Bug 491795 - KImageformats doesn't display some XCF files created with Gimp 3
Summary: KImageformats doesn't display some XCF files created with Gimp 3
Status: CONFIRMED
Alias: None
Product: frameworks-kimageformats
Classification: Frameworks and Libraries
Component: general (other bugs)
Version First Reported In: 6.5.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Alex Merry
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-08-16 16:50 UTC by maderios
Modified: 2025-07-30 08:20 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


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Description maderios 2024-08-16 16:50:30 UTC
STEPS TO REPRODUCE
1. Open a tif file in Gimp git version, use it as background layer
2. Add other tif file as layer on the top of background layer
3. Right click on layer -> trans parency -> color to alpha
4. Save file as .xcf
5. Open this file in Digikam git 

OBSERVED RESULT
File and/or thumbail are not displayed
See attachment example image
When I convert this file to .psd then to .xcf, Kimageformats can display it

SOFTWARE/OS VERSIONS
Arch Linux
Qt 6.7.2
KF6 6.5
Gimp 2.99  fd3d547338 commit
Comment 2 Albert Astals Cid 2024-08-19 22:33:13 UTC
Mirco is this something that you could have a look?
Comment 3 Mirco Miranda 2024-08-23 09:46:47 UTC
The plugin supports up to version 12 of the XCF format. We are now at 20 or 21 in GIMP 2.99 and they will continue to add features until the official release.

Looking at it now doesn't make much sense.

I just tried to remove the rejection based on the version number and the image loads although the result is different than in GIMP 2.99 (which is a good sign).
Comment 4 maderios 2024-08-23 09:54:14 UTC
(In reply to Mirco Miranda from comment #3)
> The plugin supports up to version 12 of the XCF format. We are now at 20 or
> 21 in GIMP 2.99 and they will continue to add features until the official
> release.
Official Gimp 3.0 release is very near now, they don't add features:  
GIMP 3.0 Enters String Freeze   
https://x.com/GIMP_Official/status/1825949792821981472

> 
> Looking at it now doesn't make much sense.
> 
> I just tried to remove the rejection based on the version number and the
> image loads although the result is different than in GIMP 2.99 (which is a
> good sign).
Comment 5 maderios 2025-03-15 20:01:56 UTC
Fresh news
core: Add version 23 to XCF switch statement
https://gitlab.gnome.org/GNOME/gimp/-/commit/206273c6b5da01d42c816056afacf98b29c97e00
Comment 6 maderios 2025-07-15 20:08:40 UTC
I found out why some XCF files/images created with Gimp 3  and later are not displayed in Digikam/KImage formats. Two causes.
1)  Gimp V3 introduced "non destructive editing"    
This "non destructive editing" is not supported by KImageformats: if I uncheck "fx" (see Ofnuts explanations in forum link below)  next the layer for images affected with issue, images are displayed normally, but i loose filter effect :(
https://www.gimp-forum.net/Thread-Non-destructive-editing-in-Gimp3
https://www.gimp.org/news/2025/06/23/gimp-3-1-2-released/#non-destructive-editing
2)  KImageformat can't handle "better compression" (zlib compression, i think) available in saving options.
Comment 7 maderios 2025-07-17 12:36:13 UTC
I found another reason why KImageformats can't display some Gimp 3 XCF files inside Digikam
1) open tif file with Gimp 3. This file is displayed normally by Kimageformats inside Digikam
2) convert it to XCF format with Gimp 3
3) This file is no more displayed by Kimageformats
Comment 8 maderios 2025-07-17 12:38:37 UTC
(In reply to maderios from comment #7)
> I found another reason why KImageformats can't display some Gimp 3 XCF files
> inside Digikam
> 1) open tif file with Gimp 3. This file is displayed normally by
> Kimageformats inside Digikam
> 2) convert it to XCF format with Gimp 3
> 3) This file is no more displayed by Kimageformats

To know: this issue doesn't happen with png and jpeg files
Comment 9 Mirco Miranda 2025-07-19 08:59:27 UTC
The current implementation of the plugin supports XCF files up to version 12 (GIMP 2.10 without zlib compression support).

The plugin rejects all XCF files with versions greater than 12.
Comment 10 maderios 2025-07-30 08:20:23 UTC
(In reply to maderios from comment #1)
> Image link here
> https://www.dropbox.com/scl/fi/lm0xxqbofilvu65wvh6bp/jun16-3-color2alpha.
> xcf?rlkey=mw7blqojtw2zor1hfkc9ewgds&st=cq9dtojo&dl=0

New link   now   https://www.dropbox.com/scl/fi/lbflec0bnusogjwcbth4o/jun16-3-color2alpha-bug-fx.xcf?rlkey=m6a9ehc9py2f1wxtnbik9cfwn&st=wg7ueri0&dl=0