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

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

import { Platform } from 'react-native';
import type { CameraProps, Orientation } from 'react-native-vision-camera';
import type { Point, Size } from 'src/types';
import { normalizePrecision } from './convert';

export const applyScaleFactor = (
  { x, y }: Point,
  source: Size,
  target: Size,
  resizeMode: CameraProps['resizeMode'] = 'cover',
): Point => {
  'worklet';

  const ratio = {
    width: target.width / source.width,
    height: target.height / source.height,
  };

  let scaleFactor;
  if (resizeMode === 'contain') {
    scaleFactor = Math.min(ratio.width, ratio.height);
  } else if (resizeMode === 'cover') {
    scaleFactor = Math.max(ratio.width, ratio.height);
  } else {
    throw new Error(`Invalid resize mode: ${resizeMode}`);
  }

  let newX = x * scaleFactor;
  let newY = y * scaleFactor;

  // Center the image if it's contain mode
  if (
    (ratio.width < ratio.height && resizeMode === 'contain') ||
    (ratio.width > ratio.height && resizeMode === 'cover')
  ) {
    newY += (target.height - source.height * scaleFactor) / 2;
  } else {
    newX += (target.width - source.width * scaleFactor) / 2;
  }

  return { x: normalizePrecision(newX), y: normalizePrecision(newY) };
};

export const applyTransformation = (
  { x, y }: Point,
  { width, height }: Size,
  orientation: Orientation,
): Point => {
  'worklet';

  if (Platform.OS === 'android') {
    switch (orientation) {
      case 'portrait':
        return { x, y };
      default:
        console.warn(`Unsupported orientation: ${orientation}`);
        return { x, y };
    }
  } else if (Platform.OS === 'ios') {
    switch (orientation) {
      case 'portrait':
        return { x: height - y, y: width - x };
      case 'landscape-left':
        return { x: width - x, y };
      case 'landscape-right':
        return { x: x, y: height - y };
      case 'portrait-upside-down':
        return { x: y, y: x };
      default:
        console.warn(`Unsupported orientation: ${orientation}`);
        return { x, y };
    }
  } else {
    throw new Error(`Unsupported platform: ${Platform.OS}`);
  }
};