Bug 476556 - Images vignettes are very low quality with PNG files
Summary: Images vignettes are very low quality with PNG files
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Thumbs-Engine (show other bugs)
Version: 8.1.0
Platform: Appimage Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-11-04 18:01 UTC by philippe.quaglia
Modified: 2023-11-05 09:25 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In: 8.2.0
Sentry Crash Report:


Attachments
See exemple on the capture attached, with Tiff and PNG vignette, while original images are similar (100.58 KB, image/png)
2023-11-04 18:01 UTC, philippe.quaglia
Details

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Description philippe.quaglia 2023-11-04 18:01:02 UTC
Created attachment 162864 [details]
See exemple on the capture attached, with Tiff and PNG vignette, while original images are similar

SUMMARY
***
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***


STEPS TO REPRODUCE
1. Convert a high quality Tiff file to PNG using the batch conversion tool
2. Tiff and PNG images are visually similars
3. PNG vignettes are of very low quality, while TIFF vignettes are ok
4. Refreching the vignettes (F5) does not change anything

OBSERVED RESULT
2. Tiff and PNG images are visually similars
3. PNG vignettes are of very low quality, while TIFF vignettes are ok

EXPECTED RESULT
Tiff and PNG images of similar good quality

SOFTWARE/OS VERSIONS
Ubuntu 23.10

ADDITIONAL INFORMATION
Comment 1 Maik Qualmann 2023-11-04 20:49:08 UTC
The problem is fixed in digiKam-8.2.0, I'm looking for the corresponding bug entry.

Maik
Comment 2 Maik Qualmann 2023-11-04 20:53:34 UTC
Fixed with Bug 472253.

The issue only affects the low quality embedded preview image. If you set the preview to load to a full image, you'll at least see a decent image. However, the thumbnail is still affected.

Maik
Comment 3 Maik Qualmann 2023-11-04 20:55:20 UTC
The digiKam-8.2.0 AppImage from https://files.kde.org/digikam/ fixes the problem for newly created images.

Maik
Comment 4 philippe.quaglia 2023-11-05 09:15:38 UTC
Thanks, I have downloaded release 8.2.0. However, is there a mean to "recreate" the thumbnails ? I tried with F5, but it does not change, the thumbnail is still bad.
Comment 5 Maik Qualmann 2023-11-05 09:25:27 UTC
No, the embedded thumbnail is broken with digiKam-8.1.0 converted images.  You have to convert the PNG images again.

Maik