Configurable letterbox background.

Allow three types of the letterbox wallpaper:
- Solid background using color specified in R.color.config_letterboxBackgroundColorSolid color
- Color specified in R.attr.colorBackground for the letterboxed application
- Color specified in R.attr.colorBackgroundFloating for the letterboxed application

Also, adding ADB commands for each config value:
- adb shell cmd window set-letterbox-background-color [reset|color]
- adb shell cmd window get-letterbox-background-color
- adb shell cmd window set-letterbox-background-type [reset|solid_color|app_color_background|app_color_background_floating]
- adb shell cmd window get-letterbox-background-type

Test: manual with ADB commands, atest LetterboxTest
Fix: 179088234
Change-Id: I23cf0b52c9f95d1f92255731bc7be165a575c7cd

12 files changed, 365 insertions, 75 deletions

diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index bdd541a2f0ac..4728f11a402d 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -5090,6 +5090,13 @@ public class Activity extends ContextThemeWrapper
             mTaskDescription.setBackgroundColor(colorBackground);
         }
 
+        int colorBackgroundFloating = a.getColor(
+                com.android.internal.R.styleable.ActivityTaskDescription_colorBackgroundFloating,
+                0);
+        if (colorBackgroundFloating != 0 && Color.alpha(colorBackgroundFloating) == 0xFF) {
+            mTaskDescription.setBackgroundColorFloating(colorBackgroundFloating);
+        }
+
         final int statusBarColor = a.getColor(
                 com.android.internal.R.styleable.ActivityTaskDescription_statusBarColor, 0);
         if (statusBarColor != 0) {
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 520959cc40e7..43d0269beae2 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -1072,13 +1072,15 @@ public class ActivityManager {
         private static final String ATTR_TASKDESCRIPTIONCOLOR_PRIMARY =
                 ATTR_TASKDESCRIPTION_PREFIX + "color";
         private static final String ATTR_TASKDESCRIPTIONCOLOR_BACKGROUND =
-                ATTR_TASKDESCRIPTION_PREFIX + "colorBackground";
+                ATTR_TASKDESCRIPTION_PREFIX + "color_background";
         private static final String ATTR_TASKDESCRIPTIONICON_FILENAME =
                 ATTR_TASKDESCRIPTION_PREFIX + "icon_filename";
         private static final String ATTR_TASKDESCRIPTIONICON_RESOURCE =
                 ATTR_TASKDESCRIPTION_PREFIX + "icon_resource";
         private static final String ATTR_TASKDESCRIPTIONICON_RESOURCE_PACKAGE =
                 ATTR_TASKDESCRIPTION_PREFIX + "icon_package";
+        private static final String ATTR_TASKDESCRIPTIONCOLOR_BACKGROUND_FLOATING =
+                ATTR_TASKDESCRIPTION_PREFIX + "color_background_floating";
 
         private String mLabel;
         @Nullable
@@ -1086,6 +1088,7 @@ public class ActivityManager {
         private String mIconFilename;
         private int mColorPrimary;
         private int mColorBackground;
+        private int mColorBackgroundFloating;
         private int mStatusBarColor;
         private int mNavigationBarColor;
         private boolean mEnsureStatusBarContrastWhenTransparent;
@@ -1106,7 +1109,7 @@ public class ActivityManager {
          */
         public TaskDescription(String label, @DrawableRes int iconRes, int colorPrimary) {
             this(label, Icon.createWithResource(ActivityThread.currentPackageName(), iconRes),
-                    colorPrimary, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1);
+                    colorPrimary, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1, 0);
             if ((colorPrimary != 0) && (Color.alpha(colorPrimary) != 255)) {
                 throw new RuntimeException("A TaskDescription's primary color should be opaque");
             }
@@ -1121,7 +1124,7 @@ public class ActivityManager {
          */
         public TaskDescription(String label, @DrawableRes int iconRes) {
             this(label, Icon.createWithResource(ActivityThread.currentPackageName(), iconRes),
-                    0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1);
+                    0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1, 0);
         }
 
         /**
@@ -1130,14 +1133,14 @@ public class ActivityManager {
          * @param label A label and description of the current state of this activity.
          */
         public TaskDescription(String label) {
-            this(label, null, 0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1);
+            this(label, null, 0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1, 0);
         }
 
         /**
          * Creates an empty TaskDescription.
          */
         public TaskDescription() {
-            this(null, null, 0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1);
+            this(null, null, 0, 0, 0, 0, false, false, RESIZE_MODE_RESIZEABLE, -1, -1, 0);
         }
 
