Custom Geometry Reader

CustomGeometryReader.swift

//
//  CustomGeometryReader.swift
//
//
//  Created by Arutyun Enfendzhyan on 10.01.22.
//

import SwiftUI

struct CustomGeometryReader: View {
    @Binding var rect: CGRect
    @StateObject var view = ResisableUIView()
    
    var body: some View {
        Impl(view: view)
            .onReceive(view.$rect) { rect = $0 }
    }
    
    struct Impl: UIViewRepresentable {
        typealias UIViewType = CustomGeometryReader.ResisableUIView
        
        let view: UIViewType
        func makeUIView(context: Context) -> UIViewType { view }
        func updateUIView(_ uiView: UIViewType, context: Context) {}
    }
    
    final class ResisableUIView: UIView, ObservableObject {
        @Published var rect = CGRect.zero
        
        override func layoutSubviews() {
            super.layoutSubviews()
            rect = convert(frame, to: nil)
        }
    }
}

public extension View {
    func frame(reader: Binding<CGRect>) -> some View { background(CustomGeometryReader(rect: reader)) }
    func frame(reader: Binding<CGSize>) -> some View {
        frame(reader: .init { .init(origin: .zero, size: reader.wrappedValue) } set: { reader.wrappedValue = $0.size })
    }
    func frame(reader: Binding<CGPoint>) -> some View {
        frame(reader: .init { .init(origin: reader.wrappedValue, size: .zero) } set: { reader.wrappedValue = $0.origin })
    }
}

// MARK: Example Usage

struct CustomGeometryReader_Previews: PreviewProvider, View, Init {
    @State var rect = CGRect.zero
    
    var body: some View {
        VStack {
            Text("\(rect)" as String)
            Color.blue
                .frame(width: 100, height: 100)
                .frame(reader: $rect)
                .padding(.leading)
        }
    }
}

Apple's GeometryReader couldn't be more complicated, whenever I needed to obtain the size of a view. Therefore I decided to create CustomGeometryReader, where instead of using preferences to pass around the frame, just use a state. Although it lacks the coordinate space, it's an easy workaround, use multiple CustomGeometryReaders. Maybe I will add it in the future.