/**
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* @fileoverview
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* {@interface QrcodeDecoder} wrapper around ZXing library.
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*
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* @author mebjas <minhazav@gmail.com>
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*
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* ZXing library forked from https://github.com/zxing-js/library.
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*
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* The word "QR Code" is registered trademark of DENSO WAVE INCORPORATED
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* http://www.denso-wave.com/qrcode/faqpatent-e.html
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*/
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import * as ZXing from "../third_party/zxing-js.umd";
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import {
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QrcodeResult,
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QrcodeResultDebugData,
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QrcodeResultFormat,
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Html5QrcodeSupportedFormats,
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Logger,
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QrcodeDecoderAsync
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} from "./core";
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/**
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* ZXing based Code decoder.
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*/
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export class ZXingHtml5QrcodeDecoder implements QrcodeDecoderAsync {
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private readonly formatMap: Map<Html5QrcodeSupportedFormats, any>
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= new Map([
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[Html5QrcodeSupportedFormats.QR_CODE, ZXing.BarcodeFormat.QR_CODE ],
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[Html5QrcodeSupportedFormats.AZTEC, ZXing.BarcodeFormat.AZTEC ],
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[Html5QrcodeSupportedFormats.CODABAR, ZXing.BarcodeFormat.CODABAR ],
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[Html5QrcodeSupportedFormats.CODE_39, ZXing.BarcodeFormat.CODE_39 ],
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[Html5QrcodeSupportedFormats.CODE_93, ZXing.BarcodeFormat.CODE_93 ],
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[
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Html5QrcodeSupportedFormats.CODE_128,
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ZXing.BarcodeFormat.CODE_128 ],
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[
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Html5QrcodeSupportedFormats.DATA_MATRIX,
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ZXing.BarcodeFormat.DATA_MATRIX ],
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[
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Html5QrcodeSupportedFormats.MAXICODE,
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ZXing.BarcodeFormat.MAXICODE ],
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[Html5QrcodeSupportedFormats.ITF, ZXing.BarcodeFormat.ITF ],
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[Html5QrcodeSupportedFormats.EAN_13, ZXing.BarcodeFormat.EAN_13 ],
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[Html5QrcodeSupportedFormats.EAN_8, ZXing.BarcodeFormat.EAN_8 ],
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[Html5QrcodeSupportedFormats.PDF_417, ZXing.BarcodeFormat.PDF_417 ],
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[Html5QrcodeSupportedFormats.RSS_14, ZXing.BarcodeFormat.RSS_14 ],
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[
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Html5QrcodeSupportedFormats.RSS_EXPANDED,
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ZXing.BarcodeFormat.RSS_EXPANDED ],
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[Html5QrcodeSupportedFormats.UPC_A, ZXing.BarcodeFormat.UPC_A ],
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[Html5QrcodeSupportedFormats.UPC_E, ZXing.BarcodeFormat.UPC_E ],
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[
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Html5QrcodeSupportedFormats.UPC_EAN_EXTENSION,
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ZXing.BarcodeFormat.UPC_EAN_EXTENSION ]
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]);
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private readonly reverseFormatMap: Map<any, Html5QrcodeSupportedFormats>
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= this.createReverseFormatMap();
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private hints: Map<any, any>;
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private verbose: boolean;
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private logger: Logger;
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public constructor(
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requestedFormats: Array<Html5QrcodeSupportedFormats>,
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verbose: boolean,
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logger: Logger) {
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if (!ZXing) {
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throw "Use html5qrcode.min.js without edit, ZXing not found.";
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}
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this.verbose = verbose;
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this.logger = logger;
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const formats = this.createZXingFormats(requestedFormats);
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const hints = new Map();
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hints.set(ZXing.DecodeHintType.POSSIBLE_FORMATS, formats);
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// TODO(minhazav): Make this configurable by developers.
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hints.set(ZXing.DecodeHintType.TRY_HARDER, false);
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this.hints = hints;
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}
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decodeAsync(canvas: HTMLCanvasElement): Promise<QrcodeResult> {
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return new Promise((resolve, reject) => {
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try {
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resolve(this.decode(canvas));
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} catch (error) {
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reject(error);
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}
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});
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}
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private decode(canvas: HTMLCanvasElement): QrcodeResult {
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// Note: Earlier we used to instantiate the zxingDecoder once as state
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// of this class and use it for each scans. There seems to be some
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// stateful bug in ZXing library around RSS_14 likely due to
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// https://github.com/zxing-js/library/issues/211.
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// Recreating a new instance per scan doesn't lead to performance issues
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// and temporarily mitigates this issue.
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// TODO(mebjas): Properly fix this issue in ZXing library.
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const zxingDecoder = new ZXing.MultiFormatReader(
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this.verbose, this.hints);
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const luminanceSource
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= new ZXing.HTMLCanvasElementLuminanceSource(canvas);
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const binaryBitmap
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= new ZXing.BinaryBitmap(
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new ZXing.HybridBinarizer(luminanceSource));
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let result = zxingDecoder.decode(binaryBitmap);
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return {
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text: result.text,
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format: QrcodeResultFormat.create(
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this.toHtml5QrcodeSupportedFormats(result.format)),
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debugData: this.createDebugData()
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};
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}
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private createReverseFormatMap(): Map<any, Html5QrcodeSupportedFormats> {
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let result = new Map();
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this.formatMap.forEach(
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(value: any, key: Html5QrcodeSupportedFormats, _) => {
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result.set(value, key);
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});
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return result;
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}
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private toHtml5QrcodeSupportedFormats(zxingFormat: any)
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: Html5QrcodeSupportedFormats {
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if (!this.reverseFormatMap.has(zxingFormat)) {
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throw `reverseFormatMap doesn't have ${zxingFormat}`;
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}
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return this.reverseFormatMap.get(zxingFormat)!;
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}
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private createZXingFormats(
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requestedFormats: Array<Html5QrcodeSupportedFormats>):
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Array<any> {
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let zxingFormats = [];
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for (const requestedFormat of requestedFormats) {
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if (this.formatMap.has(requestedFormat)) {
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zxingFormats.push(
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this.formatMap.get(requestedFormat));
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} else {
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this.logger.logError(`${requestedFormat} is not supported by`
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+ "ZXingHtml5QrcodeShim");
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}
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}
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return zxingFormats;
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}
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private createDebugData(): QrcodeResultDebugData {
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return { decoderName: "zxing-js" };
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}
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}
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