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PDF Association

Mission Statement: To promote Open Standards-based electronic document implementations using PDF technology through education, expertise and shared experience for stakeholders worldwide.
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Interview with Dietrich von Seggern for PDF Days Europe 2017

Who: Dietrich von Seggern Company: callas software GmbH Position: Managing Director PDF Association: The PDF Days Europe will be held in Berlin again. Do you have any personal relationship with Berlin? Dietrich von Seggern: Yes, definitely. I first cam …

Interop workshops: building a test matrix

How will the PDF 2.0 interop workshops work? This article explains the process of building the test-matrix to establish possibilities for pair-wise testing.

PDF Days Europe agenda looks to the future

Berlin. Those interested in the PDF format can now register for this year’s PDF Days Europe in Berlin. A comprehensive agenda awaits, with over 35 contributions on 15 and 16 May covering all aspects of PDF technology. The focus will be on the PDF Assoc …

SHA-1 is gone… and it’s deprecated in PDF 2.0 as well

As we reported yesterday, those in the crypto world are well-aware that Google and others have proven that SHA-1, the venerable cryptographic hash function standard, is dead. The consequences, however, are yet to be determined. Somewhere, it is safe to …

PDF Days Europe 2017 – Secure your ticket now!

With over 35 informative sessions across a wide range of topics, including the dramatic new “Camelot2” project, this year’s PDF Days event is especially relevant as we look forward into the future of PDF technology.

3 ways developers can impress the boss with PDF


PDF lightbulbIn 2015 there are plenty of software developers younger than the PDF format, published in 1993. Few of them think much about PDF. What’s hot in software development these days is the web, mobile computing, cloud services and other networking technologies.

What can a 22 year old page-description model offer to developers with something to prove?

Quite a lot.

This article highlights three areas in which supporting various features of PDF can help developers offer new and powerful options to their product and project managers. While there are many features to mention, these three apply straightforwardly to web-connected implementations, and thus relate to what’s hot in software development today.

Let’s start with something of straightforward value: making things work faster, with less bandwidth consumed. Both users and server administrators like that sort of thing!

1. Linearized PDF

Linearization of PDF enables efficient incremental access in a network environment. PDF processors that support this feature can enhance performance in several ways:

  • Process the requested page as soon as that page’s data has downloaded, without waiting for the rest of the file.
  • Over slower connections, display a page incrementally as it arrives, and choosing the most important data to display first.
  • Permit user interaction, such as using a link or clicking a button before the entire page has been received and displayed.

Linearization is less important for smaller files, but many PDF documents are 10, 20, 50 or even hundreds of megabytes, and bandwidth varies substantially for different users. Linearization is an effective strategy for ensuring that pages are displayed on-screen very quickly, even for massive documents, but the feature may also be leveraged for indexing, data mining and other applications.

To learn more about PDF linearization, see Annex F in ISO 32000-1. You can download the specification for free from Adobe’s website, or pay the ISO if you prefer. It’s the same document.

2. PDF Annotations

Screenshot of annotations menu.Being documents, PDF files are objects that users frequently wish to annotate by adding or editing comments, strike-outs, highlights, etc. Sometimes it’s desirable to add arrows or boxes, or even voice recordings or supplementary files.

PDF can accommodate all that. The format offers a fully standardized model that allows developers to use their preferred look and feel. There’s no need to copy Adobe’s style.

Even better for the connected world; the PDF model includes lightweight mechanisms such as FDF and XFDF which facilitate transaction of annotations with a server.

Perhaps your users want to markup documents in the cloud, with each user receiving updates when others make changes? PDF provides all the structures you’d need to accomplish that, and more. The annotation model also includes a variety of metadata. Developers can build a complete, flexible, web-friendly and highly interoperable annotation system that leverages the metadata elements defined in the PDF specification.

To learn more about annotations in PDF see clause 12.5 in ISO 32000-1.

3. Tagged PDF

One of the perennial complaints about PDF is that it’s “just a page”. Gathering indexable content or repurposing text or graphics can produce surprising results because, among other reasons, PDF does not require that page content be organized as a human would consume it.

For that, there’s tagged PDF.

Introduced with PDF 1.4 in 2001, tagged PDF defines structure types and attributes that allow page content (text, graphics and images, annotations and form fields) to be extracted and reused for other purposes.

Tagged PDF (specified in clause 14.8 of ISO 32000-1) allows developers to distinguish the author’s intended content from decorative artifacts, arrange content into correct logical order for reuse, and characterize the semantics of content via structure elements specifying headings, lists, tables and so on.

Software leveraging tagged PDF documents can deliver very high quality results when converting from PDF to HTML, capturing text for indexing, reading text aloud, and for many other interactive and non-interactive purposes. There’s even a subset standard, PDF/UA (ISO 14289), that provides comprehensive instructions for using tagged PDF correctly for the purposes of accessibility to disabled users.

To learn more about tagged PDF see clause 14.8 in ISO 32000-1.

Conclusion

PDF is far richer than a page-description model. Not only does the format include a broad range of powerful features but it’s ISO-standardized. What’s more, PDF isn’t going anywhere – it’s accepted world-wide as the de facto standard for final-form electronic documents.

Developers thinking about use-cases that involve documents should consider the wide range of possibilities affording by this rich, open and universally-accepted format.

Want to learn more? Join your fellow developers at the PDF Technical Conference 2015, in San Jose!


Tags: Indexing, Linearization, annotations, tagged PDF, viewing
Categories: Collaboration, Document Management, PDF