Android 8.0 Oreo brought along light/dark theme shift dependent on your wallpaper's hues, but only for Google's new Pixel
phones, while each and every device with OLED display could benefit from a true Dark Mode in its own right.
You see, unlike LCDs, where the backlight shines with the same intensity no mater what color is displayed, the OLED display pixels are themselves the source of light, and when displaying white, in particular, they are lit with maximum current. Thus, OLEDs surpass LCDs in battery draw when displaying darker or more colorful imagery like movies, for example, but take the back seat on predominantly white backgrounds - while browsing, for instance.
Asked to embed such a Dark Mode for all, and way back in November, Google's Android Open Source Project (AOSP) moderators are responding today that "our engineering team has added this feature. It will be available in a future Android release
." Now, what's an imminent major Android update coming down the pipe? Why, 9.0 Pie, or whatever Google calls the P version.
Long story short, we now have some tangential evidence that one of the new features in Android P will be a Dark Mode native to your phone's settings which may allow those of us with OLED displays to squeeze some extra juice out of their battery.