Hi Paul, Jonathan, Thank you both for your prompt replies and your feedback. I have now opened a new bug report here: https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=21987
Andreas On Wed, 12 Dec 2018 at 14:53, Paul Poulain <paul.poul...@biblibre.com> wrote: > Hi Andreas, > > (and if you can't provide a patch, please file a bug on buzilla, this > description is perfect ! ) > > Le 12/12/2018 à 13:49, Jonathan Druart a écrit : > > Hi Andreas, > > > > This module has never been enhanced much and as you noticed there is > > room for such enhancements :) > > All of what you describe in your email makes sense to me, and I am > > sure the changes will be accepted if a patch is provided. > > > > Cheers, > > Jonathan > > Le mer. 12 déc. 2018 à 06:42, Andreas Roussos <arouss1...@gmail.com> a > écrit : > >> Dear Developers, > >> > >> We use local cover images in our setup, and also resize the covers > >> we scan to a width of 160px before uploading and attaching them to > >> a Koha bibliographic record (we upload one cover per biblio). > >> > >> While using phpMyAdmin to view the contents of the 'biblioimages' > >> table (relevant screenshot here: https://imgur.com/a/cSEVLBI), we > >> noticed that the size of the BLOBs for the 'thumbnail' column was in > >> some cases twice as big as that of the 'imagefile' column. In fact, > >> this happens for more than 50% of uploaded covers as you can see > >> from the output of the SQL queries below: > >> > >> mysql> SELECT COUNT( * ) AS count > >> FROM biblioimages > >> WHERE LENGTH( thumbnail ) > ( LENGTH( imagefile ) * 2 ) ; > >> +-------+ > >> | count | > >> +-------+ > >> | 1356 | > >> +-------+ > >> > >> mysql> SELECT COUNT( * ) AS count, > >> SUM( LENGTH( imagefile ) ) AS images_size, > >> SUM( LENGTH( thumbnail ) ) AS thumbnails_size > >> FROM biblioimages ; > >> +-------+-------------+-----------------+ > >> | count | images_size | thumbnails_size | > >> +-------+-------------+-----------------+ > >> | 2347 | 68323933 | 115839686 | > >> +-------+-------------+-----------------+ > >> > >> It would appear that for each 160px-wide JPG with 24-bit depth that > >> we have uploaded, the 'imagefile' column has been populated with an > >> PNG of 8 bit depth with the same dimensions as the uploaded file, > >> whereas the 'thumbnail' column contains a 24-bit PNG image with a > >> width reduced to 140 pixels. > >> > >> I've tracked down the creation of resized 24-bit PNGs to this code: > >> > https://github.com/Koha-Community/Koha/blob/master/C4/Images.pm#L182-L183 > >> > >> Do thumbnails for covers need to be true colour (24-bit) images? > >> > >> Also, why is it that _scale_image() returns an image of 8-bit depth > >> if the source image's dimensions are less than 600x800? (i.e. when > >> no resizing is performed) > >> > >> Thank you in advance for your time. > >> > >> Kind regards, > >> Andreas > >> _______________________________________________ > >> Koha-devel mailing list > >> Koha-devel@lists.koha-community.org > >> http://lists.koha-community.org/cgi-bin/mailman/listinfo/koha-devel > >> website : http://www.koha-community.org/ > >> git : http://git.koha-community.org/ > >> bugs : http://bugs.koha-community.org/ > > _______________________________________________ > > Koha-devel mailing list > > Koha-devel@lists.koha-community.org > > http://lists.koha-community.org/cgi-bin/mailman/listinfo/koha-devel > > website : http://www.koha-community.org/ > > git : http://git.koha-community.org/ > > bugs : http://bugs.koha-community.org/ > > -- > Paul Poulain, Associé-gérant / co-owner > BibLibre, Services en logiciels libres pour les bibliothèques > BibLibre, Open Source software and services for libraries > > _______________________________________________ > Koha-devel mailing list > Koha-devel@lists.koha-community.org > http://lists.koha-community.org/cgi-bin/mailman/listinfo/koha-devel > website : http://www.koha-community.org/ > git : http://git.koha-community.org/ > bugs : http://bugs.koha-community.org/
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