Question

如何确保我可以用人脸识别的正方形保存图片？

我想确保当用户拍摄照片时，在照片中能够识别出人脸，如图像中所见。照片会保存有细节，例如用于面部面部识别的正方形。

链接：Expo

代码：

import {
  Constants,
  Camera,
  FileSystem,
  Permissions,
  BarCodeScanner,
} from 'expo';
import React from 'react';
import {
  Alert,
  StyleSheet,
  Text,
  View,
  TouchableOpacity,
  Slider,
  Platform,
  ImageBackground,
} from 'react-native';
import GalleryScreen from './GalleryScreen';
import isIPhoneX from 'react-native-is-iphonex';

import {
  Ionicons,
  MaterialIcons,
  Foundation,
  MaterialCommunityIcons,
  Octicons,
} from '@expo/vector-icons';

const landmarkSize = 2;

const flashModeOrder = {
  off: 'on',
  on: 'auto',
  auto: 'torch',
  torch: 'off',
};

const flashIcons = {
  off: 'flash-off',
  on: 'flash-on',
  auto: 'flash-auto',
  torch: 'highlight',
};

const wbOrder = {
  auto: 'sunny',
  sunny: 'cloudy',
  cloudy: 'shadow',
  shadow: 'fluorescent',
  fluorescent: 'incandescent',
  incandescent: 'auto',
};

const wbIcons = {
  auto: 'wb-auto',
  sunny: 'wb-sunny',
  cloudy: 'wb-cloudy',
  shadow: 'beach-access',
  fluorescent: 'wb-iridescent',
  incandescent: 'wb-incandescent',
};

export default class CameraScreen extends React.Component {
  state = {
    flash: 'off',
    zoom: 0,
    autoFocus: 'on',
    type: 'back',
    whiteBalance: 'auto',
    ratio: '16:9',
    ratios: [],
    barcodeScanning: false,
    faceDetecting: true,
    faces: [],
    newPhotos: false,
    permissionsGranted: false,
    pictureSize: undefined,
    pictureSizes: [],
    pictureSizeId: 0,
    showGallery: false,
    showMoreOptions: false,
  };

  async componentWillMount() {
    const { status } = await Permissions.askAsync(Permissions.CAMERA);
    this.setState({ permissionsGranted: status === 'granted' });
  }

  componentDidMount() {
    FileSystem.makeDirectoryAsync(
      FileSystem.documentDirectory + 'photos'
    ).catch(e => {
      console.log(e, 'Directory exists');
    });
  }

  getRatios = async () => {
    const ratios = await this.camera.getSupportedRatios();
    return ratios;
  };

  toggleView = () =>
    this.setState({ showGallery: !this.state.showGallery, newPhotos: false });

  toggleMoreOptions = () =>
    this.setState({ showMoreOptions: !this.state.showMoreOptions });

  toggleFacing = () =>
    this.setState({ type: this.state.type === 'back' ? 'front' : 'back' });

  toggleFlash = () =>
    this.setState({ flash: flashModeOrder[this.state.flash] });

  setRatio = ratio => this.setState({ ratio });

  toggleWB = () =>
    this.setState({ whiteBalance: wbOrder[this.state.whiteBalance] });

  toggleFocus = () =>
    this.setState({ autoFocus: this.state.autoFocus === 'on' ? 'off' : 'on' });

  zoomOut = () =>
    this.setState({
      zoom: this.state.zoom - 0.1 < 0 ? 0 : this.state.zoom - 0.1,
    });

  zoomIn = () =>
    this.setState({
      zoom: this.state.zoom + 0.1 > 1 ? 1 : this.state.zoom + 0.1,
    });

  setFocusDepth = depth => this.setState({ depth });

  toggleBarcodeScanning = () =>
    this.setState({ barcodeScanning: !this.state.barcodeScanning });

  toggleFaceDetection = () =>
    this.setState({ faceDetecting: !this.state.faceDetecting });

  takePicture = () => {
    if (this.camera) {
      this.camera.takePictureAsync({ onPictureSaved: this.onPictureSaved });
    }
  };