         /**
@@ -1152,7 +1155,7 @@ public class ActivityManager {
         @Deprecated
         public TaskDescription(String label, Bitmap icon, int colorPrimary) {
             this(label, icon != null ? Icon.createWithBitmap(icon) : null, colorPrimary, 0, 0, 0,
-                    false, false, RESIZE_MODE_RESIZEABLE, -1, -1);
+                    false, false, RESIZE_MODE_RESIZEABLE, -1, -1, 0);
             if ((colorPrimary != 0) && (Color.alpha(colorPrimary) != 255)) {
                 throw new RuntimeException("A TaskDescription's primary color should be opaque");
             }
@@ -1168,7 +1171,7 @@ public class ActivityManager {
         @Deprecated
         public TaskDescription(String label, Bitmap icon) {
             this(label, icon != null ? Icon.createWithBitmap(icon) : null, 0, 0, 0, 0, false, false,
-                    RESIZE_MODE_RESIZEABLE, -1, -1);
+                    RESIZE_MODE_RESIZEABLE, -1, -1, 0);
         }
 
         /** @hide */
@@ -1177,7 +1180,7 @@ public class ActivityManager {
                 int statusBarColor, int navigationBarColor,
                 boolean ensureStatusBarContrastWhenTransparent,
                 boolean ensureNavigationBarContrastWhenTransparent, int resizeMode, int minWidth,
-                int minHeight) {
+                int minHeight, int colorBackgroundFloating) {
             mLabel = label;
             mIcon = icon;
             mColorPrimary = colorPrimary;
@@ -1190,6 +1193,7 @@ public class ActivityManager {
             mResizeMode = resizeMode;
             mMinWidth = minWidth;
             mMinHeight = minHeight;
+            mColorBackgroundFloating = colorBackgroundFloating;
         }
 
         /**
@@ -1217,6 +1221,7 @@ public class ActivityManager {
             mResizeMode = other.mResizeMode;
             mMinWidth = other.mMinWidth;
             mMinHeight = other.mMinHeight;
+            mColorBackgroundFloating = other.mColorBackgroundFloating;
         }
 
         /**
@@ -1253,6 +1258,9 @@ public class ActivityManager {
             if (other.mMinHeight != -1) {
                 mMinHeight = other.mMinHeight;
             }
+            if (other.mColorBackgroundFloating != 0) {
+                mColorBackgroundFloating = other.mColorBackgroundFloating;
+            }
         }
 
         private TaskDescription(Parcel source) {
@@ -1292,6 +1300,19 @@ public class ActivityManager {
         }
 
         /**
+         * Sets the background color floating for this task description.
+         * @hide
+         */
+        public void setBackgroundColorFloating(int backgroundColor) {
+            // Ensure that the given color is valid
+            if ((backgroundColor != 0) && (Color.alpha(backgroundColor) != 255)) {
+                throw new RuntimeException(
+                        "A TaskDescription's background color floating should be opaque");
+            }
+            mColorBackgroundFloating = backgroundColor;
+        }
+
+        /**
          * @hide
          */
         public void setStatusBarColor(int statusBarColor) {
@@ -1461,6 +1482,14 @@ public class ActivityManager {
         }
 
         /**
+         * @return The background color floating.
+         * @hide
+         */
+        public int getBackgroundColorFloating() {
+            return mColorBackgroundFloating;
+        }
+
+        /**
          * @hide
          */
         public int getStatusBarColor() {
@@ -1537,6 +1566,10 @@ public class ActivityManager {
             if (mColorBackground != 0) {
                 out.attributeIntHex(null, ATTR_TASKDESCRIPTIONCOLOR_BACKGROUND, mColorBackground);
             }
+            if (mColorBackgroundFloating != 0) {
+                out.attributeIntHex(null, ATTR_TASKDESCRIPTIONCOLOR_BACKGROUND_FLOATING,
+                        mColorBackgroundFloating);
+            }
             if (mIconFilename != null) {
                 out.attribute(null, ATTR_TASKDESCRIPTIONICON_FILENAME, mIconFilename);
             }
@@ -1563,6 +1596,11 @@ public class ActivityManager {
             if (colorBackground != 0) {
                 setBackgroundColor(colorBackground);
             }
+            final int colorBackgroundFloating = in.getAttributeIntHex(null,
+                    ATTR_TASKDESCRIPTIONCOLOR_BACKGROUND_FLOATING, 0);
+            if (colorBackgroundFloating != 0) {
+                setBackgroundColorFloating(colorBackgroundFloating);
+            }
             final String iconFilename = in.getAttributeValue(null,
                     ATTR_TASKDESCRIPTIONICON_FILENAME);
             if (iconFilename != null) {
@@ -1615,6 +1653,7 @@ public class ActivityManager {
                 dest.writeInt(1);
                 dest.writeString(mIconFilename);
             }
+            dest.writeInt(mColorBackgroundFloating);
         }
 
         public void readFromParcel(Parcel source) {
@@ -1632,6 +1671,7 @@ public class ActivityManager {
             mMinWidth = source.readInt();
             mMinHeight = source.readInt();
             mIconFilename = source.readInt() > 0 ? source.readString() : null;
+            mColorBackgroundFloating = source.readInt();
         }
 
         public static final @android.annotation.NonNull Creator<TaskDescription> CREATOR
@@ -1655,7 +1695,8 @@ public class ActivityManager {
                     + (mEnsureNavigationBarContrastWhenTransparent
                             ? " (contrast when transparent)" : "")
                     + " resizeMode: " + ActivityInfo.resizeModeToString(mResizeMode)
-                    + " minWidth: " + mMinWidth + " minHeight: " + mMinHeight;
+                    + " minWidth: " + mMinWidth + " minHeight: " + mMinHeight
+                    + " colorBackgrounFloating: " + mColorBackgroundFloating;
         }
 
         @Override
@@ -1678,7 +1719,8 @@ public class ActivityManager {
                             == other.mEnsureNavigationBarContrastWhenTransparent
                     && mResizeMode == other.mResizeMode
                     && mMinWidth == other.mMinWidth
-                    && mMinHeight == other.mMinHeight;
+                    && mMinHeight == other.mMinHeight
+                    && mColorBackgroundFloating == other.mColorBackgroundFloating;
         }
 
         /** @hide */
@@ -1826,6 +1868,8 @@ public class ActivityManager {
                 pw.print(ActivityInfo.resizeModeToString(td.getResizeMode()));
                 pw.print(" minWidth="); pw.print(td.getMinWidth());
                 pw.print(" minHeight="); pw.print(td.getMinHeight());
+                pw.print(" colorBackgroundFloating=#");
+                pw.print(Integer.toHexString(td.getBackgroundColorFloating()));
                 pw.println(" }");
             }
         }
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index 14f1e0e20ef6..f13f859681e1 100644
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -9193,6 +9193,9 @@
         <!-- @hide From Theme.colorBackground, used for the TaskDescription background
                    color. -->
         <attr name="colorBackground" />
+        <!-- @hide From Theme.colorBackgroundFloating, used for the TaskDescription background
+                   color floating. -->
+        <attr name="colorBackgroundFloating" />
         <!-- @hide From Theme.statusBarColor, used for the TaskDescription status bar color. -->
         <attr name="statusBarColor"/>
         <!-- @hide From Theme.navigationBarColor, used for the TaskDescription navigation bar
diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index 5e0cda69911b..57ea2b2aeca1 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -4636,6 +4636,23 @@
          corners of the activity won't be rounded. -->
     <integer name="config_letterboxActivityCornersRadius">0</integer>
 
+    <!-- Corners appearance of the letterbox background.
+            0 - Solid background using color specified in R.color.config_letterboxBackgroundColor.
+            1 - Color specified in R.attr.colorBackground for the letterboxed application.
+            2 - Color specified in R.attr.colorBackgroundFloating for the letterboxed application.
+        If given value is outside of this range, the option 0 will be assummed. -->
+    <integer name="config_letterboxBackgroundType">0</integer>
+
+    <!-- Color of the letterbox background if one following conditions is true
+            - Option 0 is selected for R.integer.config_letterboxBackgroundType.
+            - Option 1 is selected for R.integer.config_letterboxBackgroundType and
+            R.attr.colorBackground isn't specified for the app.
+            - Option 2 is selected for R.integer.config_letterboxBackgroundType and
+            R.attr.colorBackgroundFloating isn't specified for the app.
+        Defaults to black if not specified.
+     -->
+    <color name="config_letterboxBackgroundColor">#000</color>
+
     <!-- If true, hide the display cutout with display area -->
     <bool name="config_hideDisplayCutoutWithDisplayArea">false</bool>
 
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index dfccdf4bd9a5..4611bf7e12e1 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -4133,6 +4133,8 @@
 
   <java-symbol type="dimen" name="config_taskLetterboxAspectRatio" />
   <java-symbol type="integer" name="config_letterboxActivityCornersRadius" />
+  <java-symbol type="integer" name="config_letterboxBackgroundType" />
+  <java-symbol type="color" name="config_letterboxBackgroundColor" />
 
   <java-symbol type="bool" name="config_hideDisplayCutoutWithDisplayArea" />
 
diff --git a/core/tests/coretests/src/android/app/activity/ActivityManagerTest.java b/core/tests/coretests/src/android/app/activity/ActivityManagerTest.java
index 0c351d149d8b..81eb213ce78a 100644
--- a/core/tests/coretests/src/android/app/activity/ActivityManagerTest.java
+++ b/core/tests/coretests/src/android/app/activity/ActivityManagerTest.java
@@ -132,7 +132,8 @@ public class ActivityManagerTest extends AndroidTestCase {
                 true,                    // ensureNavigationBarContrastWhenTransparent
                 RESIZE_MODE_RESIZEABLE,  // resizeMode
                 10,                      // minWidth
-                20                       // minHeight
+                20,                      // minHeight
+                0                        // colorBackgroundFloating
         );
 
         TaskDescription td2 = new TaskDescription();
@@ -155,7 +156,8 @@ public class ActivityManagerTest extends AndroidTestCase {
                 false,                     // ensureNavigationBarContrastWhenTransparent
                 RESIZE_MODE_UNRESIZEABLE,  // resizeMode
                 10,                        // minWidth
-                20                         // minHeight
+                20,                        // minHeight
+                0                          // colorBackgroundFloating
         );
 
         TaskDescription td2 = new TaskDescription(
@@ -169,7 +171,8 @@ public class ActivityManagerTest extends AndroidTestCase {
                 true,                    // ensureNavigationBarContrastWhenTransparent
                 RESIZE_MODE_RESIZEABLE,  // resizeMode
                 102,                     // minWidth
-                202                      // minHeight
+                202,                     // minHeight
+                0                        // colorBackgroundFloating
         );
 
         // Must overwrite all public and hidden fields, since other has all fields set.
@@ -198,7 +201,8 @@ public class ActivityManagerTest extends AndroidTestCase {
                 false,                     // ensureNavigationBarContrastWhenTransparent
                 RESIZE_MODE_UNRESIZEABLE,  // resizeMode
                 10,                        // minWidth
-                20                         // minHeight
+                20,                        // minHeight
+                0                          // colorBackgroundFloating
         );
 
         // Normal parceling should keep everything the same.
@@ -219,7 +223,8 @@ public class ActivityManagerTest extends AndroidTestCase {
                 false,                     // ensureNavigationBarContrastWhenTransparent
                 RESIZE_MODE_UNRESIZEABLE,  // resizeMode
                 10,                        // minWidth
-                20                         // minHeight
+                20,                        // minHeight
+                0                          // colorBackgroundFloating
         );
         // Recycled bitmap will be ignored while parceling.
         tdParcelled = new TaskDescription(parcelingRoundTrip(tdBitmapRecycled));
diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index b1da2f0fe888..f043a60d5c5e 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -204,6 +204,9 @@ import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_ANIM;
 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_LAYOUT_REPEATS;
 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_STARTING_WINDOW_VERBOSE;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND;
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING;
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_SOLID_COLOR;
 import static com.android.server.wm.WindowManagerService.UPDATE_FOCUS_NORMAL;
 import static com.android.server.wm.WindowManagerService.UPDATE_FOCUS_WILL_PLACE_SURFACES;
 import static com.android.server.wm.WindowState.LEGACY_POLICY_VISIBILITY;
@@ -249,6 +252,7 @@ import android.content.res.CompatibilityInfo;
 import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
+import android.graphics.Color;
 import android.graphics.PixelFormat;
 import android.graphics.Point;
 import android.graphics.Rect;
@@ -321,6 +325,7 @@ import com.android.server.wm.ActivityMetricsLogger.TransitionInfoSnapshot;
 import com.android.server.wm.SurfaceAnimator.AnimationType;
 import com.android.server.wm.Task.ActivityState;
 import com.android.server.wm.WindowManagerService.H;
+import com.android.server.wm.WindowManagerService.LetterboxBackgroundType;
 import com.android.server.wm.utils.InsetUtils;
 
 import com.google.android.collect.Sets;
@@ -859,6 +864,9 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
                         pw.print(Integer.toHexString(taskDescription.getStatusBarColor()));
                         pw.print(" navigationBarColor=");
                         pw.println(Integer.toHexString(taskDescription.getNavigationBarColor()));
+                        pw.print(" backgroundColorFloating=");
+                        pw.println(Integer.toHexString(
+                                taskDescription.getBackgroundColorFloating()));
             }
         }
         if (results != null) {
@@ -1361,7 +1369,8 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
             if (mLetterbox == null) {
                 mLetterbox = new Letterbox(() -> makeChildSurface(null),
                         mWmService.mTransactionFactory,
-                        mWmService::isLetterboxActivityCornersRounded);
+                        mWmService::isLetterboxActivityCornersRounded,
+                        this::getLetterboxBackgroundColor);
                 mLetterbox.attachInput(w);
             }
             getPosition(mTmpPoint);
@@ -1381,6 +1390,31 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
         }
     }
 
+    private Color getLetterboxBackgroundColor() {
+        final WindowState w = findMainWindow();
+        if (w == null || w.isLetterboxedForDisplayCutout()) {
+            return Color.valueOf(Color.BLACK);
+        }
+        @LetterboxBackgroundType int letterboxBackgroundType =
+                mWmService.getLetterboxBackgroundType();
+        switch (letterboxBackgroundType) {
+            case LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING:
+                if (taskDescription != null && taskDescription.getBackgroundColorFloating() != 0) {
+                    return Color.valueOf(taskDescription.getBackgroundColorFloating());
+                }
+                return mWmService.getLetterboxBackgroundColor();
+            case LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND:
+                if (taskDescription != null && taskDescription.getBackgroundColor() != 0) {
+                    return Color.valueOf(taskDescription.getBackgroundColor());
+                }
+                // Falling through
+            case LETTERBOX_BACKGROUND_SOLID_COLOR:
+                return mWmService.getLetterboxBackgroundColor();
+        }
+        throw new AssertionError(
+                "Unexpected letterbox background type: " + letterboxBackgroundType);
+    }
+
     /** @return {@code true} when main window is letterboxed and activity isn't transparent. */
     private boolean isLetterboxed(WindowState mainWindow) {
         return mainWindow.isLetterboxedAppWindow() && fillsParent();
diff --git a/services/core/java/com/android/server/wm/Letterbox.java b/services/core/java/com/android/server/wm/Letterbox.java
index 02a43b74aa33..2274a4a91595 100644
--- a/services/core/java/com/android/server/wm/Letterbox.java
+++ b/services/core/java/com/android/server/wm/Letterbox.java
@@ -19,6 +19,7 @@ package com.android.server.wm;
 import static android.os.IInputConstants.DEFAULT_DISPATCHING_TIMEOUT_MILLIS;
 import static android.view.SurfaceControl.HIDDEN;
 
