pdf.js/examples/node/pdf2png/pdf2png.js
Jonas Jenwald 4a7e29865d [api-minor] Use the NodeCanvasFactory/NodeCMapReaderFactory classes as defaults in Node.js environments (issue 11900)
This moves, and slightly simplifies, code that's currently residing in the unit-test utils into the actual library, such that it's bundled with `GENERIC`-builds and used in e.g. the API-code.

As an added bonus, this also brings out-of-the-box support for CMaps in e.g. the Node.js examples.
2020-07-02 04:44:23 +02:00

106 lines
3.4 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.
*/
var Canvas = require("canvas");
var assert = require("assert").strict;
var fs = require("fs");
function NodeCanvasFactory() {}
NodeCanvasFactory.prototype = {
create: function NodeCanvasFactory_create(width, height) {
assert(width > 0 && height > 0, "Invalid canvas size");
var canvas = Canvas.createCanvas(width, height);
var context = canvas.getContext("2d");
return {
canvas: canvas,
context: context,
};
},
reset: function NodeCanvasFactory_reset(canvasAndContext, width, height) {
assert(canvasAndContext.canvas, "Canvas is not specified");
assert(width > 0 && height > 0, "Invalid canvas size");
canvasAndContext.canvas.width = width;
canvasAndContext.canvas.height = height;
},
destroy: function NodeCanvasFactory_destroy(canvasAndContext) {
assert(canvasAndContext.canvas, "Canvas is not specified");
// Zeroing the width and height cause Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
canvasAndContext.canvas.width = 0;
canvasAndContext.canvas.height = 0;
canvasAndContext.canvas = null;
canvasAndContext.context = null;
},
};
var pdfjsLib = require("pdfjs-dist/es5/build/pdf.js");
// Some PDFs need external cmaps.
var CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
var CMAP_PACKED = true;
// Loading file from file system into typed array.
var pdfPath =
process.argv[2] || "../../../web/compressed.tracemonkey-pldi-09.pdf";
var data = new Uint8Array(fs.readFileSync(pdfPath));
// Load the PDF file.
var loadingTask = pdfjsLib.getDocument({
data: data,
cMapUrl: CMAP_URL,
cMapPacked: CMAP_PACKED,
});
loadingTask.promise
.then(function (pdfDocument) {
console.log("# PDF document loaded.");
// Get the first page.
pdfDocument.getPage(1).then(function (page) {
// Render the page on a Node canvas with 100% scale.
var viewport = page.getViewport({ scale: 1.0 });
var canvasFactory = new NodeCanvasFactory();
var canvasAndContext = canvasFactory.create(
viewport.width,
viewport.height
);
var renderContext = {
canvasContext: canvasAndContext.context,
viewport: viewport,
canvasFactory: canvasFactory,
};
var renderTask = page.render(renderContext);
renderTask.promise.then(function () {
// Convert the canvas to an image buffer.
var image = canvasAndContext.canvas.toBuffer();
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."
);
}
});
});
});
})
.catch(function (reason) {
console.log(reason);
});