SwiftUI RectGetter example

RectGetter.swift

struct RectGetterDemoView: View {
    @State private var canvasRect = CGRect()
    
    var body: some View {
        Text("Demo").background(RectGetter($canvasRect))
    }
}

struct RectGetter: View {
    @Binding var rect: CGRect
    
    init(_ rect: Binding<CGRect>) {
        _rect = rect
    }
    
    var body: some View {
        GeometryReader { proxy in
            self.createView(proxy: proxy)
        }
    }
    
    func createView(proxy: GeometryProxy) -> some View {
        DispatchQueue.main.async {
            self.rect = proxy.frame(in: .global)
        }
        
        return Rectangle().fill(Color.clear)
    }
}