+import android.graphics.Color;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.os.IBinder;
@@ -45,6 +46,8 @@ public class Letterbox {
     private final Supplier<SurfaceControl.Builder> mSurfaceControlFactory;
     private final Supplier<SurfaceControl.Transaction> mTransactionFactory;
     private final Supplier<Boolean> mAreCornersRounded;
+    private final Supplier<Color> mColorSupplier;
+
     private final Rect mOuter = new Rect();
     private final Rect mInner = new Rect();
     private final LetterboxSurface mTop = new LetterboxSurface("top");
@@ -64,10 +67,12 @@ public class Letterbox {
      */
     public Letterbox(Supplier<SurfaceControl.Builder> surfaceControlFactory,
             Supplier<SurfaceControl.Transaction> transactionFactory,
-            Supplier<Boolean> areCornersRounded) {
+            Supplier<Boolean> areCornersRounded,
+            Supplier<Color> colorSupplier) {
         mSurfaceControlFactory = surfaceControlFactory;
         mTransactionFactory = transactionFactory;
         mAreCornersRounded = areCornersRounded;
+        mColorSupplier = colorSupplier;
     }
 
     /**
@@ -268,6 +273,7 @@ public class Letterbox {
 
         private final String mType;
         private SurfaceControl mSurface;
+        private Color mColor;
 
         private final Rect mSurfaceFrameRelative = new Rect();
         private final Rect mLayoutFrameGlobal = new Rect();
@@ -292,9 +298,8 @@ public class Letterbox {
                     .setColorLayer()
                     .setCallsite("LetterboxSurface.createSurface")
                     .build();
-            t.setLayer(mSurface, -1)
-                    .setColor(mSurface, new float[]{0, 0, 0})
-                    .setColorSpaceAgnostic(mSurface, true);
+
+            t.setLayer(mSurface, -1).setColorSpaceAgnostic(mSurface, true);
         }
 
         void attachInput(WindowState win) {
@@ -344,6 +349,14 @@ public class Letterbox {
                 if (mSurface == null) {
                     createSurface(t);
                 }
+
+                mColor = mColorSupplier.get();
+                final float[] rgbTmpFloat = new float[3];
+                rgbTmpFloat[0] = mColor.red();
+                rgbTmpFloat[1] = mColor.green();
+                rgbTmpFloat[2] = mColor.blue();
+                t.setColor(mSurface, rgbTmpFloat);
+
                 t.setPosition(mSurface, mSurfaceFrameRelative.left, mSurfaceFrameRelative.top);
                 t.setWindowCrop(mSurface, mSurfaceFrameRelative.width(),
                         mSurfaceFrameRelative.height());
@@ -358,7 +371,8 @@ public class Letterbox {
         }
 
         public boolean needsApplySurfaceChanges() {
-            return !mSurfaceFrameRelative.equals(mLayoutFrameRelative);
+            return !mSurfaceFrameRelative.equals(mLayoutFrameRelative)
+                    || mColorSupplier.get() != mColor;
         }
     }
 }
diff --git a/services/core/java/com/android/server/wm/Task.java b/services/core/java/com/android/server/wm/Task.java
index 6a3110f52c91..689442619a4a 100644
--- a/services/core/java/com/android/server/wm/Task.java
+++ b/services/core/java/com/android/server/wm/Task.java
@@ -2090,7 +2090,9 @@ class Task extends WindowContainer<WindowContainer> {
                 td.setEnsureNavigationBarContrastWhenTransparent(
                         atd.getEnsureNavigationBarContrastWhenTransparent());
             }
-
+            if (td.getBackgroundColorFloating() == 0) {
+                td.setBackgroundColorFloating(atd.getBackgroundColorFloating());
+            }
         }
 
         // End search once we get to root.
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 931f52933e2a..b334c2a5516b 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -160,6 +160,7 @@ import android.content.res.Configuration;
 import android.content.res.TypedArray;
 import android.database.ContentObserver;
 import android.graphics.Bitmap;
+import android.graphics.Color;
 import android.graphics.Insets;
 import android.graphics.Matrix;
 import android.graphics.Point;
@@ -1010,10 +1011,30 @@ public class WindowManagerService extends IWindowManager.Stub
 
