June 17, 2010, 8:31 PM — We do a lot with PDFs in our Web applications: while we occasionally just deliver them as static documents, as nearly all sites do, the majority of our downloads are dynamically-generated, customized for the specific needs and privileges of the person viewing them. We program in numerous features that the PDF standard defines, to make them as meaningful and easy-to-read as possible for that person.
It's all wasted, of course, when the end-user doesn't have the background to recognize or take advantage of the features. "Bookmarks" illustrate this: while tools to support bookmarks have been available since mid-1993 (!), many otherwise-sophisticated end-users aren't familiar with them. Essentially all the explanations on the Web are written for producers, that is, the people creating bookmarks. For bookmarks to serve the consumers, tell them this:
I'd like you to meet PDF bookmarks
When you view or open a PDF document, you're likely to see several special navigational icons on the left side of the window 
; we can't say this is more than "likely" because the details depend on the configuration of your installation, operating system, and the particular document you're reading. Among the three in the image above, the top one, suggestive of one piece of paper overlapping another, is likely the most familiar. It's called "Pages", and indexes all the content of the document through thumbnails images of each page in sequence. The binoculars, lowest in this sequence, help navigate through textual search results.
In between these two, and present in only a fraction of all PDFs, is the "Bookmarks" icon. As one Reader instance explains it, Bookmarks make it so you can "[g]o to specific points of interest using bookmark links". If you select the icon, the Bookmarks open up to reveal their contents, arranged as a "tree": 
. Select one of the labels or lines of text, such as "Program Evaluation Report", and the Reader will take you to the page where that section of the whole document begins. The little '+' sign means that a section has more parts inside it; select the '+' and you'll see details: 
.
That's it. Now you understand bookmarks. You're ahead of many other PDF readers, though, because bookmarks are often misunderstood:
- most PDFs don't have them. They appear only when someone goes to the trouble of editing them in;
- they're distinct from the "bookmarks" in Microsoft Word. While there are similarities, there are also large differences, and they need to be learned as separate facilities;
- PDFs have several other navigational devices, including internal hyperlinks and named destinations, and casual users rarely have a chance or even much need to be precise in the exact function of what they're using; and
- bookmarks are easy to miss. Plenty of people who have been reading PDFs for years have never noticed or investigated the Bookmarks icon.
Coming up
"Smart Development" will return next week to chat about how PDF features are put to actual use in commercial and government operations, and also to pass on recent work in such other standards as SVG, LDAP, and SNMP.