  handleMountError = ({ message }) => console.error(message);

  onPictureSaved = async photo => {
    await FileSystem.moveAsync({
      from: photo.uri,
      to: `${FileSystem.documentDirectory}photos/${Date.now()}.jpg`,
    });
    this.setState({ newPhotos: true });
  };

  onBarCodeScanned = code => {
    this.setState(
      { barcodeScanning: !this.state.barcodeScanning },
      Alert.alert(`Barcode found: ${code.data}`)
    );
  };

  onFacesDetected = ({ faces }) => this.setState({ faces });
  onFaceDetectionError = state => console.warn('Faces detection error:', state);

  collectPictureSizes = async () => {
    if (this.camera) {
      const pictureSizes = await this.camera.getAvailablePictureSizesAsync(
        this.state.ratio
      );
      let pictureSizeId = 0;
      if (Platform.OS === 'ios') {
        pictureSizeId = pictureSizes.indexOf('High');
      } else {
        // returned array is sorted in ascending order - default size is the largest one
        pictureSizeId = pictureSizes.length - 1;
      }
      this.setState({
        pictureSizes,
        pictureSizeId,
        pictureSize: pictureSizes[pictureSizeId],
      });
    }
  };

  previousPictureSize = () => this.changePictureSize(1);
  nextPictureSize = () => this.changePictureSize(-1);

  changePictureSize = direction => {
    let newId = this.state.pictureSizeId + direction;
    const length = this.state.pictureSizes.length;
    if (newId >= length) {
      newId = 0;
    } else if (newId < 0) {
      newId = length - 1;
    }
    this.setState({
      pictureSize: this.state.pictureSizes[newId],
      pictureSizeId: newId,
    });
  };

  renderGallery() {
    return <GalleryScreen onPress={this.toggleView.bind(this)} />;
  }

  renderFace({ bounds, faceID, rollAngle, yawAngle }) {
    return (
      <View
        key={faceID}
        transform={[
          { perspective: 600 },
          { rotateZ: `${rollAngle.toFixed(0)}deg` },
          { rotateY: `${yawAngle.toFixed(0)}deg` },
        ]}
        style={[
          styles.face,
          {
            ...bounds.size,
            left: bounds.origin.x,
            top: bounds.origin.y,
          },
        ]}>
        <Text style={styles.faceText}>ID: {faceID}</Text>
        <Text style={styles.faceText}>rollAngle: {rollAngle.toFixed(0)}</Text>
        <Text style={styles.faceText}>yawAngle: {yawAngle.toFixed(0)}</Text>
      </View>
    );
  }

  renderLandmarksOfFace(face) {
    const renderLandmark = position =>
      position && (
        <View
          style={[
            styles.landmark,
            {
              left: position.x - landmarkSize / 2,
              top: position.y - landmarkSize / 2,
            },
          ]}
        />
      );
    return (
      <View key={`landmarks-${face.faceID}`}>
        {renderLandmark(face.leftEyePosition)}
        {renderLandmark(face.rightEyePosition)}
        {renderLandmark(face.leftEarPosition)}
        {renderLandmark(face.rightEarPosition)}
        {renderLandmark(face.leftCheekPosition)}
        {renderLandmark(face.rightCheekPosition)}
        {renderLandmark(face.leftMouthPosition)}
        {renderLandmark(face.mouthPosition)}
        {renderLandmark(face.rightMouthPosition)}
        {renderLandmark(face.noseBasePosition)}
        {renderLandmark(face.bottomMouthPosition)}
      </View>
    );
  }

  renderFaces = () => (
    <View style={styles.facesContainer} pointerEvents="none">
      {this.state.faces.map(this.renderFace)}
    </View>
  );

  renderLandmarks = () => (
    <View style={styles.facesContainer} pointerEvents="none">
      {this.state.faces.map(this.renderLandmarksOfFace)}
    </View>
  );

