Bug 465851 - Images look slightly blurry with zoom level < 100%
Summary: Images look slightly blurry with zoom level < 100%
Status: ASSIGNED
Alias: None
Product: gwenview
Classification: Applications
Component: general (show other bugs)
Version: 20.08.2
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Gwenview Bugs
URL:
Keywords:
: 501351 (view as bug list)
Depends on:
Blocks:
 
Reported: 2023-02-16 16:40 UTC by Jan Rathmann
Modified: 2025-03-26 17:39 UTC (History)
1 user (show)

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


Attachments
Patch to make Gwenview render images more sharply (1.07 KB, patch)
2023-02-16 16:40 UTC, Jan Rathmann
Details
Example of blurry rendering in Gwenview, view at 100% (3.43 MB, image/png)
2023-02-16 16:41 UTC, Jan Rathmann
Details
Example of sharper rendering in Firefox, view at 100% (3.74 MB, image/png)
2023-02-16 16:42 UTC, Jan Rathmann
Details
Example of sharper rendering in patched Gwenview, view at 100% (3.71 MB, image/png)
2023-02-16 16:42 UTC, Jan Rathmann
Details

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Description Jan Rathmann 2023-02-16 16:40:18 UTC
Created attachment 156309 [details]
Patch to make Gwenview render images more sharply

SUMMARY
Some images (photos) look slightly blurry when they are displayed with a zoom level < 100% (this is the default if I simply open an image file that has a higher resolution than my screen).

STEPS TO REPRODUCE
1. Open a photo in Gwenview with small, fine-grained details.

OBSERVED RESULT
Photo looks slightly blurry.
(see attached screenshot, view at 100%)

EXPECTED RESULT
Photo looks "sharp".
(see attached screenshot of the same image displayed by Firefox, view at 100%)

ADDITIONAL INFORMATION
I discovered this problem by developing RAW files in darktable, wondering why the image looks sharp in darktable but a bit blurry in Gwenview.
I compared the rendering of Gwenview with:
* Firefox
* digiKam
* Eye of Gnome
On all of them it looks "good/sharp".

I get a sharp rendering in Gwenview by replacing Qt::SmoothTransformation with Qt::FastTransformation in one function, see attached patch.
Comment 1 Jan Rathmann 2023-02-16 16:41:31 UTC
Created attachment 156310 [details]
Example of blurry rendering in Gwenview, view at 100%
Comment 2 Jan Rathmann 2023-02-16 16:42:09 UTC
Created attachment 156311 [details]
Example of sharper rendering in Firefox, view at 100%
Comment 3 Jan Rathmann 2023-02-16 16:42:54 UTC
Created attachment 156312 [details]
Example of sharper rendering in patched Gwenview, view at 100%
Comment 4 Bug Janitor Service 2023-10-24 18:07:06 UTC
A possibly relevant merge request was started @ https://invent.kde.org/graphics/gwenview/-/merge_requests/229
Comment 5 John Kizer 2025-03-26 17:39:47 UTC
*** Bug 501351 has been marked as a duplicate of this bug. ***