Skip to main content

The power of HTML 5 and Javascript: Rendering PDF’s in your browser

Today I was once again amazed about the power that HTML5 and Javascript can offer when I discovered PDF.js. This Javascript library is written by a couple of clever guys over at Mozilla and allows you to display PDFs inside your browser using Javascript and HTML5. The code is available for download on Github.
Benefits
The traditional approach to rendering PDFs in a browser is to use a native-code plugin, either Adobe’s own PDF Reader or other commercial renderers, or some open source alternative. From a security perspective, this enlarges the trusted code base and increases the risk of code based injection attacks. An HTML5-based implementation is completely immune to this class of problems.
If you want to see a demo of pdf.js, click on this link. There are still glitches and rendering artifacts but it already shows the potential of this library.
A quick sample
Download the latest code required from Github to start developing. Create a web page and embed the following Javascript references:
<script type="text/javascript" src="scripts/pdf.js"></script>  
<script type="text/javascript" src="scripts/metrics.js"></script>
<script type="text/javascript" src="scripts/fonts.js"></script>
<script type="text/javascript" src="scripts/glyphlist.js"></script>


Add the new <canvas> HTML5 control to the body of your page


<canvas id="pdf-canvas" style="border:1px solid black;"/>


Now you can start rendering your PDF by writing some Javascript code:
<script type="text/javascript">
'use strict';      
getPdf('myPDFFile.pdf', function getPdf(data) {
 // Instantiate PDFDoc with PDF data          
 var pdf = new PDFDoc(data);          
 var page = pdf.getPage(1);          
 var scale = 1.5;

 // Prepare canvas using PDF page dimensions          
 var canvas = document.getElementById('pdf-canvas');
 var context = canvas.getContext('2d');
 canvas.height = page.height * scale;
 canvas.width = page.width * scale;          
 
 // Render PDF page into canvas context
 page.startRendering(context);      
});  
</script>

Popular posts from this blog

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Col...