react-native-vision-camera/lib/hooks/useCamera.js

VisionCamera is the fastest and most powerful Camera for react-native.

import { useEffect, useMemo } from 'react';
import { getCameraDevice } from '../devices/getCameraDevice';
import { useCameraController } from './internal/useCameraController';
import { useCameraControllerConfiguration } from './internal/useCameraControllerConfiguration';
import { useCameraSession } from './internal/useCameraSession';
import { useCameraSessionIsRunning } from './internal/useCameraSessionIsRunning';
import { useListenerSubscription } from './internal/useListenerSubscription';
import { useCameraDevices } from './useCameraDevices';
import { useOrientation } from './useOrientation';
function defaultOnErrorHandler(error) {
    console.error(error);
}
/**
 * Use the Camera.
 *
 * This creates a {@linkcode CameraSession}, manages
 * the input and outputs (including orientation and
 * mirror modes), wraps listeners as stable React
 * callbacks, and returns a {@linkcode CameraController}.
 *
 * @example
 * ```ts
 * const camera = useCamera({
 *   isActive: true,
 *   device: 'back',
 *   outputs: []
 * })
 * ```
 */
export function useCamera({ isActive, device, outputs = [], constraints, onSessionConfigSelected, mirrorMode, onConfigured, orientationSource = 'device', onStarted, onStopped, onError = defaultOnErrorHandler, onInterruptionStarted, onInterruptionEnded, onSubjectAreaChanged, enableDistortionCorrection, enableLowLightBoost, enableSmoothAutoFocus, getInitialExposureBias, getInitialZoom, }) {
    // 1. Create session
    const session = useCameraSession({ enableMultiCamSupport: false });
    // 2. Update output orientations
    const orientationSourceOrUndefined = orientationSource === 'custom' ? undefined : orientationSource;
    const orientation = useOrientation(orientationSourceOrUndefined);
    useEffect(() => {
        if (orientation == null)
            return;
        for (const output of outputs) {
            output.outputOrientation = orientation;
        }
    }, [orientation, outputs]);
    // 3. Get the input - either find one via position, or use the user provided one
    const devices = useCameraDevices();
    const input = useMemo(() => {
        if (typeof device === 'string') {
            // The user passed a `CameraPosition` (e.g. "back") - try to find a device ourselves
            const position = device;
            const foundDevice = getCameraDevice(devices, position);
            if (foundDevice == null) {
                throw new Error(`This device does not have any "${position}" Cameras!`);
            }
            return foundDevice;
        }
        else {
            // The user passed an actual device. return as-is.
            return device;
        }
    }, [device, devices]);
    // 4. Configure the session with the input + outputs to create a `CameraController`
    const controller = useCameraController(session, input, outputs, {
        mirrorMode: mirrorMode,
        onConfigured: onConfigured,
        getInitialExposureBias: getInitialExposureBias,
        getInitialZoom: getInitialZoom,
        constraints: constraints,
        onSessionConfigSelected: onSessionConfigSelected,
    });
    // 5. Configure the Controller with some settings
    useCameraControllerConfiguration(controller, {
        enableSmoothAutoFocus: enableSmoothAutoFocus,
        enableDistortionCorrection: enableDistortionCorrection,
        enableLowLightBoost: enableLowLightBoost,
    });
    // 6. Start (or stop) the Session if we have a Controller and `isActive` is true.
    const hasController = controller != null;
    useCameraSessionIsRunning(session, isActive && hasController);
    // 7. Set up listeners and delegate to JS
    useListenerSubscription(session, 'addOnStartedListener', onStarted);
    useListenerSubscription(session, 'addOnStoppedListener', onStopped);
    useListenerSubscription(session, 'addOnErrorListener', onError);
    useListenerSubscription(session, 'addOnInterruptionStartedListener', onInterruptionStarted);
    useListenerSubscription(session, 'addOnInterruptionEndedListener', onInterruptionEnded);
    useListenerSubscription(controller, 'addSubjectAreaChangedListener', onSubjectAreaChanged);
    // 8. Give the user the controller
    return controller;
}