Fix scrim busyness regression

Scrim opacity on the keyguard should vary according to how many
notifications are visible.
A busy lock screen has a more opaque scrim, and an empty lock screen
has a more transparent scrim.

Test: atest packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
Test: swipe away or receive notifications on the keyguard
Change-Id: I672b5e1a82d65dd326b40069d61223c3c0161493

3 files changed, 68 insertions, 13 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 255e5e48dbae..d8d388c4be08 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
@@ -167,6 +167,7 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener,
     private Callback mCallback;
     private boolean mWallpaperSupportsAmbientMode;
     private boolean mScreenOn;
+    private float mNotificationDensity;
 
     // Scrim blanking callbacks
     private Choreographer.FrameCallback mPendingFrameCallback;
@@ -251,7 +252,7 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener,
         mCurrentInFrontTint = state.getFrontTint();
         mCurrentBehindTint = state.getBehindTint();
         mCurrentInFrontAlpha = state.getFrontAlpha();
-        mCurrentBehindAlpha = state.getBehindAlpha();
+        mCurrentBehindAlpha = state.getBehindAlpha(mNotificationDensity);
         applyExpansionToAlpha();
 
         // Cancel blanking transitions that were pending before we requested a new state
@@ -396,12 +397,13 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener,
             // Either darken of make the scrim transparent when you
             // pull down the shade
             float interpolatedFract = getInterpolatedFraction();
+            float alphaBehind = mState.getBehindAlpha(mNotificationDensity);
             if (mDarkenWhileDragging) {
-                mCurrentBehindAlpha = MathUtils.lerp(mScrimBehindAlphaUnlocking,
-                        mScrimBehindAlphaKeyguard, interpolatedFract);
+                mCurrentBehindAlpha = MathUtils.lerp(mScrimBehindAlphaUnlocking, alphaBehind,
+                        interpolatedFract);
                 mCurrentInFrontAlpha = (1f - interpolatedFract) * SCRIM_IN_FRONT_ALPHA_LOCKED;
             } else {
-                mCurrentBehindAlpha = MathUtils.lerp(0 /* start */, mScrimBehindAlphaKeyguard,
+                mCurrentBehindAlpha = MathUtils.lerp(0 /* start */, alphaBehind,
                         interpolatedFract);
                 mCurrentInFrontAlpha = 0;
             }
@@ -415,15 +417,14 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener,
     public void setNotificationCount(int notificationCount) {
         final float maxNotificationDensity = 3;
         float notificationDensity = Math.min(notificationCount / maxNotificationDensity, 1f);
-        float newAlpha = MathUtils.map(0, 1,
-                GRADIENT_SCRIM_ALPHA, GRADIENT_SCRIM_ALPHA_BUSY,
-                notificationDensity);
-        if (mScrimBehindAlphaKeyguard != newAlpha) {
-            mScrimBehindAlphaKeyguard = newAlpha;
+        if (mNotificationDensity == notificationDensity) {
+            return;
+        }
+        mNotificationDensity = notificationDensity;
 
-            if (mState == ScrimState.KEYGUARD || mState == ScrimState.BOUNCER) {
-                scheduleUpdate();
-            }
+        if (mState == ScrimState.KEYGUARD) {
+            applyExpansionToAlpha();
+            scheduleUpdate();
         }
     }
 
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 381e4af31853..053c5a3b5966 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java
@@ -18,6 +18,7 @@ package com.android.systemui.statusbar.phone;
 
 import android.graphics.Color;
 import android.os.Trace;
+import android.util.MathUtils;
 
 import com.android.keyguard.KeyguardUpdateMonitor;
 import com.android.systemui.statusbar.ScrimView;
@@ -55,6 +56,13 @@ public enum ScrimState {
             mCurrentBehindAlpha = mScrimBehindAlphaKeyguard;
             mCurrentInFrontAlpha = 0;
         }
+
+        @Override
+        public float getBehindAlpha(float busynessFactor) {
+            return MathUtils.map(0 /* start */, 1 /* stop */,
+                   ScrimController.GRADIENT_SCRIM_ALPHA, ScrimController.GRADIENT_SCRIM_ALPHA_BUSY,
+                   busynessFactor);
+        }
     },
 
     /**
@@ -183,7 +191,7 @@ public enum ScrimState {
         return mCurrentInFrontAlpha;
     }
 
-    public float getBehindAlpha() {
+    public float getBehindAlpha(float busyness) {
         return mCurrentBehindAlpha;
     }
 
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 8347fb098bd5..168d8d36290d 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
@@ -356,6 +356,52 @@ public class ScrimControllerTest extends SysuiTestCase {
         Assert.assertTrue(mScrimController.wasAnimationJustCancelled());
     }
 
+    /**
+     * Number of visible notifications affects scrim opacity.
+     */
+    @Test
+    public void testNotificationDensity() {
+        mScrimController.transitionTo(ScrimState.KEYGUARD);
+        mScrimController.finishAnimationsImmediately();
+
+        mScrimController.setNotificationCount(0);
+        mScrimController.finishAnimationsImmediately();
+        Assert.assertEquals("lower density when no notifications",
+                ScrimController.GRADIENT_SCRIM_ALPHA,  mScrimBehind.getViewAlpha(), 0.01f);
+
+        mScrimController.setNotificationCount(3);
+        mScrimController.finishAnimationsImmediately();
+        Assert.assertEquals("stronger density when notifications are visible",
+                ScrimController.GRADIENT_SCRIM_ALPHA_BUSY,  mScrimBehind.getViewAlpha(), 0.01f);
+    }
+
+    /**
+     * Moving from/to states conserves old notification density.
+     */
+    @Test
+    public void testConservesNotificationDensity() {
+        testConservesNotificationDensity(0 /* count */, ScrimController.GRADIENT_SCRIM_ALPHA);
+        testConservesNotificationDensity(3 /* count */, ScrimController.GRADIENT_SCRIM_ALPHA_BUSY);
+    }
+
+    /**
+     * Conserves old notification density after leaving state and coming back.
+     *
+     * @param count How many notification.
+     * @param expectedAlpha Expected alpha.
+     */
+    private void testConservesNotificationDensity(int count, float expectedAlpha) {
+        mScrimController.setNotificationCount(count);
+        mScrimController.transitionTo(ScrimState.UNLOCKED);
+        mScrimController.finishAnimationsImmediately();
+
+        mScrimController.transitionTo(ScrimState.KEYGUARD);
+        mScrimController.finishAnimationsImmediately();
+
+        Assert.assertEquals("Doesn't respect notification busyness after transition",
+                expectedAlpha,  mScrimBehind.getViewAlpha(), 0.01f);
+    }
+
     private void assertScrimTint(ScrimView scrimView, boolean tinted) {
         final boolean viewIsTinted = scrimView.getTint() != Color.TRANSPARENT;
         final String name = scrimView == mScrimInFront ? "front" : "back";