gesture on off nil : DragGesture. in swiftui code example

Example: drag gesture swiftui

struct ContentView: View {
    // 1.
    @State private var currentPosition: CGSize = .zero
    @State private var newPosition: CGSize = .zero
    
    var body: some View {
        // 2.
        Circle()
            .frame(width: 100, height: 100)
            .foregroundColor(Color.red)
            .offset(x: self.currentPosition.width, y: self.currentPosition.height)
            // 3.
            .gesture(DragGesture()
                .onChanged { value in
                    self.currentPosition = CGSize(width: value.translation.width + self.newPosition.width, height: value.translation.height + self.newPosition.height)
            }   // 4.
                .onEnded { value in
                    self.currentPosition = CGSize(width: value.translation.width + self.newPosition.width, height: value.translation.height + self.newPosition.height)
                    print(self.newPosition.width)
                    self.newPosition = self.currentPosition
                }
        )
    }
}