PDF reflow - some background info

Found this at wikipedia. As per the bit I hilighted, I thought it may be pertinent to some of the pdf reflow inconsistencies we have run into on the edge. Also, when people are optimizing their pdfs (especially if they are using automated settings) tags are often removed in the process.

http://en.wikipedia.org/wiki/Compari...e-book_formats

Since the format is designed to reproduce page images, the text traditionally could not be re-flowed to fit the screen width or size. As a result PDF files designed for printing on standard paper sizes are less easily viewed on screens with limited size or resolution, such as those found on mobile phones and PDAs. Adobe has addressed this by adding a re-flow facility to its Acrobat Reader software, but for this to work the document must be marked for re-flowing at creation,[6] which means that existing PDF documents will not benefit unless they are tagged and resaved. The Windows Mobile (aka Pocket PC) version of Adobe Acrobat will automatically attempt to tag a PDF for reflow during the synchronization process using an installed plugin to Active Sync. However, this tagging process will not work on most locked or password protected PDF documents. It also doesn't work at present (2009–10) on the Windows Mobile Device Center (the successor to Active Sync) as found in Windows Vista and Windows 7. This limits automatic tagging support during synchronization to Windows XP/2000.

One other condition for reflow of PDF documents is that they can not be scanned pages unless they have been OCRed. A scanned page is an image which can be magnified or zoomed on but there is no way you are going to get part of that image on one page and the other part on another page.

ivan