The purpose of PDF, or Portable Document Format, is to ensure that a group of users will see the same document formatted the same way no matter what device or operating system it is being viewed on. PDF has wide support across many different applications and web browsers. There are also applications to convert e-texts to PDF files, which are reviewed below.
PDFs are especially useful in a classroom setting because students and the teacher can all have the same document, with the same pagination, font size, and graphics. This simplifies discussion about the text because 'page 3' will be the same for all participants. This is in contrast to HTML.
HTML, or hypertext markup language, is dynamic and easily altered. Essentially, most text on websites are in html. Because it is dynamic users can change the size, font, color, etc. Text that is in HTML format will also automatically continue the text on a new line when it reaches the edge of a screen/window. HTML, unlike PDF, will look different to each person based on the device they are using and their personal preferences. This is not ideal in situations like a classroom setting where consistency takes precedence.
Designed to create PDFs that are optimally sized for Kindle device screens. The PDF files are great for creating in class handouts. There are three options for page size tailored for each generation of Kindle device (each intended for a different kindle model) along with three choices for font size. By far, the Aozora-Kindle option for creating PDF's produces the best looking files for print. There will often be some white space around the text when printed out. This might seem like a waste of space/paper, but is useful for note taking. While many other services can parse and displap rubi correctly, only Aozora-Kindle accomplishes this feat without spacing or formatting issues.
There are also bookmarklets (ブックマークレット). Like regular bookmarks, you can but them in your browser's bookmarks toolbar. When you click them, they run a script or 'tiny program' to perform a task and save you time. They are divided by the kindle model: 2, 3, 4, or DX. And then subdivided by font size: 小、中、大. If you convert Aozora Bunko texts often, consider adding the one that best suits your needs to your bookmarks toolbar.
Out of all the options, A2K is also the only one tailored to e-readers. Other methods can produce a PDF that is difficult to read on an e-reader or tablet's small screen.
Don't confuse Adobe Acrobat with it's free little-brother: Adobe Acrobate Reader. The former is for-purchase software that will allow you to create and manipulate PDF documents. The latter is a free tool that allows anyone to read a PDF file and do some basic editing, such as highlights and comments. This is a quick synopsis of for for-pay software, the free version does not have PDF creation abilities.
Adobe Acrobat is a great tool, but expensive. It costs $200 for the pro version, $140 for the standard one. However, many institutions like Universities often include this on work computers for faculty, or provide access to it via the learning commons at most libraries on university campuses. Acrobat's functions are mostly self-explanatory, and with one-click a PDF can be created from a web-page. Unfortunately, Acrobat's algorithm does not seem to process rubi correctly. Instead of appearing above kanji (for horizontal text) or on the right (for vertical text) it appears in the form of 'bracketted' rubi:
Properly displayed rubi: ...事実を
Bracketted Rubi: ...example pending.
In the future this will hopfulle be fixed, but for now there is no easy solution to the bracketted rubi issue.
MS Word is by far the most familiar word processing software available. It supports all of the criteria in the above table. Simple copy & paste the text of any Aozora Bunko Text into word for editing.and them simply 'Save As' a pdf file. Unfortunately the font size of rubi will be the same as the actual kanji they are glossing. This causes some minor spacing issues, and looks a little unusual. For shorter texts, though somewhat tedious, the rubi's font-size and spacing from the kanji can be adjusted manually, five glossed words at a time.
The rubi issues are unfortunate. However, if numbered lines is a priority, MS Word is currently the only option. The Line numbering function is located at: Page Layout tab >> the Page Setup group >> Line Numbers. Note that lines of text with and without rubi have different linespacing. This can be visually distracting, to reduce the problem, change the line spacing to 1.5.
PDFonFly is a website the converts text to a PDF in one of two ways. By giving it a url to automatically generate a PDF, or by copying and pasting the text into a text box for conversion. It's simple and straight forward. Unlike MS Word it will format rubi at the correct size with an appropriate amount of space between the kanji being glossed and the actual rubi. Unfortunately it has the same line-spacing issues as MSWord. However, this is a fairly straight forward and easy to use tool, and unlike Aozora-Kindle, you can copy & paste only the text you want from any source. Note that in the pdf there will be a watermark in the lower-right corner, the printed copy will not actually display this.