Support animating just the backlight when turning off.

Bug: 7224614
Change-Id: Ic9fa7a9e458c89d347b03bce6829f952bdf3b6a5

2 files changed, 26 insertions, 8 deletions

diff --git a/services/java/com/android/server/power/DisplayPowerController.java b/services/java/com/android/server/power/DisplayPowerController.java
index d0e758fe3929..b9f9df7b9b8e 100644
--- a/services/java/com/android/server/power/DisplayPowerController.java
+++ b/services/java/com/android/server/power/DisplayPowerController.java
@@ -197,6 +197,12 @@ final class DisplayPowerController {
     // May be 0 if no warm-up is required.
     private int mLightSensorWarmUpTimeConfig;
 
+    // True if we should animate the backlight when turning the screen on or off, which
+    // tends to be efficient for LCD displays but not for OLED displays.
+    // False if we should play the electron beam animation instead, which is better for
+    // OLED displays.
+    private boolean mElectronBeamAnimatesBacklightConfig;
+
     // The pending power request.
     // Initially null until the first call to requestPowerState.
     // Guarded by mLock.
@@ -362,6 +368,9 @@ final class DisplayPowerController {
                     com.android.internal.R.integer.config_lightSensorWarmupTime);
         }
 
+        mElectronBeamAnimatesBacklightConfig = resources.getBoolean(
+                com.android.internal.R.bool.config_animateScreenLights);
+
         if (!DEBUG_PRETEND_PROXIMITY_SENSOR_ABSENT) {
             mProximitySensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
             if (mProximitySensor != null) {
@@ -481,7 +490,8 @@ final class DisplayPowerController {
     private void initialize() {
         final Executor executor = AsyncTask.THREAD_POOL_EXECUTOR;
         Display display = mDisplayManager.getDisplay(Display.DEFAULT_DISPLAY);
-        mPowerState = new DisplayPowerState(new ElectronBeam(display),
+        mPowerState = new DisplayPowerState(
+                mElectronBeamAnimatesBacklightConfig ? null : new ElectronBeam(display),
                 new PhotonicModulator(executor,
                         mLights.getLight(LightsService.LIGHT_ID_BACKLIGHT),
                         mSuspendBlocker));
diff --git a/services/java/com/android/server/power/DisplayPowerState.java b/services/java/com/android/server/power/DisplayPowerState.java
index 1bd781144189..dba45b39dbb1 100644
--- a/services/java/com/android/server/power/DisplayPowerState.java
+++ b/services/java/com/android/server/power/DisplayPowerState.java
@@ -50,7 +50,7 @@ final class DisplayPowerState {
     private static final int DIRTY_BRIGHTNESS = 1 << 2;
 
     private final Choreographer mChoreographer;
-    private final ElectronBeam mElectronBeam;
+    private final ElectronBeam mElectronBeam; // may be null if only animating backlights
     private final PhotonicModulator mScreenBrightnessModulator;
 
     private int mDirty;
@@ -134,16 +134,22 @@ final class DisplayPowerState {
      * @return True if the electron beam was prepared.
      */
     public boolean prepareElectronBeam(boolean warmUp) {
-        boolean success = mElectronBeam.prepare(warmUp);
-        invalidate(DIRTY_ELECTRON_BEAM);
-        return success;
+        if (mElectronBeam != null) {
+            boolean success = mElectronBeam.prepare(warmUp);
+            invalidate(DIRTY_ELECTRON_BEAM);
+            return success;
+        } else {
+            return true;
+        }
     }
 
     /**
      * Dismisses the electron beam surface.
      */
     public void dismissElectronBeam() {
-        mElectronBeam.dismiss();
+        if (mElectronBeam != null) {
+            mElectronBeam.dismiss();
+        }
     }
 
     /**
@@ -224,7 +230,9 @@ final class DisplayPowerState {
         pw.println("  mScreenBrightness=" + mScreenBrightness);
         pw.println("  mElectronBeamLevel=" + mElectronBeamLevel);
 
-        mElectronBeam.dump(pw);
+        if (mElectronBeam != null) {
+            mElectronBeam.dump(pw);
+        }
     }
 
     private void invalidate(int dirty) {
@@ -243,7 +251,7 @@ final class DisplayPowerState {
                 PowerManagerService.nativeSetScreenState(false);
             }
 
-            if ((mDirty & DIRTY_ELECTRON_BEAM) != 0) {
+            if ((mDirty & DIRTY_ELECTRON_BEAM) != 0 && mElectronBeam != null) {
                 mElectronBeam.draw(mElectronBeamLevel);
             }