Bug 388253 - App icons affected by rendering bug in list views
Summary: App icons affected by rendering bug in list views
Status: RESOLVED DOWNSTREAM
Alias: None
Product: Discover
Classification: Applications
Component: discover (show other bugs)
Version: 5.11.4
Platform: Ubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: Aleix Pol
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-12-26 16:44 UTC by Nate Graham
Modified: 2018-04-05 08:48 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:


Attachments
Icon rendering bug, but only in list view (1.22 MB, video/webm)
2017-12-26 16:44 UTC, Nate Graham
Details
Gedit icon: rendering bug in list view (44.11 KB, image/png)
2017-12-26 16:46 UTC, Nate Graham
Details
Gedit icon: looks fine on the app page (for all backends, PackageKit and Flatpak) (37.93 KB, image/png)
2017-12-26 16:46 UTC, Nate Graham
Details
attachment-6008-0.html (1.52 KB, text/html)
2018-01-20 11:17 UTC, AS
Details
Apps from flatpak repos don't have issues with icons in list view (149.11 KB, image/png)
2018-01-22 09:19 UTC, AS
Details

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Description Nate Graham 2017-12-26 16:44:51 UTC
Created attachment 109532 [details]
Icon rendering bug, but only in list view

On my Kubuntu 17.10 machine, app icons are affected by a strange rendering bug-- but only on list views. It's like parts of them are scaled a bit. But on the Application pages, the icons look perfect. I've attached comparison screenshots and a screen recording that illustrate the issue for Gedit's icon; take a look at how the the pencil appears in the different views.
Comment 1 Nate Graham 2017-12-26 16:46:01 UTC
Created attachment 109533 [details]
Gedit icon: rendering bug in list view
Comment 2 Nate Graham 2017-12-26 16:46:53 UTC
Created attachment 109534 [details]
Gedit icon: looks fine on the app page (for all backends, PackageKit and Flatpak)
Comment 3 Nate Graham 2017-12-26 16:48:36 UTC
FWIW I'm using Kirigami from KDE Frameworks 5.40.0.
Comment 4 Nate Graham 2017-12-28 16:23:40 UTC
FWIW can't reproduce using Discover and Kirigami from git master in KDE Neon. But it is definitely visible using Discover 5.11.4 and Kirigami from KF 5.40 in Kubuntu 17.10.
Comment 5 Nate Graham 2018-01-02 17:12:54 UTC
Could be DPI-related? In KDE Neon, I don't see this with git master when running unscaled, but when I run Discover with QT_SCALE_FACTOR=1.4 (i.e. fractional scaling), the bug re-appears.
Comment 6 Aleix Pol 2018-01-02 17:43:10 UTC
Yes, it could very well be. Also I don't have any high dpi device to test. :(
Comment 7 Nate Graham 2018-01-02 17:49:14 UTC
Me neither, but you can simulate it with `QT_SCALE_FACTOR=1.4 plasma-discover`
Comment 8 Nate Graham 2018-01-07 00:22:58 UTC
Aleix, we've gotten another report in Bug 388633 that shows the same visual artifact in KInfoCenter with a HiDPI scale factor. I'm inclined to think that this is deeper down in the stack. Any ideas what framework might be responsible?
Comment 9 Aleix Pol 2018-01-19 21:13:12 UTC
Kirigami is responsible for rendering the icons.
That said, it also may be that the icons are too low-res. AppStream only offers resolutions up to 128²px.
I'll look deep into this issue soon when I get a new laptop with a high dpi screen.
Comment 10 AS 2018-01-20 11:17:20 UTC
Created attachment 110011 [details]
attachment-6008-0.html

> I'll look deep into this issue soon when I get a new laptop with a high
dpi
screen.

I'd point out that issue exists even for my 1366x720 resolution laptop on
Kubuntu 17.10. Icon size seems to not be the main culprit here.

On Jan 20, 2018 2:43 AM, "Aleix Pol" <bugzilla_noreply@kde.org> wrote:

https://bugs.kde.org/show_bug.cgi?id=388253

--- Comment #9 from Aleix Pol <aleixpol@kde.org> ---
Kirigami is responsible for rendering the icons.
That said, it also may be that the icons are too low-res. AppStream only
offers
resolutions up to 128²px.
I'll look deep into this issue soon when I get a new laptop with a high dpi
screen.

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You are receiving this mail because:
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Comment 11 Nate Graham 2018-01-20 15:14:40 UTC
Same here; I also have really blurry, pixellated icons in Kubuntu 17.10 even at a standard scale factor of 1. Doesn't reproduce in KDE Neon with a newer version of Discover, though.
Comment 12 Aleix Pol 2018-01-21 14:13:16 UTC
Yes, Ubuntu has historically had bad Appstream data. Let's not mix issues.
Comment 13 AS 2018-01-22 09:19:26 UTC
Created attachment 110042 [details]
Apps from flatpak repos don't have issues with icons in list view

In the pic Nautilus and Builder icons don't suffer from the rendering issue as they are available through flatpak.
Comment 14 AS 2018-01-22 09:23:33 UTC
When I made flatpak as my default source I found that apps available through flatpak has proper icons but those available only through Packagekit had the rendering issue.
Comment 15 Nate Graham 2018-02-06 23:27:31 UTC
I finally figured out the problem here.

What appears to be a "rendering bug" is actually just the odd method of scaling up small images that Qt uses. We see the same effect in all other places where images are scaled up:
KInfoCenter: https://bugs.kde.org/show_bug.cgi?id=388633
Folder View: https://bugs.kde.org/show_bug.cgi?id=376848

The reason why in my case the issue went away on the app page was that the app page showed the Flathub version (my default backend), and Flathub provides nice high-resolution icons.

It's up to packagers to provide nicer icons.