Converting between view coordinate systems - Example 1

Example1.swift

import UIKit

let frame = CGRect(origin: .zero,
                   size: .init(width: 150, height: 150))
let window = UIWindow(frame: frame)
let rootView = UIView(frame: window.bounds)
rootView.backgroundColor = .white
window.addSubview(rootView)

let view = UIView(frame: CGRect(origin: .init(x: 25, y: 25),
                                   size: CGSize(width: 100, height: 100)))
view.backgroundColor = UIColor.green.withAlphaComponent(0.5)
rootView.addSubview(view)

let subview = UIView(frame: CGRect(origin: .init(x: 25, y: 25),
                                   size: .init(width: 50, height: 50)))
subview.backgroundColor = UIColor.blue.withAlphaComponent(0.5)
view.addSubview(subview)

let convertToWindow = subview.convert(subview.bounds, to: window)

// {x 25 y 25 w 50 h 50 }
subview.frame
// {x 50 y 50 w 50 h 50 }
convertToWindow

window.makeKeyAndVisible()

import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = window