Allow forcing of night mode or night color temperature

[cshong87]

OS: Ubuntu MATE 20.04 LTS.

I prefer my screen color temperature to be warmer for my comfort, regardless of day or night.

In Microsoft Windows 10, there is a setting that allow me to force turning on of night light. I can turn on night light without schedule. And, I can manually adjust the temperature for my comfort.

However, this feature does not exist in Redshift for Linux. In Redshift for Linux, there is no GUI setting for me to force warmer screen color temperature or force night mode. There is also no GUI setting for me to manually adjust the screen color temperature.

Please add the following features to Redshift:

1. Allow forcing of night mode or night color temperature, even in day time.
2. Add GUI to allow me to change the color temperature, just like what you see in Windows's night light setting. In case if I force night color temperature, there should be a slider like UI control for me to adjust the color temperature. If I allow redshift to automatic adjust temperature based on day/night time, there should be two slider like UI controls, one for day time, another one for night time.

[Bachsau]

Maybe just add a "static" provider meaning "always on". I currently do this by setting a polar latitude. You just have to change it twice a year, which sucks a bit.

[aaronfc]

Probably not what you want but I also wanted to have it "always on" and I did it by creating this config file (old config path but because I am using an old version, should work also in the new one as there's a fallback):

$ cat ~/.config/redshift.conf
[redshift]
temp-day=3700
temp-night=3700