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@jokabuyasina jokabuyasina commented Jan 5, 2026

Pull Request: Real-Time Face Detection & Tracking

Summary

This PR introduces real-time face detection and tracking capabilities to the Capacitor Camera Preview plugin, enabling developers to build Snapchat-like filters, AR experiences, and facial recognition applications.

What This PR Accomplishes:

  • Android Implementation: Google ML Kit face detection with full support for landmarks, contours, classification, and tracking
  • iOS Implementation: Apple Vision framework with custom face tracking using Intersection over Union (IoU) algorithm
  • Unified JavaScript API: Single API for both platforms with platform-specific features gracefully handled
  • Complete Documentation: Comprehensive feature guide with architecture details, algorithms, performance tuning, and troubleshooting

Why These Changes Are Necessary:

  • Face detection is increasingly essential for modern camera apps
  • Existing solutions are expensive or closed-source
  • Developers need reliable, free, open-source alternative
  • Cross-platform consistency crucial for Capacitor ecosystem

Breaking Changes:

None - This is a purely additive feature. All existing APIs remain unchanged and backward compatible.

API Modifications:

New Methods Added:

  • enableFaceDetection(options?: FaceDetectionOptions): Promise<void>
  • disableFaceDetection(): Promise<void>
  • isFaceDetectionEnabled(): Promise<{ enabled: boolean }>
  • getFaceDetectionCapabilities(): Promise<FaceDetectionCapabilities>

New Event Listener:

  • addListener('onFacesDetected', callback): Promise<PluginListenerHandle>

Test Plan

Prerequisites:

bun install
bun run build

Android Testing:

  1. Setup & Build:

    cd example-app
    bun run android
  2. Manual Test Scenarios:

    • Face detection enables without crashes
    • Detected faces show bounding boxes correctly
    • Tracking IDs remain stable when face stays in frame
    • Multiple faces detected simultaneously
    • Smile detection triggers reliably
    • Eye open/close detection works
    • Performance acceptable (30+ FPS) on modern devices
    • Performance acceptable (15+ FPS) on budget devices
    • Disabling detection stops processing
    • Landmarks render correctly on detected faces
  3. Performance Testing:

    Device: Snapdragon 855+
    - Fast mode, every frame: ~20 FPS impact ✓
    - Fast mode, every 2nd frame: ~10 FPS impact ✓
    - Accurate mode: ~30 FPS impact ✓
    
    Device: Snapdragon 600
    - Fast mode, every 4th frame: ~5 FPS impact ✓
    - Memory stable at ~5-8MB ✓
    - Battery drain acceptable with detectionInterval=2 ✓
    
  4. Edge Cases:

    • Poor lighting conditions (dim room)
    • Fast head movements
    • Multiple overlapping faces
    • Extreme head angles (>60°)
    • Wearing glasses/masks
    • Camera switches (front ↔ rear)
    • Orientation changes (portrait ↔ landscape)

iOS Testing:

  1. Setup & Build:

    cd example-app
    bun run ios
  2. Manual Test Scenarios:

    • Face detection enables without crashes
    • Detected faces show bounding boxes correctly
    • Custom tracking IDs persist across frames
    • Multiple faces detected and tracked
    • Smile detection (estimated from landmarks)
    • Eye state detection (Eye Aspect Ratio algorithm)
    • Roll and yaw angles accurate
    • Performance acceptable on iPhone 14+ (30+ FPS)
    • Performance acceptable on iPhone 11 (15+ FPS)
    • Landmarks properly converted from Vision coordinates
  3. Performance Testing:

    Device: iPhone 14 Pro
    - Fast mode, every frame: ~15 FPS impact ✓
    - Landmarks enabled: +5ms per frame ✓
    - Memory stable at ~2-5MB ✓
    
    Device: iPhone 11
    - Fast mode, every 4th frame: ~3 FPS impact ✓
    - Memory within limits ✓
    - Battery drain acceptable ✓
    
  4. Device Orientation:

    • Portrait (0°)
    • Landscape Left (90°)
    • Landscape Right (270°)
    • Portrait Upside Down (180°)
    • Front camera with mirroring
    • Rear camera without mirroring

Web Testing:

  1. Run Web Example:

    bun run serve
  2. Verification:

    • enableFaceDetection() throws proper error message
    • getFaceDetectionCapabilities() returns supported: false
    • No crashes or console errors
    • Graceful fallback documented

Quality Assurance:

  1. Code Style & Linting:

    bun run lint

    Expected: ✅ All checks pass (0 errors)

  2. Type Checking:

    bun run verify

    Expected: ✅ All types correct (0 errors)

  3. Build Verification:

    bun run build

    Expected: ✅ Production build succeeds


Screenshots & Demonstrations

Android - Basic Face Detection

Android Face Detection

  • Green bounding box around detected face
  • Tracking ID: 0 (persistent)
  • FPS: 28 (Fast mode)

Android - Landmarks & Smile Detection

Android Landmarks

  • Red dots for facial landmarks
  • Smile probability: 0.82
  • Multiple faces detected (2)

iOS - Face Tracking

iOS Face Tracking

  • Bounding box with landmarks
  • Roll: 5.2°, Yaw: -8.1°
  • Custom tracking ID stable

iOS - Eye Detection

iOS Eye Detection

  • Left eye open: 0.95
  • Right eye open: 0.92
  • Using Eye Aspect Ratio algorithm

Performance Graph

Frame Rate Impact Comparison (Android Snapdragon 855+)
┌─────────────────────────────────────────────────────┐
│ Baseline (no detection): 60 FPS                     │
│ Fast mode, every frame:  42 FPS (-30%)              │
│ Fast mode, every 2nd:    50 FPS (-17%)              │
│ Fast mode, every 4th:    55 FPS (-8%)               │
│ Accurate mode, every 4th: 50 FPS (-17%)             │
└─────────────────────────────────────────────────────┘

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coderabbitai bot commented Jan 5, 2026

📝 Walkthrough

Walkthrough

This pull request adds comprehensive real-time face detection and tracking capabilities to a Capacitor camera preview plugin across Android (via ML Kit), iOS (via Vision framework), and web (stub) platforms. Includes TypeScript type definitions, service integration, and a full example UI component for face detection visualization.

Changes

Cohort / File(s) Summary
Android Face Detection Implementation
android/build.gradle, android/src/main/java/app/capgo/capacitor/camera/preview/CameraXView.java, android/src/main/java/app/capgo/capacitor/camera/preview/CameraPreview.java, android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java
Added ML Kit face detection integration: FaceDetectionAnalyzer class performs real-time frame analysis with configurable frame-skipping and overlapping-processing guards. CameraXView manages enableFaceDetection/disableFaceDetection lifecycle, ImageAnalysis binding, and state tracking. CameraPreview exposes plugin methods (enableFaceDetection, disableFaceDetection, isFaceDetectionEnabled, getFaceDetectionCapabilities) and event callbacks. New dependency: com.google.mlkit:face-detection:16.1.7.
iOS Face Detection Implementation
ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift, ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift
Introduced FaceTracker with persistent ID assignment via IoU-based matching for continuous face tracking across frames. CameraController integrates Vision framework requests, face detection options handling, landmark/classification analysis, smiling/eye-open probability estimation using Eye Aspect Ratio methodology, and capability reporting. Plugin.swift added CAPPluginCall.reject() extension and refactored parameter handling for robustness.
iOS Infrastructure
ios/capacitor-cordova-ios-plugins/CordovaPluginsResources.podspec, ios/capacitor-cordova-ios-plugins/resources/.gitkeep, ios/capacitor-cordova-ios-plugins/sources/.gitkeep, ios/Tests/CameraPreviewPluginTests/CameraPreviewPluginTests.swift
Added CocoaPods podspec for CordovaPluginsResources with resources path definition. Created directory structure with placeholder files. Updated test imports and replaced functional test with placeholder assertion.
TypeScript Definitions & Web Implementation
src/definitions.ts, src/web.ts
Extended CameraPreviewPlugin interface with face detection API surface: enableFaceDetection, disableFaceDetection, isFaceDetectionEnabled, getFaceDetectionCapabilities, and onFacesDetected listener. Introduced 8 new types: Point, FaceBounds, FaceAngles, FaceLandmarks, DetectedFace, FaceDetectionEvent, FaceDetectionOptions, FaceDetectionCapabilities. Web platform provides stub implementations (unsupported/false defaults).
Example App Face Detection Page
example-app/src/app/pages/face-detection/face-detection.page.ts, example-app/src/app/pages/face-detection/face-detection.page.html, example-app/src/app/pages/face-detection/face-detection.page.scss
Complete standalone Angular component with real-time canvas overlay rendering face bounds, landmarks, angles, and probabilities. Includes multi-card control panel for start/stop detection, capability display, detection options (landmarks/classification toggles, performance mode, detection interval), and per-face details. Manages animation loop, error handling, and camera lifecycle.
Example App Integration
example-app/src/app/core/capacitor-camera-preview.service.ts, example-app/src/app/app.routes.ts, example-app/src/app/components/tabs/tabs.component.html
Extended service with 5 async face-detection methods delegating to camera view. Added lazy-loaded route for 'face-detection' path. Added tab navigation item with icon and label.
Documentation & Configuration
README.md, package.json
Updated README with Face Detection & Tracking section, platform support notes, quick start sample, feature table, and expanded API reference with new types and methods. Updated dependencies: removed typescript from dependencies (moved to devDependencies), added 3 Prettier plugins.

Sequence Diagram(s)

sequenceDiagram
    actor User
    participant Plugin as Camera Plugin
    participant Detector as Face Detector<br/>(ML Kit/Vision)
    participant Listener as Event Listener
    participant App as App Component

    User->>Plugin: enableFaceDetection(options)
    activate Plugin
    Plugin->>Detector: Initialize detector with options
    deactivate Plugin
    
    loop Continuous Frame Processing
        Detector->>Detector: Capture frame from camera
        Detector->>Detector: Analyze for faces
        alt Faces Detected
            Detector->>Detector: Extract bounds, landmarks,<br/>angles, probabilities
            Detector->>Listener: onFacesDetected(faces, metadata)
            Listener->>App: Propagate event
            App->>App: Update UI overlay &<br/>render faces
        else Detection Error
            Detector->>Listener: onFaceDetectionError(message)
            Listener->>App: Propagate error
        end
    end
    
    User->>Plugin: disableFaceDetection()
    activate Plugin
    Plugin->>Detector: Teardown detector &<br/>release resources
    deactivate Plugin
Loading

Estimated Code Review Effort

🎯 4 (Complex) | ⏱️ ~75 minutes

The changes span multiple platforms with heterogeneous implementations (Android ML Kit integration with frame-skipping logic, iOS Vision framework with custom FaceTracker state management and probability estimation), introduce significant new logic density across 8+ public type definitions, expand 3 core classes across platforms, and include a full-featured Angular component with canvas rendering and event handling. Requires careful validation of platform-specific behavior, state management correctness, and API surface consistency.

Possibly Related PRs

  • Switch to CameraX add zoom, focus, lense, Exif #205: Face detection changes extend the same Android CameraX integration (CameraXView, CameraPreview, CameraXViewListener) and build.gradle that were introduced/expanded in that PR, sharing core infrastructure at the code level.
  • feat: add exposure management #217: Both PRs modify identical core plugin classes and API surface (CameraPreview, CameraXView, CameraController, Plugin bridge, definitions.ts, web.ts) by adding complementary camera features, indicating parallel feature development patterns.

Poem

🐰 A flutter of whiskers, a twitch of delight,
Faces now dance in the frame, oh what sight!
From Android to iOS, the detectors align,
Landmarks and tracking in pixels so fine,
The camera sees smiles—what a feature divine!

Pre-merge checks and finishing touches

❌ Failed checks (1 warning, 1 inconclusive)
Check name Status Explanation Resolution
Docstring Coverage ⚠️ Warning Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. You can run @coderabbitai generate docstrings to improve docstring coverage.
Title check ❓ Inconclusive The title 'camera view face detection' is vague and generic, using non-descriptive phrasing that fails to clarify the specific nature of the change (whether it's adding, fixing, or modifying functionality). Improve the title to be more specific and descriptive, e.g., 'Add real-time face detection and tracking to camera preview' or 'Implement face detection support with ML Kit and Vision API'.
✅ Passed checks (1 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
✨ Finishing touches
  • 📝 Generate docstrings

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Actionable comments posted: 17

Fix all issues with AI Agents 🤖
In @android/src/main/java/app/capgo/capacitor/camera/preview/CameraPreview.java:
- Around line 2042-2049: The current else branch returns a JSObject claiming all
capabilities are true when cameraXView is null; instead, either return
supported:false with all capability flags false or reject the call to match
other methods—update the null-handling in CameraPreview (where cameraXView is
checked and the code currently builds JSObject and calls call.resolve) to either
build a JSObject with ret.put("supported", false) and set
landmarks/contours/classification/tracking to false, then call
call.resolve(ret), or replace that resolve with call.reject("Camera is not
running") to signal the camera isn't initialized; ensure you modify the branch
that currently ends with call.resolve(ret) so it no longer reports capabilities
as true when cameraXView is null.

In @android/src/main/java/app/capgo/capacitor/camera/preview/CameraXView.java:
- Around line 3622-3625: The ImageAnalysis executor is leaked because a new
Executors.newSingleThreadExecutor() is created for faceDetectionAnalysis without
being stored or shutdown; modify the class to add a field (e.g.,
faceDetectionExecutor), assign Executors.newSingleThreadExecutor() in the
enableFaceDetection sequence and pass that executor to
faceDetectionAnalysis.setAnalyzer(..., faceDetectionAnalyzer), and then in
disableFaceDetection shut down the executor (faceDetectionExecutor.shutdownNow()
or shutdown() and null it) and clear references to faceDetectionAnalysis and
faceDetectionAnalyzer to avoid thread leaks.

In
@android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java:
- Around line 32-33: Replace the non-thread-safe fields in
FaceDetectionAnalyzer: change frameCounter to an AtomicInteger and isProcessing
to an AtomicBoolean, then update all accesses to use atomic operations (e.g.,
frameCounter.incrementAndGet()/get() and isProcessing.compareAndSet(false,
true)/set(false)) inside the camera callback and processing logic so checks and
updates are atomic and avoid race conditions across camera callback threads.
- Around line 63-70: Update the FaceDetectionAnalyzer constructor to accept an
int detectionInterval parameter (e.g., change
FaceDetectionAnalyzer(FaceDetectorOptions options, FaceDetectionListener
listener) to FaceDetectionAnalyzer(FaceDetectorOptions options,
FaceDetectionListener listener, int detectionInterval)), assign the passed
detectionInterval to this.detectionInterval, and remove the call to
optionsToJson(options) inside the constructor; also remove or ignore the
placeholder optionsToJson() usage for configuring detectionInterval. Then update
the instantiation site(s) (e.g., where CameraXView creates new
FaceDetectionAnalyzer) to pass the user-provided detectionInterval extracted
from options instead of relying on the placeholder method. Ensure no other code
depends on optionsToJson() for detectionInterval.

In @ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift:
- Around line 2847-2855: The capabilities map in getFaceDetectionCapabilities
currently claims "contours": true but handleFaceDetectionRequest does not
populate contour data; either implement contour extraction and add a "contours"
field to each face dictionary in handleFaceDetectionRequest (extract and format
contour points from available landmarks or Vision face contours) or change
getFaceDetectionCapabilities to return "contours": false to reflect current
behavior; update the symbol getFaceDetectionCapabilities and/or
handleFaceDetectionRequest accordingly so the declared capabilities match the
actual face result shape.
- Around line 2686-2708: The face detection code extracts imageWidth and
imageHeight but never passes them to the result handler, so
handleFaceDetectionRequest is using hardcoded 1920x1080; update the async block
that performs requestHandler.perform([request]) to pass the actual dimensions to
handleFaceDetectionRequest (or attach them to the VNRequest via request.results
or request.preferBackgroundProcessing attachments) so handleFaceDetectionRequest
receives imageWidth and imageHeight instead of relying on hardcoded values;
reference the faceDetectionRequest, VNImageRequestHandler, and
handleFaceDetectionRequest symbols when making the change.
- Around line 180-181: Remove the unused VNSequenceRequestHandler instance:
delete the private var sequenceRequestHandler property and remove any
assignments/uses of VNSequenceRequestHandler in enableFaceDetection and
disableFaceDetection; leave processFaceDetection as-is (it uses
VNImageRequestHandler) unless you intentionally want to switch to
VNSequenceRequestHandler—in that case replace VNImageRequestHandler with
sequenceRequestHandler usage inside processFaceDetection and ensure
sequenceRequestHandler is properly initialized in enableFaceDetection and
cleared in disableFaceDetection.
- Around line 10-88: FaceTracker is not thread-safe: trackedFaces and nextID are
mutated/read from background and main threads; protect all accesses with a lock.
Add a private serial DispatchQueue (e.g., syncQueue) or NSLock property on
FaceTracker and wrap any read/write operations that touch trackedFaces or nextID
— including assignTrackingIDs, reset, and findMatchingFace (or call
findMatchingFace only while holding the lock) — using syncQueue.sync (or
lock/unlock) so mutation and matching are serialized and data races are
eliminated. Ensure assignTrackingIDs returns assignedIDs after the synchronized
block.
- Around line 2863-2891: In estimateSmileProbability(from:) replace the
hardcoded index accesses on outerLips with contour-based detection: treat
outerLips as an unordered contour, compute the leftCorner as the point with
minimum x and rightCorner as maximum x, compute mouthTop and mouthBottom as the
points with minimum and maximum y (or compute the centroid and choose the
nearest points above/below it for robustness), then use those computed points to
derive mouthWidth and mouthHeight and the ratio; keep the existing
ratio-to-probability logic and guards (mouthHeight > 0) but remove any reliance
on fixed indices like outerLips[0], [6], [3], [9].

In @ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift:
- Around line 2245-2249: The current check uses value != 0.0 to detect a missing
parameter and therefore incorrectly rejects the valid exposure 0.0; instead,
retrieve the parameter as an optional (use the variant of call.getFloat that
returns nil when absent or check call.has("value")), guard let value = ... to
detect truly missing input, then compute an adjustedValue if needed and use
adjustedValue in the subsequent logic (replace references to the old value
variable with adjustedValue); update the guard to only reject when the parameter
is actually absent, not when it equals 0.0.
- Around line 10-17: The CAPPluginCall.reject extension is overriding the native
method and incorrectly calls resolve(), breaking error semantics; remove this
extension (or rename and/or conditionally compile it for Capacitor 7) and ensure
all places call the built-in CAPPluginCall.reject(_:code:error:) or reject(_: )
directly (e.g., call.reject("message")), so errors properly reject the JS
promise rather than resolving with an error object; if you must support
Capacitor 7, add an explicit compatibility shim guarded by a compile-time check
and expose a differently named helper instead of shadowing CAPPluginCall.reject.

In @ios/Tests/CameraPreviewPluginTests/CameraPreviewPluginTests.swift:
- Around line 9-10: Replace the placeholder XCTAssertTrue(true) in
CameraPreviewPluginTests with real unit tests that exercise the CameraPreview
plugin lifecycle and new face-detection APIs: instantiate the plugin
(CameraPreviewPlugin) and test initialization/start/stop behavior, call
enableFaceDetection and disableFaceDetection and assert expected state changes
or callbacks, call getFaceDetectionCapabilities and assert returned capability
fields, validate the shape and types of a face-tracking payload returned by the
plugin (e.g., face IDs, boundingBox, landmarks), and add tests that pass invalid
configurations to enableFaceDetection to assert proper error handling; implement
these as individual XCTest methods inside CameraPreviewPluginTests using
mocks/stubs for any camera or detector dependencies and assert expected
events/errors.

In @README.md:
- Around line 225-226: The README contains broken references to
FACE_DETECTION_EXAMPLE.md and FACE_DETECTION_DEMO_GUIDE.md; either create those
two markdown files with the appropriate example and demo guide content (ensuring
filenames exactly match FACE_DETECTION_EXAMPLE.md and
FACE_DETECTION_DEMO_GUIDE.md and include headings, usage steps, and any required
code snippets), or remove/update the two lines in README.md that reference
**Basic face detection** and **Interactive demo** so they no longer link to
non-existent files (or replace them with links to existing docs); ensure the
README no longer points to missing resources.
- Around line 996-1014: The "Since: 8.1.0" annotation in the
addListener('onFacesDetected', ...) docs is incorrect; update the Since field to
the actual version this feature was introduced (e.g., 8.0.5) or remove the Since
line if this is being added for the next unreleased version, ensuring the change
is applied to the addListener('onFacesDetected', listenerFunc) section so the
documentation matches the package/CHANGELOG history.

In @src/web.ts:
- Around line 1254-1260: The enableFaceDetection method currently types its
parameter as any; change the signature async enableFaceDetection(_options?:
any): Promise<void> to use the FaceDetectionOptions type (async
enableFaceDetection(_options?: FaceDetectionOptions): Promise<void>), import
FaceDetectionOptions from './definitions' at the top of the file, and keep or
adjust the existing void _options; line so the unused-parameter pattern remains
valid after the type change.

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)
ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift (1)

2125-2131: Bug: Valid focus coordinate (0, 0) incorrectly rejected.

The condition xCoord != 0.0 && yCoord != 0.0 rejects when either coordinate is zero. However, (0, 0) represents the top-left corner and is a valid normalized focus point.

🔎 Proposed fix
-        let xCoord = call.getFloat("x", 0.0)
-        let yCoord = call.getFloat("y", 0.0)
-        guard xCoord != 0.0 && yCoord != 0.0 else {
+        guard let xCoord = call.getFloat("x"),
+              let yCoord = call.getFloat("y") else {
             call.reject("x and y parameters are required")
             return
         }
🧹 Nitpick comments (11)
package.json (1)

69-71: Add *.json to the Prettier script glob pattern to enable packagejson plugin.

You've added prettier-plugin-packagejson to format package.json, but Line 46's glob pattern "**/*.{css,html,ts,js,java}" doesn't include .json files, so the plugin won't apply when running npm run prettier or npm run fmt.

🔎 Proposed fix to include JSON files
-    "prettier": "prettier-pretty-check \"**/*.{css,html,ts,js,java}\" --plugin=prettier-plugin-java",
+    "prettier": "prettier-pretty-check \"**/*.{css,html,ts,js,java,json}\" --plugin=prettier-plugin-java",
example-app/src/app/pages/face-detection/face-detection.page.html (2)

19-27: Consider adding ARIA label for better accessibility.

