`minimum_resolution` tests failure due to script not considering scaling

[rene-oromtz]

Bug Description

I have a couple of desktop/workstation environments that are failing the minimum resolution tests. From the xrandr output I can see both attached devices are detected as 1920 x 1080 however, while running the tests, the resolution is halved as its scaled by 2.

Should scaling be considered while comparing the minimum resolution? Or is this a environment issue most likely with the emulator?

Cert-blocker Test Case

• cert-blocker

To Reproduce

Run com.canonical.certification::sru

Expected Result

Minimum resolution should pass

Actual Result

Resolution is detected by the script as 960 x 540

Environment

OS: plucky kernel 6.14.0-36-generic
Checkbox Version: 7.0.0dev26ubuntu25.04.1

Submissions:
https://certification.canonical.com/hardware/202008-28111/submission/456321/
https://certification.canonical.com/hardware/202102-28727/submission/456320/

Relevant log output

/tmp/nest-bi76qsfg.d0a260601df2f40e8929b34d387eb1b34ec5528812dccb31cc2977d5339eea3a/resolution_test.py:24: DeprecationWarning: Gdk.Screen.get_primary_monitor is deprecated
  geom = screen.get_monitor_geometry(screen.get_primary_monitor())
/tmp/nest-bi76qsfg.d0a260601df2f40e8929b34d387eb1b34ec5528812dccb31cc2977d5339eea3a/resolution_test.py:24: DeprecationWarning: Gdk.Screen.get_monitor_geometry is deprecated
  geom = screen.get_monitor_geometry(screen.get_primary_monitor())
Minimum acceptable display resolution: 800 x 600
Detected display resolution: 960 x 540

Additional context

Available monitors

xrandr --listmonitors
Monitors: 2
 0: +*HDMI-1 1920/700x1080/390+1920+0  HDMI-1
 1: +eDP-1 1920/340x1080/190+0+0  eDP-1

Manually modify check_resolution to also include scaling for verification:

check_resolution()
<python-input-4>:5: DeprecationWarning: Gdk.Screen.get_monitor_scale_factor is deprecated
Monitor 1:
  960 x 540, scale = 2
Monitor 2:
  1920 x 1080, scale = 1

[syncronize-issues-to-jira]

Thank you for reporting your feedback to us!

The internal ticket has been created: https://warthogs.atlassian.net/browse/CHECKBOX-2045.

This message was autogenerated

[rene-oromtz]

From Gdk.Monitor.get_geometry() seems that scaling should be taken in consideration:

Retrieves the size and position of an individual monitor within the display coordinate space. The returned geometry is in ”application pixels”, not in ”device pixels” (see gdk_monitor_get_scale_factor()).

I noticed that starting from Plucky, the geometry seems to be aware of the scaling, all this tests were made on same device 202102-28727:

Noble

Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=1920
monitor.get_geometry().height=1080

gi.__version__
'3.48.2'

Gdk.MAJOR_VERSION, Gdk.MINOR_VERSION, Gdk.MICRO_VERSION
(3, 24, 41)

Plucky

Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=960
monitor.get_geometry().height=540

gi.__version__
'3.50.0'

Gdk.MAJOR_VERSION, Gdk.MINOR_VERSION, Gdk.MICRO_VERSION
(3, 24, 49)

Questing

Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=960
monitor.get_geometry().height=540

gi.__version__
'3.50.0'

Gdk.MAJOR_VERSION, Gdk.MINOR_VERSION, Gdk.MICRO_VERSION
(3, 24, 50)

Maybe related to a change in Gdk between 3.24.41 and 3.24.49 versions?

[pieqq]

I investigated on my side, with a 4k monitor (3840×2160).

I used the following Python snippet:

import gi
gi.require_version("Gdk", "3.0")
from gi.repository import Gdk

display = Gdk.Display.get_default()

n_monitors = display.get_n_monitors()

for i in range(n_monitors):
    monitor = display.get_monitor(i)
    print(f"Monitor #{i+1}")
    print(f"{monitor.get_scale_factor()=}")
    print(f"{monitor.get_geometry().width=}")
    print(f"{monitor.get_geometry().height=}")

On Noble (24.04), using gi.version_info = (3, 48, 2), I get this:

# 24.04, Scaling 100% (default)
Monitor #1
monitor.get_scale_factor()=1
monitor.get_geometry().width=3840
monitor.get_geometry().height=2160

# 24.04, Scaling 200%
Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=3840
monitor.get_geometry().height=2160

# 24.04, (Fractional) Scaling 150%
Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=2560
monitor.get_geometry().height=1440

On Racoon (26.04, currently is development), using the latest live image with gi.version_info = (3, 50, 0), I get:

# 26.04, (Fractional) Scaling 150% (set by default)

Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=2560
monitor.get_geometry().height=1440

# 26.04, Scaling 200%

Monitor #1
monitor.get_scale_factor()=2
monitor.get_geometry().width=1920
monitor.get_geometry().height=1080

So there are at least two issues:

1. on 24.04, the geometry always shows the "device pixels", regardless of the scale, while on 26.04 (and the previous versions, as outlined by @rene-oromtz), it shows the "application pixels".
2. get_scale_factor() returns an int, so it's not accurate when using fractional scaling, which is applied by default on 25.10+ for high density screens apparently...

[pieqq]

I've filed https://gitlab.gnome.org/GNOME/gtk/-/issues/7852 upstream.