Bug 452411 - EPUB3 files by calibre not generating preview
Summary: EPUB3 files by calibre not generating preview
Status: RESOLVED DUPLICATE of bug 451226
Alias: None
Product: kio-extras
Classification: Frameworks and Libraries
Component: Thumbnails and previews (show other bugs)
Version: 21.12.3
Platform: Manjaro Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
Depends on:
Reported: 2022-04-08 16:40 UTC by hasezoey
Modified: 2022-04-30 11:32 UTC (History)
1 user (show)

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Latest Commit:
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Description hasezoey 2022-04-08 16:40:17 UTC
I noticed that when upgrading (or just editing) books in calibre, they somehow lose the ability to have a thumbnail (in dolphin) generated and are just the generic file attribute cover for a ".epub" file

1. have a EPUB(2) file that has a cover *before* adding to calibre
2. import original EPUB file into calibre (any latest version)
3. open "Edit book" in calibre on the imported epub
4. select "Tools -> Upgrade book internals" to upgrade the file to EPUB3
5. save the edited book
6. go to the directory where the file is (in the calibre library), in my case with dolphin
7. observe not having a cover

Generic file attribute thumbnail for edited file in calibre

Thumbnail from the EPUB cover

Operating System: Manjaro Linux
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.3
Kernel Version: 5.16.14-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-7700K CPU @ 4.20GHz
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX Vega

The most consistent way to reproduce this problem is to have a EPUB2 file upgraded to a EPUB3 file, but it also happens when applying other changes (though i could not to consistently reproduce it with something else)

this issue might be similar to https://bugs.kde.org/show_bug.cgi?id=451226, but that one seems to be fixed

in my case calibre is installed as a flatpak as version 5.40.0 

from what i can tell from my testing, all EPUB3's that *dont* have "manifest -> item -> cover -> properties="cover-image"" set, just work, all others that either have that set or reference it with "metadata -> meta -> cover -> content="cover-image"" (where "content="id"" is the id set in manifest) dont work
Comment 1 hasezoey 2022-04-30 11:32:58 UTC
I just noticed that this is very likely a duplicate of https://bugs.kde.org/show_bug.cgi?id=451226 because i was using a "outdated" version of "kio-extras" (which is extra/kio-extras 21.12.3-1 in manjaro currently), but the issue is only fixed in a newer version (which is sadly currently not build in manjaro), i had noticed this after locally building & installing kio-extras from source

*** This bug has been marked as a duplicate of bug 451226 ***