124 lines
2.7 KiB
TypeScript
124 lines
2.7 KiB
TypeScript
import type { Document } from '@toeverything/pdf-viewer';
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import {
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createPDFium,
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PageRenderingflags,
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Runtime,
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Viewer,
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} from '@toeverything/pdf-viewer';
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import wasmUrl from '@toeverything/pdfium/wasm?url';
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import { type MessageData, type MessageDataType, MessageOp } from './types';
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let inited = false;
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let viewer: Viewer | null = null;
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let doc: Document | undefined = undefined;
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const docInfo = { total: 0, width: 1, height: 1 };
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const flags = PageRenderingflags.REVERSE_BYTE_ORDER | PageRenderingflags.ANNOT;
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function post<T extends MessageOp>(type: T, data?: MessageDataType[T]) {
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const message = { type, [type]: data };
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self.postMessage(message);
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}
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function renderToImageData(index: number, scale: number) {
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if (!viewer || !doc) return;
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const page = doc.page(index);
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if (!page) return;
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const width = Math.ceil(docInfo.width * scale);
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const height = Math.ceil(docInfo.height * scale);
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const bitmap = viewer.createBitmap(width, height, 0);
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bitmap.fill(0, 0, width, height);
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page.render(bitmap, 0, 0, width, height, 0, flags);
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const data = new Uint8ClampedArray(bitmap.toUint8Array());
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bitmap.close();
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page.close();
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return new ImageData(data, width, height);
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}
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async function start() {
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inited = true;
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console.debug('pdf worker pending');
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self.postMessage({ type: MessageOp.Init });
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const pdfium = await createPDFium({
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// @ts-expect-error allow
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locateFile: () => wasmUrl,
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});
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viewer = new Viewer(new Runtime(pdfium));
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self.postMessage({ type: MessageOp.Inited });
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console.debug('pdf worker ready');
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}
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async function process({ data }: MessageEvent<MessageData>) {
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if (!inited) {
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await start();
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}
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if (!viewer) return;
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const { type } = data;
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switch (type) {
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case MessageOp.Open: {
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const buffer = data[type];
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if (!buffer) return;
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doc = viewer.open(new Uint8Array(buffer));
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if (!doc) return;
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const page = doc.page(0);
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if (!page) return;
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Object.assign(docInfo, {
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total: doc.pageCount(),
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height: Math.ceil(page.height()),
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width: Math.ceil(page.width()),
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});
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page.close();
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post(MessageOp.Opened, docInfo);
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break;
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}
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case MessageOp.Render: {
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if (!doc) return;
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const { index, kind, scale } = data[type];
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const { total } = docInfo;
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if (index < 0 || index >= total) return;
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queueMicrotask(() => {
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const imageData = renderToImageData(index, scale);
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if (!imageData) return;
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post(MessageOp.Rendered, { index, kind, imageData });
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});
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break;
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}
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}
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}
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self.addEventListener('message', (event: MessageEvent<MessageData>) => {
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process(event).catch(console.error);
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});
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start().catch(error => {
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inited = false;
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console.log(error);
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});
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