Segmenting and colorizing individuals from a surrounding scene

At a glance

Project structure

Source bundle/
├── PersonInstanceMaskDemo/
│   ├── PersonInstanceMaskDemoApp.swift
│   ├── Models/
│   │   ├── PhotoSelectionModel.swift
│   │   ├── SegmentationModel.swift
│   │   └── SegmentationResults.swift
│   ├── Views/
│   │   ├── PhotoSelectionView.swift
│   │   └── SegmentationResultsView.swift
│   └── Info.plist
├── Configuration/
│   └── SampleCode.xcconfig
└── PersonInstanceMaskDemo.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 4 project/configuration file(s) and 14 source declaration(s).

Overall architecture

flowchart LR
    N1["PersonInstanceMaskDemoApp"]
    N2["PhotoSelectionView"]
    N3["PhotoSelectionModel"]
    N4["Vision APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

PersonInstanceMaskDemo/PersonInstanceMaskDemoApp.swift:9 — architecture anchor

@main
struct PersonInstanceMaskDemoApp: App {
    var body: some Scene {
        WindowGroup {
            PhotoSelectionView()
        }
    }
}

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 Vision.

Ownership and state

classDiagram
    SelectedImage o-- UIImage : image
    SelectedImage o-- ImageState : imageState
    SelectedImage o-- PhotosPickerItem : imageSelection
    SegmentationModel o-- UIImage : segmentedImage

Ownership evidence

PersonInstanceMaskDemo/Models/PhotoSelectionModel.swift:27 — stored dependency or nearest verified ownership anchor

    struct SelectedImage: Transferable {
        let image: UIImage
        // ...
    }

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

PersonInstanceMaskDemo/Models/PhotoSelectionModel.swift:54 — representative execution boundary

            DispatchQueue.main.async {
                // ...
                    print("Failed to get the selected item.")
                // ...
            }

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

PersonInstanceMaskDemo/Models/SegmentationResults.swift:12 — representative type boundary

protocol SegmentationResults {
    var segmentationMask: CVPixelBuffer { get set }
    var numSegments: Int { get set }
    func generateSegmentedImage(baseImage: CIImage, selectedSegments: IndexSet) async -> UIImage
    func segmentForPixelValue(_ value: UInt8) -> Int
}

The source explicitly defines local protocol relationships: InstanceMaskResults → SegmentationResults, PersonSegmentationResults → SegmentationResults.

Access control

Reference code

PersonInstanceMaskDemo/Models/PhotoSelectionModel.swift:39 — representative boundary

class PhotoSelectionModel: ObservableObject {
    // ...
    private(set) var imageState: ImageState = .noneselected
    // ...
}

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

Naming conventions

• Types: App: PersonInstanceMaskDemoApp; Model: PhotoSelectionModel, SegmentationModel; View: PhotoSelectionView, SegmentationMaskView, SegmentationResultsView, SelectedImageView.
• Protocols: SegmentationResults.
• Methods: loadTransferable, runSegmentationRequestOnImage, toggleSegment, toggleSegmentAtLocation, isSelected, countFaces, segmentAtLocation, generateSegmentedImage.
• Files: PersonInstanceMaskDemo/PersonInstanceMaskDemoApp.swift, PersonInstanceMaskDemo/Models/PhotoSelectionModel.swift, PersonInstanceMaskDemo/Models/SegmentationModel.swift, PersonInstanceMaskDemo/Views/PhotoSelectionView.swift, PersonInstanceMaskDemo/Views/SegmentationResultsView.swift, PersonInstanceMaskDemo/Models/SegmentationResults.swift.

Architecture takeaways

• PersonInstanceMaskDemoApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, PhotosUI, Vision, CoreImage 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.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation