[Digikam-devel] extragear/graphics/digikam/digikam

[Gilles Caulier]

2009/6/12 Mikolaj Machowski <mikmach at wp.pl>:
> On Thursday 11 June 2009 19:36:44 Marcel Wiesweg wrote:
>> SVN commit 980402 by mwiesweg:
>>
>> Adding the lines that switch on using a thumbnail database - not enabled
>> per default:
>>
>> NOTE:
>> You need to remove the comment signs around albummanager.cpp, lines
>> 685-687, to test the thumbnail database.
>>
>> For simplicity, it is always created in the directory of the main database
>> and named "thumbnails-digikam.db". It is using the PGF format to store
>> thumbnails. I am aware there are suggestions to use JPEG or Djvu.
>
> Used this for my files (15,000):
>
> 1) size of database: 243 MB, size of .thumbnails/large: 1.3GB
> 2) creation time - for me recreation of all thumbnails takes so long that I
> have to do other things in meantime so it is incomparable (and data useless)
> but just for interest it was cut 20% - and "live" creation of thumbs
> (displaying them with empty database) was faster for me than previously
> 3) what for me is most important - time of display of images which thumbs are
> already in database: unfortunately there is scientific method, just feelings -
> maybe bit faster, definitely not slower
> 4) quality of images (used default PGF, q=4, don't know how to switch to JPG):

To switch to JPG, it's easy :

http://lxr.kde.org/source/extragear/graphics/digikam/libs/threadimageio/thumbnailcreator.cpp#481

Change this line to dbInfo.type = DatabaseThumbnail::JPEG;

recompile, install. Remove your thumbs database file and start digiKam again....

Gilles



> in normal, landscapes, portraits, etc. no difference, slightly lower quality
> (comparing to .thumbnails PNGs) with images with "hard" borders, eg. texts.
> 5) strange effect: very, very slow closing, window closes fast but after that
> digiKam makes multiple disk operations taking ca 50% of CPU
>
>
> m.
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