AOD provides an alternatative 'screen-off' experience. Instead, of completely turning the display off, it provides a distraction-free, glanceable experience for the phone in a low-powered mode. In this low-powered mode, the display will have a lower refresh rate and the UI should frequently shift its displayed contents in order to prevent burn-in.
Always-on Display (AOD) provides an alternative 'screen-off' experience. Instead, of completely turning the display off, it provides a distraction-free, glanceable experience for the phone in a low-powered mode. In this low-powered mode, the display will have a lower refresh rate and the UI should frequently shift its displayed contents in order to prevent burn-in. The recommended max on-pixel-ratio (OPR) is 5% to reduce battery consumption.
The default doze component is specified by `config_dozeComponent` in the [framework config][1]. SystemUI provides a default Doze Component: [DozeService][2]. [DozeService][2] builds a [DozeMachine][3] with dependencies specified in [DozeModule][4] and configurations in [AmbientDisplayConfiguration][13] and [DozeParameters][14].
The default doze component controls AOD and is specified by `config_dozeComponent` in the [framework config][1]. SystemUI provides a default Doze Component: [DozeService][2]. [DozeService][2] builds a [DozeMachine][3] with dependencies specified in [DozeModule][4] and configurations in [AmbientDisplayConfiguration][13] and [DozeParameters][14].
Note: The default UI used in AOD shares views with the Lock Screen and does not create its own new views. Once dozing begins, [DozeUI][17] informs SystemUI's [DozeServiceHost][18] that dozing has begun - which sends this signal to relevant SystemUI Lock Screen views to animate accordingly. Within SystemUI, [StatusBarStateController][19] #isDozing and #getDozeAmount can be used to query dozing state.
[DozeMachine][3] handles the following main states:
* AOD - persistently showing UI when the device is in a low-powered state
* Pulsing - waking up the screen to show notifications (from AOD and screen off)
@@ -42,6 +43,22 @@ Relevant sensors include:
And are configured in the [AmbientDisplayConfiguration][13] with some related configurations specified in [DozeParameters][14].
## Doze Suppressors
When Dozing is enabled, it can still be suppressed based on the device state. On a high-level, doze and/or AOD may be suppressed if the device is:
* in CAR_MODE
* not provisioned
* in power saver mode
* being suppressed by an app (see [PowerManager#suppressAmbientDisplay][16])
Refer to the documentation in [DozeSuppressors][15] for more information.
## AOD burn-in and image retention
Because AOD will show an image on the screen for an elogated period of time, AOD designs must take into consideration burn-in (leaving a permanent mark on the screen). Temporary burn-in is called image-retention.
To prevent burn-in, it is recommended to often shift UI on the screen. [DozeUi][17] schedules a call to dozeTimeTick every minute to request a shift in UI for all elements on AOD. The amount of shift can be determined by undergoing simulated AOD testing since this may vary depending on the display.
For manual local testing, set [DozeUI][17]#BURN_IN_TESTING_ENABLED to true, and then manual time broadcasts (ie: `adb shell 'date 022202222022.00 ; am broadcast -a android.intent.action.TIME_SET'`) will update the burn-in translations of the views. For a general idea where burn-in may be an issue, run the [software burn-in script][20].