  renderNoPermissions = () => (
    <View style={styles.noPermissions}>
      <Text style={{ color: 'white' }}>
        Camera permissions not granted - cannot open camera preview.
      </Text>
    </View>
  );

  renderTopBar = () => (
    <View style={styles.topBar}>
      <TouchableOpacity style={styles.toggleButton} onPress={this.toggleFacing}>
        <Ionicons name="ios-reverse-camera" size={32} color="white" />
      </TouchableOpacity>
      <TouchableOpacity style={styles.toggleButton} onPress={this.toggleFlash}>
        <MaterialIcons
          name={flashIcons[this.state.flash]}
          size={32}
          color="white"
        />
      </TouchableOpacity>
      <TouchableOpacity style={styles.toggleButton} onPress={this.toggleWB}>
        <MaterialIcons
          name={wbIcons[this.state.whiteBalance]}
          size={32}
          color="white"
        />
      </TouchableOpacity>
      <TouchableOpacity style={styles.toggleButton} onPress={this.toggleFocus}>
        <Text
          style={[
            styles.autoFocusLabel,
            { color: this.state.autoFocus === 'on' ? 'white' : '#6b6b6b' },
          ]}>
          AF
        </Text>
      </TouchableOpacity>
    </View>
  );

  renderBottomBar = () => (
    <View style={styles.bottomBar}>
      <TouchableOpacity
        style={styles.bottomButton}
        onPress={this.toggleMoreOptions}>
        <Octicons name="kebab-horizontal" size={30} color="white" />
      </TouchableOpacity>
      <View style={{ flex: 0.4 }}>
        <TouchableOpacity
          onPress={this.takePicture}
          style={{ alignSelf: 'center' }}>
          <Ionicons name="ios-radio-button-on" size={70} color="white" />
        </TouchableOpacity>
      </View>
      <TouchableOpacity style={styles.bottomButton} onPress={this.toggleView}>
        <View>
          <Foundation name="thumbnails" size={30} color="white" />
          {this.state.newPhotos && <View style={styles.newPhotosDot} />}
        </View>
      </TouchableOpacity>
    </View>
  );

  renderMoreOptions = () => (
    <View style={styles.options}>
      <View style={styles.detectors}>
        <TouchableOpacity onPress={this.toggleFaceDetection}>
          <MaterialIcons
            name="tag-faces"
            size={32}
            color={this.state.faceDetecting ? 'white' : '#858585'}
          />
        </TouchableOpacity>
        <TouchableOpacity onPress={this.toggleBarcodeScanning}>
          <MaterialCommunityIcons
            name="barcode-scan"
            size={32}
            color={this.state.barcodeScanning ? 'white' : '#858585'}
          />
        </TouchableOpacity>
      </View>

      <View style={styles.pictureSizeContainer}>
        <Text style={styles.pictureQualityLabel}>Picture quality</Text>
        <View style={styles.pictureSizeChooser}>
          <TouchableOpacity
            onPress={this.previousPictureSize}
            style={{ padding: 6 }}>
            <Ionicons name="md-arrow-dropleft" size={14} color="white" />
          </TouchableOpacity>
          <View style={styles.pictureSizeLabel}>
            <Text style={{ color: 'white' }}>{this.state.pictureSize}</Text>
          </View>
          <TouchableOpacity
            onPress={this.nextPictureSize}
            style={{ padding: 6 }}>
            <Ionicons name="md-arrow-dropright" size={14} color="white" />
          </TouchableOpacity>
        </View>
      </View>
    </View>
  );

