Bug 284625

Summary: Channel Mixer Preserve Luminosity does not work
Product: [Applications] digikam Reporter: 202020
Component: Plugin-Editor-ChannelsAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: caulier.gilles
Priority: NOR    
Version First Reported In: 2.1.1   
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed/Implemented In: 2.3.0
Sentry Crash Report:

Description 202020 2011-10-21 16:04:23 UTC 
Version:           2.1.1 (using KDE 4.7.1) 
OS:                Linux

start showfoto
load color image
select channel mixer, tick monochrome, tick preserve luminosity
move any of the sliders red, green or blue to another value than default
parts of the image gets underexposed (clipping) or overexposed (clipping), i.e. luminosity is NOT preserved.




Reproducible: Always

Steps to Reproduce:
load color image
select channel mixer, tick monochrome, tick preserve luminosity
move any of the sliders red, green or blue to another value than default

Actual Results:  
parts of the image are underexposed (clipping) or overexposed (clipping), i.e. luminosity is NOT preserved.

Expected Results:  
No under- or overexposure.

Last version known to me where this not happened is digikam/showfoto 1.1.0

Quite annoying as I extensively use showfoto for professional photography.
Comment 1 caulier.gilles 2011-10-29 08:25:38 UTC 
I confirm the dysfunction. Sound like "Preserve Luminosity" option do not have any influence. Perhaps a signal/slot broken in GUI...

Gilles Caulier
Comment 2 caulier.gilles 2011-10-29 21:03:24 UTC 
Note : Preserve luminosity work perfectly in Color mode. Dysfunction exist only in Monochrome mode.

It's not a signal/slots connection problem.

Gilles Caulier
Comment 3 caulier.gilles 2011-10-29 21:56:49 UTC 
Git commit 223d431b8817d3791ce6bf87dfb5d4a716bc70af by Gilles Caulier.
Committed on 29/10/2011 at 23:55.
Pushed by cgilles into branch 'master'.

compute right monochrome gain to preserve luminosity when this one is required
BUGS: 284625

M  +12   -2    libs/dimg/filters/bw/mixerfilter.cpp

http://commits.kde.org/digikam/223d431b8817d3791ce6bf87dfb5d4a716bc70af