Kobo and Footnotes. Again.

enuddleyarbl · 02-28-2023, 10:53 AM

I'm currently using a Sage, but I had the same issue with my Forma. I read my books as kepubs, not epubs. Footnotes don't work reliably. It's not a matter of the triggering footnote number not being selected correctly. It's just that the footnotes seem to get handled randomly. Usually, even though the note is short enough, the popup doesn't happen. When it does pop up, the popped up footnote doesn't end where the footnote ends: it just keeps going for some indefinite bit of text. Many times, even jumping from the source of the footnote to the target doesn't happen (but then, my footnotes are right below their references, so maybe the Kobo THINKS it's already at the footnote location. The footnotes work in the Calibre Editor and Viewer without problem.

My epubs are EPUB3, and the <html> line at the top of the file includes the xmlns:epub="http://www.idpf.org/2007/ops" phrase to enable the epub:type attributes.

My footnote source looks like this:

Code:

<a id="fn1" href="#fn1a" epub:type="noteref"><sup>1</sup></a>

and, immediately below the paragraph where that's located, my footnote target looks like this:

Code:

<aside id="fn1a" class="footnote" epub:type="footnote">

    <p><a href="#fn1"><sup>1</sup></a>…thenote….</p>

  </aside>

I've even tried these with divs in place of the asides and without the paragraph mark. It makes no difference. I can't see anything wrong with what I'm using: some kind of block structure to hold the footnote, ids to come back or go to, hrefs to do the coming or going, the required epub attributes, some formatting, the standard sups that footnotes usually use and the actual note.

Can anyone see the problem?

Here's Kobo's documentation on footnotes:

and here's what that says:

Quote:

Footnotes/Endnotes Are Fully Supported Across Kobo Platforms
Footnotes and endnotes on the eInk (except for the original Kobo reader and the Kobo Wi-Fi) and iOS platforms will display as a pop-up box containing the content being linked to. The pop-up boxes also contain links to the HTML sections containing the reference material. On iOS, the footnote pop-up will render more than just plain text, including images, links and other content in the footnote or endnote. On the Desktop, Android and Windows platforms users will not see a pop-up but can simply follow the link to HTML section with the reference text.

It is strongly recommended that reference notes use the appropriate ePub:type identifying attribute for footnotes and endnotes (note: this markup is only valid in EPUB3 files and cannot be used in ePub2). This attribute is currently supported on Kobo's iOS platform and its use is the best way to ensure that footnotes and endnotes will display as intended on iOS as well as future releases on other platforms. All links using the footnote or endnote attribute will display within a pop-up on Kobo's iOS platform.

Ex.

<span id="fn0005fn" epub:type="footnote">Text linking to footnote or endnote.</span>
Warning: Hyperlinked content not using the epub:type attribute footnote or endnote will display as a pop-up on Kobo's iOS and eInk platforms in cases where all the following criteria are met.

The link references a location in the EPUB and also references a specific node within the HTML. Ex.
<a href=“chapter.html#uniqueID”>link text</a>
Where chapter.html is a file within this EPUB and where uniqueID is the id of a node within that html document.

The content in the node is nine characters or more once stripped of the HTML tags. Ex.
<p id="uniqueID">123456789</p>

The node being linked to is less than or equal to 5000 characters.

The location being linked to comes after the location being linked from. Ex. A reference in Chapter 2 links to a location at the end of the file titled Endnotes or a reference at the beginning of Chapter 2 links to a location at the end of Chapter 2.

EDIT 1: I've attached a little booklet I produced which includes footnotes. See the footnote chapter if you download it. There are four footnotes in there. Not one produces a popup. The first one doesn't even jump to the footnote, though the other three do. The footnotes are roughly 600 characters long: well below the 5,000 characters specified as the limit for popups.

EDIT 2: I've updated the attached booklet with some new footnote attempts. In the very first footnote, I changed it to be under 500 characters instead of 5,000 just in case someone had a oopsie with a zero. It made no difference. I also added chapters with footnotes at the end of the chapter instead of inline. Again, no difference. And, for gravy, I set the footnotes up as endnotes and created another chapter to use them. Ditto. No difference. Twelve differently placed footnotes and not one works correctly. Yet, I'm reading an actual book right now where the identically formatted footnotes work just fine (well, mostly).

jeff47 · 07-29-2023, 09:10 PM

Have you made any progress on this? I'm in the same boat, and completely baffled. Pop ups work in my epub when I look at it in Books for macOS, but they don't work after converting to kepub.

enuddleyarbl · 07-30-2023, 07:15 AM

Not really. I just tested that sample book of mine again and not one of those 12 footnotes appears as a popup as a kepub on my Sage with the latest firmware. Most will actually jump to the footnote, though. I *thought* even that didn't work, before. But, I could be mis-remembering.

