diff --git a/.gitignore b/.gitignore index 421e6f4a4..157225dcd 100644 --- a/.gitignore +++ b/.gitignore @@ -6,3 +6,4 @@ tags Makefile node_modules/ examples/node/svgdump/ +examples/node/pdf2png/*.png diff --git a/examples/node/pdf2png/README.md b/examples/node/pdf2png/README.md new file mode 100644 index 000000000..bb7cc2923 --- /dev/null +++ b/examples/node/pdf2png/README.md @@ -0,0 +1,16 @@ +## Overview + +Example to demonstrate converting a PDF file to a PNG image using the PDF.js library. + +## Getting started + +Install the dependencies and build the project: + + $ npm install + $ gulp dist + +Install the Node canvas library to convert the first page of a PDF file to a PNG image: + + $ npm install canvas + $ cd examples/node/pdf2png + $ node pdf2png.js diff --git a/examples/node/pdf2png/pdf2png.js b/examples/node/pdf2png/pdf2png.js new file mode 100644 index 000000000..468d1bab8 --- /dev/null +++ b/examples/node/pdf2png/pdf2png.js @@ -0,0 +1,89 @@ +/* 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'); +var fs = require('fs'); + +function NodeCanvasFactory() {} +NodeCanvasFactory.prototype = { + create: function NodeCanvasFactory_create(width, height) { + assert(width > 0 && height > 0, 'Invalid canvas size'); + var canvas = new Canvas(width, height); + var context = canvas.getContext('2d'); + return { + canvas: canvas, + context: context, + }; + }, + + reset: function NodeCanvasFactory_reset(canvasAndContextPair, width, height) { + assert(canvasAndContextPair.canvas, 'Canvas is not specified'); + assert(width > 0 && height > 0, 'Invalid canvas size'); + canvasAndContextPair.canvas.width = width; + canvasAndContextPair.canvas.height = height; + }, + + destroy: function NodeCanvasFactory_destroy(canvasAndContextPair) { + assert(canvasAndContextPair.canvas, 'Canvas is not specified'); + + // Zeroing the width and height cause Firefox to release graphics + // resources immediately, which can greatly reduce memory consumption. + canvasAndContextPair.canvas.width = 0; + canvasAndContextPair.canvas.height = 0; + canvasAndContextPair.canvas = null; + canvasAndContextPair.context = null; + }, +}; + +var pdfjsLib = require('../../../build/dist'); + +// Relative path of the PDF file. +var pdfURL = '../../helloworld/helloworld.pdf'; + +// Read the PDF file into a typed array so PDF.js can load it. +var rawData = new Uint8Array(fs.readFileSync(pdfURL)); + +// Load the PDF file. +pdfjsLib.getDocument(rawData).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(1.0); + var canvasFactory = new NodeCanvasFactory(); + var canvasAndContextPair = canvasFactory.create(viewport.width, viewport.height); + var renderContext = { + canvasContext: canvasAndContextPair.context, + viewport: viewport, + canvasFactory: canvasFactory + }; + + page.render(renderContext).then(function () { + // Convert the canvas to an image buffer. + image = canvasAndContextPair.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); +});