Designing for Kobo

[AlexBell]

I've just designed an ebook which works well on my Sony PRS T2 and on my iPad with iBooks, and after being converted by calibre works well on my Kindle3 both in old mobi and azw3. I design my ebooks by hand with an HTML editor, and the html files and CSS validate to W3C standards. The ebook validates with ePubCheck and Flightcrew.

But a friend has tested it on her Kobo Touch, and it seems to be an absolute disaster - links don't go to the right page, the font size is too small, and there are several other problems. It's also a disaster using the Kobo app on my iPad2. The friend has tested other ebooks I've designed for me, and found although links didn't work the rest of the ebook worked well.

Can anyone suggest where I might have done wrong? Is there a difference between how Kobo renders ePubs and how Sony renders ePubs?

Are there any ePub designers here who read their ebooks on a Kobo?

[davidfor]

I'm not book designer, but a Kobo Touch and Glo user. I do edit my copies of ePubs to improve my reading experience, so I have some knowledge of the ePub structure.

Originally Posted by AlexBell

But a friend has tested it on her Kobo Touch, and it seems to be an absolute disaster - links don't go to the right page, the font size is too small, and there are several other problems. It's also a disaster using the Kobo app on my iPad2. The friend has tested other ebooks I've designed for me, and found although links didn't work the rest of the ebook worked well.

For the links, how much are they out? There is a navigation issue with the latest firmware (2.3.1 and 2.3.2). This is normally seen as reopening a book goes to a page or two earlier than where it was closed. I have seen some mention of links having problems, but I haven't seen them. The only books I have read lately with links were from a TOC to chapter headings. These worked perfectly. There is a workaround for the navigation problem. Setting the margins on the reader to zero sorts it out.

The only other issue with links I have seen is the actual act of selecting them. If the link is small, say a number for a footnote, and the font is small, selecting them can be next to impossible. Increasing the font size has always solved this for me. That isn't really practical and I don't know how other touch devices handle the same issue. I have seen discussion here or in the Sigil forum about how to handle the issue, so I assume it isn't just Kobo devices having the problem.

To me, font size should be set by the user. The Kobo devices have good control over font size. If an ePub uses relative sizes (em or whatever), this works very well. The same goes for the actual font. If the sized is fixed or the font is set, it can't be changed.

[AlexBell]

Thanks, David, that's most helpful and perhaps encouraging.

The navigation problem my friend reports is that the when she selects a link from the ToC to another section she is taken to the second page of that section, not the first page of the section.

The text font size in the ebook is set in ems. Most of the headings and titles are set in percentage of em. I have set the font to sans-serif; could this be causing a problem? It certainly doesn't cause any problem with my Sony; I can's select any of the other six font option ands the text changes to whatever I've selected.

Do you know of any other forum than MobileRead which discusses Kobo problems where I could get help?

[oxen]

Links jump error problem, may be caused by the link target setting. In order to make an accurate judgement, suggest you upload Epub document.

Font too small problems, is because you used em units and fixed font sizes. So that would be difficult to have the desired effect on non-testing machine. It is a good method to use % as a font size unit. So, different machines and reading system can adjust font size by font menu.

Originally Posted by AlexBell

Thanks, David, that's most helpful and perhaps encouraging.

The navigation problem my friend reports is that the when she selects a link from the ToC to another section she is taken to the second page of that section, not the first page of the section.

The text font size in the ebook is set in ems. Most of the headings and titles are set in percentage of em. I have set the font to sans-serif; could this be causing a problem? It certainly doesn't cause any problem with my Sony; I can's select any of the other six font option ands the text changes to whatever I've selected.

Do you know of any other forum than MobileRead which discusses Kobo problems where I could get help?

[davidfor]

I agree with oxen, it would be good to test the ePub to see what happens. To test the links, the full book is probably needed, but a sample with the stylesheet should do for the fonts.

[Toxaris]

Originally Posted by oxen

Font too small problems, is because you used em units and fixed font sizes. So that would be difficult to have the desired effect on non-testing machine. It is a good method to use % as a font size unit. So, different machines and reading system can adjust font size by font menu.

Sorry, that is nonsense. Fixed font size causes problems with fonts (not changeable, to big, to small, etc). Setting the font size in em or in percentages does not. In fact, for most readers percentages and ems are the same. That is, 1em is 100% and for example 1.2em equals to 120%. I always use ems for basic settings (usually p-tags) and percentages for changes within a paragraph (spans). That works well on all the readers I have seen so far.

[JSWolf]

What I have seen done that works is instead of using a single character superscripted to make it even harder to press is to use thinks like...

Go to the footnote for this sentence[1]. This is the next footnote[2].

That way, it will be easy to hit the right spots on the screen.

Now, as for the font size being a reason why the links do not work properly is rubbish. Either they are not codded correctly or this is yet another Kobo bug. Given that they work everyplace but a Kobo Reader, I would say it is a bug in the Kobo.

[AlexBell]

Thanks for all your comments. Just to make things even more complicated I put together a very simple ebook with only a few links, and my friend tells me the links work well on this ebook.

So the current plan is to make the ebook more complex in small steps until it stops working in the Kobo. Then I'll have a better idea, I hope, about what is causing the problems.

I'm afraid I can't upload the original ebook since it is a commercial ebook I designed for a small publisher in the UK. But as soon as the one I'm working on now for the MR library fails on a Kobo when it works well on the others I'll let you know and upload it for all to look at.

I understand that the Kobo uses different parts of the screen for different purposes - clicking on the centre I think brings up the menu. Is this a possible cause for the problems I'm having? The Kobo might be confused between bringing up the menu and moving to another part of the ebook.

I suppose I could put a link in the centre of the screen and see how the Kobo handles it.

[DSpider]

If the links in some ePub files work, but in your ePub files they don't, I suggest you open up both files and have a look at their underline code.

This is probably the reason why they don't work:

Originally Posted by AlexBell

I design my ebooks by hand with an HTML editor

It's called PEBKAC.

[dgatwood]

Another useful tip: Don't set the left and right margins for html or body tags to zero. If you do, Kobo (at least on iOS) will dutifully render part of the next page on the current one and won't let you go to the last page of any chapter.

[AlexBell]

Originally Posted by DSpider

If the links in some ePub files work, but in your ePub files they don't, I suggest you open up both files and have a look at their underline code.

This is probably the reason why they don't work:



It's called PEBKAC.

What's PEBKAC?

Whatever it is I don't think it explains why the links work on my Sony and iPad/iBooks, and on my Kindle Keyboard after conversion.

[AlexBell]

Originally Posted by dgatwood

Another useful tip: Don't set the left and right margins for html or body tags to zero. If you do, Kobo (at least on iOS) will dutifully render part of the next page on the current one and won't let you go to the last page of any chapter.

Thanks, that's most helpful. I have indeed set the body margins and padding to zero in the CSS:

body {
margin: 0; padding: 0; border-width: 0;
font-size: 95%;
text-align: justify;
line-height: 120%;
font-family:sans-serif;
}

@page { margin: 3pt; padding: 2pt 0 0 0; }

What values would you suggest?

[Toxaris]

I usually set it at 5 pt. Small, but not too small.

[DSpider]

Originally Posted by AlexBell

What's PEBKAC?

Google it.

[Jellby]

Originally Posted by dgatwood

Another useful tip: Don't set the left and right margins for html or body tags to zero. If you do, Kobo (at least on iOS) will dutifully render part of the next page on the current one and won't let you go to the last page of any chapter.

What? Does it mean all my books display wrong there? Shame on them!

(I always add "html body { margin: 0; }".)