[Digikam-users] Thumbnails blury in digiKam 1.0.0

[Stedtlund]

2010/1/18 Gilles Caulier <caulier.gilles at gmail.com>:
> This can be relevant of PGF compression level. In digiKam, thumbs
> compression is there :
>
> http://lxr.kde.org/source/extragear/graphics/digikam/libs/threadimageio/thumbnailcreator.cpp#501
>
> Last value passed to this method is compression level. Try 3 or 2 to
> see if quality is better. You need to force digiKam to rebuild
> thumbnails of course.

This implies that I need to build digiKam manually. I'ts not
impossible, but a little cumbersome as I have not done this before.

I looked a little of the source above and there is another thing one
can try, that's changing dbInfo.type = DatabaseThumbnail::PGF to
something else. Unfortunately this i a hard coded value, it might be a
candidate to have this one configurable from settings or config file.
Also the third parameter to writePGFImageData could be configurable in
some way.

>
> Note : perhaps it's a problem in LibPGF. I recommend to as to PGF team
> also, just to be sure...

I can do that. Where can I get in contact with them?

>
> Gilles Caulier
>
> 2010/1/18 Stedtlund <falolaf at gmail.com>:
>> 2010/1/18 Vlado Plaga <rechner at vlado-do.de>:
>>> Am Sun, 17 Jan 2010 16:36:09 +0100
>>> schrieb Stedtlund <falolaf at gmail.com>:
>>>
>>>> Hi,
>>>>
>>>> After upgrading to digiKam most of the thumbnails are blury.
>>>
>>> Do you mean upgrading digiKam 0.10 (or earlier) to 1.0?
>> Yes, that's what I mean. A miss from my side.
>>
>>>The internal
>>> thumbnails format changed. The change is described in the changelog as
>>> follows:
>>>
>>> "General : digiKam use a new database to cache thumbnails instead
>>> ~./thumbnails. File format used to store image is PGF
>>> (http://www.libpgf.org). PGF is a wavelets based image compression
>>> format and give space optimizations."
>> I read that too, but I thougth that was going to be possitive...
>>
>>>
>>> I also noticed a decline in thumbnail quality, but I did not consider
>>> it problematic enough to write a bug report for it. But maybe you could
>>> open one?
>> I can do that!
>>
>>>
>>> As I wrote in a comment on a bug report related to this change in
>>> digiKam thumbnail storage, I'd still prefer a thumbnail directory
>>> shared between applications... but since the type of directory proposed
>>> there (with subdirectories made of MD5 hash sums) apparently does not
>>> exist for thumbnails yet, this would be a fair amount of work for
>>> digiKam developers:
>>> https://bugs.kde.org/show_bug.cgi?id=210580#c15
>>>
>>>> Are there any parameters to tune to get better results?
>>>
>>> That would be a useful option indeed.
>>>
>>> Vlado
>>> _______________________________________________
>>> Digikam-users mailing list
>>> Digikam-users at kde.org
>>> https://mail.kde.org/mailman/listinfo/digikam-users
>>>
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