October 2013
Intermediate to advanced
215 pages
4h 29m
English
Content preview from Developing with PDFBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 12. Metadata
This chapter will explore the various ways in which metadata can be incorporated into a PDF file, from the simplest document-level strings to rich XML attached to individual objects.
The Document Information Dictionary
It was clear even with the original 1.0 version of PDF that the presence of metadata was a requirement for any file format, and certainly one that would be representing documents for electronic distribution and storage. For this purpose, the document information dictionary (or info dictionary, or even just info dict) was created (see Example 12-1).
As the name implies, the info dictionary is a standard PDF dictionary object. However, unlike every other object you’ve encountered so far, this object is referenced not from the catalog, but instead from the trailer. The original PDF 1.0 specification documented four (optional) keys for this dictionary, each one allowing only a string value encoded in PDFDocEncoding.
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Author - The name of the person(s) who created the document.
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CreationDate - The date and time the document was created, formatted as a date.
Note
Dates, as a type of string, were added to PDF in version 1.1, so very early PDF files may have the value of this key as a simple string.
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Creator -
The software used to author the original document that was used as the basis for conversion to PDF. If the PDF was created directly, the value may be left blank or may be the same as the
Producer. -
Producer - The name of the product that created the PDF. ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.