     // Aspect ratio of task level letterboxing, values <= MIN_TASK_LETTERBOX_ASPECT_RATIO will be
     // ignored.
-    private float mTaskLetterboxAspectRatio;
+    private volatile float mTaskLetterboxAspectRatio;
+
+    /** Enum for Letterbox background type. */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({LETTERBOX_BACKGROUND_SOLID_COLOR, LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND,
+            LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING})
+    @interface LetterboxBackgroundType {};
+    /** Solid background using color specified in R.color.config_letterboxBackgroundColor. */
+    static final int LETTERBOX_BACKGROUND_SOLID_COLOR = 0;
+
+    /** Color specified in R.attr.colorBackground for the letterboxed application. */
+    static final int LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND = 1;
+
+    /** Color specified in R.attr.colorBackgroundFloating for the letterboxed application. */
+    static final int LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING = 2;
 
     // Corners radius for activities presented in the letterbox mode, values < 0 will be ignored.
-    private int mLetterboxActivityCornersRadius;
+    private volatile int mLetterboxActivityCornersRadius;
+
+    // Color for {@link #LETTERBOX_BACKGROUND_SOLID_COLOR} letterbox background type.
+    private volatile Color mLetterboxBackgroundColor;
+
+    @LetterboxBackgroundType
+    private volatile int mLetterboxBackgroundType;
 
     final InputManagerService mInputManager;
     final DisplayManagerInternal mDisplayManagerInternal;
@@ -1240,10 +1261,15 @@ public class WindowManagerService extends IWindowManager.Stub
                 com.android.internal.R.bool.config_perDisplayFocusEnabled);
         mAssistantOnTopOfDream = context.getResources().getBoolean(
                 com.android.internal.R.bool.config_assistantOnTopOfDream);
+
         mTaskLetterboxAspectRatio = context.getResources().getFloat(
                 com.android.internal.R.dimen.config_taskLetterboxAspectRatio);
         mLetterboxActivityCornersRadius = context.getResources().getInteger(
                 com.android.internal.R.integer.config_letterboxActivityCornersRadius);
+        mLetterboxBackgroundColor = Color.valueOf(context.getResources().getColor(
+                com.android.internal.R.color.config_letterboxBackgroundColor));
+        mLetterboxBackgroundType = readLetterboxBackgroundTypeFromConfig(context);
+
         mInputManager = inputManager; // Must be before createDisplayContentLocked.
         mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
 
@@ -3901,14 +3927,7 @@ public class WindowManagerService extends IWindowManager.Stub
      * the framework implementation will be used to determine the aspect ratio.
      */
     void setTaskLetterboxAspectRatio(float aspectRatio) {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                mTaskLetterboxAspectRatio = aspectRatio;
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        mTaskLetterboxAspectRatio = aspectRatio;
     }
 
     /**
@@ -3916,29 +3935,15 @@ public class WindowManagerService extends IWindowManager.Stub
      * com.android.internal.R.dimen.config_taskLetterboxAspectRatio}.
      */
     void resetTaskLetterboxAspectRatio() {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                mTaskLetterboxAspectRatio = mContext.getResources().getFloat(
-                            com.android.internal.R.dimen.config_taskLetterboxAspectRatio);
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        mTaskLetterboxAspectRatio = mContext.getResources().getFloat(
+                com.android.internal.R.dimen.config_taskLetterboxAspectRatio);
     }
 
     /**
      * Gets the aspect ratio of task level letterboxing.
      */
     float getTaskLetterboxAspectRatio() {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                return mTaskLetterboxAspectRatio;
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        return mTaskLetterboxAspectRatio;
     }
 
     /**
@@ -3948,14 +3953,7 @@ public class WindowManagerService extends IWindowManager.Stub
      * and corners of the activity won't be rounded.
      */
     void setLetterboxActivityCornersRadius(int cornersRadius) {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                mLetterboxActivityCornersRadius = cornersRadius;
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        mLetterboxActivityCornersRadius = cornersRadius;
     }
 
     /**
@@ -3963,15 +3961,8 @@ public class WindowManagerService extends IWindowManager.Stub
      * com.android.internal.R.integer.config_letterboxActivityCornersRadius}.
      */
     void resetLetterboxActivityCornersRadius() {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                mLetterboxActivityCornersRadius = mContext.getResources().getInteger(
-                            com.android.internal.R.integer.config_letterboxActivityCornersRadius);
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        mLetterboxActivityCornersRadius = mContext.getResources().getInteger(
+                com.android.internal.R.integer.config_letterboxActivityCornersRadius);
     }
 