  renderCamera = () => (
    <View style={{ flex: 1 }}>
      <Camera
        ref={ref => {
          this.camera = ref;
        }}
        style={styles.camera}
        onCameraReady={this.collectPictureSizes}
        type={this.state.type}
        flashMode={this.state.flash}
        autoFocus={this.state.autoFocus}
        zoom={this.state.zoom}
        whiteBalance={this.state.whiteBalance}
        ratio={this.state.ratio}
        pictureSize={this.state.pictureSize}
        onMountError={this.handleMountError}
        onFacesDetected={
          this.state.faceDetecting ? this.onFacesDetected : undefined
        }
        onFaceDetectionError={this.onFaceDetectionError}
        barCodeScannerSettings={{
          barCodeTypes: [
            BarCodeScanner.Constants.BarCodeType.qr,
            BarCodeScanner.Constants.BarCodeType.pdf417,
          ],
        }}
        onBarCodeScanned={
          this.state.barcodeScanning ? this.onBarCodeScanned : undefined
        }>
        {this.renderTopBar()}
        {this.renderBottomBar()}
      </Camera>
      {this.state.faceDetecting && this.renderFaces()}
      {this.state.faceDetecting && this.renderLandmarks()}
      {this.state.showMoreOptions && this.renderMoreOptions()}
    </View>
  );

  render() {
    const cameraScreenContent = this.state.permissionsGranted
      ? this.renderCamera()
      : this.renderNoPermissions();
    const content = this.state.showGallery
      ? this.renderGallery()
      : cameraScreenContent;
    return <View style={styles.container}>{content}</View>;
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#000',
  },
  camera: {
    flex: 1,
    justifyContent: 'space-between',
  },
  topBar: {
    flex: 0.2,
    backgroundColor: 'transparent',
    flexDirection: 'row',
    justifyContent: 'space-around',
    paddingTop: Constants.statusBarHeight / 2,
  },
  bottomBar: {
    paddingBottom: isIPhoneX ? 25 : 5,
    backgroundColor: 'transparent',
    alignSelf: 'flex-end',
    justifyContent: 'space-between',
    flex: 0.12,
    flexDirection: 'row',
  },
  noPermissions: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    padding: 10,
  },
  gallery: {
    flex: 1,
    flexDirection: 'row',
    flexWrap: 'wrap',
  },
  toggleButton: {
    flex: 0.25,
    height: 40,
    marginHorizontal: 2,
    marginBottom: 10,
    marginTop: 20,
    padding: 5,
    alignItems: 'center',
    justifyContent: 'center',
  },
  autoFocusLabel: {
    fontSize: 20,
    fontWeight: 'bold',
  },
  bottomButton: {
    flex: 0.3,
    height: 58,
    justifyContent: 'center',
    alignItems: 'center',
  },
  newPhotosDot: {
    position: 'absolute',
    top: 0,
    right: -5,
    width: 8,
    height: 8,
    borderRadius: 4,
    backgroundColor: '#4630EB',
  },
  options: {
    position: 'absolute',
    bottom: 80,
    left: 30,
    width: 200,
    height: 160,
    backgroundColor: '#000000BA',
    borderRadius: 4,
    padding: 10,
  },
  detectors: {
    flex: 0.5,
    justifyContent: 'space-around',
    alignItems: 'center',
    flexDirection: 'row',
  },
  pictureQualityLabel: {
    fontSize: 10,
    marginVertical: 3,
    color: 'white',
  },
  pictureSizeContainer: {
    flex: 0.5,
    alignItems: 'center',
    paddingTop: 10,
  },
  pictureSizeChooser: {
    alignItems: 'center',
    justifyContent: 'space-between',
    flexDirection: 'row',
  },
  pictureSizeLabel: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
  },
  facesContainer: {
    position: 'absolute',
    bottom: 0,
    right: 0,
    left: 0,
    top: 0,
  },
  face: {
    padding: 10,
    borderWidth: 2,
    borderRadius: 2,
    position: 'absolute',
    borderColor: '#FFD700',
    justifyContent: 'center',
    backgroundColor: 'rgba(0, 0, 0, 0.5)',
  },
  landmark: {
    width: landmarkSize,
    height: landmarkSize,
    position: 'absolute',
    backgroundColor: 'red',
  },
  faceText: {
    color: '#FFD700',
    fontWeight: 'bold',
    textAlign: 'center',
    margin: 10,
    backgroundColor: 'transparent',
  },
  row: {
    flexDirection: 'row',
  },
});

使用脸部识别方块反应原生保存照片

0 个答案: