Bug 390488

Summary: Icons and preview of some files (pdf, png and jpg, for example) look fuzzy in info panel when fractional display scaling is used
Product: [Applications] dolphin Reporter: Patrick Silva <bugseforuns>
Component: panels: informationAssignee: Dolphin Bug Assignee <dolphin-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: meven29, nate, postix
Priority: NOR Keywords: usability
Version: 23.04.1   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In: 18.04.0
Sentry Crash Report:
Attachments: screenshot
fuzzy picture preview in dolphin 18.04 beta

Description Patrick Silva 2018-02-15 03:11:05 UTC
My display scale is 1.2 under X11.
See screenshot taken on Arch Linux, dolphin 17.12.2.
Comment 1 Patrick Silva 2018-02-15 03:11:48 UTC
Created attachment 110678 [details]
screenshot
Comment 2 Kai Uwe Broulik 2018-02-15 12:37:35 UTC
Git commit ae67f991951e826ab6d0a6cb6e1123cf6ee35ca5 by Kai Uwe Broulik.
Committed on 15/02/2018 at 12:37.
Pushed by broulik into branch 'master'.

[Information Panel] Adjust painting icons for high dpi scaling

Instead of creating our own KIconLoader (which takes ~5ms here) just use QIcon::fromTheme which already does everything right.

Differential Revision: https://phabricator.kde.org/D10532

M  +9    -14   src/panels/information/informationpanelcontent.cpp

https://commits.kde.org/dolphin/ae67f991951e826ab6d0a6cb6e1123cf6ee35ca5
Comment 3 Nate Graham 2018-02-19 18:00:42 UTC
*** Bug 390606 has been marked as a duplicate of this bug. ***
Comment 4 Nate Graham 2018-03-24 19:46:10 UTC
*** Bug 390606 has been marked as a duplicate of this bug. ***
Comment 5 Patrick Silva 2018-03-24 21:14:46 UTC
Created attachment 111618 [details]
fuzzy picture preview in dolphin 18.04 beta

I'm testing Dolphin 18.04 on Arch Linux, now icons in info panel look OK.
However, as you can see in my screenshot, picture preview is still fuzzy.
Comment 6 Nate Graham 2018-03-25 22:18:46 UTC
Can confirm. They actually look worse in HiDPI mode, as expected for small pixmaps that are being upscaled.

The fix is most likely somewhere in Dolphin's informationPanelContent.cpp. Probably the pixmaps need to be adjusted to take the device pixel ratio into account rather than using raw pixel sizes. Perhaps it's the line that does this:

m_previewJob->setScaleType(KIO::PreviewJob::Unscaled);
Comment 7 Nate Graham 2018-09-08 21:43:33 UTC
Dr. Chapatin, does this also look bad at 2x, or only for 1.2x?
Comment 8 Patrick Silva 2018-09-08 22:07:34 UTC
icon of ISO file, for example, looks bad with 1.2x scale (like you can see in the screenshot posted in comment 1) and looks good with 2x scale.
Picture preview looks bad no matter if scale is 1.2x or 2x.
Comment 9 Patrick Silva 2019-03-24 14:19:01 UTC
preview of pdf files also looks fuzzy.

Operating System: Arch Linux 
KDE Plasma Version: 5.15.3
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2
Comment 10 Nate Graham 2020-05-04 19:17:33 UTC
*** Bug 408455 has been marked as a duplicate of this bug. ***
Comment 11 Méven Car 2021-04-19 08:49:08 UTC
https://invent.kde.org/system/dolphin/-/merge_requests/147 should fix this.
Comment 12 Patrick Silva 2024-02-03 15:15:38 UTC
Cannot reproduce on Plasma 6 RC2. \o/

Operating System: Arch Linux 
KDE Plasma Version: 5.93.0
KDE Frameworks Version: 5.249.0
Qt Version: 6.7.0
Graphics Platform: X11