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我有一段代码允许您使用放大手势放大和缩小带有渐变的圆圈。如果我将手指放在屏幕中间并缩放，这很好用，但是如果我将手指放在屏幕边缘并做放大手势，我希望它放大我手指之间的点。现在，它仍然以屏幕中心为放大中心进行放大。

如何修改我的代码以允许用户以手指放置之间的 CGPoint 为中心？

struct ContentView: View {
    @GestureState var magnificationState = MagnificationState.inactive
    @State var viewMagnificationState = CGFloat(1.0)
    
    var magnificationScale: CGFloat {
        return viewMagnificationState * magnificationState.scale
    }
    
    var body: some View {
        let gradient = Gradient(colors: [.red, .yellow, .green, .blue, .purple, .red, .yellow, .green, .blue, .purple, .red, .yellow, .green, .blue, .purple])
        
        let magnificationGesture = MagnificationGesture()
            .updating($magnificationState) { value, state, transaction in
                state = .zooming(scale: value)
            }.onEnded { value in
                self.viewMagnificationState *= value
            }
        
        
        Circle()
            .fill(
                RadialGradient(gradient: gradient, center: .center, startRadius: 50, endRadius: 2000)
            )
            .frame(width: 2000, height: 2000)
            .scaleEffect(magnificationScale)
            .gesture(magnificationGesture)
    }
}

enum MagnificationState {
    case inactive
    case zooming(scale: CGFloat)
    
    var scale: CGFloat {
        switch self {
        case .zooming(let scale):
            return scale
        default:
            return CGFloat(1.0)
        }
    }
}
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