WaveDemo.swift

struct ContentView: View {
    
    @State private var percent = 50.0
    @State private var waveOffset = Angle(degrees: 0)
    @State private var waveOffset2 = Angle(degrees: 180)
    @State var timerTest : Timer?
    var body: some View {
        VStack {
            ZStack(alignment: .center) {
                Rectangle().frame(width: 200, height: 220)
                Wave(offset: Angle(degrees: self.waveOffset.degrees), percent: Double(percent)/100)
                    .fill(Color(red: 0, green: 0.5, blue: 0.75, opacity: 0.5))
                    .frame(width: 200, height: 220)
                Wave(offset: Angle(degrees: self.waveOffset2.degrees), percent: Double(percent)/100)
                    .fill(Color(red: 0, green: 0.5, blue: 0.75, opacity: 0.5))
                    .opacity(0.5)
                    .frame(width: 200, height: 220)
            }
            .mask(
                Image.init(systemName: "applelogo")
                    .resizable()
                    .frame(width: 200, height: 200)
            )
            .onTapGesture {
                guard timerTest == nil else  { return }
                timerTest =  Timer.scheduledTimer(withTimeInterval: 0.02, repeats: true) { _ in
                    if percent <= 100 {
                        withAnimation(Animation.linear(duration: 0.03)) {
                            percent += 0.25
                        }
                    } else {
                        self.timerTest?.invalidate()
                        self.timerTest = nil
                    }
                }
                
            }
            Slider(value: self.$percent, in: 0...100)
        }
        .padding(.all)
        .onAppear {
            withAnimation(Animation.linear(duration: 2).repeatForever(autoreverses: false)) {
                self.waveOffset = Angle(degrees: 360)
                self.waveOffset2 = Angle(degrees: -180)
            }
        }
    }
}