Slide-to-Unlock animation in SwiftUI

Shimmer.swift

import SwiftUI

public struct Shimmer: AnimatableModifier {

    private let gradient: Gradient

    @State private var position: CGFloat = 0

    public var animatableData: CGFloat {
        get { position }
        set { position = newValue }
    }

    private let animation = Animation
        .linear(duration: 2)
        .delay(1)
        .repeatForever(autoreverses: false)

    init(sideColor: Color = Color(white: 0.25), middleColor: Color = .white) {
        gradient = Gradient(colors: [sideColor, middleColor, sideColor])
    }

    public func body(content: Content) -> some View {
        LinearGradient(
            gradient: gradient,
            startPoint: .init(x: position - 0.2 * (1 - position), y: 0.5),
            endPoint: .init(x: position + 0.2 * position, y: 0.5)
        )
        .mask(content)
        .onAppear {
            withAnimation(animation) {
                    position = 1
                }
        }
    }
}


// Use it like this

Text("slide to unlock")
    .modifier(Shimmer())