vision-camera-simple-scanner/src/utils/convert.ts

High performance barcode scanner for React Native using VisionCamera, forked from vision-camera-barcode-scanner

import { Platform } from 'react-native';
import type { Code, Frame } from 'react-native-vision-camera';
import type {
  AndroidBarcode,
  Barcode,
  BoundingBox,
  Point,
  iOSBarcode,
} from 'src/types';
import { normalizeAndroidCodeType, normalizeiOSCodeType } from './types';

export const isIOSBarcode = (
  barcode: iOSBarcode | AndroidBarcode,
): barcode is iOSBarcode => {
  'worklet';
  return Platform.OS === 'ios';
};

export const isAndroidBarcode = (
  barcode: iOSBarcode | AndroidBarcode,
): barcode is AndroidBarcode => {
  'worklet';
  return Platform.OS === 'android';
};

export const computeBoundingBoxFromCornerPoints = (
  cornerPoints: Point[],
): BoundingBox => {
  'worklet';
  const xArray = cornerPoints.map((corner) => corner.x);
  const yArray = cornerPoints.map((corner) => corner.y);
  // @NOTE we can't use destructuring here because babel would wrap it in non-worklet functions
  const x = Math.min.apply(null, xArray);
  const y = Math.min.apply(null, yArray);
  const width = Math.max.apply(null, xArray) - x;
  const height = Math.max.apply(null, yArray) - y;
  return {
    origin: { x, y },
    size: {
      width,
      height,
    },
  };
};

export const normalizePrecision = (number: number): number => {
  'worklet';
  return Math.round(number);
};

export const normalizeNativeBarcode = (
  barcode: iOSBarcode | AndroidBarcode,
  frame: Frame,
): Barcode => {
  'worklet';
  if (isIOSBarcode(barcode)) {
    const { payload, symbology, boundingBox, corners } = barcode;
    return {
      value: payload,
      type: normalizeiOSCodeType(symbology),
      boundingBox: {
        origin: {
          x: normalizePrecision(boundingBox.origin.x * frame.width),
          y: normalizePrecision(boundingBox.origin.y * frame.height),
        },
        size: {
          width: normalizePrecision(boundingBox.size.width * frame.width),
          height: normalizePrecision(boundingBox.size.height * frame.height),
        },
      },
      // This explicitly defined to match android's implementation which is to start top left and go clockwise.
      // https://developers.google.com/android/reference/com/google/mlkit/vision/barcode/common/Barcode#public-point[]-getcornerpoints
      cornerPoints: [
        corners.topLeft,
        corners.topRight,
        corners.bottomRight,
        corners.bottomLeft,
      ].map(({ x, y }) => ({
        x: normalizePrecision(x * frame.width),
        y: normalizePrecision(y * frame.height),
      })),
      native: barcode,
    };
  } else if (isAndroidBarcode(barcode)) {
    const { rawValue, format, cornerPoints } = barcode;
    return {
      value: rawValue,
      type: normalizeAndroidCodeType(format),
      boundingBox: computeBoundingBoxFromCornerPoints(cornerPoints),
      cornerPoints,
      native: barcode,
    };
  } else {
    throw new Error(`Unsupported platform: ${Platform.OS}`);
  }
};

export const convertVisionCameraCodeToBarcode = (
  code: Code,
): Omit<Barcode, 'native'> => {
  return {
    value: code.value ?? null,
    type: code.type,
    boundingBox: {
      origin: {
        x: code.frame?.x ?? 0,
        y: code.frame?.y ?? 0,
      },
      size: {
        width: code.frame?.width ?? 0,
        height: code.frame?.height ?? 0,
      },
    },
    cornerPoints: code.corners ?? [],
  };
};