Bug 242017 - Gwenview is unable to process PNG comments
Summary: Gwenview is unable to process PNG comments
Status: CONFIRMED
Alias: None
Product: gwenview
Classification: Applications
Component: general (other bugs)
Version First Reported In: 18.12.2
Platform: Fedora RPMs Linux
: NOR normal
Target Milestone: ---
Assignee: Gwenview Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-06-17 18:10 UTC by Christopher Yeleighton
Modified: 2025-09-04 14:39 UTC (History)
4 users (show)

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


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description Christopher Yeleighton 2010-06-17 18:10:20 UTC
Version:           2.3 (using KDE 4.3.5) 
OS:                Linux

Text comments embedded in PNG images by GIMP are invisible to Gwenview.  It cannot read them and it *silently* fails setting them.

Reproducible: Always

Steps to Reproduce:
1. Create an image with GIMP.
2. Tell GIMP to display the image information window.
3. Set the text comment to "Comment test".
4. Save the image as PNG preserving comments.
5. Open the file in Gwenview.

Actual Results:  
5. Gwenview displays the image but the Info box is empty.

Expected Results:  
5. Gwenview should display the PNG comment in the Info box.

OS: Linux (x86_64) release 2.6.31.12-0.2-desktop
Compiler: gcc
Comment 1 Andrew Crouthamel 2018-11-09 01:08:06 UTC
Dear Bug Submitter,

This bug has been stagnant for a long time. Could you help us out and re-test if the bug is valid in the latest version? I am setting the status to NEEDSINFO pending your response, please change the Status back to REPORTED when you respond.

Thank you for helping us make KDE software even better for everyone!
Comment 2 Andrew Crouthamel 2018-11-20 03:59:02 UTC
Dear Bug Submitter,

This is a reminder that this bug has been stagnant for a long time. Could you help us out and re-test if the bug is valid in the latest version? This bug will be moved back to REPORTED Status for manual review later, which may take a while. If you are able to, please lend us a hand.

Thank you for helping us make KDE software even better for everyone!
Comment 3 Dan Shelley 2019-03-30 23:52:52 UTC
Hello, I am able to reproduce this bug following the steps provided from your report!

I also used the gnu strings utility to verify the comment is saved with the PNG image.

> $ gwenview --version
> gwenview 18.12.2
Comment 4 paulr 2019-03-31 01:52:29 UTC
I also confirm this bug, or is it an unimplemented feature ?

kde plasma: 5.12.6
kde frameworks: 5.44.0
Qt version: 5.9.5
kernel: 4.15.0-46
OS: kubuntu 18.04
Comment 5 Justin Zobel 2020-11-29 23:41:59 UTC
Thanks for the reports. I am no good at GIMP so can you please provide:

1. An image with comments added
2. The command to verify those comments are visible (gnu strings command)

I've set the bug status to "needsinfo" pending your response, please change back to "reported" or "resolved" when you respond, thanks.
Comment 6 Christopher Yeleighton 2020-12-01 14:38:33 UTC
convert -comment 'Gwenview is unable to process PNG comments' canvas:black 242017.png
identify -format '%[comment]\n' 242017.png
Comment 7 Justin Zobel 2020-12-01 21:07:53 UTC
Thanks for the info, adjusting status for investigation.
Comment 8 Madhav Kanbur 2021-01-31 11:11:06 UTC
PNG stores metadata in "chunks" (key-value pairs) instead of EXIF. Gwenview uses the exiv2 library for extracting image metadata.

The problem now, is that there are two keys of interest when it comes to comments - 
1. Description
2. Comment

Read more about them here - http://www.vias.org/pngguide/chapter11_04.html

exiv2 deals only with the "Description" key and ignores the "Comment" key - https://github.com/Exiv2/exiv2/blob/68d65d0f0c41b0c4f9411354d5fa0d15641ac087/src/pngchunk_int.cpp#L384

It seems that most applications (GIMP, convert etc.) prefer using the "Comment" key.

Also, I tried compiling exiv2 from source after making changes on L387 and that fixed the problem. So either we add some png specific code to gwenview or raise an issue upstream.
Comment 9 A Linux User 2025-09-04 12:18:21 UTC
Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please check if this is still an issue with Gwenview 25.08.0 (the latest released version)?