     /**
@@ -3985,14 +3976,67 @@ public class WindowManagerService extends IWindowManager.Stub
      * Gets corners raidus for activities presented in the letterbox mode.
      */
     int getLetterboxActivityCornersRadius() {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                return mLetterboxActivityCornersRadius;
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
+        return mLetterboxActivityCornersRadius;
+    }
+
+    /**
+     * Gets color of letterbox background which is  used when {@link
+     * #getLetterboxBackgroundType()} is {@link #LETTERBOX_BACKGROUND_SOLID_COLOR} or as
+     * fallback for other backfround types.
+     */
+    Color getLetterboxBackgroundColor() {
+        return mLetterboxBackgroundColor;
+    }
+
+
+    /**
+     * Sets color of letterbox background which is used when {@link
+     * #getLetterboxBackgroundType()} is {@link #LETTERBOX_BACKGROUND_SOLID_COLOR} or as
+     * fallback for other backfround types.
+     */
+    void setLetterboxBackgroundColor(Color color) {
+        mLetterboxBackgroundColor = color;
+    }
+
+    /**
+     * Resets color of letterbox background to {@link
+     * com.android.internal.R.color.config_letterboxBackgroundColor}.
+     */
+    void resetLetterboxBackgroundColor() {
+        mLetterboxBackgroundColor = Color.valueOf(mContext.getResources().getColor(
+                com.android.internal.R.color.config_letterboxBackgroundColor));
+    }
+
+    /**
+     * Gets {@link LetterboxBackgroundType} specified in {@link
+     * com.android.internal.R.integer.config_letterboxBackgroundType} or over via ADB command.
+     */
+    @LetterboxBackgroundType
+    int getLetterboxBackgroundType() {
+        return mLetterboxBackgroundType;
+    }
+
+    /** Sets letterbox background type. */
+    void setLetterboxBackgroundType(@LetterboxBackgroundType int backgroundType) {
+        mLetterboxBackgroundType = backgroundType;
+    }
+
+    /**
+     * Resets cletterbox background type to {@link
+     * com.android.internal.R.integer.config_letterboxBackgroundType}.
+     */
+    void resetLetterboxBackgroundType() {
+        mLetterboxBackgroundType = readLetterboxBackgroundTypeFromConfig(mContext);
+    }
+
+    @LetterboxBackgroundType
+    private static int readLetterboxBackgroundTypeFromConfig(Context context) {
+        int backgroundType = context.getResources().getInteger(
+                com.android.internal.R.integer.config_letterboxBackgroundType);
+        return backgroundType == LETTERBOX_BACKGROUND_SOLID_COLOR
+                    || backgroundType == LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND
+                    || backgroundType == LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING
+                    ? backgroundType : LETTERBOX_BACKGROUND_SOLID_COLOR;
     }
 
     @Override
diff --git a/services/core/java/com/android/server/wm/WindowManagerShellCommand.java b/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
index badd29aba968..645786c02fc0 100644
--- a/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
+++ b/services/core/java/com/android/server/wm/WindowManagerShellCommand.java
@@ -18,6 +18,11 @@ package com.android.server.wm;
 
 import static android.os.Build.IS_USER;
 
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND;
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING;
+import static com.android.server.wm.WindowManagerService.LETTERBOX_BACKGROUND_SOLID_COLOR;
+
+import android.graphics.Color;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.os.ParcelFileDescriptor;
@@ -34,6 +39,7 @@ import com.android.internal.os.ByteTransferPipe;
 import com.android.internal.protolog.ProtoLogImpl;
 import com.android.server.LocalServices;
 import com.android.server.statusbar.StatusBarManagerInternal;
+import com.android.server.wm.WindowManagerService.LetterboxBackgroundType;
 
 import java.io.IOException;
 import java.io.PrintWriter;
@@ -119,6 +125,14 @@ public class WindowManagerShellCommand extends ShellCommand {
                     return runSetLetterboxActivityCornersRadius(pw);
                 case "get-letterbox-activity-corners-radius":
                     return runGetLetterboxActivityCornersRadius(pw);
+                case "set-letterbox-background-type":
+                    return runSetLetterboxBackgroundType(pw);
+                case "get-letterbox-background-type":
+                    return runGetLetterboxBackgroundType(pw);
+                case "set-letterbox-background-color":
+                    return runSetLetterboxBackgroundColor(pw);
+                case "get-letterbox-background-color":
+                    return runGetLetterboxBackgroundColor(pw);
                 case "reset":
                     return runReset(pw);
                 default:
@@ -581,6 +595,79 @@ public class WindowManagerShellCommand extends ShellCommand {
         return 0;
     }
 
