使用GeometryReader包裹视图，并将GeometryProxy的size参数传递给需要设置宽度和高度的子视图。这将确保视图仅在其预期范围内渲染。以下是示例代码：

import SwiftUI

struct ContentView: View {
    var body: some View {
        GeometryReader { proxy in
            VStack {
                Text("Hello World!")
                    .frame(width: proxy.size.width, height: proxy.size.height)
            }
            .frame(width: proxy.size.width, height: proxy.size.height)
        }
    }
}

#if DEBUG
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif