Bug 221985

Summary: update histogram before preview
Product: [Applications] digikam Reporter: DrSlony <bugs>
Component: Showfoto-CoreAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: wishlist CC: bugs, caulier.gilles, marcel.wiesweg, tschenser
Priority: NOR    
Version: 1.0.0   
Target Milestone: ---   
Platform: Gentoo Packages   
OS: Linux   
Latest Commit: Version Fixed In: 5.0.0
Sentry Crash Report:

Description DrSlony 2010-01-10 00:17:52 UTC 
Version:           1.0.0 (using KDE 4.3.4)
OS:                Linux
Installed from:    Gentoo Packages

If it is possible, it would be great if the histogram would get updated instantly, while a RAW file's preview is being calculated when tweaking it in showfoto. My system is old, but I assume that even on an entry level system the preview will still take at least a second to calculate, and when you work on a lot of photos each second adds up. If the histogram would get immediately updated, we could often not care about waiting for a preview when its apparent from the histogram that something's wrong, and we'd carry on tweaking till the histogram is right, then wait for the preview.
Comment 1 Marcel Wiesweg 2010-01-10 14:24:40 UTC 
With the histogram calculated from image data, how do you want to update the histogram without the corresponding image?
Comment 2 caulier.gilles 2010-01-11 08:49:31 UTC 
Perhaps DrSlony want mean about to record histogram in metadata. PNG support this feature as a dedicated chunk, but not Exif, IPTC, and XMP.

This can be done in a dedicated XMP tag from digiKam namespace for example... But this tag will be only managed by digiKam of course. Editing image in gimp for example will not update histogram XMp tag.

Gilles
Comment 3 Jens Mueller 2010-01-11 09:56:49 UTC 
From my understandings DrSlony means that a optimal workflow would be:

1) load raw file and create full histogram of that image data
2) move histogram values according to sliders on the fly (without doing a new raw development)
3) if the slider stops start a new fullsized raw processing in background and if finished update preview and histogram from that data

For example dxo (one of the best raw developer out there, but proprietary) work like that.

As digikam do not dive deep into raw decoding, but compute histogram data on top of an existing image, this is at least not trival to archive.
Comment 4 DrSlony 2016-07-03 11:13:11 UTC 
Using digiKam-5.0.0 on a laptop, histogram update is fast enough. Agreed to keep it closed.