|
I doubt there's any method that will work for all readers/devices. But the best technique I know of is to make an absolutely positioned div of fixed height and set its margins to auto.
This will of course only work if your vertically centered content is the only content in a single html file.
A more complex, but similar in spirit technique is to use SVG. IIRC there is a demo of this in the calibre epub advanced formatting demo.
|