hyprctl monitors -j rounds monitor scale to 2 decimals

[crmne]

Description

When a monitor is configured with a high-precision scale such as 1.33333, Hyprland appears to apply it, but hyprctl monitors -j reports the scale rounded to two decimals (1.33).

This makes the JSON IPC state lossy for tools that need to round-trip monitor configuration or validate whether the resulting logical resolution lands on whole pixels.

I originally opened this as issue #15150, but it was auto-closed with a request to open a discussion instead.

Reproduction

Configure a monitor with:

monitorv2 {
  output = desc:Microstep MPG321UR-QD
  mode = 3840x2160@143.99
  position = 0x0
  scale = 1.33333
}

Reload Hyprland, then run:

hyprctl monitors -j

Expected result

The monitor JSON reports the configured precision:

"scale": 1.33333

Actual result

The monitor JSON reports only two decimals:

"scale": 1.33

Why this matters

For a 3840x2160 monitor:

• 3840 / 1.33333 = 2880 logical px
• 2160 / 1.33333 = 1620 logical px

That is a sharp integer logical resolution.

If tools read back 1.33, they see:

• 3840 / 1.33 = 2887.22
• 2160 / 1.33 = 1624.06

That looks like a fractional/non-sharp resolution even though the configured value was sharp.

Version

Hyprland 0.55.2 built from branch v0.55.2 at commit 39d7e209c79d451efab1b21151d5938289da838d clean (version: bump to 0.55.2).
Date: Sat May 16 12:59:19 2026
Tag: v0.55.2, commits: 7319

Libraries:
Hyprgraphics: built against 0.5.1, system has 0.5.1
Hyprutils: built against 0.13.1, system has 0.13.1
Hyprcursor: built against 0.1.13, system has 0.1.13
Hyprlang: built against 0.6.8, system has 0.6.8
Aquamarine: built against 0.11.0, system has 0.11.0

Version ABI string: 39d7e209c79d451efab1b21151d5938289da838d_aq_0.11_hu_0.13_hg_0.5_hc_0.1_hlg_0.6
no flags were set

Notes

The generated config file contains scale = 1.33333, so this appears to be precision loss in the hyprctl monitors -j IPC output rather than in the config parser.

[frebib]

I see the same thing with 1.875

hl.monitor({
    output = "desc:...",
    mode = "3840x2160@240.0",
    position = "0x0",
    scale = 1.875,
    bitdepth = 10
})

$ hyprctl monitors -j | jq '.[0].scale'
1.88

[frebib]

#15628 fixes this