Bug 1954171

Summary: cairo subpixel positioning causes somewhat blurry mono fonts
Product: [Fedora] Fedora Reporter: Julian Sikorski <belegdol>
Component: cairoAssignee: Benjamin Otte <otte>
Status: CLOSED WORKSFORME QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 35CC: ajax, caillon+fedoraproject, chkr, gnome-sig, lxtnow, mailinglists, mavit, mcatanza, mclasen, otte, rhughes, rstrode, sandmann, tagoh
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Last Closed: 2022-11-30 16:10:15 UTC Type: Bug
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Description Flags
screenshot of blurry keepass UI
none
blurry F35 screenshot
none
sharp F33 screenshot
none
gnome-chess screenshot
none
OK F37 screenshot none

Description Julian Sikorski 2021-04-27 17:58:06 UTC
Description of problem:
After upgrading to Fedora 34 keepass UI became blurry. This happens on both my machines, one running nvidia and X.org and another running amd and Wayland. Fedora 33 was working fine.

Version-Release number of selected component (if applicable):
mono-core-6.12.0-4.fc34.x86_64
keepass-2.47-2.fc34.x86_64

How reproducible:
always

Steps to Reproduce:
1. Install Fedora 34
2. Install keepass
3. Start keepass

Actual results:
UI fonts are blurry

Expected results:
UI fonts are sharp

Comment 1 Julian Sikorski 2021-04-27 18:01:51 UTC
Created attachment 1776129 [details]
screenshot of blurry keepass UI

Comment 2 Julian Sikorski 2021-07-14 14:09:12 UTC
Someone at github suggested this might be due to fontconfig changes. @tagoh, have there been any between F33 and F34 which might have caused this?

Comment 3 Julian Sikorski 2021-11-13 09:59:41 UTC
Created attachment 1841532 [details]
blurry F35 screenshot

Comment 4 Julian Sikorski 2021-11-13 10:00:07 UTC
Created attachment 1841533 [details]
sharp F33 screenshot

Comment 5 Julian Sikorski 2021-11-13 10:03:54 UTC
I tried disabling harfbuzz in freetype but it did not help.

Comment 6 Julian Sikorski 2021-11-14 10:18:52 UTC
It turns out this is caused by cairo. Rebuilding 1.16.0-9 and downgrading to it restores the sharp fonts.

Comment 7 Michael Catanzaro 2021-11-14 14:29:37 UTC
Hi Matthias, can you please advise Mono developers how to handle changes in cairo? Thanks.

Comment 8 Julian Sikorski 2021-11-14 15:57:26 UTC
Git bisect indicates that upstream cairo commit e4a79db0108be6a2b06dfce51a44bcbdead66ebd is the first one causing blurry fonts. The vertical position of the text shifts a bit a few commits later, but the blurriness stays unchanged.

Comment 9 Julian Sikorski 2021-11-19 18:13:31 UTC
Created attachment 1842762 [details]
gnome-chess screenshot

I tried gnome-chess (gtk4 app) and it is also somewhat blurry. Is this blurriness the intended outcome?

Comment 10 Ben Cotton 2022-11-29 16:55:57 UTC
This message is a reminder that Fedora Linux 35 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 35 on 2022-12-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '35'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change the 'version' 
to a later Fedora Linux version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora Linux 35 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora Linux, you are encouraged to change the 'version' to a later version
prior to this bug being closed.

Comment 11 Julian Sikorski 2022-11-30 16:10:05 UTC
Created attachment 1928831 [details]
OK F37 screenshot

On Fedora 37 the buttons are bigger and the blurriness is better. Maybe because I got used to it, or maybe because I work with higher DPI screens these days. In any case, it is good enough.

Comment 12 Michael Catanzaro 2022-11-30 16:13:20 UTC
I just turned it off, that's why it seems better. See bug #1943794.

Comment 13 Julian Sikorski 2022-11-30 16:19:49 UTC
(In reply to Michael Catanzaro from comment #12)
> I just turned it off, that's why it seems better. See bug #1943794.

Is a gtk4 change supposed affect how fonts are rendered in mono apps?

Comment 14 Michael Catanzaro 2022-11-30 17:15:52 UTC
Oh no, of course not. Sorry, my comment was off base.

Maybe something else changed in cairo....

Comment 15 Red Hat Bugzilla 2023-09-18 00:26:09 UTC
The needinfo request[s] on this closed bug have been removed as they have been unresolved for 120 days