487a7ddc7d
Given that Node.js doesn't support Workers, general PDF.js performance will be worse when compared to browsers. In an attempt to improve at least memory usage a little bit, update the Node.js examples to release page resources once parsing is done for that page.
73 lines
2.7 KiB
JavaScript
73 lines
2.7 KiB
JavaScript
/* Copyright 2014 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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const PDF_PATH = "../../web/compressed.tracemonkey-pldi-09.pdf";
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const PAGE_NUMBER = 1;
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const PAGE_SCALE = 1.5;
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const SVG_NS = "http://www.w3.org/2000/svg";
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pdfjsLib.GlobalWorkerOptions.workerSrc =
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"../../node_modules/pdfjs-dist/build/pdf.worker.js";
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function buildSVG(viewport, textContent) {
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// Building SVG with size of the viewport (for simplicity)
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const svg = document.createElementNS(SVG_NS, "svg:svg");
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svg.setAttribute("width", viewport.width + "px");
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svg.setAttribute("height", viewport.height + "px");
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// items are transformed to have 1px font size
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svg.setAttribute("font-size", 1);
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// processing all items
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textContent.items.forEach(function (textItem) {
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// we have to take in account viewport transform, which includes scale,
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// rotation and Y-axis flip, and not forgetting to flip text.
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const tx = pdfjsLib.Util.transform(
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pdfjsLib.Util.transform(viewport.transform, textItem.transform),
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[1, 0, 0, -1, 0, 0]
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);
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const style = textContent.styles[textItem.fontName];
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// adding text element
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const text = document.createElementNS(SVG_NS, "svg:text");
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text.setAttribute("transform", "matrix(" + tx.join(" ") + ")");
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text.setAttribute("font-family", style.fontFamily);
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text.textContent = textItem.str;
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svg.appendChild(text);
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});
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return svg;
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}
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async function pageLoaded() {
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// Loading document and page text content
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const loadingTask = pdfjsLib.getDocument({ url: PDF_PATH });
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const pdfDocument = await loadingTask.promise;
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const page = await pdfDocument.getPage(PAGE_NUMBER);
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const viewport = page.getViewport({ scale: PAGE_SCALE });
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const textContent = await page.getTextContent();
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// building SVG and adding that to the DOM
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const svg = buildSVG(viewport, textContent);
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document.getElementById("pageContainer").appendChild(svg);
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// Release page resources.
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page.cleanup();
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}
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document.addEventListener("DOMContentLoaded", function () {
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if (typeof pdfjsLib === "undefined") {
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// eslint-disable-next-line no-alert
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alert("Please build the pdfjs-dist library using\n `gulp dist-install`");
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return;
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}
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pageLoaded();
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});
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