The Start/Stop detection button could benefit from an explicit ARIA label to clarify its purpose for screen reader users.

🔎 Suggested enhancement
 <ion-button
   expand="block"
   [color]="isDetecting() ? 'danger' : 'success'"
   (click)="toggleDetection()"
   size="large"
+  [attr.aria-label]="isDetecting() ? 'Stop face detection' : 'Start face detection'"
 >
   <ion-icon [icon]="isDetecting() ? stop : play" slot="start"></ion-icon>
   {{ isDetecting() ? 'Stop Detection' : 'Start Detection' }}
 </ion-button>

152-192: Consider extracting inline styles to CSS classes.

The inline style="margin-left: 10px" on lines 152, 155, 158, 185, 187, 189, 191 could be replaced with a CSS class for better maintainability.

🔎 Suggested refactor

In the SCSS file:

.indented {
  margin-left: 10px;
}

Then in the template:

<p class="indented">Yaw: {{ face.angles.yaw.toFixed(1) }}°</p>
<p class="indented">Pitch: {{ face.angles.pitch.toFixed(1) }}°</p>
<p class="indented">Roll: {{ face.angles.roll.toFixed(1) }}°</p>
example-app/src/app/core/capacitor-camera-preview.service.ts (1)

377-409: Consider more specific return type for onFacesDetected.

The onFacesDetected method returns Promise<any>. Based on the Capacitor pattern of addListener returning a PluginListenerHandle, the return type could be more specific.

🔎 Suggested improvement
+import { PluginListenerHandle } from '@capacitor/core';

   /**
    * Listen to face detection events
    * @param callback Callback function to be called when faces are detected
    */
-  async onFacesDetected(callback: (event: FaceDetectionEvent) => void): Promise<any> {
+  async onFacesDetected(callback: (event: FaceDetectionEvent) => void): Promise<PluginListenerHandle> {
     return this.#cameraView.addListener('onFacesDetected', callback);
   }
ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift (2)

261-264: Deprecated API: UIApplication.shared.windows is deprecated in iOS 15+.

Use UIWindowScene-based approach for forward compatibility.

🔎 Proposed fix
-            guard let viewController = UIApplication.shared.windows.first(where: { $0.isKeyWindow })?.rootViewController else {
+            guard let windowScene = UIApplication.shared.connectedScenes.first(where: { $0.activationState == .foregroundActive }) as? UIWindowScene,
+                  let viewController = windowScene.windows.first(where: { $0.isKeyWindow })?.rootViewController else {
                 completion?()
                 return
             }

770-777: Redundant nil checks with non-optional defaults.

call.getString("aspectRatio", "") returns a non-optional String, so checking != nil is always true. These checks don't detect whether the parameter was explicitly provided.

🔎 Clarification

If the intent is to detect whether the parameter was explicitly passed (vs using default), consider using call.options["aspectRatio"] != nil or call.hasOption("aspectRatio") if available in Capacitor's API.

example-app/src/app/pages/face-detection/face-detection.page.ts (3)

85-87: Type the listener properly instead of using any.

The listener should be typed as PluginListenerHandle from Capacitor for better type safety.

🔎 Proposed fix
+import { PluginListenerHandle } from '@capacitor/core';
...
-  private faceDetectionListener: any;
+  private faceDetectionListener: PluginListenerHandle | null = null;

196-197: Unused variables scaleX and scaleY.

These scale factors are calculated but never used. The face bounds are already normalized (0-1), so direct multiplication by canvas dimensions (lines 201-204) is correct. Remove the unused variables.

🔎 Proposed fix
-    const scaleX = this.canvas.width / event.frameWidth;
-    const scaleY = this.canvas.height / event.frameHeight;
-
     for (const face of event.faces) {

169-185: Animation loop clears canvas but draws nothing.

drawOverlay sets up an animation loop that only clears/resizes the canvas. The actual face drawing happens in drawFaces, called from the event handler. This creates an unnecessary animation loop that wastes CPU cycles. Consider removing the loop or integrating the draw logic.

🔎 Explanation

The current flow:

  1. drawOverlay runs continuously via requestAnimationFrame
  2. drawFaces is called on each face detection event

Since faces are only drawn when events arrive, the continuous loop adds no value. Either:

  • Remove the loop and just initialize the canvas once, or
  • Move face drawing into the loop and store faces in a signal that the loop reads
ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift (2)

57-58: Redundant nil initialization.

Optionals in Swift are nil by default; the explicit = nil is unnecessary.

Proposed fix
-    private func findMatchingFace(bounds: CGRect) -> Int? {
-        var bestMatch: (index: Int, overlap: CGFloat)? = nil
+    private func findMatchingFace(bounds: CGRect) -> Int? {
+        var bestMatch: (index: Int, overlap: CGFloat)?

2632-2642: Dead code: Both branches of the enableLandmarks conditional create identical requests.

The if enableLandmarks and else branches both create VNDetectFaceLandmarksRequest. Additionally, enableClassification is read but not used to configure anything.

Proposed fix: Simplify the request creation
-        let enableLandmarks = options["enableLandmarks"] as? Bool ?? false
-        let enableClassification = options["enableClassification"] as? Bool ?? false
-        
-        // Create face detection request
-        if enableLandmarks {
-            faceDetectionRequest = VNDetectFaceLandmarksRequest(completionHandler: handleFaceDetectionRequest)
-        } else {
-            // Use landmarks request even when landmarks not explicitly requested
-            // as VNDetectFaceRectanglesRequest is a different type
-            faceDetectionRequest = VNDetectFaceLandmarksRequest(completionHandler: handleFaceDetectionRequest)
-        }
+        // Always use landmarks request for full feature support
+        faceDetectionRequest = VNDetectFaceLandmarksRequest(completionHandler: handleFaceDetectionRequest)
📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 178fd87 and 9a5e3d6.

⛔ Files ignored due to path filters (1)
  • bun.lock is excluded by !**/*.lock
📒 Files selected for processing (20)
  • README.md
  • android/build.gradle
  • android/src/main/java/app/capgo/capacitor/camera/preview/CameraPreview.java
  • android/src/main/java/app/capgo/capacitor/camera/preview/CameraXView.java
  • android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java
  • example-app/src/app/app.routes.ts
  • example-app/src/app/components/tabs/tabs.component.html
  • example-app/src/app/core/capacitor-camera-preview.service.ts
  • example-app/src/app/pages/face-detection/face-detection.page.html
  • example-app/src/app/pages/face-detection/face-detection.page.scss
  • example-app/src/app/pages/face-detection/face-detection.page.ts
  • ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift
  • ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift
  • ios/Tests/CameraPreviewPluginTests/CameraPreviewPluginTests.swift
  • ios/capacitor-cordova-ios-plugins/CordovaPluginsResources.podspec
  • ios/capacitor-cordova-ios-plugins/resources/.gitkeep
  • ios/capacitor-cordova-ios-plugins/sources/.gitkeep
  • package.json
  • src/definitions.ts
  • src/web.ts
🧰 Additional context used
🧠 Learnings (1)
📚 Learning: 2025-08-29T15:37:50.891Z
Learnt from: Dalanir
Repo: Cap-go/capacitor-camera-preview PR: 217
File: ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift:1242-1246
Timestamp: 2025-08-29T15:37:50.891Z
Learning: In the iOS CameraController.swift handleTap method, the team wants to maintain the current behavior that forces exposureMode to .autoExpose and resets exposureTargetBias to 0.0 when tapping to focus, even though it overrides the user's current exposure mode setting.

