在旋转视图上调整拖动手势

Question

我在视图中有一张图片。

添加旋转以旋转视图
添加了拖动手势来平移图像
当图像未旋转时拖动手势工作正常
一旦视图旋转到特定角度，拖动手势就会受到干扰，因为视图已旋转。

那么，如何根据旋转角度调整dragOffset和位置呢？

代码：

struct ImageView: View {
    @State private var dragOffset: CGSize = .zero
    @State private var position: CGSize = .zero
    
    @State private var currentRotation: Angle = .zero
    @GestureState private var twistAngle: Angle = .zero
    
    public var body: some View {
        let rotationGesture = RotationGesture(minimumAngleDelta: .degrees(10))
            .updating($twistAngle, body: { (value, state, _) in
                state = value
            })
            .onEnded{ self.currentRotation += [=10=] }
        
        let dragGesture = DragGesture()
            .onChanged({ (value) in
                self.dragOffset = value.translation
            })
            .onEnded({ (value) in
                self.position.width += value.translation.width
                self.position.height += value.translation.height
                self.dragOffset = .zero
            })
        
        let gestures = rotationGesture
            .simultaneously(with: dragGesture)
        
        Image.placeholder320x192
            .offset(x: dragOffset.width + position.width, y: dragOffset.height + position.height)
            .rotationEffect(currentRotation + twistAngle)
            .gesture(gestures, including: .gesture)
    }
}

Answer 1

修饰符的顺序很重要。您当前在 offset 之前旋转 - 因此您正在应用偏移然后旋转。这使得偏移出现在一个角度。相反，您想旋转然后偏移。

变化：

Image.placeholder320x192
    .offset(x: dragOffset.width + position.width, y: dragOffset.height + position.height)
    .rotationEffect(currentRotation + twistAngle)
    .gesture(gestures, including: .gesture)

为此：

Image.placeholder320x192
    .rotationEffect(currentRotation + twistAngle)
    .offset(x: dragOffset.width + position.width, y: dragOffset.height + position.height)
    .gesture(gestures, including: .gesture)

在旋转视图上调整拖动手势

Adjust Drag Gesture on Rotated View

gesture

ios

swift

swiftui