Duplicate covers from Calibre.

[crutledge]

I am getting duplicate cover pages in the calibre output from Sigil files.

In Sigil, the first two files of the document are Cover.xhtml and Title Page.xhtml (also an image). After compiling the Sigil file with Calibre, two cover pages appear in all outputs (epub, lrf, and mobi).

On checking the Calibre file, I have found that a new file has been inserted at the beginning entitled titlepage.xhmtl. This new file contains the cover image and is encoded as <title>Cover</title>. This is the source of the duplicate. The cover image is ticked as Cover in the Sigil Book Browser.


After checking with Kovid and sending him both the Sigil file and the Caliber file I received the following answer:

Quote from Kovid
"The problem is that the sigil file doesn't identify the cover as a cover. There needs to be a guide element in the OPF file. Compare it with the OPF from the calibre epub. "

How can I look at the OPF file in Sigil? Can I edit if necessary? As a workaround, I could make it match Calibre.
His quick fix of adjusting Calibre doesn't seem to work. I'm dead in the water for production.



Charlie

[kevinp]

Dead in the water? Just don't add the cover image in Sigil. If you're recompiling the book in Calibre, let Calibre add the cover.

[Sabardeyn]

All EPUB files are simple ZIP archives - with it's extension changed.

Use any unzip software to decompress the files in the archive and you should find an OPF file. Just open that in any text handling software (Notepad, Notepad++, etc). Make sure when you're done that you save it as straight text; otherwise formatting info is included and will ruin the file for use in epub readers.

[Valloric]

Originally Posted by crutledge

After checking with Kovid and sending him both the Sigil file and the Caliber file I received the following answer:

Quote from Kovid
"The problem is that the sigil file doesn't identify the cover as a cover. There needs to be a guide element in the OPF file. Compare it with the OPF from the calibre epub. "

I'd also like to see both of these files for myself. Create an issue on the tracker and then attach the epubs.

[Valloric]

Since the discussion started here, I'll respond here.

I've seen your issue crutledge, and I've examined the two files. There's absolutely nothing wrong with the epub file Sigil produced. You marked the cover image as the cover, and Sigil added a special meta tag identifying the cover to the OPF. RS's like the iPad will be able to load this cover and show it on the bookshelf.

Again, the epub itself is perfectly valid and also quite sensible.

Calibre then loads this epub file and invents a "titlepage.xhtml" file out of thin air that wraps your cover image in an SVG and then adds it to the front of your book. My first reaction would be that this is a bug in Calibre, but since Kovid has seen the files, I guess it's a feature. I'm guessing it's because Kovid wants your epub file to also have a special XHTML page for the cover that is also present in the guide section of the OPF. This is not necessary at all, and I'm strongly against a converter making these kinds of decisions about the "preferred" structure of EPUB files.*

An irrefutable fact of the matter is that your original epub file was valid and completely sensible.

Kovid's comment that "There needs to be a guide element in the OPF file" is patently false (sorry Kovid but it's true, and you know it). There doesn't need to be any such thing. You could add it, but nothing says you should.

If you want to add this information to your book, you could do so by right clicking the XHTML file containing the cover image in the original file and going to Add Semantics -> Cover. This would prevent Calibre from inventing new content files.

*This "feature" really pisses me off. Inventing new files out of the blue and casually inserting them into the book? C'mon. I can understand the motivation and the good intentions behind it, but this is a damn good example of those intentions paving a road...