Bug 497336

Summary:	[retrocompatibility] Color issue with Filter Layers: Color Adjustment curves
Product:	[Applications] krita	Reporter:	David REVOY <info>
Component:	Filter Layers	Assignee:	Dmitry Kazakov <dimula73>
Status:	RESOLVED FIXED
Severity:	major	CC:	dimula73, halla
Priority:	NOR	Keywords:	regression
Version:	5.2.7
Target Milestone:	---
Platform:	Appimage
OS:	Linux
Latest Commit:	https://invent.kde.org/graphics/krita/-/commit/c94a5e594ed9acc19438acd07bad2b3d97b2658c	Version Fixed In:
Sentry Crash Report:
Attachments:	^ The jpg on left (color as saved in 2017), the Krita files in modern Krita on right. The curve was applied on the "Hue" channel instead of the Lightness.

Description David REVOY 2024-12-11 17:27:33 UTC

Created attachment 176527 [details]
^ The jpg on left (color as saved in 2017), the Krita files in modern Krita on right. The curve was applied on the "Hue" channel instead of the Lightness.

Hi, 

I opened an old (2017) Krita files and saw the color rendering was surprisingly really off. (see attachment ). The artwork uses a Color Adjustement (curves) as a filter layer on the top of the stack.

I guess the issue comes from the fact that in 2017, the Color Adjustment curves didn't had all the channels it has nowadays. 

From what I understand of the bug: 
- in 2017, I modified the 4rth channel, and at that time the fourth was "Lightness" (to adjust the contrast).
- in 2024, with the new Hue and Saturation channel, my curve was applied to the 4rth option: "Hue".  

Files:
====
The artwork (jpg exported from the built in PNG): https://www.peppercarrot.com/en/viewer/misc__2017-04-22_merci_by-David-Revoy.html
Krita KRA source: https://www.peppercarrot.com/0_sources/0ther/misc/zip/2017-04-22_merci_by-David-Revoy.zip

Comment 1 Dmitry Kazakov 2024-12-12 13:08:41 UTC

Git commit 28ba6500890c9d14994a14255cb67bbc3efbf8b1 by Dmitry Kazakov.
Committed on 12/12/2024 at 13:08.
Pushed by dkazakov into branch 'master'.

Fix backward compatibility of Per-Channel filter

In Krita 5.1.0 we added two additional "virtual" channels to the
per-channel filter ("Hue" and "Saturation"). And we added them **not**
to the end of the list, but **before** the "Lightness" channel, which
basically broke all the files created in Krita version before 5.1.0.

The patch manually remaps the channels depending on the number of channels
present in the configuration XML.

M  +68   -8    plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
M  +22   -0    plugins/filters/colorsfilters/kis_multichannel_utils.cpp

https://invent.kde.org/graphics/krita/-/commit/28ba6500890c9d14994a14255cb67bbc3efbf8b1

Comment 2 Dmitry Kazakov 2024-12-12 13:11:14 UTC

Git commit c94a5e594ed9acc19438acd07bad2b3d97b2658c by Dmitry Kazakov.
Committed on 12/12/2024 at 13:11.
Pushed by dkazakov into branch 'krita/5.2'.

Fix backward compatibility of Per-Channel filter

In Krita 5.1.0 we added two additional "virtual" channels to the
per-channel filter ("Hue" and "Saturation"). And we added them **not**
to the end of the list, but **before** the "Lightness" channel, which
basically broke all the files created in Krita version before 5.1.0.

The patch manually remaps the channels depending on the number of channels
present in the configuration XML.

M  +68   -8    plugins/filters/colorsfilters/kis_multichannel_filter_base.cpp
M  +22   -0    plugins/filters/colorsfilters/kis_multichannel_utils.cpp

https://invent.kde.org/graphics/krita/-/commit/c94a5e594ed9acc19438acd07bad2b3d97b2658c

Comment 3 Dmitry Kazakov 2024-12-12 13:12:10 UTC

Hi, David!

Thank you very much for this report and sample files! The bug was really important and critical, so I fixed it with high priority! :)