Quote:
Originally Posted by Doitsu
AFAIK, there are no mainstream epub2 apps that actually support ligatures (and other OpenType features). What apps/readers do you use to test ligatures?
Is there a ligature bug in the Calibre subsetting code? If so, you might want to report it to Kovid, if you haven't already done so. (When I reported a font subsetting problem with Arabic fonts a couple of years ago he fixed it the same day and the fix made it into the weekly Calibre build.)
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Doits:
The problem or challenge isn't ePUB readers. AFAIK. We had an unpleasant surprise with a book that we made for a client. The client chose a font that uses ligs (ligatures--I'm a lazy typist, b/c I just do so damn much of it.) Anyway, long story short, it ends up on Amazon, as it goes. But, wait, what to my wondering eyes should appear? MISSING letters. Not just missing letters--missing pairs of letters.
It took a while to sort out what must have happened. Amazon ASSUMES that the LITB will be in Georgia font. Because it's in Georgia, they use
all the available characters--
including ligs. Ligs that are NOT in the original book. Because, as you point out, nothing makes use of them, right? But, if you've embedded font X, and for whatever reason, your font makes it into the LITB (don't ask me why some do, some don't, I have ZERO idea), and you've subset it with any of the usual suspects,
KABLAMMO, the ligatured letters will disappear, because the subset font doesn't have any ligs remaining. (n.b.: I discussed this with Toxaris, and
he's tweaked FontShrinker, so that Ligs are included now, BTW.) Right?
So, you create a book
without included/typeset ligatures, but
with an embedded body font. The client puts it up on Amazon. For reasons that aren't clear, the embedded font remains in the LookInside (which normally, it does not). Amazon
assumes that it's using Georgia, and uses ligatures wherever they are typically used. But the subset body font doesn't have ligatures,
because they were removed when you subset it.
Net result: the book displays on Amazon, in the embedded body font--but without the Amazon-assumed ligatures.
That's the issue. Since Toxaris was kind enough to adjust FS to include ligs--so that I don't have to get ulcers about every book in which a client requests an embedded body font (and BEFORE any of the self-appointed eBook police feel that they have to add their $0.02, yes, of course, it's overridable. We don't impose the body font on the reader.)--that's what we use now.
Suffice to say, that was a nice dash of cold water in our faces. I nearly fainted, to be honest, when I saw the cursed thing on the LITB. At first, I couldn't quite figure out,
"What the...?" but after staring at it, and realizing that the missing characters were all ligs, the rest of the deduction was easy,
Watson. :-D
So, that's the
why, Doits. It's not a bug; it's just set to work the way it should work (the Calibre subsetter) for ePUBs. But in the cosmic scope of th eBookverse...well.
Hitch