Update the documentation for brightness configuration.
This should always match the documentation in frameworks/base, since
that's the canonical document.
Bug: 74328541
Test: N/A
Change-Id: I7b3266bb3c07631f13fe295ee883909ce24aff79
diff --git a/overlay/frameworks/base/core/res/res/values/config.xml b/overlay/frameworks/base/core/res/res/values/config.xml
index b7a7593..d0831b0 100644
--- a/overlay/frameworks/base/core/res/res/values/config.xml
+++ b/overlay/frameworks/base/core/res/res/values/config.xml
@@ -26,14 +26,24 @@
<!-- MMS user agent prolfile url -->
<string name="config_mms_user_agent_profile_url" translatable="false">http://www.gstatic.com/android/sms/G011C.xml</string>
- <!-- Array of light sensor LUX values to define our levels for auto backlight brightness support.
- The N entries of this array define N 1 zones as follows:
+ <!-- Array of light sensor lux values to define our levels for auto backlight brightness support.
+ The N entries of this array define N + 1 control points as follows:
+ (1-based arrays)
- Zone 0: 0 <= LUX < array[0]
- Zone 1: array[0] <= LUX < array[1]
+ Point 1: (0, value[1]): lux <= 0
+ Point 2: (level[1], value[2]): 0 < lux <= level[1]
+ Point 3: (level[2], value[3]): level[2] < lux <= level[3]
...
- Zone N: array[N - 1] <= LUX < array[N]
- Zone N + 1 array[N] <= LUX < infinity
+ Point N+1: (level[N], value[N+1]): level[N] < lux
+
+ The control points must be strictly increasing. Each control point
+ corresponds to an entry in the brightness backlight values arrays.
+ For example, if lux == level[1] (first element of the levels array)
+ then the brightness will be determined by value[2] (second element
+ of the brightness values array).
+
+ Spline interpolation is used to determine the auto-brightness
+ backlight values for lux levels between these control points.
Must be overridden in platform specific overlays -->
<integer-array name="config_autoBrightnessLevels">
