Bug 126914

Summary:	Gamma table doesn't work for scanners with more than 256 entries
Product:	[Applications] kooka	Reporter:	Rune Kock <rune.kock>
Component:	libkscan	Assignee:	Klaas Freitag <freitag>
Status:	ASSIGNED ---
Severity:	normal
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Rune Kock 2006-05-07 18:39:42 UTC

Version:            (using KDE KDE 3.5.1)
Installed from:    SuSE RPMs
OS:                Linux

Some scanners have gamma tables with more than 256 entries.  E.g. the Canon Pixma series (http://home.arcor.de/wittawat/pixma/index.html) have gamma tables with 4096 entries.

libkscan and Kooka seem to be hard-coded to 256-entry gamma tables.

This means that if I use custom gamma-settings in Kooka, the result is quite wrong -- sometimes way too dark, sometimes too light.  As long as custom gamma-settings is disabled, the scans are fine.

(Thanks to Wittawat Yamwong for investigating this issue).

Comment 1 Jonathan Marten 2011-11-10 22:06:26 UTC

Git commit 802137b2189647fd625dd313ecf491a0d96ff69e by Jonathan Marten.
Committed on 10/11/2011 at 22:55.
Pushed by marten into branch 'master'.

Finish the porting of gamma table editing

It should now be possible to edit gamma tables and correctly update
the scanner with them.  At the moment only a single gamma table is
supported, if the scanner has individual gamma tables for each
colour channel then the same gamma table is sent to each.

This should also work (although I am not able to test it) for scanners
with other than 256 gamma table entries, bug 126914.

Also clean up the code and API, and add API documentation to the
gamma table classes.

CCBUG:126914

M  +66   -75   libkscan/gammadialog.cpp
M  +56   -21   libkscan/gammadialog.h
M  +43   -39   libkscan/gammawidget.cpp
M  +32   -17   libkscan/gammawidget.h
M  +124  -46   libkscan/kgammatable.cpp
M  +167  -33   libkscan/kgammatable.h
M  +3    -2    libkscan/kscancontrols.cpp
M  +33   -55   libkscan/kscanoption.cpp
M  +4    -5    libkscan/kscanoption.h
M  +72   -112  libkscan/scanparams.cpp
M  +3    -1    libkscan/scanparams.h

http://commits.kde.org/kooka/802137b2189647fd625dd313ecf491a0d96ff69e

Comment 2 Jonathan Marten 2011-11-10 22:28:00 UTC

Implemented in KDE4 port, but unable to test because I do not have any suitable hardware.  If you can compile from source please try out this version with gamma tables and an affected scanner.  See http://techbase.kde.org/Projects/Kooka
for Git access and build instructions.

Comment 3 Rune Kock 2011-11-11 14:42:42 UTC

Thanks for fixing this old bug.  The Pixma scanner has found a new home, but I may be able to test it anyway.  No promises and no time-frame.

I would assume that many new scanners feature a big gamma table by now, so maybe someone else will be able to test.