Explore a location with a highly detailed map and Look Around

At a glance

Project structure

Source bundle/
├── MapKitLookAround/
│   ├── AppDelegate.swift
│   ├── Itinerary.swift
│   ├── ItineraryViewController.swift
│   ├── SceneDelegate.swift
│   ├── TourViewController.swift
│   ├── MapDataResults.swift
│   └── Resources/
│       ├── Base.lproj/
│       │   ├── LaunchScreen.storyboard
│       │   └── Main.storyboard
│       └── Info.plist
├── Configuration/
│   └── SampleCode.xcconfig
└── MapKitLookAround.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 7 project/configuration file(s) and 13 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["ItineraryViewController"]
    N3["MapKit APIs"]
    N1 --> N2
    N2 --> N3

Reference code

MapKitLookAround/AppDelegate.swift:10 — architecture anchor

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into MapKit.

Ownership and state

classDiagram
    MapItemID *-- Int : uniqueID
    MapRouteID o-- MapItemID : startItemID
    MapRouteID o-- MapItemID : endItemID
    TourStop *-- String : title

Ownership evidence

MapKitLookAround/Itinerary.swift:15 — stored dependency or nearest verified ownership anchor

struct MapItemID: Hashable {
    var uniqueID: Int
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

MapKitLookAround/Itinerary.swift:46 — representative execution boundary

struct ItineraryStop: Sendable, Identifiable {
    // ...
    var id: MapItemID { mapItemID }
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

MapKitLookAround/AppDelegate.swift:11 — representative type boundary

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

MapKitLookAround/Itinerary.swift:81 — representative boundary

@MainActor
class Itinerary {
    // ...
    private var lookAroundSceneResults = MapDataResults<MapItemID, MKLookAroundScene?>()
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Main application flow

sequenceDiagram
    participant ItineraryViewController
    participant Task
    participant lookAroundSnapshotResults
    participant itinerary
    participant MKLookAroundSnapshotter
    participant dataSource
    ItineraryViewController->>Task: Start asynchronous work
    ItineraryViewController->>lookAroundSnapshotResults: result()
    ItineraryViewController->>itinerary: lookAroundScene()
    ItineraryViewController->>MKLookAroundSnapshotter: MKLookAroundSnapshotter()
    ItineraryViewController->>dataSource: apply()

Reference code

MapKitLookAround/ItineraryViewController.swift:122 — configureCell()

                    if let lookaroundScene = try await itinerary.lookAroundScene(for: item.mapItemID) {

                        // Use the specified image size.
                        let snapshotOptions = MKLookAroundSnapshotter.Options()
                        snapshotOptions.size = ItineraryViewController.thumbnailSize

                        // Turn off all point of interest labels in the snapshot.
                        snapshotOptions.pointOfInterestFilter = MKPointOfInterestFilter.excludingAll

                        // Set the resolution for the snapshot to the display scale, which is part of the trait collection.
                        snapshotOptions.traitCollection = traitCollection

                        // Create the snapshot.
                        return try await MKLookAroundSnapshotter(scene: lookaroundScene, options: snapshotOptions).snapshot.image
                    }

                    // Otherwise, store an error.
                    else {
                        throw MapDataError.sceneRequestFailed(item.mapItemID, item.mapItem.placemark.title)
                    }

Naming conventions

• Types: Controller: ItineraryViewController, TourViewController; Delegate: AppDelegate, SceneDelegate.
• Protocols: no local protocol declaration in the scanned source.
• Methods: hash, lookAroundScene, viewDidLoad, createCollectionView, configureDataSource, configureCell, prepare, viewDidAppear.
• Files: MapKitLookAround/AppDelegate.swift, MapKitLookAround/Itinerary.swift, MapKitLookAround/ItineraryViewController.swift, MapKitLookAround/SceneDelegate.swift, MapKitLookAround/TourViewController.swift, MapKitLookAround/MapDataResults.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches MapKit, UIKit, CoreLocation through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation