Possible bug in eBook conversion - Suggestion for check book

arspr · 03-25-2015, 03:05 PM

Hi Kovid,

Because of what jbennion posted in the Kobo bug thread and the solution I posted, I think you should check it.

Basically Kobo ACCESS renderer (for kepubs) goes FUBAR when there are missing or bad linked font files in @font-face in css stylesheets.

In the exact case posted there, the book page_styles.css contained:

Code:

@font-face {
    font-family: "Caecilia";
    font-weight: normal;
    font-style: normal;
    src: url(res:///Data/fonts/Caecilia-Roman.otf)

(and italic and bold and both).

Caecilia is used by "calibre_" class, and the book always contains <body class="calibre_"> in each html file. But the ebook doesn't contain any embedded font file itself.

This situation causes havoc in Kobo Readers.

So the possible bug in Calibre would be:

page_styles.css is created by Calibre, isn't it? Although I've asked jbennion if he has manually edited the epub file, (he did a MOBI to EPUB conversion), I do think you might check if it were possible that Calibre created those font-face settings with those strange urls without embedding the font files themselves.

And the suggestion for Check Book:

As this situation is deadly for Kobos it would be really nice if Check Book informed about missing font files in the used @font-face.

theducks · 03-25-2015, 03:39 PM

IIRC a res: url says the font is on the device, not embedded

Code:

src: url(../fonts/Caecilia-Roman.otf)

jackie_w · 03-25-2015, 08:30 PM

@arspr, To add a bit more detail to what theducks said, the @font-face code

Code:

src: url(res:///Data/fonts/... ...)

is typical of an epub which has been specifically prepared to use on a Sony PRS505/600/350/650 device. It externally references fonts stored on the Sony itself rather than embedded in the epub.

I'd guess the user deliberately put them in there using the calibre conversion Look&Feel ExtraCSS option. IMO it's a bad idea to force device specific code into one's calibre master epubs. I would have guessed that it would be completely ignored by the Kobo rather than causing havoc, but as I haven't tested it myself I could be wrong.

arspr · 03-26-2015, 12:33 PM

I'm updating several pictures of jbennion's book in both OK and wrong flavours.

I'm on Kobo Aura H2O running FW 3.13.1.

Nevertheless as this is a private ebook, I'll try to update Jellby's test book with some tests about missing font files. (But I'm going on holidays this Easter, next week, so it'll take a while

).

BetterRed · 03-26-2015, 08:06 PM

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Moved from Editor to Conversion subforum

03-25-2015, 03:05 PM	#1
arspr Dead account. Bye Posts: 587 Karma: 668244 Join Date: Mar 2011 Device: none	Possible bug in eBook conversion - Suggestion for check book Hi Kovid, Because of what jbennion posted in the Kobo bug thread and the solution I posted, I think you should check it. Basically Kobo ACCESS renderer (for kepubs) goes FUBAR when there are missing or bad linked font files in @font-face in css stylesheets. In the exact case posted there, the book *page_styles.css* contained: Code: @font-face { font-family: "Caecilia"; font-weight: normal; font-style: normal; src: url(res:///Data/fonts/Caecilia-Roman.otf) (and italic and bold and both). Caecilia is used by "calibre_" class, and the book always contains <body class="calibre_"> in each html file. But the ebook doesn't contain any embedded font file itself. This situation causes havoc in Kobo Readers. So the possible bug in Calibre would be: page_styles.css is created by Calibre, isn't it? Although I've asked jbennion if he has manually edited the epub file, (he did a MOBI to EPUB conversion), I do think you might check if it were possible that Calibre created those font-face settings with those strange urls without embedding the font files themselves. And the suggestion for Check Book: As this situation is deadly for Kobos it would be really nice if Check Book informed about missing font files in the used @font-face.

03-25-2015, 03:39 PM	#2
theducks Well trained by Cats Posts: 31,267 Karma: 61916422 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	IIRC a res: url says the font is on the device, not embedded Code: src: url(../fonts/Caecilia-Roman.otf)

03-25-2015, 08:30 PM	#3
jackie_w Grand Sorcerer Posts: 6,269 Karma: 16544702 Join Date: Sep 2009 Location: UK Device: ClaraHD, Forma, Libra2, Clara2E, LibraCol, PBTouchHD3	@arspr, To add a bit more detail to what theducks said, the @font-face code Code: src: url(res:///Data/fonts/... ...) is typical of an epub which has been specifically prepared to use on a Sony PRS505/600/350/650 device. It externally references fonts stored on the Sony itself rather than embedded in the epub. I'd guess the user deliberately put them in there using the calibre conversion Look&Feel ExtraCSS option. IMO it's a bad idea to force device specific code into one's calibre master epubs. I would have guessed that it would be completely ignored by the Kobo rather than causing havoc, but as I haven't tested it myself I could be wrong. Last edited by jackie_w; 03-25-2015 at 08:39 PM.

03-26-2015, 12:33 PM	#4
arspr Dead account. Bye Posts: 587 Karma: 668244 Join Date: Mar 2011 Device: none	I'm updating several pictures of jbennion's book in both OK and wrong flavours. I'm on Kobo Aura H2O running FW 3.13.1. Nevertheless as this is a private ebook, I'll try to update Jellby's test book with some tests about missing font files. (But I'm going on holidays this Easter, next week, so it'll take a while ). Attached Thumbnails

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