Bug 396041

Summary: Wrong rendering tab icons
Product: [Plasma] plasmashell Reporter: varlesh <varlesh>
Component: Application Launcher (Kickoff) widgetAssignee: David Edmundson <kde>
Status: RESOLVED UPSTREAM    
Severity: normal CC: justin.zobel, nate, plasma-bugs-null
Priority: NOR    
Version First Reported In: 5.13.2   
Target Milestone: 1.0   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Tab icons + original icons
3 tabs (1 & 3 icons have wrong rendering)

Description varlesh 2018-07-01 07:52:59 UTC
Created attachment 113667 [details]
Tab icons + original icons

Tab icons  1, 3 and 5 (left to right) -  have wrong rendering.
If change icons order position - anyway 1, 3 and 5 icons have wrong rendering.
Possible for  this tabs used wrong area icon size. Icons have 32px.
Bug reproduced on Breeze Plasma Theme and other themes too.
Comment 1 varlesh 2018-07-01 08:00:35 UTC
If set 3 tabs on settings - anyway 1 and 3 tabs icons have wrong rendering.
Comment 2 varlesh 2018-07-01 08:01:52 UTC
Created attachment 113668 [details]
3 tabs (1 & 3 icons have wrong rendering)
Comment 3 David Edmundson 2018-07-01 08:49:11 UTC
What is wrong with the rendering?
Comment 4 varlesh 2018-07-01 08:52:21 UTC
1, 3 and 5 tab icons blurred and used wrong size. See attached files and compare with original icons
Comment 5 varlesh 2018-07-01 09:17:49 UTC
For example, first attached file, icon Computer:
- on first line it's third icon blurred and not use pixel align
- on second line it's second icon and looking good (as original)
Comment 6 Christoph Feck 2018-07-31 02:29:51 UTC
Caused by floating-point layout calculations in QtQuick. Not sure if rounding to full pixels is possible.
Comment 7 Justin Zobel 2020-11-30 01:20:03 UTC
(In reply to Christoph Feck from comment #6)
> Caused by floating-point layout calculations in QtQuick. Not sure if
> rounding to full pixels is possible.

Is this possible in newer Qt versions?
Comment 8 Nate Graham 2020-11-30 02:51:14 UTC
No, blurry icons at fractional scale with Qt scaling is still an issue in Qt, and it's not really easily solvable, if at all. See the extended conversation at https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/130#note_132515.

It's possible that Qt could do some magic here to re-render icons to make them conform to the pixel grid better, but that's a real moonshot. Only a higher resolution screen will make this better, in general. That's been the approach of Apple and the smartphone companies: throw more pixels at the problem so that pixel mis-alignments become invisible.