2021 WELCOME

Year2021View.swift

import SwiftUI
struct CircularEffect: AnimatableModifier {
    var param: CGFloat
    let count: Int
    let radius: CGFloat
    var animatableData: CGFloat {
        get { return param }
        set { param = newValue }
    }
    
    func scale(_ index: Int)-> CGFloat {
        return 1.5*sin(param*CGFloat.pi)*CGFloat(index)/CGFloat(count)
    }
    func opacity(_ index: Int)-> Double {
        return index == count-1 ? 1.0 : 0.16*Double(index)/Double(count)
    }
    func innerRadius(_ index: Int)-> CGSize {
        let ratio = 0.3+0.7*sin(param*CGFloat.pi)
        return CGSize(width: cos(param*CGFloat.pi*2)*radius*ratio, height: sin(param*CGFloat.pi*2)*radius*ratio)
    }
   
    func body(content: Content) -> some View {
        ZStack {
            ForEach (0..<count) { index in
                content
                    .hueRotation(Angle(degrees: Double(index)/Double(count)*90.0-90.0))
                    .scaleEffect(self.scale(index))
                    .rotationEffect(Angle(radians: Double.pi + Double(2*param*CGFloat.pi*2)))
                    .offset(self.innerRadius(index))
                    .rotationEffect(Angle(radians: Double(index)/Double(count)*Double.pi*2 + Double(param*CGFloat.pi*2)))
                    .opacity(self.opacity(index))
                    .blendMode(.plusLighter)
            }
        }
    }
}
struct Year2021View: View {
    @State var param: CGFloat = 0.0
    var body: some View {
        VStack {
            Text("2021")
                .font(.largeTitle)
                .foregroundColor(Color("gold"))
                //.modifier(CircularEffect(param: self.param, count: 3, radius: 21)) try to have fun with multiple effects ;)
                .modifier(CircularEffect(param: self.param, count: 200, radius: 128))
        }
        .onTapGesture {
            withAnimation(Animation.easeInOut(duration: 10.0).repeatForever(autoreverses: false)) {
                self.param = 1.0
            }
        }
    }
}