+    private int runSetLetterboxBackgroundType(PrintWriter pw) throws RemoteException {
+        @LetterboxBackgroundType final int backgroundType;
+
+        String arg = getNextArgRequired();
+        if ("reset".equals(arg)) {
+            mInternal.resetLetterboxBackgroundType();
+            return 0;
+        }
+        switch (arg) {
+            case "solid_color":
+                backgroundType = LETTERBOX_BACKGROUND_SOLID_COLOR;
+                break;
+            case "app_color_background":
+                backgroundType = LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND;
+                break;
+            case "app_color_background_floating":
+                backgroundType = LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING;
+                break;
+            default:
+                getErrPrintWriter().println(
+                        "Error: 'reset', 'solid_color' or 'app_color_background' should "
+                        + "be provided as an argument");
+                return -1;
+        }
+
+        mInternal.setLetterboxBackgroundType(backgroundType);
+        return 0;
+    }
+
+    private int runGetLetterboxBackgroundType(PrintWriter pw) throws RemoteException {
+        @LetterboxBackgroundType final int backgroundType = mInternal.getLetterboxBackgroundType();
+        switch (backgroundType) {
+            case LETTERBOX_BACKGROUND_SOLID_COLOR:
+                pw.println("Letterbox background type is 'solid_color'");
+                break;
+            case LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND:
+                pw.println("Letterbox background type is 'app_color_background'");
+                break;
+            case LETTERBOX_BACKGROUND_APP_COLOR_BACKGROUND_FLOATING:
+                pw.println("Letterbox background type is 'app_color_background_floating'");
+                break;
+            default:
+                throw new AssertionError("Unexpected letterbox background type: " + backgroundType);
+        }
+        return 0;
+    }
+
+    private int runSetLetterboxBackgroundColor(PrintWriter pw) throws RemoteException {
+        final Color color;
+        String arg = getNextArgRequired();
+        try {
+            if ("reset".equals(arg)) {
+                mInternal.resetLetterboxBackgroundColor();
+                return 0;
+            }
+            color = Color.valueOf(Color.parseColor(arg));
+        } catch (IllegalArgumentException  e) {
+            getErrPrintWriter().println(
+                    "Error: 'reset' or color in #RRGGBB format should be provided as "
+                            + "an argument " + e + " but got " + arg);
+            return -1;
+        }
+
+        mInternal.setLetterboxBackgroundColor(color);
+        return 0;
+    }
+
+    private int runGetLetterboxBackgroundColor(PrintWriter pw) throws RemoteException {
+        final Color color = mInternal.getLetterboxBackgroundColor();
+        pw.println("Letterbox background color is " + Integer.toHexString(color.toArgb()));
+        return 0;
+    }
+
     private int runReset(PrintWriter pw) throws RemoteException {
         int displayId = getDisplayId(getNextArg());
 
@@ -611,6 +698,12 @@ public class WindowManagerShellCommand extends ShellCommand {
         // set-letterbox-activity-corners-radius
         mInternal.resetLetterboxActivityCornersRadius();
 
+        // set-letterbox-background-type
+        mInternal.resetLetterboxBackgroundType();
+
+        // set-letterbox-background-color
+        mInternal.resetLetterboxBackgroundColor();
+
         pw.println("Reset all settings for displayId=" + displayId);
         return 0;
     }
@@ -652,6 +745,16 @@ public class WindowManagerShellCommand extends ShellCommand {
         pw.println("    Corners radius for activities in the letterbox mode. If radius < 0,");
         pw.println("    both it and R.integer.config_letterboxActivityCornersRadius will be");
         pw.println("    ignored and corners of the activity won't be rounded.");
+        pw.println("  set-letterbox-background-color [reset|colorName|'\\#RRGGBB']");
+        pw.println("  get-letterbox-background-color");
+        pw.println("    Color of letterbox background which is be used when letterbox background");
+        pw.println("    type is 'solid-color'. Use get(set)-letterbox-background-type to check");
+        pw.println("    and control letterbox background type. See Color#parseColor for allowed");
+        pw.println("    color formats (#RRGGBB and some colors by name, e.g. magenta or olive). ");
+        pw.println("  set-letterbox-background-type [reset|solid_color|app_color_background");
+        pw.println("    |app_color_background_floating]");
+        pw.println("  get-letterbox-background-type");
+        pw.println("    Type of background used in the letterbox mode.");
         pw.println("  reset [-d DISPLAY_ID]");
         pw.println("    Reset all override settings.");
         if (!IS_USER) {
diff --git a/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java b/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
index a045100c4cd8..fa3e3aefea3b 100644
--- a/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/LetterboxTest.java
@@ -29,6 +29,7 @@ import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.graphics.Color;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.platform.test.annotations.Presubmit;
@@ -51,11 +52,13 @@ public class LetterboxTest {
     SurfaceControl.Transaction mTransaction;
 
     private boolean mAreCornersRounded = false;
+    private int mColor = Color.BLACK;
 
     @Before
     public void setUp() throws Exception {
         mSurfaces = new SurfaceControlMocker();
-        mLetterbox = new Letterbox(mSurfaces, StubTransaction::new, () -> mAreCornersRounded);
+        mLetterbox = new Letterbox(mSurfaces, StubTransaction::new,
+                () -> mAreCornersRounded, () -> Color.valueOf(mColor));
         mTransaction = spy(StubTransaction.class);
     }
 
@@ -171,6 +174,18 @@ public class LetterboxTest {
     }
 
     @Test
+    public void testApplySurfaceChanges_setColor() {
+        mLetterbox.layout(new Rect(0, 0, 10, 10), new Rect(0, 1, 10, 10), new Point(1000, 2000));
+        mLetterbox.applySurfaceChanges(mTransaction);
+
+        verify(mTransaction).setColor(mSurfaces.top, new float[]{0, 0, 0});
+
+        mColor = Color.GREEN;
+
+        assertTrue(mLetterbox.needsApplySurfaceChanges());
+    }
+
+    @Test
     public void testApplySurfaceChanges_cornersNotRounded_surfaceBehindNotCreated() {
         mLetterbox.layout(new Rect(0, 0, 10, 10), new Rect(0, 1, 10, 10), new Point(1000, 2000));
         mLetterbox.applySurfaceChanges(mTransaction);