AnimatedGradientMaskedText.swift

import SwiftUI

struct ContentView: View {
    @State var gradient = [
        Color.red, .orange, .yellow, .green, .blue, .purple, Color.red, .orange, .yellow, .green, .blue, .purple,
    ]

    @State var startPoint = UnitPoint(x: 0, y: -1)
    @State var endPoint = UnitPoint(x: 0, y: 1)

    var body: some View {
        ZStack(alignment: .center) {
            LinearGradient(
                gradient: Gradient(colors: gradient),
                startPoint: startPoint,
                endPoint: endPoint
            )
            .mask(
                HStack {
                    Spacer()
                    VStack {
                        Spacer()
                        Text("stormid").font(Font(UIFont(name: "CenturySchoolbook", size: 200)!))
                        Spacer()
                    }
                    Spacer()
                }
            )
            .background(Color.black)
            .onAppear {
                withAnimation(Animation.easeInOut(duration: 2)
                    .repeatForever(autoreverses: true)
                ) {
                    self.startPoint = UnitPoint(x: 0, y: 0)
                    self.endPoint = UnitPoint(x: 2, y: 0)
                }
            }
        }.edgesIgnoringSafeArea(.all)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}