Epub rendering bug on ka1 - Page 2

PeterT · 01-18-2017, 04:35 PM

Sorry to say it IS resolved. The fullscreenreading option is undocumented / unexposed / unsupported.

If it doesn't work so what. Kobo has never announced that setting.

GeoffR · 01-18-2017, 08:11 PM

There is a funky thing that happens at the end of chapters occasionally in ePubs, it appears to be caused by the following piece of CSS that Kobo include in the device's built-in ePub stylesheet (%1 is a variable that refers to the line height selected by the line spacing slider):

Code:

body { padding-bottom: %1em !important; }

If you set orphans:1;widows:1; in the book's stylesheet (and make sure to remove the publisher's orphans and widows settings if they have set them) then that seems to reduce the frequence of the problem, but it still occurs occasionally.

There is a patch named `ePub disable built-in body padding-bottom` that, combined with setting orphans:1;widows:1;, fixes the problem completely (in my experience.)

As far as full-screen mode goes, there are some problems with full-screen mode when reading KePubs (and patches to fix most of them), but I've read hundreds of ePubs in full-screen mode and never come across a single problem ever.

Edit: I think there is a way to test whether the above is the cause of your problem by editing the book, without the need to patch (this relies on the Adobe ePub reader's unusual interpretation of !important that allows the publisher to override !important in the device stylesheet by subclassing in the book's stylesheet.)

In the book's stylesheet, add the following class:

Code:

.do-not-pad-my-bottom { padding-bottom: 0; }

then in the html files, change <body> to <body class="do-not-pad-my-bottom">

Edit2: If you convert the book to ePub with Calibre then you might be able to fix this problem automatically during conversion by adding body { padding-bottom: 0; } to the conversion settings in Look & Feel > Styling > Extra CSS.

Calibre automatically creates a .calibre subclass for body and adds all the styles that were applied directly to body in the original book to body.calibre in the converted book. Normally this causes nothing but problems, because it means the device's adjustment sliders can no longer override the body styles in the converted book, but for this particular problem it might be just what is needed.

Edit3: And finally I should add: the reason the padding-bottom problem seems to occur randomly is that it is triggered only when the last line of text in a chapter would fall on the last line of the page -- or if widows/orphans is set higher than 1, then maybe also when the last page of the chapter has only one line of a multi-line paragraph. That would also explain why switching from full-screen to normal reading mode, or changing the margins, etc., appear to make the problem go away (but actually just make it pop up somewhere else), because those adjustments change the position of the last available line on the page.

Stevex · 01-19-2017, 04:43 AM

Peter - I doubt - though obviously I cant be sure - whether the problem was really caused by this setting, i think rather it was coincidental and the underlying issue could equally manifest itself without the fullpage setting. The underlying problem is obviously something rare.
Geoff - Thank you very much for your very interesting post, I will definitely check this out and report back.
Anybody with an interest and an Aura1 should be able to repro this now by the way, with the epub and settings i provided
Cheers Steve

Terisa de morgan · 01-19-2017, 05:24 AM

Quote:

Originally Posted by Stevex

Peter - I doubt - though obviously I cant be sure - whether the problem was really caused by this setting, i think rather it was coincidental and the underlying issue could equally manifest itself without the fullpage setting. The underlying problem is obviously something rare.
Geoff - Thank you very much for your very interesting post, I will definitely check this out and report back.

I agree... and it is not a new bug, as it happens at my Kobo Aura with 3.11 without the Full Screen Mode. And sometimes the same book I've reading without faults. I haven't been able to find a reason.

JSWolf · 01-19-2017, 05:35 AM

delete post

01-18-2017, 08:11 PM	#17
GeoffR Wizard Posts: 3,821 Karma: 19162882 Join Date: Nov 2012 Location: Te Riu-a-Māui Device: Kobo Glo	There is a funky thing that happens at the end of chapters occasionally in ePubs, it appears to be caused by the following piece of CSS that Kobo include in the device's built-in ePub stylesheet (%1 is a variable that refers to the line height selected by the line spacing slider): Code: body { padding-bottom: %1em !important; } If you set orphans:1;widows:1; in the book's stylesheet (and make sure to remove the publisher's orphans and widows settings if they have set them) then that seems to reduce the frequence of the problem, but it still occurs occasionally. There is a patch named `ePub disable built-in body padding-bottom` that, combined with setting orphans:1;widows:1;, fixes the problem completely (in my experience.) As far as full-screen mode goes, there are some problems with full-screen mode when reading KePubs (and patches to fix most of them), but I've read hundreds of ePubs in full-screen mode and never come across a single problem ever. Edit: I think there is a way to test whether the above is the cause of your problem by editing the book, without the need to patch (this relies on the Adobe ePub reader's unusual interpretation of !important that allows the publisher to override !important in the device stylesheet by subclassing in the book's stylesheet.) In the book's stylesheet, add the following class: Code: .do-not-pad-my-bottom { padding-bottom: 0; } then in the html files, change <body> to <body class="do-not-pad-my-bottom"> Edit2: If you convert the book to ePub with Calibre then you might be able to fix this problem automatically during conversion by adding body { padding-bottom: 0; } to the conversion settings in Look & Feel > Styling > Extra CSS. Calibre automatically creates a .calibre subclass for body and adds all the styles that were applied directly to body in the original book to body.calibre in the converted book. Normally this causes nothing but problems, because it means the device's adjustment sliders can no longer override the body styles in the converted book, but for this particular problem it might be just what is needed. Edit3: And finally I should add: the reason the padding-bottom problem seems to occur randomly is that it is triggered only when the last line of text in a chapter would fall on the last line of the page -- or if widows/orphans is set higher than 1, then maybe also when the last page of the chapter has only one line of a multi-line paragraph. That would also explain why switching from full-screen to normal reading mode, or changing the margins, etc., appear to make the problem go away (but actually just make it pop up somewhere else), because those adjustments change the position of the last available line on the page. Last edited by GeoffR; 01-19-2017 at 03:05 AM. Reason: And finally ...

01-19-2017, 05:35 AM	#20
JSWolf Resident Curmudgeon Posts: 79,796 Karma: 146391129 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	delete post Last edited by JSWolf; 01-20-2017 at 10:35 AM.

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01-18-2017, 04:35 PM	#16
PeterT Grand Sorcerer Posts: 13,535 Karma: 78910202 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	Sorry to say it IS resolved. The fullscreenreading option is undocumented / unexposed / unsupported. If it doesn't work so what. Kobo has never announced that setting.

01-19-2017, 04:43 AM	#18
Stevex Addict Posts: 225 Karma: 15318 Join Date: Nov 2015 Device: Kobo Glo HD	Peter - I doubt - though obviously I cant be sure - whether the problem was really caused by this setting, i think rather it was coincidental and the underlying issue could equally manifest itself without the fullpage setting. The underlying problem is obviously something rare. Geoff - Thank you very much for your very interesting post, I will definitely check this out and report back. Anybody with an interest and an Aura1 should be able to repro this now by the way, with the epub and settings i provided Cheers Steve