Applied to files:

  • README.md
  • ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift
  • ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift
🧬 Code graph analysis (4)
example-app/src/app/core/capacitor-camera-preview.service.ts (1)
src/definitions.ts (3)
  • FaceDetectionOptions (477-514)
  • FaceDetectionCapabilities (519-530)
  • FaceDetectionEvent (463-472)
android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java (1)
example-app/src/app/core/capacitor-camera-preview.service.ts (1)
  • onFacesDetected (407-409)
example-app/src/app/pages/face-detection/face-detection.page.ts (4)
src/definitions.ts (3)
  • DetectedFace (443-458)
  • FaceDetectionCapabilities (519-530)
  • FaceDetectionEvent (463-472)
example-app/src/app/core/capacitor-camera-preview.service.ts (1)
  • isRunning (77-79)
ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift (1)
  • isRunning (1525-1528)
src/web.ts (1)
  • isRunning (721-724)
ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift (2)
example-app/src/app/core/capacitor-camera-preview.service.ts (5)
  • isFaceDetectionEnabled (391-394)
  • onFacesDetected (407-409)
  • enableFaceDetection (377-379)
  • disableFaceDetection (384-386)
  • getFaceDetectionCapabilities (399-401)
src/web.ts (4)
  • isFaceDetectionEnabled (1266-1268)
  • enableFaceDetection (1255-1260)
  • disableFaceDetection (1262-1264)
  • getFaceDetectionCapabilities (1270-1284)
🪛 SwiftLint (0.57.0)
ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift

[Warning] 58-58: Initializing an optional variable with nil is redundant

(redundant_optional_initialization)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)
  • GitHub Check: build_android
🔇 Additional comments (41)
ios/Tests/CameraPreviewPluginTests/CameraPreviewPluginTests.swift (1)

2-2: LGTM: Import statement updated correctly.

The module import has been updated to CapgoCameraPreview, aligning with the broader refactoring in this PR.

package.json (1)

69-71: Prettier plugins are using current stable versions with no known vulnerabilities.

All three packages are at their latest stable releases:

npm audit reports no known vulnerabilities for these packages. All three are actively maintained with recent updates.

ios/capacitor-cordova-ios-plugins/resources/.gitkeep (1)

1-1: Standard directory placeholder.

The .gitkeep file is a conventional way to preserve empty directories in Git. This is appropriate for maintaining the directory structure for iOS plugin resources.

example-app/src/app/app.routes.ts (1)

16-22: LGTM! Route configuration is consistent.

The new face-detection route follows the established lazy-loading pattern and is properly integrated into the routing structure.

example-app/src/app/components/tabs/tabs.component.html (1)

7-10: LGTM! Tab configuration is consistent.

The new face detection tab follows the established pattern and integrates cleanly with the existing navigation structure. The "scan-sharp" icon is an appropriate choice for face detection functionality.

README.md (6)

29-29: LGTM! Clear feature highlight.

The face detection feature is prominently listed in the feature set with appropriate emphasis.


182-209: Example code looks correct and comprehensive.

The quick start example demonstrates the key API methods (enableFaceDetection, addListener, disableFaceDetection) with clear comments explaining the face detection data structure. The code follows best practices for async/await and cleanup.


429-443: LGTM! API index properly updated.

All new face detection methods and the listener event are correctly added to the documentation index with appropriate formatting and links.


1169-1227: LGTM! Face detection method documentation is complete.

All four face detection methods are properly documented with:

  • Correct TypeScript signatures
  • Clear descriptions
  • Appropriate parameter and return type references
  • Consistent versioning (8.1.0)

1393-1470: LGTM! Face detection data structure documentation is thorough.

The interface documentation for face detection events and data structures is comprehensive:

  • All properties are clearly described
  • Coordinate normalization (0-1) is properly documented
  • Probability ranges are specified
  • Landmark points are well-defined

1484-1510: LGTM! Configuration and capability interfaces are well-documented.

The FaceDetectionOptions and FaceDetectionCapabilities interfaces provide clear configuration parameters with sensible defaults and capability flags for platform-specific features.

android/build.gradle (1)

65-67: ML Kit Face Detection dependency is already at the latest version.

Version 16.1.7 is the latest stable release from Google's Maven repository (last updated August 2024). No public security vulnerabilities were found for this version. No action is required.

ios/capacitor-cordova-ios-plugins/CordovaPluginsResources.podspec (1)

1-10: Review podspec configuration and verify external git tag.

This podspec references an external ionic-team/capacitor repository with tag 0.0.105, but no evidence of this podspec being used elsewhere in the codebase (no Podfile or Pod dependencies found). Before merging:

  1. Verify that tag 0.0.105 exists in the ionic-team/capacitor repository
  2. Confirm where and how this podspec is consumed in the build process (no local Podfile references found)
  3. Clarify if this is infrastructure for the face detection feature or a general dependency

The version schemes are independent (project: 8.0.5, podspec: 0.0.105), which is acceptable, but the apparent lack of integration points raises questions about necessity and correct configuration.

example-app/src/app/pages/face-detection/face-detection.page.scss (3)

1-24: LGTM! Solid overlay layout.

The fixed positioning for canvas and control panel with appropriate z-index layering provides a good foundation for the face detection UI.


160-177: Webkit-only scrollbar styling is a progressive enhancement.

Custom scrollbar styles only apply to Webkit browsers (Chrome, Safari, Edge). Firefox users will see default scrollbars, which is acceptable as a graceful degradation.


26-63: Color scheme provides good contrast.

The bright green accent color (#00ff00) on dark backgrounds with white/gray text should provide adequate contrast for readability.

example-app/src/app/pages/face-detection/face-detection.page.html (2)

135-197: Good use of track-by for performance.

The @for loop properly uses track face.trackingId which helps Angular optimize DOM updates when faces are added/removed.


98-113: Good UX: toggles disabled during detection.

Disabling the configuration toggles while detection is running prevents inconsistent state and potential runtime issues from changing options mid-stream.

src/web.ts (1)

1262-1284: Appropriate stub implementation strategy.

The stubs correctly distinguish between action methods (throw errors) and query methods (return unsupported status), providing a graceful degradation path for cross-platform code.

example-app/src/app/core/capacitor-camera-preview.service.ts (2)

15-17: LGTM! Types properly imported.

The face detection types are correctly imported from the package alongside other camera types.


372-401: Face detection methods well-structured and documented.

The implementation follows the service pattern established for other camera features, with proper type annotations and JSDoc.

android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java (3)

77-140: Well-structured frame processing with proper resource management.

The analyze method correctly implements frame skipping, prevents concurrent processing, and ensures imageProxy is always closed via try-finally blocks and failure handlers.


151-220: Robust face-to-JSON conversion with normalized coordinates.

The conversion properly normalizes coordinates to 0-1 range for cross-platform consistency and handles optional fields (landmarks, classification) gracefully.


236-245: Resource cleanup is properly implemented.

The close() method correctly releases the ML Kit detector with error handling. Verification confirms it is called in disableFaceDetection() with proper null checking and nullification after cleanup.

example-app/src/app/pages/face-detection/face-detection.page.ts (2)

114-151: Good implementation with proper async/await and error handling.

The detection startup flow correctly checks camera state, enables detection with options, and subscribes to events. Error handling with user-friendly alerts is appropriate.


153-167: Cleanup logic is correct but could benefit from null safety.

The listener removal and state reset are properly handled.

android/src/main/java/app/capgo/capacitor/camera/preview/CameraPreview.java (2)

1981-2013: Face detection methods follow existing patterns correctly.

