Font Formats for iPad eBooks
To deliver your own fonts for eBooks on the iPad or other iOS devices you will need to include the following in an extra file called com.apple.ibooks.display-options.xml inside the META-INF folder:
<?xml version="1.0" encoding="UTF-8"?>
But what format of fonts can you use?
There are several formats for fonts:
truetype, opentype, WOFF (Web Open Font Format) and some others.
WOFF is recommended by the IDPF and is mentioned in the specification for ePUB3, however, this format is not often available.
Including a truetype font will break validation to the ePUB3 standard (as of this writing). The iPad's support for the OpenType format seems a bit patchy from my experience. Sometimes, fonts in this format seem to have difficulty diplaying properly in sizes other than 100%.
For the sake of devices such as those that use the Adobe Digital Editions toolkit, you will need to specify the opentype form first in the @font-face rule like this:
src: url('fonts/Alegreya-Regular.otf') format('opentype'), url('fonts/Alegreya-Regular.woff') format('woff');
However, this will then deliver the Opentype font to the iPad (and this is bad), so you will need to utilise the @media and orientation method to deliver an alternative @font-face rule that reverses the above order, prioritising the WOFF font for the Apple devices.
Posted on 23 Aug around 11pm