Shell panel font is blurry under wayland

Bug #1714459 reported by Didier Roche on 2017-09-01
10
This bug affects 2 people
Affects Status Importance Assigned to Milestone
GNOME Shell
Unknown
Unknown
gnome-shell (Ubuntu)
Undecided
Unassigned

Bug Description

gnome-shell doesn't respect hinting and subpixel order under Wayland. Note that the Xorg session has the fix for this.

Check the referenced bug for screenshots and comparing with the gtk renderer of decoration in the wired bugzilla bug.

More context on the IRC discussion at https://irclogs.ubuntu.com/2017/09/01/%23ubuntu-desktop.html#t09:01

tags: added: artful gnome-17.10 visual-quality
Daniel van Vugt (vanvugt) wrote :

Screenshot (Wayland on top and Xorg below)

Daniel van Vugt (vanvugt) wrote :

It appears neither X nor Wayland can figure out my monitor's subpixel order:

$ xrandr --verbose | grep Subpixel
 Subpixel: unknown
 Subpixel: unknown
 Subpixel: unknown
 Subpixel: unknown
 Subpixel: unknown

$ weston-info | grep subpixel
 subpixel_orientation: unknown, output_transform: normal,

Yet Xorg is using subpixel rendering showing in the screenshot of comment #1. Sounds like someone is just guessing HRGB when run on Xorg, and refusing to guess when run on Wayland (hence using the safe default of greyscale which appears more blurry).

Daniel van Vugt (vanvugt) wrote :

I think the bigger issue around blurriness is that the font colour used in the top bar changes as the cursor enters/leaves. So the top bar's text is always too dim or too bright compared to window titles.

Daniel van Vugt (vanvugt) wrote :

Screenshot of too bright

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in gnome-shell (Ubuntu):
status: New → Confirmed
Daniel van Vugt (vanvugt) wrote :

And here is some X11 code guessing the subpixel order. COGL has it hard-coded on line 329:
  https://git.gnome.org/browse/mutter/tree/cogl/cogl/cogl-xlib-renderer.c#n306

So it looks like a mistake that it works at all on X11. Although I might be looking at the wrong code...

Daniel van Vugt (vanvugt) wrote :

BTW, the default settings used by apps/toolkits are here:

org.gnome.settings-daemon.plugins.xsettings rgba-order 'rgb'
org.gnome.settings-daemon.plugins.xsettings antialiasing 'rgba'
org.gnome.settings-daemon.plugins.xsettings hinting 'slight'

Daniel van Vugt (vanvugt) wrote :

Also, the vertical blurring seen in the panel on Wayland suggests it is defaulting to hinting=none. We would like hinting=slight to be slightly sharper and consistent with the Ubuntu defaults.

Didier Roche (didrocks) on 2017-09-20
tags: added: rls-aa-incoming-bug
tags: added: rls-aa-incoming
removed: rls-aa-incoming-bug
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