DNSB · 07-30-2023, 11:51 AM

One issue with Kobo's endnote implementation is that if the amount of characters from the start of the footnote to the end of the file is > 5,000 characters, it will not do a popup. This results in oddities such as the first 5 endnotes not popping up and the remaining 11 endnotes showing as popups in one book I was reading.

jeff47 · 07-30-2023, 04:19 PM

Quote:

Originally Posted by DNSB

One issue with Kobo's endnote implementation is that if the amount of characters from the start of the footnote to the end of the file is > 5,000 characters, it will not do a popup. This results in oddities such as the first 5 endnotes not popping up and the remaining 11 endnotes showing as popups in one book I was reading.

I don't, at least in my sample, the issue is the length of the file. I've just got a short sample and my footnotes are at the end of the file (just before it splits) and the whole endnote file is less than 5000.

So strange. I've checked the header elements, css, everything I can think of. There's some factor here that isn't obvious that is tripping us up. Someone with access to the render code needs to tell us what's really going on! It's not as simple at the Kobo labs epub_spec says.

jackie_w · 07-31-2023, 10:44 AM

Quote:

Originally Posted by enuddleyarbl

Not really. I just tested that sample book of mine again and not one of those 12 footnotes appears as a popup as a kepub on my Sage with the latest firmware. Most will actually jump to the footnote, though. I *thought* even that didn't work, before. But, I could be mis-remembering.

I had a look at your sample epub3. I don't think there is anything wrong with the way you've coded your footnotes/endnotes.

The problem is with your NAV/NCX. Kobos (at least for kepubs) are very picky about TOCs. If you stick to the golden rule for NAV/NCX your Kobo reading life will run more smoothly, i.e. make sure that there is a one-to-one relationship between HTML files in the epub and TOC entries in the NAV/NCX.

Using your sample epub3, as an example:

You have one file, plays.xhtml, with 4 entries in the NAV/NCX. You can either reduce the NAV to a single entry of 'Plays' or split plays.xhtml into 4 parts with one NAV entry per part. Whichever method you prefer, do it for all the HTML files which currently have multiple NAV entries
You have 2 files, Cover and Jacket which are currently missing from the NAV. Add them.
You can leave the inline TOC, toc.xhtml, as-is because the Kobo sees it as "just another chapter" in the book, not its navigation system.

It's possible that item 2 may be less important than item 1 but I'm not sure. I've just enforced the one-to-one rule on all my epubs/kepubs for years.

I've attached an edited version of your sample epub3. Use your normal method of transforming it to kepub and you should see that all the footnotes/endnotes now pop-up as expected.

jeff47 · 07-31-2023, 10:52 AM

Quote:

Originally Posted by jackie_w

I had a look at your sample epub3. I don't think there is anything wrong with the way you've coded your footnotes/endnotes.

The problem is with your NAV/NCX. Kobos (at least for kepubs) are very picky about TOCs. If you stick to the golden rule for NAV/NCX your Kobo reading life will run more smoothly. Make sure that there is a one-to-one relationship between HTML files in the epub and TOC entries in the NAV/NCX.

I'll have to try this too! Can we trust the nav/ncx generated by Sigil to be "sane"? Is there a way to test it? (and is the Golden Rule you mention a one-to-one relationship?)

jackie_w · 07-31-2023, 11:10 AM

Quote:

Originally Posted by jeff47

I'll have to try this too! Can we trust the nav/ncx generated by Sigil to be "sane"? Is there a way to test it? (and is the Golden Rule you mention a one-to-one relationship?)

Yes, the Golden Rule is the one-to-one relationship.

(I re-worded my earlier post to try and make it clearer)

I'm afraid I don't know anything about Sigil's nav/ncx generation capabilities, I use the calibre Editor plus a home-grown editor utility for nav/ncx fine-tuning. I never include an inline TOC page in any of my books. All those densely-packed hyperlinks are a PITA when trying to read on a phone.

Quoth · 07-31-2023, 11:37 AM

Quote:

Originally Posted by jackie_w

All those densely-packed hyperlinks are a PITA when trying to read on a phone.

You can have a CSS for the Contents Page that puts big top or bottom margins.

Code:

<p class="block_11"><a href="index_split_005.html#id_ch1" class="text_1">Chapter 1: An Unexpected Case</a></p>

Code:

.block_11 {
    display: block;
    font-family: "Droid Sans", sans-serif;
    margin-bottom: 8pt;
    margin-left: 16pt;
    margin-right: 0;
    margin-top: 3pt;
    padding-bottom: 0;
    padding-left: 0;
    padding-right: 0;
    padding-top: 0;
    text-indent: 0
    }

But actually that's purely the automatic conversion of a Contents page created in the ebook MSS in LO Writer odt edit, but a Save As in docx for Calibre. System TOC/NCX perfect automatic generation.

