(One UI) "Immersive" vs "Full screen" differences (and possibly a way to control this?)

[pressRtowin]

I'm not quite sure how this works, but certain apps trigger a "full screen" mode that is distinct from immersive mode. These apps are usually media apps or games, and this mode blocks gesture navigation from working if the nav/gesture/task bars are hidden, instead showing them the first time you attempt the gesture, and allowing the gesture to function as usual if you repeat it within the short window of time that the bottom bars are visible. This functions this way, even if the status bar is not hidden, and additionally, apps that do not have this property do not behave this way, even if both the status bar and nav bar are hidden. As such, this is distinct and unrelated to immersive mode (which also makes details about this nearly impossible to search for, since almost everyone conflates the two).

Interestingly, from what I can tell, this isn't a hard-coded property of the apps themselves, but rather a system-level status that apps can trigger at-will. For instance, Samsung Browser by default does not trigger this state, but if you navigate to YouTube and play a video (you may also need to put the video into full screen at least once, but you can leave full screen immediately after), the state will be triggered (and some time after the video is stopped, the state seems to be disabled, but this seems to take a bit of waiting). Also, Good Lock modules seem to have a way of changing the behavior of this as well. The Home Up module contains a toggle that allows bottom gestures (home/recents) to work in full screen apps, and the NavStar module has a setting to allow the back gesture to function as well.

What I'm wondering is if SystemUI Tuner might be able to control this state somehow. I'd love for it to be enabled in all apps, similarly to how I can force immersive mode to be enabled in most apps, mainly because it allows you to reliably pull up the taskbar while in immersive mode, without accidentally triggering a home or recents gesture.

[mirh]

That sounds a lot like BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE?
https://medium.com/swlh/modifying-system-ui-visibility-in-android-11-e66a4128898b

Though I guess after aosp-mirror/platform_frameworks_base@a9b8fa2 screwed the old tricks some kind of workaround might be needed.