120 lines
3.4 KiB
TypeScript
120 lines
3.4 KiB
TypeScript
import { DeesElement, property, html, customElement, domtools, type TemplateResult, type CSSResult, } from '@design.estate/dees-element';
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import { Deferred } from '@push.rocks/smartpromise';
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import type pdfjsTypes from 'pdfjs-dist';
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declare global {
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interface HTMLElementTagNameMap {
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'dees-pdf': DeesPdf;
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}
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}
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@customElement('dees-pdf')
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export class DeesPdf extends DeesElement {
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// DEMO
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public static demo = () => html` <dees-pdf></dees-pdf> `;
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// INSTANCE
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@property()
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public pdfUrl: string =
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'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/examples/learning/helloworld.pdf';
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constructor() {
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super();
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// you have access to all kinds of things through this.
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// this.setAttribute('gotIt','true');
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}
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public render(): TemplateResult {
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return html`
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<style>
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:host {
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font-family: 'Mona Sans', 'Inter', sans-serif;
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display: block;
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box-sizing: border-box;
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max-width: 800px;
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}
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:host([hidden]) {
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display: none;
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}
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#pdfcanvas {
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box-shadow: 0px 0px 5px #ccc;
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width: 100%;
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}
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</style>
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<canvas id="pdfcanvas" .height=${0} .width=${0}></canvas>
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`;
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}
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public static pdfJsReady: Promise<any>;
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public static pdfjsLib: typeof pdfjsTypes;
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public async connectedCallback() {
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super.connectedCallback();
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if (!DeesPdf.pdfJsReady) {
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const pdfJsReadyDeferred = domtools.plugins.smartpromise.defer();
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DeesPdf.pdfJsReady = pdfJsReadyDeferred.promise;
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const loadDeferred = domtools.plugins.smartpromise.defer();
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const script = document.createElement('script');
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script.addEventListener('load', () => {
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console.log('pdf.js loaded!');
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loadDeferred.resolve();
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});
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script.src = 'https:////mozilla.github.io/pdf.js/build/pdf.js';
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document.getElementsByTagName('head')[0].appendChild(script);
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// The workerSrc property shall be specified.
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await loadDeferred.promise;
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DeesPdf.pdfjsLib = window['pdfjs-dist/build/pdf'];
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DeesPdf.pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';
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pdfJsReadyDeferred.resolve();
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}
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await DeesPdf.pdfJsReady;
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this.displayContent();
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}
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public async displayContent() {
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await DeesPdf.pdfJsReady;
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// Asynchronous download of PDF
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const loadingTask = DeesPdf.pdfjsLib.getDocument(this.pdfUrl);
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loadingTask.promise.then(
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(pdf) => {
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console.log('PDF loaded');
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// Fetch the first page
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const pageNumber = 1;
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pdf.getPage(pageNumber).then((page) => {
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console.log('Page loaded');
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const scale = 10;
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const viewport = page.getViewport({ scale: scale });
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// Prepare canvas using PDF page dimensions
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const canvas: any = this.shadowRoot.querySelector('#pdfcanvas');
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const context = canvas.getContext('2d');
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canvas.height = viewport.height;
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canvas.width = viewport.width;
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// Render PDF page into canvas context
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const renderContext = {
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canvasContext: context,
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viewport: viewport,
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};
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const renderTask = page.render(renderContext);
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renderTask.promise.then(function () {
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console.log('Page rendered');
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});
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});
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},
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(reason) => {
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// PDF loading error
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console.error(reason);
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}
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);
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}
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}
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