Re: [Koha-devel] Cover image 'thumbnail' size is bigger than 'imagefile' size

2018-12-12 Thread Andreas Roussos
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 
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  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
>
> ___
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> bugs : http://bugs.koha-community.org/
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Re: [Koha-devel] Cover image 'thumbnail' size is bigger than 'imagefile' size

2018-12-12 Thread Paul Poulain

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  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
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--
Paul Poulain, Associé-gérant / co-owner
BibLibre, Services en logiciels libres pour les bibliothèques
BibLibre, Open Source software and services for libraries

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Re: [Koha-devel] Cover image 'thumbnail' size is bigger than 'imagefile' size

2018-12-12 Thread Jonathan Druart
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  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/
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[Koha-devel] Cover image 'thumbnail' size is bigger than 'imagefile' size

2018-12-12 Thread Andreas Roussos
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
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