The iPhone has a hidden universal access feature called smart color inversion. Can say
However with a new tweak AutoInvert You can simplify your life and set up automatic activation of smart inversions depending on the brightness level of your display.
The tweak developer recommends using it together with auto brightness, because then the display will adapt itself to the lighting.
When you install the AutoInvert tweak, a panel with its options will appear in the Settings. There is practically nothing to choose here. Moreover, respring is not necessary for applying the changes.
In the case, as in the screenshot, the smart inversion will beautomatically turn on when the brightness level drops below 50%. Most often this happens in the dark and in dimly lit rooms. Thanks to smart inversion and a dark display, you reduce the strain on your eyes. When the lighting is sufficient, you will again see the display in normal colors.
If you want to install a tweak, you can download it from the Packix repository. It works on all devices with jailbreak iOS 11 and 12.