ScalingButtonStyle.swift

struct ScalingButtonStyle: ButtonStyle {
    var scale = CGFloat(0.95)
    
    func makeBody(configuration: Configuration) -> some View {
        let animation: Animation? = {
            if configuration.isPressed {
                /// pressing down
                return .spring(
                    response: 0.19,
                    dampingFraction: 0.45,
                    blendDuration: 1
                )
            } else {
                return .spring(
                    response: 0.4,
                    dampingFraction: 0.4,
                    blendDuration: 1
                )
            }
        }()

        return configuration.label
            .opacity(configuration.isPressed ? 0.95 : 1)
            .scaleEffect(configuration.isPressed ? scale : 1)
            .animation(animation, value: configuration.isPressed)
    }
}

extension ButtonStyle where Self == ScalingButtonStyle {
    static var scaling: ScalingButtonStyle {
        ScalingButtonStyle()
    }

    static func scaling(_ scale: CGFloat) -> ScalingButtonStyle {
        ScalingButtonStyle(scale: scale)
    }
}