Quote:
Originally Posted by therealjoeblow
There's nothing magic about epub that requires special software to 'render' it - it's just simple HTML files packed in a zip container and renamed .epub instead of .zip. You can open the html files in any web browser.
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That's not true.
First off, it's based on XHTML and CSS, not HTML. But even with that, if you created a 100% valid XHTML/CSS file set, it might not be a valid EPUB. And if you created a 100% valid EPUB file, it might not be valid HTML. The two standards have significant overlap, but each also has several of its own tags.
For example, the "display" element in CSS doesn't have "oeb-page-head" or "oeb-page-foot" properties, which exist in OPS (part of EPUB). Meanwhile, the "display" element in CSS has "inline-block", which is
not valid OPS.
Also, the XHTML/CSS file set won't have a manifest or structure definition, which is defined in the OPF standard--another part of EPUB.
The rendering engine (ADE in
most but not
all cases) knows how to extract the components of the EPUB file, read the manifest, find all the components including embedded fonts, images, etc., and turn it into a book with pages. This is very different than a web browser, which doesn't even break an individual web "page" into individual screen-sized pages. It just flows them infinitely (until it runs out of memory) and puts a scroll bar on the side.