My problem with PDF technical books is that they are typically formatted for 8.5x11 or A4 paper, typically with a really huge margin. I wish that there was something in the PDF spec to allow for multiple sizes to be specified in a single file, so that the same file can be used for printing as well as viewing on a 6 inch reader.
It sounds like what you're really asking for is a proper e-book format, like EPUB. PDF is not an e-book format, it's a presentation format, for print-equivalent documents. They aren't interchangeable.
Right, but the problem with EPUB and Mobi is that I haven't really seen technical books done well with them, with various tables, diagrams, charts, etc. These are presented much better when they have a human eye lay them out on the page.
That's where a multi-format PDF would come in handy -- you could still have a human editor lay out the pages for 2 or 3 different page sizes, and then the reader would pick the appropriate one (given the constraints of the reader device and font size).
Have you looked at many O'reilly, Pragmatic Programmers, or Apress books? I own a library of over a thousand titles from those publishers and generally any ePub created in the past 3-4yrs from them is top notch.
I just bought this bundle, which is all O'reilly, so I'm assuming the ePub's are from them. Was looking at the Emacs one, and so far not too bad. But there are still issues, such as I came across a table that had the headers line at the bottom of one page, and the rest of the table on the next page. Things like this, you can probably put hits / rules in the ePub file for, but it still benefits more from having a human do the layout.
I already own that ePub so I'll check it on my end to see if it's specific to the Humble Bumble version. Which table should I check? Also, which reader are you using out of curiosity?
I tried it using Google play books, and also FBreader. The specific table depends on the screen size, font, orientation, etc. In my case, it was one of the tables in the preface, when viewing portrait mode on my phone. When bringing it up on my tablet, the same effect could be seen on any other table that happens to start at the end of the page.
You could get close to this by just using multiple PDFs. However, no one seems to do this (@haskellbook is the only exception I can think of), so perhaps editors feel it's not worth the extra time and effort.
I looked at a few technical books I have and none of them are in 8.5x11 or A4 sizes. Most books I have are much smaller than that, and more easily handled.
PDF spec actually supports different page sizes (crop box, trim box, bleed box, media box, etc) for different pages. But it seems like what you what is essentially two separate PDFs with different page sizes combined together, and the reader picks one based on the viewport. I'm not sure PDF spec natively supports that, but PDF does support JavaScript and I can imagine JavaScript querying the viewport and then hiding/showing pages.
While not really related to specifying multiple sizes, PDFs do have the concept of an artbox, which could be used by the PDF author to indicate the area of the page that actually contains content.
A useful feature of a PDF reader on these devices could be to display only this area with a smaller, perhaps user defined, margin.
This at least would fix the 'huge margin' problem.
