From 218a0cb4c2e8e859732ac5a4475f1fd1207782bc Mon Sep 17 00:00:00 2001
From: Lucas Dupin <dupin@google.com>
Date: Mon, 9 Jul 2018 14:32:53 -0700
Subject: Hide wallpaper when backdrop arrives

Some apps may set a backdrop image after the device enters doze,
causing the artwork to be visible in AOD. Let's draw black.

Test: manual
Test: packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
Change-Id: Ib13e14f285594349c1df263f713883449884ff00
Fixes: 110959983
---
 .../android/systemui/statusbar/phone/ScrimController.java  | 10 ++++++++++
 .../com/android/systemui/statusbar/phone/ScrimState.java   | 12 ++++++++++--
 .../systemui/statusbar/phone/ScrimControllerTest.java      | 14 ++++++++++++++
 3 files changed, 34 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 61f0e1cb29c7..31e5305410e8 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
@@ -892,6 +892,16 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener, OnCo
         for (ScrimState state : ScrimState.values()) {
             state.setHasBackdrop(hasBackdrop);
         }
+
+        // Backdrop event may arrive after state was already applied,
+        // in this case, back-scrim needs to be re-evaluated
+        if (mState == ScrimState.AOD || mState == ScrimState.PULSING) {
+            float newBehindAlpha = mState.getBehindAlpha(mNotificationDensity);
+            if (mCurrentBehindAlpha != newBehindAlpha) {
+                mCurrentBehindAlpha = newBehindAlpha;
+                updateScrims();
+            }
+        }
     }
 
     public void setLaunchingAffordanceWithPreview(boolean launchingAffordanceWithPreview) {
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java
index 19015fcdacf7..081ebfac5f1b 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java
@@ -105,7 +105,6 @@ public enum ScrimState {
         public void prepare(ScrimState previousState) {
             final boolean alwaysOnEnabled = mDozeParameters.getAlwaysOn();
             mBlankScreen = mDisplayRequiresBlanking;
-            mCurrentBehindAlpha = mWallpaperSupportsAmbientMode && !mHasBackdrop ? 0f : 1f;
             mCurrentInFrontAlpha = alwaysOnEnabled ? mAodFrontScrimAlpha : 1f;
             mCurrentInFrontTint = Color.BLACK;
             mCurrentBehindTint = Color.BLACK;
@@ -115,6 +114,11 @@ public enum ScrimState {
             mAnimateChange = mDozeParameters.shouldControlScreenOff();
         }
 
+        @Override
+        public float getBehindAlpha(float busyness) {
+            return mWallpaperSupportsAmbientMode && !mHasBackdrop ? 0f : 1f;
+        }
+
         @Override
         public boolean isLowPowerState() {
             return true;
@@ -129,10 +133,14 @@ public enum ScrimState {
         public void prepare(ScrimState previousState) {
             mCurrentInFrontAlpha = 0;
             mCurrentInFrontTint = Color.BLACK;
-            mCurrentBehindAlpha = mWallpaperSupportsAmbientMode && !mHasBackdrop ? 0f : 1f;
             mCurrentBehindTint = Color.BLACK;
             mBlankScreen = mDisplayRequiresBlanking;
         }
+
+        @Override
+        public float getBehindAlpha(float busyness) {
+            return mWallpaperSupportsAmbientMode && !mHasBackdrop ? 0f : 1f;
+        }
     },
 
     /**
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 89d562a2099c..9c558748697a 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
@@ -151,6 +151,20 @@ public class ScrimControllerTest extends SysuiTestCase {
         assertScrimTint(mScrimInFront, true /* tinted */);
     }
 
+    @Test
+    public void setHasBackdrop_withAodWallpaperAndAlbumArt() {
+        mScrimController.setWallpaperSupportsAmbientMode(true);
+        mScrimController.transitionTo(ScrimState.AOD);
+        mScrimController.finishAnimationsImmediately();
+        mScrimController.setHasBackdrop(true);
+        mScrimController.finishAnimationsImmediately();
+        // Front scrim should be transparent
+        // Back scrim should be visible with tint
+        assertScrimVisibility(VISIBILITY_FULLY_TRANSPARENT, VISIBILITY_FULLY_OPAQUE);
+        assertScrimTint(mScrimBehind, true /* tinted */);
+        assertScrimTint(mScrimInFront, true /* tinted */);
+    }
+
     @Test
     public void transitionToAod_withFrontAlphaUpdates() {
         // Assert that setting the AOD front scrim alpha doesn't take effect in a non-AOD state.
-- 
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