From 69bda6014fd5a4c70a99906675cfdc394a275376 Mon Sep 17 00:00:00 2001
From: Lucas Dupin <dupin@google.com>
Date: Fri, 18 May 2018 17:24:52 -0700
Subject: [PATCH] Keep scrim black when "always on" is off

The first frame when waking up is expensive and we
need a black scrim hiding what was left behind.

Bug: 78022321
Test: atest packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
Change-Id: I99e2b7960daf2cbe51bec6aee4b15c74d532078c
---
 .../systemui/statusbar/phone/ScrimController.java    | 12 ++++++++++--
 .../statusbar/phone/ScrimControllerTest.java         | 10 ++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
index ae93d986ea368..9ba0880b37484 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
@@ -450,10 +450,18 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener, OnCo
     }
 
     /**
-     * Sets the front alpha while in AOD.
+     * Sets the front scrim opacity in AOD so it's not as bright.
+     * <p>
+     * Displays usually don't support multiple dimming settings when in low power mode.
+     * The workaround is to modify the front scrim opacity when in AOD, so it's not as
+     * bright when you're at the movies or lying down on bed.
+     * <p>
+     * This value will be lost during transitions and only updated again after the the
+     * device is dozing when the light sensor is on.
      */
     public void setAodFrontScrimAlpha(float alpha) {
-        if (mState == ScrimState.AOD && mCurrentInFrontAlpha != alpha) {
+        if (mState == ScrimState.AOD && mDozeParameters.getAlwaysOn()
+                && mCurrentInFrontAlpha != alpha) {
             mCurrentInFrontAlpha = alpha;
             scheduleUpdate();
         }
diff --git a/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java b/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
index 4e047901fb508..a2a866e79af3c 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
@@ -184,6 +184,16 @@ public class ScrimControllerTest extends SysuiTestCase {
         mScrimController.finishAnimationsImmediately();
         assertScrimVisibility(VISIBILITY_FULLY_OPAQUE, VISIBILITY_FULLY_OPAQUE);
 
+        // ... and alpha updates should be completely ignored if always_on is off.
+        // Passing it forward would mess up the wake-up transition.
+        mAlwaysOnEnabled = false;
+        mScrimController.transitionTo(ScrimState.UNLOCKED);
+        mScrimController.transitionTo(ScrimState.AOD);
+        mScrimController.finishAnimationsImmediately();
+        mScrimController.setAodFrontScrimAlpha(0.3f);
+        Assert.assertEquals(ScrimState.AOD.getFrontAlpha(), mScrimInFront.getViewAlpha(), 0.001f);
+        Assert.assertNotEquals(0.3f, mScrimInFront.getViewAlpha(), 0.001f);
+
         // Reset value since enums are static.
         mScrimController.setAodFrontScrimAlpha(0f);
     }