7.0-7.2: Extracting covers problem?

jindroush · 12-18-2023, 09:56 AM

Hi,
I noticed this after upgrading to 7.0 (and verified in 7.2):

Certain epubs, while extracting covers by E and book button fail to extract the cover correctly, and even produce rendered red error message (above actual cover image or instead it) in the cover.jpg:

https://www.dropbox.com/scl/fi/y2g96...i9rxlm048&dl=0

This mentions unknown entity nbsp (the page code contains  , correctly formatted IMO).
I'm not claiming it's a regression in 7.x, but I never saw it before.

My questions:
a) Is this known/expected behaviour of extract cover?
b) Why is code for extracting the cover and actually displaying it different? I mean, sometimes the rendering of the cover is wildly different to the same cover displayed by ebook-viewer. Is it because the extractor and viewer don't share the codebase? Talking only about EPUBs.

kovidgoyal · 12-18-2023, 10:02 AM

They definitely dont share the same codebase, the viewer does a hell of a lot of more work to format books before displaying them. Rendering covers is a much for basic task. As for your error you have likely got   in a XHTML file where its illegal an EPUB to EPUB conversion will fix it.

jindroush · 12-18-2023, 10:12 AM

Doh! Really, changing   to & # 160 ; fixes that.

DNSB · 12-18-2023, 12:48 PM

For what it's may be worth, for ePub3/HTML5, the only predefined named entities are &, <, >, '. and " ( & < > ' and "). You can defined named entities but for the most part, I just use the numeric entities if really needed.

12-18-2023, 09:56 AM	#1
jindroush Connoisseur Posts: 94 Karma: 104 Join Date: Nov 2014 Device: Kindle	7.0-7.2: Extracting covers problem? Hi, I noticed this after upgrading to 7.0 (and verified in 7.2): Certain epubs, while extracting covers by E and book button fail to extract the cover correctly, and even produce rendered red error message (above actual cover image or instead it) in the cover.jpg: https://www.dropbox.com/scl/fi/y2g96...i9rxlm048&dl=0 This mentions unknown entity nbsp (the page code contains  , correctly formatted IMO). I'm not claiming it's a regression in 7.x, but I never saw it before. My questions: a) Is this known/expected behaviour of extract cover? b) Why is code for extracting the cover and actually displaying it different? I mean, sometimes the rendering of the cover is wildly different to the same cover displayed by ebook-viewer. Is it because the extractor and viewer don't share the codebase? Talking only about EPUBs.

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12-18-2023, 10:02 AM	#2
kovidgoyal creator of calibre Posts: 45,345 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	They definitely dont share the same codebase, the viewer does a hell of a lot of more work to format books before displaying them. Rendering covers is a much for basic task. As for your error you have likely got   in a XHTML file where its illegal an EPUB to EPUB conversion will fix it.

12-18-2023, 10:12 AM	#3
jindroush Connoisseur Posts: 94 Karma: 104 Join Date: Nov 2014 Device: Kindle	Doh! Really, changing   to & # 160 ; fixes that.

12-18-2023, 12:48 PM	#4
DNSB Bibliophagist Posts: 46,181 Karma: 168983734 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	For what it's may be worth, for ePub3/HTML5, the only predefined named entities are &, <, >, '. and " ( & < > ' and "). You can defined named entities but for the most part, I just use the numeric entities if really needed.

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