Glo Kobo Glo gets stuck when using the TOC to jump to a certain chapter.

[stefano.p]

Product: Kobo Glo (untested on other devices)
Firmware: 2.8.1
Plugins: Kobo Touch Extended Driver 1.5.0 (not really needed)
File types: KePub
Sideloaded or from Kobobooks: both
On external SD: internal memory only. It has not been tested on external SD.
Steps to reproduce:

1. get a kepub with embedded fonts (there are attached two examples created for testing purpose)
2. set "document default" font on your device
3. open the TOC and tap on a chapter. Not all chapters cause the issue. Those chapters defined in the same xhtml file are very likely to make your device to hang up. However, "testTOC_0.kepub.epub" has 4 chapters defined in 4 different xhtml files and yet it seems not possible to jump to chapter 3.

Current result: Kobo device freezes.
Workaround: setting any fonts exept "document default" one.
Note:in order to recreate the issue with kepub coming directly from kobobooks, here is a an example:http://www.kobobooks.it/ebook/Favole...EnZWdMA5Ww&r=1
You cannot download it for free though, and it is protected with adobe drm.

In general, almost all ebooks from Garzanti publisher (italian books) are suitable to reproduce said issue.

Update:
When the screen gets blank, endlessly trying to load the page, here is a way to recover. Just tap on the title so that a menu appears at the top of the screen. Then tap in the middle of the page. All characters will get back again. Of course, this does not solve the fact that the chapter loaded might not be the one you had selected.

[tshering]

I had no problem jumping to chapter 3, but my touch (FW 2.6.1) hung up after setting some highlights and paging.

If you look at the xhtml files, you will notice that in each file the tag <span class="koboSpan" id="kobo.6.2"> is not closed before the next kobo tag, <span class="koboSpan" id="kobo.6.3">, opens. Instead, it is closed at the end of the chapter.
This causes problems with highlighting, and probably also with the TOC navigation.
You can try this: put </span> in front of <span class="koboSpan" id="kobo.6.3"> in each file, and delete the last but one </span> in the paragraph (= in the chapter).

Try setting a highlight that contains the heading and some lines of the following text. With the original version, the whole chapter will be highlighted. With the modified version, it works as it should.

If the kobo spans of this book are set by the most recent plugin for calibre, you might consider writing a bug report.

Note: I only looked at testTOC_0.kepub.epub.

[stefano.p]

Originally Posted by tshering

I had no problem jumping to chapter 3, but my touch (FW 2.6.1) hung up after setting some highlights and paging.

You had no problem because you are using fw 2.6.1 and not 2.8.1. This issue seems to affect Kobo Glo (and Aura maybe). I have a Kobo Mini with 2.8.1 and there is no crash.

Originally Posted by tshering

If you look at the xhtml files, you will notice that in each file the tag <span class="koboSpan" id="kobo.6.2"> is not closed before the next kobo tag, <span class="koboSpan" id="kobo.6.3">, opens. Instead, it is closed at the end of the chapter.
This causes problems with highlighting, and probably also with the TOC navigation.
You can try this: put </span> in front of <span class="koboSpan" id="kobo.6.3"> in each file, and delete the last but one </span> in the paragraph (= in the chapter).

Try setting a highlight that contains the heading and some lines of the following text. With the original version, the whole chapter will be highlighted. With the modified version, it works as it should.

If the kobo spans of this book are set by the most recent plugin for calibre, you might consider writing a bug report.

Ok, I'll try what you suggested.

Originally Posted by tshering

Note: I only looked at testTOC_0.kepub.epub.

If you try the second file you'll notice that you can't jump to Section 2.2 from the TOC. No crash in 2.6.1, but you'll jump to the wrong chapter.

[tshering]

Originally Posted by stefano.p

If you try the second file you'll notice that you can't jump to Section 2.2 from the TOC. No crash in 2.6.1, but you'll jump to the wrong chapter.

I did not try the second file, since I knew this problem already.

[jgoguen]

Originally Posted by tshering

If you look at the xhtml files, you will notice that in each file the tag <span class="koboSpan" id="kobo.6.2"> is not closed before the next kobo tag, <span class="koboSpan" id="kobo.6.3">, opens.

This is just tag nesting, perfectly valid and absolutely essential to some designs and layouts.

Originally Posted by tshering

Instead, it is closed at the end of the chapter.

I ran every test file through a XML validator and I can't find where this occurs. What I saw is that the worse case is a <span> opened at the start of a paragraph may not close until the end of that same paragraph. Can you point me at a file in either of these test files where a span isn't closed until the very end? That would be a serious problem and I very much doubt that books would display properly.

