[APP] Galactic Night: nightmode for rooted Galaxy-series devices
Edited: Now in Google Play
, now in the 0.99rc2 version, provides red, green or sepia (or blue if you really want!) night modes for rooted OLED Galaxy S2, S3 and Note devices (not tested on Galaxy 7.7 but might work). You can invert the screen colors (so you can browse in white on black, or green on black, or red on black). There is also an Outdoor mode which washes out the colors but might improve legibility outdoors.
I like reading ebooks in green on black when in the dark.
As of my present knowledge, various pre-release versions of this have been tested on:
Galaxy S2: Gingerbread and ICS
Galaxy S3: ICS
Galaxy Note: JB
It should work on ICS on the Note as well, but I don't have any reports. GN works by adjusting the mDNIe profile. If you have some Samsung device I haven't heard of which has a Screen Mode setting in the Display settings that includes Dynamic/Normal/Movie options (and maybe others), there is a chance that this will work for you.
My benchmarking has not shown any statistically significant impact on graphics rendering speed.
Use at your own risk. If a mode screws up the screen display, you should be able to get back to normal by pressing "Standard" or rebooting, but I offer no guarantees.
Several users have asked for customizable settings. These could easily be provided, and could adjust for screen color tint and so on, but I haven't implemented them yet. I might in fact leave those for a Pro version.
You might be curious how the nightmode differs from that in ChainFire3D. ChainFire3D's nightmode works by dropping channels. E.g., in red mode, it simply drops the green and blue channels. This means that things on screen that were in pure green or pure blue get changed to black. Galactic Night uses a different color adjustment which is equivalent to this algorithm: first convert the RGB color on the screen to a luminosity, and then use the luminosity to set the night mode color. Thus, in red mode, pure white will go to maximum brightness red, but red, green and blue will go to different shades of red. This preserves a lot of the legibility.
There is also an odd "No blue" mode which converts RGB images to RG images, so white goes to yellow, blue goes to a dark yellow, etc. I've heard that blue light makes it harder to fall asleep, so it might help with falling asleep if you switch your phone to "No blue" mode for an hour before going to bed, if you can tolerate how ugly it looks.
Here is a photo of GN in action. It is not possible to take a screenshot of it in action, because the color changing is done between framebuffer and display, so the framebuffer that the screenshot accesses will not reflect the color changes.
I've already posted about this in a few device-specific forums, but now it's ready for wider dissemination.