Cover-image redux

<Garth, brace yourself, more of Ric¹s nutty graphics ahead>

After listening to the discussion on Monday about covers and cover-images, I
started thinking about what kinds of graphics could be on a cover page.
Naturally, given my background, I thought of SVG and OpenGL. There is also
CSS3, with all its bells and whistles too.  So to see what it might be like,
I created an EPUB with an OpenGL (WebGL) animation on the title page.  You
can see the result here (Tiny-EPUB GLCover
<https://readium.firebaseapp.com/?> ).

One cannot specify a ³cover-image² property which references a XHTML page
(EPUBCheck throws an error). So I just leave that property out.  In Readium,
our UA doesn¹t see a  cover page, so it just fetches the metadata and
creates a plain title page, just like normal.  But when the book itself is
opened, the real, WebGL-enabled title page is shown and voila!  an WebGL
animation is displayed.  In iBooks, the result is the same except that
iBooks has a bit of a problem laying out the title page so it¹s not quite
right, probably because iBooks doesn¹t handle mixed (reflow/fixed) pages
very well.

One could also create SVG animations or CSS3 animations as well.  In theory,
the UA could even figure out that the library page with thumbnails should be
animated, but the overhead would be huge and the idea of a significant
number of animations occurring in the library page at one time is kind of
dizzying. Probably not a good idea.

I am not suggesting that this is a great idea or plan to do it with all my
books, just demonstrating that within the scope of the EPUB spec as it
stands you can do some ³interesting² demos.

Ric