@ashleysmart/react-native-vision-camera-face-detector/lib/module/Camera.js

Frame Processor Plugin to detect faces using MLKit Vision Face Detector for React Native Vision Camera!

function _extends() { _extends = Object.assign ? Object.assign.bind() : function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }
import React from 'react';
import { Camera as VisionCamera, useFrameProcessor } from '@ashleysmart/react-native-vision-camera';
import { useSharedValue } from 'react-native-worklets-core';
import { detectFaces } from './FaceDetector';

// types

/**
 * Create a Worklet function that persists between re-renders.
 * The returned function can be called from both a Worklet context and the JS context, but will execute on a Worklet context.
 *
 * @param {function} func The Worklet. Must be marked with the `'worklet'` directive.
 * @param {DependencyList} dependencyList The React dependencies of this Worklet.
 * @returns {WorkletType} A memoized Worklet
 */
function useWorklet(func, dependencyList) {
  const worklet = React.useMemo(() => {
    const context = 'VisionCamera.async';
    return Worklets.createRunInContextFn(func, context);
  }, dependencyList);
  return worklet;
}

/**
 * Vision camera wrapper
 *
 * @param {ComponentType} props Camera + face detection props
 * @returns
 */
export const Camera = /*#__PURE__*/React.forwardRef(({
  faceDetectionOptions,
  faceDetectionCallback,
  ...props
}, ref) => {
  /**
   * Is there an async task already running?
   */
  const isAsyncContextBusy = useSharedValue(false);
  /**
   * Throws logs/errors back on js thread
   */
  const logOnJs = Worklets.createRunInJsFn((log, error) => {
    if (error) {
      console.error(log, error.message ?? JSON.stringify(error));
    } else {
      console.log(log);
    }
  });
  /**
   * Async context that will handle face detection
   */
  const runOnAsyncContext = useWorklet(frame => {
    'worklet';

    try {
      detectFaces({
        frame,
        callback: faceDetectionCallback,
        options: faceDetectionOptions
      });
    } catch (error) {
      logOnJs('Execution error:', error);
    } finally {
      frame.decrementRefCount();
      isAsyncContextBusy.value = false;
    }
  }, [faceDetectionOptions, faceDetectionCallback]);
  /**
   * Detect faces on frame on an async context without blocking camera preview
   *
   * @param {Frame} frame Current frame
   */
  function runAsync(frame) {
    'worklet';

    if (isAsyncContextBusy.value) return;
    // set async context as busy
    isAsyncContextBusy.value = true;
    // cast to internal frame and increment ref count
    const internal = frame;
    internal.incrementRefCount();
    // detect faces in async context
    runOnAsyncContext(internal);
  }

  /**
  * Camera frame processor
  */
  const cameraFrameProcessor = useFrameProcessor(frame => {
    'worklet';

    runAsync(frame);
  }, [runOnAsyncContext]);
  return /*#__PURE__*/React.createElement(VisionCamera, _extends({}, props, {
    ref: ref,
    frameProcessor: cameraFrameProcessor,
    pixelFormat: "yuv"
  }));
});
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