SwiftUI - 旋转手势RotationGesture基本使

1.带有圆角的矩形形状

struct RotationGesturesView: View {
    var body: some View {
        RoundedRectangle(cornerRadius: 25.0, style: .continuous)
            .fill(Color.blue)
            .frame(width: 200, height: 200, alignment: .center)
            .padding()
            .background(Color.red)
    }
}

2. 实现RotationGesture

struct RotationGesturesView: View {
    //放大手势
    @GestureState var magniValue:CGFloat = 1
    var magnificationGestures:some Gesture {
        MagnificationGesture()
            //current 当前值
            //state 实时值
            //动画
            .updating($magniValue) { (current, state, trans) in
                state = current
            }
    }

    var body: some View {
        RoundedRectangle(cornerRadius: 25.0, style: .continuous)
            .fill(Color.blue)
            .frame(width: 200, height: 200, alignment: .center)
            .padding()
            .background(Color.red)
    }
}

GestureState 用于手势系列的属性包装器，用法类似State。

3.调用放大手势

struct RotationGesturesView: View {
    //放大手势
    @GestureState var magniValue:CGFloat = 1
    var magniGestures:some Gesture {
        MagnificationGesture(minimumScaleDelta: 1)
            //current 当前值
            //state 实时值
            //动画
            .updating($magnification) { (current, state, trans) in
                state = current
            }
    }

    var body: some View {
        RoundedRectangle(cornerRadius: 25.0, style: .continuous)
            .fill(Color.blue)
            .frame(width: 200, height: 200, alignment: .center)
            .padding()
            .background(Color.red)
  
            .scaleEffect(magniValue)
            .gesture(magniGestures)
    }
}