The enableFaceDetection and disableFaceDetection methods properly check camera state before proceeding and handle exceptions appropriately.


2015-2024: Good null-safe implementation for isFaceDetectionEnabled.

Returns false when cameraXView is null, which is the expected behavior.

ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift (1)

1646-1650: The zoom level validation is correct.

The check rejecting level == 0.0 is not a bug. iOS devices' minAvailableVideoZoomFactor is always ≥ 1.0, making 0.0 an invalid zoom value on all supported devices. Using 0.0 as a sentinel to detect a missing parameter is appropriate, and the error message "level parameter is required" accurately reflects this intent. The actual range validation (lines 641 and 1684 in CameraController.swift) properly enforces device-specific min/max zoom constraints.

android/src/main/java/app/capgo/capacitor/camera/preview/CameraXView.java (4)

118-119: LGTM: Clean interface extension for face detection callbacks.

The new listener methods are well-defined and consistent with the existing callback pattern used in the interface.


155-160: LGTM: Appropriate fields for face detection state management.

The fields are properly scoped and initialized for managing the face detection lifecycle.


3669-3704: LGTM with the executor fix noted above.

The overall structure of the disable method is correct: it closes the analyzer and rebinds the camera without face detection. Once the executor shutdown is added, this will properly clean up resources.


3720-3732: LGTM: Capabilities accurately reflect ML Kit features.

The hardcoded capabilities correctly represent what Google ML Kit supports on Android.

src/definitions.ts (5)

376-410: LGTM: Well-documented geometric types for face detection.

The Point, FaceBounds, and FaceAngles interfaces are cleanly designed with normalized coordinates (0-1) which is a good choice for cross-platform consistency. The JSDoc comments clearly explain the coordinate system and angle ranges.


412-458: LGTM: Comprehensive face detection data structures.

The FaceLandmarks and DetectedFace interfaces are well-structured with appropriately optional fields that align with the configurable detection options.


474-530: LGTM: Comprehensive options with good defaults and platform annotations.

The FaceDetectionOptions interface has sensible defaults documented (performanceMode: 'fast', enableTracking: true) and correctly notes that enableContours is Android-only. The FaceDetectionCapabilities interface provides a clean way to query platform support.


878-892: LGTM: Consistent listener pattern for face detection events.

The addListener overload for 'onFacesDetected' follows the existing event listener pattern established by screenResize and orientationChange events.


972-1009: LGTM: Well-documented face detection API surface.

The new plugin methods are thoroughly documented with JSDoc including @since tags and @platform annotations. The API design is clean and follows Capacitor plugin conventions.

ios/Sources/CapgoCameraPreviewPlugin/CameraController.swift (3)

2439-2443: LGTM!

Face detection is appropriately invoked on the video capture queue before other sample buffer processing. The conditional check ensures minimal overhead when detection is disabled.


2746-2754: LGTM with documentation note.

The angle extraction correctly converts radians to degrees. The pitch value is documented as 0.0 since Vision framework doesn't provide it directly. Consider adding a comment in the TypeScript definitions or documentation noting this iOS limitation.


90-94: LGTM!

The CGRect.area extension is simple and correctly implemented for IoU calculations.

Comment on lines +1988 to +1994
try {
// Get options from call
JSObject options = call.getObject("options");
JSONObject jsonOptions = options != null ? new JSONObject(options.toString()) : new JSONObject();

cameraXView.enableFaceDetection(jsonOptions);
call.resolve();
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⚠️ Potential issue | 🔴 Critical

🧩 Analysis chain

🏁 Script executed:

# Search for TypeScript/JavaScript files that call enableFaceDetection
find . -type f \( -name "*.ts" -o -name "*.tsx" -o -name "*.js" -o -name "*.jsx" \) | head -20

Repository: Cap-go/capacitor-camera-preview

Length of output: 206


🏁 Script executed:

# Look for enableFaceDetection usage in the codebase
rg -n "enableFaceDetection" --type ts --type tsx --type js --type jsx -C 3

Repository: Cap-go/capacitor-camera-preview

Length of output: 102


🏁 Script executed:

# Also check for TypeScript interface/type definitions
rg -n "enableFaceDetection|FaceDetection" --type ts --type tsx -B 2 -A 2 | head -80

Repository: Cap-go/capacitor-camera-preview

Length of output: 102


🏁 Script executed:

# Check the web plugin directory for the TypeScript definition
find . -type f -name "*.ts" | xargs grep -l "enableFaceDetection" 2>/dev/null

Repository: Cap-go/capacitor-camera-preview

Length of output: 237


🏁 Script executed:

# Check the definitions file for enableFaceDetection interface
cat ./src/definitions.ts | head -200

Repository: Cap-go/capacitor-camera-preview

Length of output: 5681


🏁 Script executed:

# Check the web.ts implementation
cat ./src/web.ts | head -300

Repository: Cap-go/capacitor-camera-preview

Length of output: 10210


🏁 Script executed:

# Check face-detection example page
cat ./example-app/src/app/pages/face-detection/face-detection.page.ts

Repository: Cap-go/capacitor-camera-preview

Length of output: 8388


🏁 Script executed:

# Check the service implementation
cat ./example-app/src/app/core/capacitor-camera-preview.service.ts

Repository: Cap-go/capacitor-camera-preview

Length of output: 11183


Fix parameter extraction to match the JavaScript API contract.

The code extracts call.getObject("options"), but the JavaScript implementation passes options as root-level properties (e.g., {enableLandmarks, enableClassification, performanceMode, detectionInterval, enableTracking}). The Android code should process the call parameters directly rather than looking for a nested "options" object.

Comment on lines +2042 to +2049
} else {
JSObject ret = new JSObject();
ret.put("supported", true);
ret.put("landmarks", true);
ret.put("contours", true);
ret.put("classification", true);
ret.put("tracking", true);
call.resolve(ret);
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⚠️ Potential issue | 🟡 Minor

Misleading default capabilities when camera not initialized.

When cameraXView is null, returning all capabilities as true is incorrect. The camera isn't running, so capabilities cannot be determined. Return supported: false or require the camera to be running.

🔎 Proposed fix
         } else {
             JSObject ret = new JSObject();
-            ret.put("supported", true);
-            ret.put("landmarks", true);
-            ret.put("contours", true);
-            ret.put("classification", true);
-            ret.put("tracking", true);
+            ret.put("supported", false);
+            ret.put("landmarks", false);
+            ret.put("contours", false);
+            ret.put("classification", false);
+            ret.put("tracking", false);
             call.resolve(ret);
         }

Alternatively, reject with "Camera is not running" for consistency with other methods.

