Bug 146260

Summary: In preview canvas, first load reduced image and then full image
Product: digikam Reporter: Arnd Baecker <arnd.baecker>
Component: Preview-ImageAssignee: Digikam Developers <digikam-bugs-null>
Status: REPORTED ---    
Severity: wishlist CC: caulier.gilles, sergio, simon.eu
Priority: NOR    
Version: 0.9.3   
Target Milestone: ---   
Platform: Debian stable   
OS: Linux   
Latest Commit: Version Fixed In:

Description Arnd Baecker 2007-06-01 17:54:22 UTC
Version:            (using KDE KDE 3.5.5)
Installed from:    Debian stable Packages

To make the light-table feel faster it should first load
the reduced image and then (in a background thread)
the full image. Once that is loaded the reduced image is replaced.

Remark: Marcel already provided a patch for this.
Things are, however, a bit tricky, because the 
zoom levels are different for reduced size vs. full image.

Suggestion for this: the only relevant (for the user) image size
is the actual one. Reduced image sizes are an implementation detail.
Therefore also zoom levels given with respect to the reduced image
size are, in my opinion, useless.
Thus (for example) a 100% display should show the same region, regardless 
of preview or full image. 
(Of course, 100% for the reduced image would not look good - though
until one has zoomed in, the full image will be displayed soon).

Technically one could use a scale factor (which is 1.0
for the full image, and <1,  for the reduced image, corresponding
to the ratio reduced/full) whose inverse is used as multiplier 
for the slider values etc.

Note: this delayed loading would also be useful for the 
AlbumGUI preview mode (F3) and also for the image editor itself
(of course also including showfoto).
Comment 1 Arnd Baecker 2007-06-03 16:29:24 UTC
Just for completeness (and that the credits are attributed correctly):
This goes back to the suggestion by Frank in #16
of http://bugs.kde.org/show_bug.cgi?id=140131 
and seems to be an approach also taken by other applications.
Comment 2 Johannes Wienke 2010-01-20 22:00:41 UTC
*** Bug 223618 has been marked as a duplicate of this bug. ***
Comment 3 Sergio Cambra 2012-03-14 18:49:34 UTC
I would like to have this feature in the view mode too, not only in light table
Comment 4 Justin Zobel 2021-03-09 05:51:25 UTC
Thank you for the bug report.

As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists.

If this bug is no longer persisting or relevant please change the status to resolved.