Bug 393995

Summary:	[GridDelegate] Previews are blurry
Product:	[Frameworks and Libraries] frameworks-kdeclarative	Reporter:	Harald Sitter <sitter>
Component:	general	Assignee:	Marco Martin <notmart>
Status:	RESOLVED FIXED
Severity:	normal	CC:	bugseforuns, filipfila.kde, kde, kde, kdelibs-bugs, nate, unassigned-bugs
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:	https://cgit.kde.org/kdeclarative.git/commit/?id=715ce3c20837d538d753ae37d144322fb4ed59af	Version Fixed In:	5.57
Sentry Crash Report:
Attachments:	smooth=false screenshot smooth=true screenshot Plasma 5.16 beta

Description Harald Sitter 2018-05-08 11:55:44 UTC

This recently improved a bit but icons continue to be very blurry.

Icon smoothing seems to severely blur the icon previews. I am attaching two screenshots. One with smoothing the other without, this should highlight the blur caused by the smoothing. It looks really bad.

Do we usually smooth icons? If so, are we requesting too large preview sizes to cause the smoothing?
I'd think that if we request 32x32 (e.g.) and get 32x32 smoothing wouldn't even kick in since we don't scale, so something must definitely be wrong there.

CCing kbroulik as he worked on this

Comment 1 Nate Graham 2018-05-08 17:14:20 UTC

Needz moar attachments

Comment 2 Harald Sitter 2018-05-14 09:04:34 UTC

Created attachment 112635 [details]
smooth=false screenshot

Comment 3 Harald Sitter 2018-05-14 09:04:48 UTC

Created attachment 112636 [details]
smooth=true screenshot

Comment 4 Harald Sitter 2018-05-14 09:05:03 UTC

I think I fell asleep while reporting this bug lol

Comment 5 Harald Sitter 2018-05-14 09:08:44 UTC

(screenshots are the other way around from what they are labeled as)

Comment 6 Patrick Silva 2018-10-16 17:16:39 UTC

Previews are still blury.

Operating System: Arch Linux 
KDE Plasma Version: 5.14.1
Qt Version: 5.11.2
KDE Frameworks Version: 5.51.0

Comment 7 Filip Fila 2019-03-04 21:36:38 UTC

Based on the research in https://phabricator.kde.org/D19467 it seems that all previews are blurry and that is a general issue with GridViewKCM.

Comment 8 Filip Fila 2019-03-04 21:47:04 UTC

FWIW and concerning the Icons KCM, the previews become sharp with view.implicitCellWidth = Kirigami.Units.gridUnit * 16

Proof: https://i.ibb.co/CzSs5xp/Screenshot-20190304-224455.png

Comment 9 David Edmundson 2019-03-04 22:10:53 UTC

Try this: https://phabricator.kde.org/D19530

Comment 10 Patrick Silva 2019-05-17 16:47:08 UTC

Created attachment 120140 [details]
Plasma 5.16 beta

Previews look blurry when I set 1.2 as scale factor on Plasma 5.16 beta.

Operating System: Arch Linux 
KDE Plasma Version: 5.15.90
KDE Frameworks Version: 5.58.0
Qt Version: 5.13.0 beta3

Comment 11 Nate Graham 2019-05-17 16:51:15 UTC

Since these are pixmaps, there is no way for them to not be blurry with fractional scaling, I'm afraid. It's just a fact of life with fractional scaling: you lose out on the ability for things to be "pixel-perfect".

Comment 12 Christoph Feck 2019-05-17 20:56:38 UTC

Nate, an application can create pixmaps with the same scale factor as the screen, and thus can of course be pixel-perfect. It has to be adapted, though.

Comment 13 Nate Graham 2019-05-17 21:02:23 UTC

But the pixmap's contents may not be able to scale cleanly without being blurry. My point was that something that's pixel-perfect at 1x or 2x may not be able to be pixel-perfect at 1.2x.

Comment 14 Christoph Feck 2019-05-30 19:51:45 UTC

The pixmaps are not pre-rendered images, but created on the fly from SVG graphics, so the contents can be made pixel-perfect according to the scaling ratio of the screen the pixmap is displayed on.

Anyway, does this need to be reopened, or is it actually already fixed?

Comment 15 Nate Graham 2019-05-30 20:07:38 UTC

This bug was tracking integer scaling blurriness which is now fixed, so it should remain closed. I can reproduce factional scale factor blurriness though. Since it seems that this should theoretically be fixable, please file a new bug for it. Thanks!