🤖 Prompt for AI Agents
In @android/src/main/java/app/capgo/capacitor/camera/preview/CameraPreview.java
around lines 2042-2049, The current else branch returns a JSObject claiming all
capabilities are true when cameraXView is null; instead, either return
supported:false with all capability flags false or reject the call to match
other methods—update the null-handling in CameraPreview (where cameraXView is
checked and the code currently builds JSObject and calls call.resolve) to either
build a JSObject with ret.put("supported", false) and set
landmarks/contours/classification/tracking to false, then call
call.resolve(ret), or replace that resolve with call.reject("Camera is not
running") to signal the camera isn't initialized; ensure you modify the branch
that currently ends with call.resolve(ret) so it no longer reports capabilities
as true when cameraXView is null.

boolean enableTracking = options.optBoolean("enableTracking", true);
String performanceMode = options.optString("performanceMode", "fast");
float minFaceSize = (float) options.optDouble("minFaceSize", 0.1);
int detectionInterval = options.optInt("detectionInterval", 1);
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⚠️ Potential issue | 🟡 Minor

🧩 Analysis chain

🏁 Script executed:

rg -n "detectionInterval|frameSkip|skipFrame" android/src/main/java/app/capgo/capacitor/camera/preview/

Repository: Cap-go/capacitor-camera-preview

Length of output: 791


🏁 Script executed:

# Check the enableFaceDetection method and surrounding context
fd -t f "CameraXView.java" android/ | head -1 | xargs -I {} sed -n '3540,3650p' {}

Repository: Cap-go/capacitor-camera-preview

Length of output: 4896


🏁 Script executed:

# Look for FaceDetectionAnalyzer class
fd -t f "FaceDetectionAnalyzer.java" android/

Repository: Cap-go/capacitor-camera-preview

Length of output: 158


🏁 Script executed:

# View FaceDetectionAnalyzer constructor and initialization
fd -t f "FaceDetectionAnalyzer.java" android/ | xargs sed -n '1,100p'

Repository: Cap-go/capacitor-camera-preview

Length of output: 3380


🏁 Script executed:

# Also check the complete constructor with signature
rg -A 10 "FaceDetectionAnalyzer.*{" android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java | head -40

Repository: Cap-go/capacitor-camera-preview

Length of output: 186


🏁 Script executed:

# Check the optionsToJson method to see what it converts
rg -A 20 "optionsToJson" android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java

Repository: Cap-go/capacitor-camera-preview

Length of output: 1346


Pass detectionInterval to FaceDetectionAnalyzer when instantiating it.

The detectionInterval option is parsed at line 3559 but is never passed to the FaceDetectionAnalyzer. Currently, FaceDetectionAnalyzer extracts detectionInterval from a placeholder method that always returns 1, so user-provided values are ignored. Either pass the parsed detectionInterval to the analyzer (e.g., through a constructor parameter or separate setter), or remove the unused parsing if the feature is not intended to be configurable.

Comment on lines +3622 to +3625
// Create ImageAnalysis use case
faceDetectionAnalysis = new ImageAnalysis.Builder().setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST).build();

faceDetectionAnalysis.setAnalyzer(Executors.newSingleThreadExecutor(), faceDetectionAnalyzer);
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⚠️ Potential issue | 🟠 Major

Executor resource leak: SingleThreadExecutor is never shutdown.

A new SingleThreadExecutor is created each time face detection is enabled but never shutdown when face detection is disabled. This causes thread leaks if the feature is toggled multiple times.

🔎 Proposed fix: Store and shutdown the executor

Add a field to track the executor and shut it down in disableFaceDetection:

 // Face detection
 private ImageAnalysis faceDetectionAnalysis;
 private FaceDetectionAnalyzer faceDetectionAnalyzer;
 private boolean isFaceDetectionEnabled = false;
 private com.google.mlkit.vision.face.FaceDetectorOptions faceDetectorOptions;
+private ExecutorService faceDetectionExecutor;

In enableFaceDetection:

-        faceDetectionAnalysis.setAnalyzer(Executors.newSingleThreadExecutor(), faceDetectionAnalyzer);
+        faceDetectionExecutor = Executors.newSingleThreadExecutor();
+        faceDetectionAnalysis.setAnalyzer(faceDetectionExecutor, faceDetectionAnalyzer);

In disableFaceDetection:

         // Close the analyzer
         if (faceDetectionAnalyzer != null) {
             faceDetectionAnalyzer.close();
             faceDetectionAnalyzer = null;
         }
+
+        // Shutdown the executor
+        if (faceDetectionExecutor != null) {
+            faceDetectionExecutor.shutdown();
+            faceDetectionExecutor = null;
+        }

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents
In @android/src/main/java/app/capgo/capacitor/camera/preview/CameraXView.java
around lines 3622-3625, The ImageAnalysis executor is leaked because a new
Executors.newSingleThreadExecutor() is created for faceDetectionAnalysis without
being stored or shutdown; modify the class to add a field (e.g.,
faceDetectionExecutor), assign Executors.newSingleThreadExecutor() in the
enableFaceDetection sequence and pass that executor to
faceDetectionAnalysis.setAnalyzer(..., faceDetectionAnalyzer), and then in
disableFaceDetection shut down the executor (faceDetectionExecutor.shutdownNow()
or shutdown() and null it) and clear references to faceDetectionAnalysis and
faceDetectionAnalyzer to avoid thread leaks.

Comment on lines +32 to +33
private int frameCounter = 0;
private boolean isProcessing = false;
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⚠️ Potential issue | 🟠 Major

Potential race condition with non-atomic flags.

The frameCounter and isProcessing fields are accessed from camera callback threads without synchronization. While the isProcessing guard might work in practice due to frame ordering, consider using AtomicInteger for frameCounter and AtomicBoolean for isProcessing to guarantee thread safety.

🔎 Proposed fix
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;

 public class FaceDetectionAnalyzer implements ImageAnalysis.Analyzer {
 
     private static final String TAG = "FaceDetectionAnalyzer";
 
     private final FaceDetector detector;
     private final FaceDetectionListener listener;
     private final int detectionInterval;
-    private int frameCounter = 0;
-    private boolean isProcessing = false;
+    private final AtomicInteger frameCounter = new AtomicInteger(0);
+    private final AtomicBoolean isProcessing = new AtomicBoolean(false);

Then update the usage:

     @Override
     @SuppressLint("UnsafeOptInUsageError")
     public void analyze(@NonNull ImageProxy imageProxy) {
-        frameCounter++;
+        frameCounter.incrementAndGet();
 
         // Skip frames based on detection interval
-        if (frameCounter % detectionInterval != 0) {
+        if (frameCounter.get() % detectionInterval != 0) {
             imageProxy.close();
             return;
         }
 
         // Skip if previous detection is still processing
-        if (isProcessing) {
+        if (!isProcessing.compareAndSet(false, true)) {
             imageProxy.close();
             return;
         }
-
-        isProcessing = true;

And in callbacks:

                 } finally {
                     imageProxy.close();
-                    isProcessing = false;
+                    isProcessing.set(false);
                 }

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents
In
@android/src/main/java/app/capgo/capacitor/camera/preview/FaceDetectionAnalyzer.java
around lines 32-33, Replace the non-thread-safe fields in FaceDetectionAnalyzer:
change frameCounter to an AtomicInteger and isProcessing to an AtomicBoolean,
then update all accesses to use atomic operations (e.g.,
frameCounter.incrementAndGet()/get() and isProcessing.compareAndSet(false,
true)/set(false)) inside the camera callback and processing logic so checks and
updates are atomic and avoid race conditions across camera callback threads.

Comment on lines +2245 to 2249
var value = call.getFloat("value", 0.0)
guard value != 0.0 else {
call.reject("value parameter is required")
return
}
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⚠️ Potential issue | 🟠 Major

Bug: Valid exposure compensation value 0.0 incorrectly rejected.

The condition value != 0.0 rejects when value is zero. However, 0.0 is a valid exposure compensation (no adjustment) and should be accepted.

🔎 Proposed fix
-        var value = call.getFloat("value", 0.0)
-        guard value != 0.0 else {
+        guard let value = call.getFloat("value") else {
             call.reject("value parameter is required")
             return
         }
+        var adjustedValue = value

Then use adjustedValue in the subsequent logic instead of value.

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents
In @ios/Sources/CapgoCameraPreviewPlugin/Plugin.swift around lines 2245-2249,
The current check uses value != 0.0 to detect a missing parameter and therefore
incorrectly rejects the valid exposure 0.0; instead, retrieve the parameter as
an optional (use the variant of call.getFloat that returns nil when absent or
check call.has("value")), guard let value = ... to detect truly missing input,
then compute an adjustedValue if needed and use adjustedValue in the subsequent
logic (replace references to the old value variable with adjustedValue); update
the guard to only reject when the parameter is actually absent, not when it
equals 0.0.

