This isn't possible - Android's APIs only allow painting on top of the screen, not modifying what's already there. This is why all the non-root solutions are just a red overlay.
Re:Night Shift compared to f.lux
by NoGravitas on Wednesday March 29, 2017 @08:44AM
(#13985506)
Unfortunately, I'm pretty sure it can't be done without root. With root, you have a couple of good options.
The built-in LiveDisplay feature in LineageOS can do this without root.
Sorry, I forgot to specify stock Android as well.
Re:Night Shift compared to f.lux
by laxentasken on Wednesday March 29, 2017 @03:41AM
(#13984182)
I guess twilight is out of the question? Outstanding app imo.
Re:Night Shift compared to f.lux
by EpicBlackCrayon on Wednesday March 29, 2017 @03:38AM
(#13984171)
Twilight?
It doesn't pass #2 - the black areas of the screen are visibly red.
Every application that I've tried so far does this, which leads me to believe that it is an inherent limitation in stock Android APIs (which also explains why apps that require root can work around that limitation).
1. Doesn't require root.
2. Actually filters blue out, instead of adding red (i.e. a pure black screen should remain pure black).
The built-in feature in Nougat previews was great, until they removed it...