Improved the performance of the shelf / scrim

We are now caching the light status bar state and
are only reevaluating it if it changed / alpha changed.
Similarly, we now cache the background color for the
scrim, since that usually doesn't even change
in the shade, only on the lockscreen with transparency.

Change-Id: I417bf8286b8ccdfcfb143e8ea365b01c2b348be7
Test: runtest systemui-jank -c android.platform.systemui.tests.jank.SystemUiJankTests -m testNotificationListPull_manyNotifications
Bug: 33252359

packages/SystemUI/src/com/android/systemui/statusbar/ActivatableNotificationView.java

@@ -182,6 +182,7 @@ public abstract class ActivatableNotificationView extends ExpandableOutlineView
     private int mStartTint;
     private int mOverrideTint;
     private float mOverrideAmount;
+    private boolean mShadowHidden;
 
     public ActivatableNotificationView(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -210,6 +211,7 @@ public abstract class ActivatableNotificationView extends ExpandableOutlineView
         super.onFinishInflate();
         mBackgroundNormal = (NotificationBackgroundView) findViewById(R.id.backgroundNormal);
         mFakeShadow = (FakeShadowView) findViewById(R.id.fake_shadow);
+        mShadowHidden = mFakeShadow.getVisibility() != VISIBLE;
         mBackgroundDimmed = (NotificationBackgroundView) findViewById(R.id.backgroundDimmed);
         mBackgroundNormal.setCustomBackground(R.drawable.notification_material_bg);
         mBackgroundDimmed.setCustomBackground(R.drawable.notification_material_bg_dim);
@@ -1020,9 +1022,13 @@ public abstract class ActivatableNotificationView extends ExpandableOutlineView
     @Override
     public void setFakeShadowIntensity(float shadowIntensity, float outlineAlpha, int shadowYEnd,
             int outlineTranslation) {
-        mFakeShadow.setFakeShadowTranslationZ(shadowIntensity * (getTranslationZ()
-                + FakeShadowView.SHADOW_SIBLING_TRESHOLD), outlineAlpha, shadowYEnd,
-                outlineTranslation);
+        boolean hiddenBefore = mShadowHidden;
+        mShadowHidden = shadowIntensity == 0.0f;
+        if (!mShadowHidden || !hiddenBefore) {
+            mFakeShadow.setFakeShadowTranslationZ(shadowIntensity * (getTranslationZ()
+                            + FakeShadowView.SHADOW_SIBLING_TRESHOLD), outlineAlpha, shadowYEnd,
+                    outlineTranslation);
+        }
     }
 
     public int getBackgroundColorWithoutTint() {

packages/SystemUI/src/com/android/systemui/statusbar/phone/LightBarController.java

@@ -43,7 +43,18 @@ public class LightBarController implements BatteryController.BatteryStateChangeC
     private boolean mDockedLight;
     private int mLastStatusBarMode;
     private int mLastNavigationBarMode;
+
+    /**
+     * Whether the navigation bar should be light factoring in already how much alpha the scrim has
+     */
     private boolean mNavigationLight;
+
+    /**
+     * Whether the flags indicate that a light status bar is requested. This doesn't factor in the
+     * scrim alpha yet.
+     */
+    private boolean mHasLightNavigationBar;
+    private boolean mScrimAlphaBelowThreshold;
     private float mScrimAlpha;
 
     private final Rect mLastFullscreenBounds = new Rect();
@@ -90,7 +101,9 @@ public class LightBarController implements BatteryController.BatteryStateChangeC
         if ((diffVis & View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR) != 0
                 || nbModeChanged) {
             boolean last = mNavigationLight;
-            mNavigationLight = isNavigationLight(newVis, navigationBarMode);
+            mHasLightNavigationBar = isLight(vis, navigationBarMode,
+                    View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR);
+            mNavigationLight = mHasLightNavigationBar && mScrimAlphaBelowThreshold;
             if (mNavigationLight != last) {
                 updateNavigation();
             }
@@ -113,12 +126,11 @@ public class LightBarController implements BatteryController.BatteryStateChangeC
 
     public void setScrimAlpha(float alpha) {
         mScrimAlpha = alpha;
-        reevaluate();
-    }
-
-    private boolean isNavigationLight(int vis, int barMode) {
-        return isLight(vis, barMode, View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR)
-                && mScrimAlpha < NAV_BAR_INVERSION_SCRIM_ALPHA_THRESHOLD;
+        boolean belowThresholdBefore = mScrimAlphaBelowThreshold;
+        mScrimAlphaBelowThreshold = mScrimAlpha < NAV_BAR_INVERSION_SCRIM_ALPHA_THRESHOLD;
+        if (mHasLightNavigationBar && belowThresholdBefore != mScrimAlphaBelowThreshold) {
+            reevaluate();
+        }
     }
 
     private boolean isLight(int vis, int barMode, int flag) {

packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java

@@ -338,13 +338,13 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener,
     private void setCurrentScrimAlpha(View scrim, float alpha) {
         if (scrim == mScrimBehind) {
             mCurrentBehindAlpha = alpha;
+            mLightBarController.setScrimAlpha(mCurrentBehindAlpha);
         } else if (scrim == mScrimInFront) {
             mCurrentInFrontAlpha = alpha;
         } else {
             alpha = Math.max(0.0f, Math.min(1.0f, alpha));
             mCurrentHeadsUpAlpha = alpha;
         }
-        mLightBarController.setScrimAlpha(mCurrentBehindAlpha);
     }
 
     protected void updateScrimColor(View scrim) {

packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java

@@ -359,6 +359,7 @@ public class NotificationStackScrollLayout extends ViewGroup
     private boolean mInHeadsUpPinnedMode;
     private boolean mHeadsUpAnimatingAway;
     private int mStatusBarState;
+    private int mCachedBackgroundColor;
 
     public NotificationStackScrollLayout(Context context) {
         this(context, null);
@@ -445,8 +446,11 @@ public class NotificationStackScrollLayout extends ViewGroup
                         + alphaInv * Color.green(scrimColor)),
                 (int) (mBackgroundFadeAmount * Color.blue(mBgColor)
                         + alphaInv * Color.blue(scrimColor)));
-        mBackgroundPaint.setColor(color);
-        invalidate();
+        if (mCachedBackgroundColor != color) {
+            mCachedBackgroundColor = color;
+            mBackgroundPaint.setColor(color);
+            invalidate();
+        }
     }
 
     private void initView(Context context) {
@@ -2092,9 +2096,14 @@ public class NotificationStackScrollLayout extends ViewGroup
      * Update the background bounds to the new desired bounds
      */
     private void updateBackgroundBounds() {
-        getLocationInWindow(mTempInt2);
-        mBackgroundBounds.left = mTempInt2[0];
-        mBackgroundBounds.right = mTempInt2[0] + getWidth();
+        if (mAmbientState.isPanelFullWidth()) {
+            mBackgroundBounds.left = 0;
+            mBackgroundBounds.right = getWidth();
+        } else {
+            getLocationInWindow(mTempInt2);
+            mBackgroundBounds.left = mTempInt2[0];
+            mBackgroundBounds.right = mTempInt2[0] + getWidth();
+        }
         if (!mIsExpanded) {
             mBackgroundBounds.top = 0;
             mBackgroundBounds.bottom = 0;