Slider sets itself off

[pflanzenandi]

The slider moves to the left by itself since v. 17.0. The dimming of the screen light is not affected by this.

• OS:Ubuntu 20.04
• GNOME Version: 3.36.3

[kiyui]

@pflanzenandi I have actually noticed that it may shift a bit to either direction when logging into GNOME and directly previewing the aggregate menu. Is this what you mean or are there other ways to reproduce it?

[pflanzenandi]

I cannot reproduce it exactly. But the slider always moves to the off position aka to the left on itself.
On an entire working day, I might look at this menu once an hour. And each time the slider has moved to the left (off).

In principle, this is only a cosmetic (annoying) bug, because the Night Light value is not changed by it.

I also connect my laptop via HDMI to an external monitor. Maybe this is the trigger.

[kiyui]

Mm thanks, I'll try to observe this and figure out what causes it 😅

[julienfalque]

I have a similar issue but for me the slider is moved to the right instead of left (maybe because I enabled "Swap slider axis"). It seems to happen everytime I reboot or wake from suspend.

[pflanzenandi]

@kiyui

I think the bug only occurs, if the slider is fully extended to the right.

[kiyui]

@pflanzenandi by fully extended to the right you mean that the night light is effectively disabled right? That might be an indicator, though I've added some logs so I can actually confirm it locally.

Compared to the previous release, v15, the slider now listens to changes from D-Bus so that even if the settings in GNOME Control Centre are changed, it should reflect on the slider.

Perhaps this shift is due to how GNOME tweens the night light over time, and the "Permanent night light" span of ∓6 hours may be too much. Another thing I can think of perhaps how I'm calculating the slider percentage, const percent = (this._proxy.Temperature - minimum) / (maximum - minimum) plus the mix of uint32 and double types 🤔

[kiyui]

The cause is actually quite simple and I did note it before:

The following is a representation of how the "Temperature" value updates over time when the slider is moved where,

• The first x is the initial D-Bus value
• The second x is the first value the proxy reports
• The third x is the final value the proxy reports

The unmarked head and tail span of the line is the actual system GSettings value

The only real fix for this would be to either,

• Note the final "resting" temperature (time-sensitive & hacky, probably needs RxJS 🤪)
• Ignore minor changes in temperature

I'm gonna note this as not really a bug™, but am open to suggestions or fixes