The only things at all manually edited were some large images

Code:

image-height: auto;
image-width: 90%;

12 pt ought to be 1em
The wordprocessor doesn't do em, so pt is next best.
I use cm when editing for PDFs.

jeff47 · 07-31-2023, 12:16 PM

Quote:

Originally Posted by jackie_w

Yes, the Golden Rule is the one-to-one relationship.

(I re-worded my earlier post to try and make it clearer)

I'm afraid I don't know anything about Sigil's nav/ncx generation capabilities, I use the calibre Editor plus a home-grown editor utility for nav/ncx fine-tuning. I never include an inline TOC page in any of my books. All those densely-packed hyperlinks are a PITA when trying to read on a phone.

To clarify - are you talking about OEBPS/text/nav.xhtml or OEBPS/ncx/toc.ncx? Or both?

DNSB · 07-31-2023, 01:19 PM

Quote:

Originally Posted by jeff47

To clarify - are you talking about OEBPS/text/nav.xhtml or OEBPS/ncx/toc.ncx? Or both?

Since you are using epub:type, you are using ePub 3. The nav.xhtml file is the navigation document for an ePub3. An ePub3 can have a toc.ncx for backwards compatibility with an ePub2 renderer which needs the toc.ncx file.

jackie_w · 07-31-2023, 01:54 PM

Quote:

Originally Posted by jeff47

To clarify - are you talking about OEBPS/text/nav.xhtml or OEBPS/ncx/toc.ncx? Or both?

Yes, what DNSB said, and calibre's Editor automatically keeps NAV and NCX synchronised in an epub3. I always keep both in the book because I'm never sure (particularly with Android reading apps) how well epub "standards" are followed - a belt and braces approach.

jackie_w · 07-31-2023, 02:12 PM

Quote:

Originally Posted by Quoth

You can have a CSS for the Contents Page that puts big top or bottom margins.

Well, yes, obviously I could do that, but what's the point? Personally, I find an inline TOC file about as useful as a chocolate teapot. The NCX and/or NAV (not in spine) does the job in all the reading apps I use.

Introducing any wordprocessing app into my epub cleanup workflow seems similarly unnecessary. Editing the epub directly in a proper epub editor works fine, on its own, for me.

Aleron Ives · 07-31-2023, 03:50 PM

Quote:

Originally Posted by jackie_w

I find an inline TOC file about as useful as a chocolate teapot. The NCX and/or NAV (not in spine) does the job in all the reading apps I use.

Maybe it's not technically useful, but I do like having an inline TOC, since it replicates part of the print reading experience. I like seeing an overview of the book's structure so I have some idea of what to expect before I begin chapter 1.

DNSB · 07-31-2023, 03:56 PM

Quote:

Originally Posted by Aleron Ives

Maybe it's not technically useful, but I do like having an inline TOC, since it replicates part of the print reading experience. I like seeing an overview of the book's structure so I have some idea of what to expect before I begin chapter 1.

For some reason, about 40% of the ebooks I read that have a HTML ToC place the ToC at the end of the file. This used to be popular with ebooks published on Amazon since by going to the ToC, it appeared you had nearly finished the book. But that reason has long since been deprecated.

Personally, I would just tap in the middle of the cover image and then tap on the ToC link in the bottom left corner. This also has the advantage that exiting the ToC leaves me on the page I was reading.

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07-29-2023, 09:10 PM	#2
jeff47 Connoisseur Posts: 69 Karma: 50592 Join Date: Oct 2010 Device: Kobo Libre H20	Have you made any progress on this? I'm in the same boat, and completely baffled. Pop ups work in my epub when I look at it in Books for macOS, but they don't work after converting to kepub.

07-30-2023, 07:15 AM	#3
enuddleyarbl Guru Posts: 766 Karma: 1537886 Join Date: Sep 2013 Device: Kobo Forma	Not really. I just tested that sample book of mine again and not one of those 12 footnotes appears as a popup as a kepub on my Sage with the latest firmware. Most will actually jump to the footnote, though. I thought even that didn't work, before. But, I could be mis-remembering.

07-30-2023, 11:51 AM	#4
DNSB Bibliophagist Posts: 43,607 Karma: 165170966 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	One issue with Kobo's endnote implementation is that if the amount of characters from the start of the footnote to the end of the file is > 5,000 characters, it will not do a popup. This results in oddities such as the first 5 endnotes not popping up and the remaining 11 endnotes showing as popups in one book I was reading.

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