Merge "Making the config_screenThresholdLevels a float array to fix the issue where it was always greater than all possible brightness values"

core/res/res/values/config.xml

@@ -1649,6 +1649,11 @@
          darkening hysteresis constraint value is the n-th element of
          config_screenDarkeningThresholds.
 
+         Historically, it has been assumed that this will be an integer array with values in the
+         range of [0, 255]. However, it is now assumed to be a float array with values in the
+         range of [0, 1]. To accommodate both the possibilities, we internally check the scale on
+         which the thresholds are defined, and calibrate it accordingly.
+
          The (zero-based) index is calculated as follows: (MAX is the largest index of the array)
          condition                       calculated index
          value < level[0]                0

services/core/java/com/android/server/display/DisplayPowerController.java

@@ -975,8 +975,8 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                     com.android.internal.R.array.config_screenBrighteningThresholds);
             int[] screenDarkeningThresholds = resources.getIntArray(
                     com.android.internal.R.array.config_screenDarkeningThresholds);
-            int[] screenThresholdLevels = resources.getIntArray(
+            float[] screenThresholdLevels = BrightnessMappingStrategy.getFloatArray(resources
-                    com.android.internal.R.array.config_screenThresholdLevels);
+                    .obtainTypedArray(com.android.internal.R.array.config_screenThresholdLevels));
             float screenDarkeningMinThreshold =
                     mDisplayDeviceConfig.getScreenDarkeningMinThreshold();
             float screenBrighteningMinThreshold =

services/core/java/com/android/server/display/HysteresisLevels.java

@@ -39,8 +39,7 @@ public class HysteresisLevels {
     private final float mMinBrightening;
 
     /**
-     * Creates a {@code HysteresisLevels} object with the given equal-length
+     * Creates a {@code HysteresisLevels} object for ambient brightness.
-     * integer arrays.
      * @param brighteningThresholds an array of brightening hysteresis constraint constants.
      * @param darkeningThresholds an array of darkening hysteresis constraint constants.
      * @param thresholdLevels a monotonically increasing array of threshold levels.
@@ -61,6 +60,28 @@ public class HysteresisLevels {
         mMinBrightening = minBrighteningThreshold;
     }
 
+    /**
+     * Creates a {@code HysteresisLevels} object for screen brightness.
+     * @param brighteningThresholds an array of brightening hysteresis constraint constants.
+     * @param darkeningThresholds an array of darkening hysteresis constraint constants.
+     * @param thresholdLevels a monotonically increasing array of threshold levels.
+     * @param minBrighteningThreshold the minimum value for which the brightening value needs to
+     *                                return.
+     * @param minDarkeningThreshold the minimum value for which the darkening value needs to return.
+     */
+    HysteresisLevels(int[] brighteningThresholds, int[] darkeningThresholds,
+            float[] thresholdLevels, float minDarkeningThreshold, float minBrighteningThreshold) {
+        if (brighteningThresholds.length != darkeningThresholds.length
+                || darkeningThresholds.length != thresholdLevels.length + 1) {
+            throw new IllegalArgumentException("Mismatch between hysteresis array lengths.");
+        }
+        mBrighteningThresholds = setArrayFormat(brighteningThresholds, 1000.0f);
+        mDarkeningThresholds = setArrayFormat(darkeningThresholds, 1000.0f);
+        mThresholdLevels = constraintInRangeIfNeeded(thresholdLevels);
+        mMinDarkening = minDarkeningThreshold;
+        mMinBrightening = minBrighteningThreshold;
+    }
+
     /**
      * Return the brightening hysteresis threshold for the given value level.
      */
@@ -112,6 +133,37 @@ public class HysteresisLevels {
         return levelArray;
     }
 
+    /**
+     * This check is due to historical reasons, where screen thresholdLevels used to be
+     * integer values in the range of [0-255], but then was changed to be float values from [0,1].
+     * To accommodate both the possibilities, we first check if all the thresholdLevels are in [0,
+     * 1], and if not, we divide all the levels with 255 to bring them down to the same scale.
+     */
+    private float[] constraintInRangeIfNeeded(float[] thresholdLevels) {
+        if (isAllInRange(thresholdLevels, /* minValueInclusive = */ 0.0f, /* maxValueInclusive = */
+                1.0f)) {
+            return thresholdLevels;
+        }
+
+        Slog.w(TAG, "Detected screen thresholdLevels on a deprecated brightness scale");
+        float[] thresholdLevelsScaled = new float[thresholdLevels.length];
+        for (int index = 0; thresholdLevels.length > index; ++index) {
+            thresholdLevelsScaled[index] = thresholdLevels[index] / 255.0f;
+        }
+        return thresholdLevelsScaled;
+    }
+
+    private boolean isAllInRange(float[] configArray, float minValueInclusive,
+                                 float maxValueInclusive) {
+        int configArraySize = configArray.length;
+        for (int index = 0; configArraySize > index; ++index) {
+            if (configArray[index] < minValueInclusive || configArray[index] > maxValueInclusive) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     void dump(PrintWriter pw) {
         pw.println("HysteresisLevels");
         pw.println("  mBrighteningThresholds=" + Arrays.toString(mBrighteningThresholds));