118 lines
3.8 KiB
JavaScript
118 lines
3.8 KiB
JavaScript
/*
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***** BEGIN LICENSE BLOCK *****
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Copyright © 2021 Corporation for Digital Scholarship
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Vienna, Virginia, USA
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http://digitalscholar.org/
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This file is part of Zotero.
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Zotero is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Zotero is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with Zotero. If not, see <http://www.gnu.org/licenses/>.
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***** END LICENSE BLOCK *****
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*/
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const SCALE_FACTOR = 4;
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window.pdfjsLib.GlobalWorkerOptions.workerSrc = 'resource://zotero/pdf-reader/pdf.worker.js';
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function errObject(err) {
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return JSON.parse(JSON.stringify(err, Object.getOwnPropertyNames(err)));
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}
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async function renderAnnotations(buf, annotations, send) {
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let num = 0;
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let pdfDocument = await window.pdfjsLib.getDocument({ data: buf }).promise;
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let pages = new Map();
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for (let annotation of annotations) {
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let pageIndex = annotation.position.pageIndex;
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let page = pages.get(pageIndex) || [];
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page.push(annotation);
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pages.set(pageIndex, page);
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}
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for (let [pageIndex, annotations] of pages) {
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let { canvas, viewport } = await renderPage(pdfDocument, pageIndex);
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for (let annotation of annotations) {
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let position = p2v(annotation.position, viewport);
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let rect = position.rects[0];
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let [left, top, right, bottom] = rect;
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let width = right - left;
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let height = bottom - top;
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let newCanvas = document.createElement('canvas');
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newCanvas.width = width;
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newCanvas.height = height;
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let newCanvasContext = newCanvas.getContext('2d');
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newCanvasContext.drawImage(canvas, left, top, width, height, 0, 0, width, height);
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newCanvas.toBlob(async (blob) => {
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let image = await new Response(blob).arrayBuffer();
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send({ id: annotation.id, image });
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}, 'image/png');
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num++;
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}
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}
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return num;
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}
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function p2v(position, viewport) {
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return {
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pageIndex: position.pageIndex,
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rects: position.rects.map(rect => {
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let [x1, y2] = viewport.convertToViewportPoint(rect[0], rect[1]);
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let [x2, y1] = viewport.convertToViewportPoint(rect[2], rect[3]);
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return [Math.min(x1, x2), Math.min(y1, y2), Math.max(x1, x2), Math.max(y1, y2)];
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})
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};
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}
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async function renderPage(pdfDocument, pageIndex) {
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let page = await pdfDocument.getPage(pageIndex + 1);
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var canvas = document.createElement('canvas');
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var viewport = page.getViewport({ scale: SCALE_FACTOR });
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var context = canvas.getContext('2d', { alpha: false });
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canvas.height = viewport.height;
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canvas.width = viewport.width;
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await page.render({ canvasContext: context, viewport: viewport }).promise;
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return { canvas, viewport };
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}
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window.addEventListener('message', async (event) => {
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if (event.source === parent) {
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return;
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}
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let message = event.data;
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if (message.action === 'renderAnnotations') {
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try {
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let { buf, annotations } = message.data;
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let num = await renderAnnotations(
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buf,
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annotations,
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(annotation) => {
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parent.postMessage({ action: 'renderedAnnotation', data: { annotation } }, parent.origin, [annotation.image]);
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}
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);
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parent.postMessage({ responseID: message.id, data: num }, parent.origin);
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}
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catch (e) {
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console.log(e);
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parent.postMessage({
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responseID: message.id,
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error: errObject(e)
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}, parent.origin);
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}
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}
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});
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setTimeout(() => {
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parent.postMessage({ action: 'initialized' }, parent.origin);
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}, 100);
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