missing alt attribute not detected or fixed

[Aaron Shepard]

In Edit Book, the Check Book function does not detect or fix missing alt attributes in img tags. (Missing alt attributes are flagged as an error by epubcheck.) To fix this, calibre only needs to add an empty alt attribute like so:

alt=""

Running calibre 2.59 on Mac OS X El Capitan. I'm inputting files produced by the Kindle Comic Creator, which omits the attribute. I realize I can add the attribute in Edit Book with Find and Replace, but it would be much more convenient to have it included in the Check Book function, which should be finding it anyway.

[Kovid Goyal (kovid)]

Check Book does not perform schema checks, which is what checking for
missing attributes is. Schema checks are useless. The only
piece of software on the *planet* that cares that <img> tags have alt
attributes is a schema checker, in this case epubcheck. No actual book
reading software will give two hoots about whether an <img> tag has a
missing alt attribute or an empty alt attribute.

Schema checking is a waste of everyone's time and energy and I have no
interest in helping perpetuate it.

 status wontfix

[Aaron Shepard (5-aaron)]

Thanks for explaining that, Kovid. I did notice that the error did not affect display in iBooks. But don't Google Play and the iBookstore require that submitted EPUBs verify in epubcheck?

Another reason you might consider: If epubcheck is listing 121 errors of missing alt attributes (as it does for the book I'm working on now), it's hard to spot any more important errors that might be buried in the list.

Anyway, I understand your argument, and I appreciate all that you do. I will just plan to correct it manually.

Aaron

[Kovid Goyal (kovid)]

I can certainly appreciate that correcting the meaningless errors from
epubcheck manually can be tedious, if you are preparing a book for sale.
However the problem is that it is impossible to correct all of them
automatically -- and once I start down that road there will be endless
requests to fix this error or that. Not to mention that I do not want to
encourage the use of schema checkers, since IMO they are a bad idea.