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PDF.js heavily relies on the use of Promises. If promises are new to you, it's recommended you become familiar with them before continuing on. This tutorial shows how PDF.js can be used as a library in a web browser. examples/ provides more examples, including usage in Node.js (at examples/node/).
- Getting Started
An introduction to PDF.js with examples. Introduction....
- API
A general-purpose, web standards-based platform for parsing...
- Getting Started
Jan 18, 2024 · Explore JavaScript Promises with exercises on random resolution, chained arithmetic, parallel data fetching, fastest response, and cancellation. Improve your async skills with concise code and clear explanations. Learn effective methods for handling promises, simplifying errors, and creating resilient, maintainable code.
Jul 14, 2024 · Master Promises in JavaScript with 10 hands-on exercises. Learn async/await, error handling, chaining, and more for efficient asynchronous coding.
- Francesco Saviano
- What Is PDF.js
- Basic Integration
- Rendering Using Svg
- Rendering Text-Layers
- Zooming In/Out
- Conclusion
PDF.js is Portable Document Format (PDF) built around HTML5-based technologies, which means it can be used in modern browsers without installing any third-party plugins. PDF.js is already in use at many different places including some online file sharing services like Dropbox, CloudUp, and Jumpshareto let users view PDF documents online without rel...
Downloading the Necessary Files
PDF.js, as it’s name states is a JavaScript library which can be used in browser to render PDF documents. The first step is to fetch necessary JavaScript files required by PDF.js to work properly. Following are two main files required by PDF.js: 1. pdf.js 2. pdf.worker.js To fetch aforementioned files, if you are a Node.js user, you can follow these steps as mentioned on the GitHub repo. After you are done with the gulp genericcommand, you will have those necessary files. If, like me, you don...
Web Workers and PDF.js
The two files you downloaded contain methods to fetch, parse and render a PDF document. pdf.jsis the main library, which essentially has methods to fetch a PDF document from some URL. But parsing and rendering PDF is not a simple task. In fact, depending on the nature of the PDF, the parsing and rendering phases might take a bit longer which might result in the blocking of other JavaScript functions. HTML5 introduced Web Workers, which are used to run code in a separate thread from that of br...
Promises in PDF.js
The JavaScript API of PDF.js is quite elegant and easy to use and is heavily based on Promises. Every call to the API returns a Promise, which allows asynchronous operations to be handled cleanly.
PDF.js supports two modes of rendering. It’s default and popular mode of rendering is Canvas based. But it also allows you to render PDF documents using SVG. Let’s render the Hello World! PDF document from previous example in SVG. Update success callback of pdf.getPage()with the following code to see PDF.js’ SVG rendering in action. Replace the
PDF.js gives you the ability to render text layers atop PDF pages that have been rendered using Canvas. To do this, we need to fetch an additional JavaScript file from PDF.js GitHub’s repo. Go ahead and download the text_layer_builder.js plugin. We also need to fetch its corresponding CSS file, text_layer_builder.css. Download both files and place ...
With PDF.js you can also control the zooming of PDF document. In fact, zooming is quite straightforward and we just need to update the scale value. Increase or decrease scalewith your desired factor to alter the zoom level. This is left as an exercise for the reader, but do try this out and let us know how you get on in the comments.
PDF.js is an awesome tool which provides us with a flexible alternative to the browsers’ native PDF components using JavaScript. The API is simple, precise and elegant and can be used as you see fit. Let me know in comments about how you are intending to use PDF.js in your next project!
- Imran Latif
• How can we use promises to specify an asynchronous workflow? • We need some way to be able to specify the steps of that workflow • In our examples so far, we've only seen single step workflows; create a promise and call then() on it • But, promises can be chained together; now things get interesting!
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May 21, 2020 · Then I created the promise to get the information of the PDF (PDF.js works with promises) and set the span with the number of pages that the PDF has we will generate another function...
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Promise How To. Here is how to use a Promise: myPromise.then(. function(value) { /* code if successful */ }, function(error) { /* code if some error */ } ); Promise.then () takes two arguments, a callback for success and another for failure. Both are optional, so you can add a callback for success or failure only.
