eewing
84 lines
3.3 KiB
JavaScript
84 lines
3.3 KiB
JavaScript
import { BrowserMultiFormatReader } from '@zxing/browser';
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import { DecodeHintType, NotFoundException } from '@zxing/library';
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import { nativeToZxingFormat, zxingToNativeFormat } from './constants';
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export class BarcodeDetector {
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reader;
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constructor(options) {
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const hints = new Map([
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[DecodeHintType.TRY_HARDER, true],
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[
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DecodeHintType.POSSIBLE_FORMATS,
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options
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? options.formats.map((f) => nativeToZxingFormat[f])
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: Object.values(nativeToZxingFormat),
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],
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]);
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this.reader = new BrowserMultiFormatReader(hints);
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}
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static getSupportedFormats() {
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return Promise.resolve(Object.values(zxingToNativeFormat));
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}
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async detect(imageSource) {
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try {
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let result;
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if (imageSource instanceof HTMLVideoElement || imageSource instanceof HTMLImageElement) {
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result = await this.reader.scanOneResult(imageSource, false);
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}
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else if (imageSource instanceof HTMLCanvasElement) {
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result = this.reader.decodeFromCanvas(imageSource);
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}
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else if (imageSource instanceof Blob) {
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const image = await this.blobToImage(imageSource);
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result = await this.reader.scanOneResult(image, false);
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}
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else if (imageSource instanceof ImageBitmap
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|| imageSource instanceof ImageData
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|| imageSource instanceof VideoFrame) {
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result = this.reader.decodeFromCanvas(this.imageDataSourceToCanvas(imageSource));
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}
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else {
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throw new TypeError('Image source is not supported');
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}
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return [{
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rawValue: result.getText(),
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format: zxingToNativeFormat[result.getBarcodeFormat()],
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boundingBox: new DOMRectReadOnly(), // TODO: think of a way to map this in a meaningful way
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cornerPoints: result.getResultPoints().map((p) => ({ x: p.getX(), y: p.getY() })),
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}];
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}
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catch (err) {
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if (err && !(err instanceof NotFoundException)) {
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throw err;
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}
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return [];
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}
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}
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async blobToImage(blob) {
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return new Promise((resolve, reject) => {
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const imageObjUrl = URL.createObjectURL(blob);
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const image = new Image();
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image.onload = () => {
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URL.revokeObjectURL(imageObjUrl);
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resolve(image);
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};
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image.onerror = () => reject();
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image.src = imageObjUrl;
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});
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}
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imageDataSourceToCanvas(source) {
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const canvas = document.createElement('canvas');
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const ctx = canvas.getContext('2d');
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const width = source instanceof VideoFrame ? source.displayWidth : source.width;
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const height = source instanceof VideoFrame ? source.displayHeight : source.height;
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if (ctx) {
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if (source instanceof ImageData) {
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ctx.putImageData(source, width, height);
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}
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else {
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ctx.drawImage(source, width, height);
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}
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}
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return canvas;
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}
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}
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//# sourceMappingURL=BarcodeDetector.js.map
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