How does Oppoa33 keep the screen brightness on and off without turning off the screen?

The operation method of setting screen brightness for oppoa33 mobile phone is as follows:

The first kind:

1. First, open "Settings" of oppoa33 mobile phone;

2. Secondly, click "Show";

3. Then click "Brightness";

4. Finally, adjust the screen brightness.

The second type:

Pull down the phone screen, find the brightness level bar in the drop-down menu bar, and adjust it.