diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index 91c849c4110f6..0598680f8c5d4 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -6683,6 +6683,13 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
         return task != null ? task.getBounds() : getBounds();
     }
 
+    @Override
+    void getAnimationPosition(Point outPosition) {
+        // Always animate from zero because if the activity doesn't fill the task, the letterbox
+        // will fill the remaining area that should be included in the animation.
+        outPosition.set(0, 0);
+    }
+
     @Override
     public void onConfigurationChanged(Configuration newParentConfig) {
         if (mCompatDisplayInsets != null) {
diff --git a/services/core/java/com/android/server/wm/WindowContainer.java b/services/core/java/com/android/server/wm/WindowContainer.java
index 5d7ec127da464..7bfddd79f8a44 100644
--- a/services/core/java/com/android/server/wm/WindowContainer.java
+++ b/services/core/java/com/android/server/wm/WindowContainer.java
@@ -2120,6 +2120,11 @@ class WindowContainer<E extends WindowContainer> extends ConfigurationContainer<
         return getBounds();
     }
 
+    /** Gets the position relative to parent for animation. */
+    void getAnimationPosition(Point outPosition) {
+        getRelativePosition(outPosition);
+    }
+
     /**
      * Applies the app transition animation according the given the layout properties in the
      * window hierarchy.
@@ -2178,9 +2183,9 @@ class WindowContainer<E extends WindowContainer> extends ConfigurationContainer<
 
         // Separate position and size for use in animators.
         mTmpRect.set(getAnimationBounds(appStackClipMode));
-        if (sHierarchicalAnimations) {
-            getRelativePosition(mTmpPoint);
-        } else {
+        getAnimationPosition(mTmpPoint);
+        if (!sHierarchicalAnimations) {
+            // Non-hierarchical animation uses position in global coordinates.
             mTmpPoint.set(mTmpRect.left, mTmpRect.top);
         }
         mTmpRect.offsetTo(0, 0);
diff --git a/services/tests/wmtests/src/com/android/server/wm/AppWindowTokenTests.java b/services/tests/wmtests/src/com/android/server/wm/AppWindowTokenTests.java
index 8f18f648f8f0a..07050d9666d5b 100644
--- a/services/tests/wmtests/src/com/android/server/wm/AppWindowTokenTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/AppWindowTokenTests.java
@@ -52,6 +52,7 @@ import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.verify;
 
 import android.content.res.Configuration;
+import android.graphics.Point;
 import android.graphics.Rect;
 import android.platform.test.annotations.Presubmit;
 import android.view.IWindowManager;
@@ -432,20 +433,35 @@ public class AppWindowTokenTests extends WindowTestsBase {
         removeGlobalMinSizeRestriction();
         final Rect stackBounds = new Rect(0, 0, 1000, 600);
         final Rect taskBounds = new Rect(100, 400, 600, 800);
-        mStack.setBounds(stackBounds);
-        mTask.setBounds(taskBounds);
+        // Set the bounds and windowing mode to window configuration directly, otherwise the
+        // testing setups may be discarded by configuration resolving.
+        mStack.getWindowConfiguration().setBounds(stackBounds);
+        mTask.getWindowConfiguration().setBounds(taskBounds);
+        mActivity.getWindowConfiguration().setBounds(taskBounds);
 
         // Check that anim bounds for freeform window match task bounds
-        mTask.setWindowingMode(WINDOWING_MODE_FREEFORM);
+        mTask.getWindowConfiguration().setWindowingMode(WINDOWING_MODE_FREEFORM);
         assertEquals(mTask.getBounds(), mActivity.getAnimationBounds(STACK_CLIP_NONE));
 
         // STACK_CLIP_AFTER_ANIM should use task bounds since they will be clipped by
         // bounds animation layer.
-        mTask.setWindowingMode(WINDOWING_MODE_FULLSCREEN);
+        mTask.getWindowConfiguration().setWindowingMode(WINDOWING_MODE_FULLSCREEN);
         assertEquals(mTask.getBounds(), mActivity.getAnimationBounds(STACK_CLIP_AFTER_ANIM));
 
+        // Even the activity is smaller than task and it is not aligned to the top-left corner of
+        // task, the animation bounds the same as task and position should be zero because in real
+        // case the letterbox will fill the remaining area in task.
+        final Rect halfBounds = new Rect(taskBounds);
+        halfBounds.scale(0.5f);
+        mActivity.getWindowConfiguration().setBounds(halfBounds);
+        final Point animationPosition = new Point();
+        mActivity.getAnimationPosition(animationPosition);
+
+        assertEquals(taskBounds, mActivity.getAnimationBounds(STACK_CLIP_AFTER_ANIM));
+        assertEquals(new Point(0, 0), animationPosition);
+
         // STACK_CLIP_BEFORE_ANIM should use stack bounds since it won't be clipped later.
-        mTask.setWindowingMode(WINDOWING_MODE_SPLIT_SCREEN_PRIMARY);
+        mTask.getWindowConfiguration().setWindowingMode(WINDOWING_MODE_SPLIT_SCREEN_PRIMARY);
         assertEquals(mStack.getBounds(), mActivity.getAnimationBounds(STACK_CLIP_BEFORE_ANIM));
     }