Originally Posted by tshering

You can try this: put </span> in front of <span class="koboSpan" id="kobo.6.3"> in each file, and delete the last but one </span> in the paragraph (= in the chapter).

With the spans being properly balanced as they are, this would actually not be a good thing Not saying the way it is now doesn't break highlighting (I've never tried nor has it been reported to me).

[PeterT]

I thunk the issue is more with the Kobo.js than the actual firmware. Remove Kobo.js and I have no issues at all with the first ePub.

[met67]

Originally Posted by jgoguen

This is just tag nesting, perfectly valid and absolutely essential to some designs and layouts.


I ran every test file through a XML validator and I can't find where this occurs. What I saw is that the worse case is a <span> opened at the start of a paragraph may not close until the end of that same paragraph. Can you point me at a file in either of these test files where a span isn't closed until the very end? That would be a serious problem and I very much doubt that books would display properly.


With the spans being properly balanced as they are, this would actually not be a good thing Not saying the way it is now doesn't break highlighting (I've never tried nor has it been reported to me).

I also have this problem with highlights: if I try to highlight a piece of text that crosses a phrase (e.g. have a '.' in the middle), very often the kobo highlights the text to the end of the chapter.
I didn't had the time to examine this problem but I think that it is very likely that it is caused by the 'extra' span.
I know that it is perfectly legal in HTML, but probably the code that Kobo uses to trace the pieces of text in a kepub doesn't expect it to be like this and so misbehaves.

[stefano.p]

Originally Posted by jgoguen

Can you point me at a file in either of these test files where a span isn't closed until the very end? That would be a serious problem and I very much doubt that books would display properly.

I have checked both test files and each paragraph has the first span that is closed at the end of the same paragraph and not at the very end. So this should be ok.

[stefano.p]

Originally Posted by PeterT

I thunk the issue is more with the Kobo.js than the actual firmware. Remove Kobo.js and I have no issues at all with the first ePub.

Well, I am more concerned about the second test file, because even in previous fw versions the behavior was not really correct (i.e. did not jump to the correct chapter when there are multiple TOC entries defined within the same xhtml file).
I have downloaded some other "original" kepub and they all share the same Kobo.js

Anyway, let's keep in mind that this issue will disappear once we choose to override the embedded font with any one available in the menu. Thus I suspect that there must be something missing in kobo's algorithms.

[jgoguen]

Originally Posted by met67

I also have this problem with highlights: if I try to highlight a piece of text that crosses a phrase (e.g. have a '.' in the middle), very often the kobo highlights the text to the end of the chapter.
I didn't had the time to examine this problem but I think that it is very likely that it is caused by the 'extra' span.
I know that it is perfectly legal in HTML, but probably the code that Kobo uses to trace the pieces of text in a kepub doesn't expect it to be like this and so misbehaves.

My suspicion is that my algorithm for deciding when to nest tags is too simplistic. Perhaps I need to always append...

[PeterT]

@jgoguen: One suggestion for you... Could you maybe embed in a converted kEpub the version of your driver that did the conversion? Might help when people send a file that is having "issues" for you to be able to validate that the conversion was done with the driver you thought was being used?

[jgoguen]

I see no reason why not. It certainly wouldn't hurt anything.

[tshering]

Originally Posted by jgoguen

This is just tag nesting, perfectly valid and absolutely essential to some designs and layouts.


I ran every test file through a XML validator and I can't find where this occurs. What I saw is that the worse case is a <span> opened at the start of a paragraph may not close until the end of that same paragraph. Can you point me at a file in either of these test files where a span isn't closed until the very end? That would be a serious problem and I very much doubt that books would display properly.

It is not a question of xml validity. The Kobo software expects that those tags are not nested.

Originally Posted by jgoguen

With the spans being properly balanced as they are, this would actually not be a good thing

Why don't you try what I proposed and judge by yourself. My proposal was meant exactly for the test file. Since I propose adding one closing tag at an early position and deleting one later, the balance is still preserved.

Originally Posted by jgoguen

Not saying the way it is now doesn't break highlighting (I've never tried nor has it been reported to me).

I thought Davidfor might have reported this, cf. this post.

[PeterT]

One more experiment I tried was to change all the span id's to be unique; this helped in the first test document, I could now jump to chapter 3 successfully, but did not help in the second test document.

(I took the brute force approach of changing kobo. to kobo.# where # was the digit on the html file's name).

[stefano.p]

If this can help, please find attached the epub version of both tests books. The kepub versions was obtained using plugin v1.5.0, as I have already specified.
So anyone can verify it in case of any doubt

Nevertheless, let's not forget that the issue reported in this thread can also be reproduced with "original kepub" coming from kobobooks.