*/.infinity/*@END_MENU_TOKEN@*/, maxHeight: /*@START_MENU_TOKEN@*/.infinity/*@END_MENU_TOKEN@*/)
                .background(Color(white: 0.1))
                .ignoresSafeArea()
            
        }
    }
    
    static var previews: some View {
        WeatherIconCloudSunRainDemoNative_Harness()
            .previewDevice("iPhone 12 Pro Max")
            .previewDisplayName("iPhone 12 Pro Max")
    }
}