SwiftUI:多点触控手势/多个手势

import SwiftUI

struct ContentView: View {
    @State private var scale: CGFloat = 1.0
    @State private var rotation: Angle = .zero
    @State private var offset: CGSize = .zero

    var body: some View {
        Image("example")
            .resizable()
            .aspectRatio(contentMode: .fit)
            .scaleEffect(scale)
            .rotationEffect(rotation)
            .offset(offset)
            .gesture(
                MagnificationGesture(minimumScaleDelta: 0.1, maximumScaleDelta: 5)
                    .onChanged { value in
                        scale = value.magnitude
                    }
                    .onEnded { _ in
                        scale = 1.0
                    },
                RotationGesture()
                    .onChanged { value in
                        rotation = value
                    }
                    .onEnded { _ in
                        rotation = .zero
                    },
                DragGesture()
                    .onChanged { value in
                        offset = value.translation
                    }
                    .onEnded { _ in
                        offset = .zero
                    }
            )
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

.gesture(
    MagnificationGesture(minimumScaleDelta: 0.1, maximumScaleDelta: 5)
        .onChanged { value in
            scale = value.magnitude
        }
        .onEnded { _ in
            scale = 1.0
        },
    RotationGesture()
        .onChanged { value in
            rotation = value
        }
        .onEnded { _ in
            rotation = .zero
        }
        .simultaneous(),
    DragGesture()
        .onChanged { value in
            offset = value.translation
        }
        .onEnded { _ in
            offset = .zero
        }
)

.gesture(
    LongPressGesture(minimumPressDuration: 0.5)
        .onChanged { _ in
            print("Long press detected")
        }
        .onEnded { _ in
            print("Long press ended")
        }
)