mirror of
https://github.com/mozilla/pdf.js.git
synced 2025-04-26 10:08:06 +02:00
86f943ca03
The `@napi-rs/canvas` package has fewer dependencies, which should *hopefully* make installing and using it easier for `pdfjs-dist` end-users. (Over the years we've seen, repeatedly, that `canvas` can be difficult to install successfully.) Furthermore, this package includes more functionality (such as `Path2D`) which reduces the overall number of dependencies in the PDF.js project. One point to note is that `@napi-rs/canvas` is a fair bit newer than `canvas`, and has a lot fewer users, however looking at the commit history it does seem to be actively maintained. Note that I've successfully tested the [Node.js examples](https://github.com/mozilla/pdf.js/tree/master/examples/node), in particular the `pdf2png` one, with this patch applied and things appear to work fine. Please see: - https://www.npmjs.com/package/@napi-rs/canvas - https://github.com/Brooooooklyn/canvas
72 lines
2.2 KiB
JavaScript
72 lines
2.2 KiB
JavaScript
/* Copyright 2017 Mozilla Foundation
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
import fs from "fs";
|
|
import { getDocument } from "pdfjs-dist/legacy/build/pdf.mjs";
|
|
|
|
// Some PDFs need external cmaps.
|
|
const CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
|
|
const CMAP_PACKED = true;
|
|
|
|
// Where the standard fonts are located.
|
|
const STANDARD_FONT_DATA_URL =
|
|
"../../../node_modules/pdfjs-dist/standard_fonts/";
|
|
|
|
// Loading file from file system into typed array.
|
|
const pdfPath =
|
|
process.argv[2] || "../../../web/compressed.tracemonkey-pldi-09.pdf";
|
|
const data = new Uint8Array(fs.readFileSync(pdfPath));
|
|
|
|
// Load the PDF file.
|
|
const loadingTask = getDocument({
|
|
data,
|
|
cMapUrl: CMAP_URL,
|
|
cMapPacked: CMAP_PACKED,
|
|
standardFontDataUrl: STANDARD_FONT_DATA_URL,
|
|
});
|
|
|
|
try {
|
|
const pdfDocument = await loadingTask.promise;
|
|
console.log("# PDF document loaded.");
|
|
// Get the first page.
|
|
const page = await pdfDocument.getPage(1);
|
|
// Render the page on a Node canvas with 100% scale.
|
|
const canvasFactory = pdfDocument.canvasFactory;
|
|
const viewport = page.getViewport({ scale: 1.0 });
|
|
const canvasAndContext = canvasFactory.create(
|
|
viewport.width,
|
|
viewport.height
|
|
);
|
|
const renderContext = {
|
|
canvasContext: canvasAndContext.context,
|
|
viewport,
|
|
};
|
|
|
|
const renderTask = page.render(renderContext);
|
|
await renderTask.promise;
|
|
// Convert the canvas to an image buffer.
|
|
const image = canvasAndContext.canvas.toBuffer("image/png");
|
|
fs.writeFile("output.png", image, function (error) {
|
|
if (error) {
|
|
console.error("Error: " + error);
|
|
} else {
|
|
console.log("Finished converting first page of PDF file to a PNG image.");
|
|
}
|
|
});
|
|
// Release page resources.
|
|
page.cleanup();
|
|
} catch (reason) {
|
|
console.log(reason);
|
|
}
|