HighlightTappable.swift

struct ContentView: View {
    var body: some View {
        Image(nsImage: NSImage(named: .init(NSImage.applicationIconName))!)
            .resizable()
            .frame(width: 100, height: 100)
            .tapWithHighlight(onTap: {
                print("Tap")
            }, onLongPress: {
                print("Long Press")
            })
            .padding(100)
    }
}

struct HighlightTappable: ViewModifier {

    @State private var isPressed = false
    var onTap: () -> Void
    var onLongPress: () -> Void

    func body(content: Content) -> some View {
        content
            .brightness(isPressed ? -0.5 : 0)
            .onTapGesture {
                onTap()
            }
            .onLongPressGesture(minimumDuration: 2, pressing: {
                isPressed = $0
            }, perform: {
                onLongPress()
            })
    }
}

extension View {
    func tapWithHighlight(onTap: @escaping () -> Void, onLongPress: @escaping () -> Void) -> some View {
        self.modifier(HighlightTappable(onTap: onTap, onLongPress: onLongPress))
    }
}