vision-camera-mrz-scanner/lib/commonjs/util/boundingBoxAdjustToView.js

VisionCamera Frame Processor Plugin to detect and read MRZ data from passports using MLKit Text Recognition.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.boundingBoxAdjustToView = void 0;
var _reactNative = require("react-native");
/**
 * It takes a frame and a view, and returns an object with two functions: adjustPoint and adjustRect
 * @param {Dimensions} frame - Dimensions - the dimensions of the video frame
 * @param {Dimensions} view - Dimensions
 * @returns An object with two functions.
 * @resource https://github.com/bglgwyng/FrameProcessorExample/blob/e8e99d58c878d4dce9a8adf74a7447d253be93ab/adjustToView.ts#L21
 */
const boundingBoxAdjustToView = _reactNative.Platform.OS === 'ios' ? (frame, view) => {
  const widthRatio = view.width / frame.width;
  const heightRatio = view.height / frame.height;
  return {
    adjustPoint: point => ({
      x: point.x * widthRatio,
      y: point.y * heightRatio
    }),
    adjustRect(rect) {
      return {
        left: rect.left * widthRatio,
        top: rect.top * heightRatio,
        width: rect.width * widthRatio,
        height: rect.height * heightRatio
      };
    }
  };
} : (frame, view, landscape, verticalPadding, horizontalPadding) => {
  const {
    width,
    height
  } = view;
  /* Calculating the aspect ratio of the view. */
  const aspectRatio = width / height;
  const frameWidth = frame.width;
  const frameHeight = frame.height;
  const frameAspectRatio = frameWidth / frameHeight;

  /* Setting the widthRatio, heightRatio, offsetX, and offsetY to 0. */
  let widthRatio;
  let heightRatio;
  let offsetX = 0;
  let offsetY = 0;
  const verticalCropPadding = verticalPadding || 0;
  const horizontalCropPadding = horizontalPadding || 0;

  // /* Calculating the ratio of the frame to the view. */

  if (!landscape) {
    if (frameAspectRatio < aspectRatio) {
      widthRatio = width / frameWidth;
      const croppedFrameHeight = aspectRatio * frameWidth;
      offsetY = (frameHeight - croppedFrameHeight) / 2;
      heightRatio = height / croppedFrameHeight;
    } else {
      heightRatio = height / frameHeight;
      const croppedFrameWidth = aspectRatio * frameHeight;
      offsetX = (frameWidth - croppedFrameWidth) / 2;
      widthRatio = width / croppedFrameWidth;
    }
  } else {
    const croppedFrameWidth = aspectRatio * frameHeight;
    const croppedFrameHeight = aspectRatio * frameWidth;
    if (!landscape) {
      offsetX = (frameWidth - croppedFrameWidth) / 2;
    } else {
      offsetY = (frameHeight - croppedFrameHeight) / 2;
    }
    heightRatio = height / frameHeight;
    widthRatio = width / croppedFrameWidth;
  }

  /* Returning an object with two functions. */
  return {
    adjustPoint: point => ({
      x: (point.x - offsetX) * widthRatio,
      y: (point.y - offsetY) * heightRatio
    }),
    adjustRect: rect => ({
      top: (rect.top - offsetY - verticalCropPadding) * heightRatio,
      left: (rect.left - offsetX - horizontalCropPadding) * widthRatio,
      height: (rect.height + verticalCropPadding) * heightRatio,
      width: (rect.width + horizontalCropPadding) * widthRatio
    })
  };
};
exports.boundingBoxAdjustToView = boundingBoxAdjustToView;
//# sourceMappingURL=boundingBoxAdjustToView.js.map