VisionCamera Patterns

Quick Guide: Use VisionCamera for high-performance camera features in React Native. Control the camera lifecycle with isActive (never unmount/remount). Use useCameraDevice to select back/front cameras, useCameraPermission for permissions. Capture photos with takePhoto(), record video with startRecording()/stopRecording(), scan codes with useCodeScanner, and process frames in real time with useFrameProcessor worklets. Frame processors run on a parallel JS thread via JSI -- keep them fast or use runAsync/runAtTargetFps to avoid blocking the pipeline.

<critical_requirements>

CRITICAL: Before Using This Skill

(You MUST set isActive based on screen focus AND app state -- camera must pause when backgrounded or navigated away)

(You MUST request permissions before rendering the Camera -- useCameraPermission returns hasPermission and requestPermission)

(You MUST include the 'worklet' directive as the first line of every frame processor function body)

(You MUST enable only the pipelines you need (photo, video, codeScanner, frameProcessor) -- unused pipelines waste resources)

(You MUST use useSharedValue (not useState) for data shared between frame processors and the React thread)