EDIT: just saw that @trewelu already found this 2 years ago
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I have found a (semi-automatic) way to display CBR/CBZ covers in the Library app:
- Extract the cover from CBR file
- Convert it to grayscale (optional)
- Resize it to something small, like 370x475 px
- Save it in PNG format
- Rename it to "comic_filename.cbr.png"
- Copy the PNG to /system/cover_chache/1/your_comics_folder_name/
So, if your comic file is "Comic1.cbr", your cover image should be named "Comic1.cbr.png".
This displays the covers only in the Library app, but not on the desktop screen; still haven't found where exactly those covers are cached.
To extract and rename covers from many CBR files at once, this shell script can be used on OSX (it assumes that the covers are the first images in the archive, in JPG format):
Code:
#!/bin/bash
find . -name "*.cbr" | while read f ; do
cover=$(unrar vb "$f" | sed -n 1p);
echo "Cover: $cover";
coverfull="$f"".jpg";
unrar e "$f" "$cover";
mv "$cover" "$coverfull"; done