Lecture 8 of Stanford’s iOS development course from Spring 2020 covers some persistence topics (UserDefaults API and JSON encoding/decoding) and the conceptual underpinnings of multi-touch gesture handling. We start adding these capabilities to EmojiArt by making its Model be convertible to/from JSON (using the Codable protocol) and then storing it (for now) in a lightweight storage vehicle. After that, pinch and drag gestures are added to EmojiArt to allow the user to zoom in and out and pan around in their document.