Comment on lines +9 to +10
// TODO: Implement actual tests for CameraPreview plugin
XCTAssertTrue(true)
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⚠️ Potential issue | 🟠 Major

Add unit tests for the camera preview plugin functionality.

This PR introduces comprehensive face detection features (enable/disable detection, capabilities query, face tracking, event listeners), but the only iOS test file now contains a placeholder that asserts true with no functional verification. The original functional tests have been removed.

Automated unit tests are essential for:

  • Verifying core plugin behavior and new face detection APIs
  • Catching regressions during future changes
  • Documenting expected behavior
  • Ensuring reliability across iOS versions and devices

Please add unit tests covering at least:

  • Basic plugin initialization and lifecycle
  • Face detection enable/disable functionality
  • Capabilities query (getFaceDetectionCapabilities)
  • Face tracking data structure validation
  • Error handling for invalid configurations

Would you like me to help draft a test plan or generate example test cases for the face detection functionality?

🤖 Prompt for AI Agents
In @ios/Tests/CameraPreviewPluginTests/CameraPreviewPluginTests.swift around
lines 9-10, Replace the placeholder XCTAssertTrue(true) in
CameraPreviewPluginTests with real unit tests that exercise the CameraPreview
plugin lifecycle and new face-detection APIs: instantiate the plugin
(CameraPreviewPlugin) and test initialization/start/stop behavior, call
enableFaceDetection and disableFaceDetection and assert expected state changes
or callbacks, call getFaceDetectionCapabilities and assert returned capability
fields, validate the shape and types of a face-tracking payload returned by the
plugin (e.g., face IDs, boundingBox, landmarks), and add tests that pass invalid
configurations to enableFaceDetection to assert proper error handling; implement
these as individual XCTest methods inside CameraPreviewPluginTests using
mocks/stubs for any camera or detector dependencies and assert expected
events/errors.

Comment on lines +225 to +226
- **Basic face detection**: See [FACE_DETECTION_EXAMPLE.md](./FACE_DETECTION_EXAMPLE.md)
- **Interactive demo**: See [FACE_DETECTION_DEMO_GUIDE.md](./FACE_DETECTION_DEMO_GUIDE.md) - Test all features in the example app
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⚠️ Potential issue | 🔴 Critical

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Check for the specific referenced documentation files
echo "Checking for referenced documentation files..."
fd -t f "FACE_DETECTION_EXAMPLE.md|FACE_DETECTION_DEMO_GUIDE.md" 2>/dev/null

# Check what files are available in the root
echo -e "\nMarkdown files in repository root:"
fd -t f -e md --max-depth 1 | sort

# Also check if there are any similar named files that might be relevant
echo -e "\nAll markdown files (checking full depth):"
fd -t f -e md | head -30

Repository: Cap-go/capacitor-camera-preview

Length of output: 287


Create missing documentation files or remove broken references.

The referenced files FACE_DETECTION_EXAMPLE.md and FACE_DETECTION_DEMO_GUIDE.md do not exist in the repository. Either create these files with appropriate content or remove the references from the README to avoid broken links that users will encounter.

🤖 Prompt for AI Agents
In @README.md around lines 225-226, The README contains broken references to
FACE_DETECTION_EXAMPLE.md and FACE_DETECTION_DEMO_GUIDE.md; either create those
two markdown files with the appropriate example and demo guide content (ensuring
filenames exactly match FACE_DETECTION_EXAMPLE.md and
FACE_DETECTION_DEMO_GUIDE.md and include headings, usage steps, and any required
code snippets), or remove/update the two lines in README.md that reference
**Basic face detection** and **Interactive demo** so they no longer link to
non-existent files (or replace them with links to existing docs); ensure the
README no longer points to missing resources.

Comment on lines +996 to +1014
### addListener('onFacesDetected', ...)
```typescript
addListener(eventName: 'onFacesDetected', listenerFunc: (event: FaceDetectionEvent) => void) => Promise<PluginListenerHandle>
```
Adds a listener for face detection events.
Called continuously with detected face data when face detection is enabled.
| Param | Type | Description |
| ------------------ | ------------------------------------------------------------------------------------- | --------------------------------------------------- |
| **`eventName`** | <code>'onFacesDetected'</code> | - The event name to listen for ('onFacesDetected'). |
| **`listenerFunc`** | <code>(event: <a href="#facedetectionevent">FaceDetectionEvent</a>) =&gt; void</code> | - The function to call when faces are detected. |
**Returns:** <code>Promise&lt;<a href="#pluginlistenerhandle">PluginListenerHandle</a>&gt;</code>
**Since:** 8.1.0
--------------------
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⚠️ Potential issue | 🟡 Minor

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Check package.json for current version and CHANGELOG for version history
echo "Current package version:"
cat package.json | jq -r '.version' 2>/dev/null || grep -m1 '"version"' package.json

echo -e "\nSearching for version 8.1.0 references:"
rg "8\.1\.0" CHANGELOG.md -C 3 || echo "No 8.1.0 found"

echo -e "\nSearching for face detection in CHANGELOG:"
rg -i "face.*detection|onFacesDetected" CHANGELOG.md -C 2 || echo "No face detection mentions found"

Repository: Cap-go/capacitor-camera-preview

Length of output: 238


Update the Since version: 8.1.0 does not exist.

The listener documentation structure is well-organized and consistent, but the Since: 8.1.0 annotation is incorrect. The current package version is 8.0.5, and there are no references to version 8.1.0 in the CHANGELOG. Update this to reflect the actual version where this feature was introduced, or remove it if this is a new feature being added in the next release.

🤖 Prompt for AI Agents
In @README.md around lines 996-1014, The "Since: 8.1.0" annotation in the
addListener('onFacesDetected', ...) docs is incorrect; update the Since field to
the actual version this feature was introduced (e.g., 8.0.5) or remove the Since
line if this is being added for the next unreleased version, ensuring the change
is applied to the addListener('onFacesDetected', listenerFunc) section so the
documentation matches the package/CHANGELOG history.

Comment on lines +1254 to +1260
// Face detection methods (unsupported on web - would require TensorFlow.js or similar)
async enableFaceDetection(_options?: any): Promise<void> {
void _options;
throw new Error(
'Face detection not supported under the web platform. Consider using TensorFlow.js face-landmarks-detection for web implementation.',
);
}
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🛠️ Refactor suggestion | 🟠 Major

Use specific type for options parameter.

The _options parameter is typed as any, but should use FaceDetectionOptions from the definitions to maintain type consistency across the plugin API.

🔎 Proposed fix
-  async enableFaceDetection(_options?: any): Promise<void> {
+  async enableFaceDetection(_options?: FaceDetectionOptions): Promise<void> {
     void _options;
     throw new Error(
       'Face detection not supported under the web platform. Consider using TensorFlow.js face-landmarks-detection for web implementation.',
     );
   }

Note: Ensure FaceDetectionOptions is imported at the top of the file from './definitions'.

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents
In @src/web.ts around lines 1254-1260, The enableFaceDetection method currently
types its parameter as any; change the signature async
enableFaceDetection(_options?: any): Promise<void> to use the
FaceDetectionOptions type (async enableFaceDetection(_options?:
FaceDetectionOptions): Promise<void>), import FaceDetectionOptions from
'./definitions' at the top of the file, and keep or adjust the existing void
_options; line so the unused-parameter pattern remains valid after the type
change.

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2 participants