1 files changed, 53 insertions, 0 deletions
diff --git a/core/java/android/view/ViewRoot.java b/core/java/android/view/ViewRoot.java
new file mode 100644
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+++ b/core/java/android/view/ViewRoot.java
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+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.view;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.UiThread;
+
+/**
+ * Provides an interface to the root-Surface of a View Hierarchy or Window. This
+ * is used in combination with the {@link android.view.SurfaceControl} API to enable
+ * attaching app created SurfaceControl to the ViewRoot's surface hierarchy, and enable
+ * SurfaceTransactions to be performed in sync with the ViewRoot drawing. This object
+ * is obtained from {@link android.view.View#getViewRoot} and
+ * {@link android.view.Window#getViewRoot}. It must be used from the UI thread of
+ * the object it was obtained from.
+ */
+@UiThread
+public interface ViewRoot {
+    /**
+     * Create a transaction which will reparent {@param child} to the ViewRoot. See
+     * {@link SurfaceControl.Transaction#reparent}. This transacton must be applied
+     * or merged in to another transaction by the caller, otherwise it will have
+     * no effect.
+     *
+     * @param child The SurfaceControl to reparent.
+     * @return A new transaction which performs the reparent operation when applied.
+     */
+    @Nullable SurfaceControl.Transaction buildReparentTransaction(@NonNull SurfaceControl child);
+
+    /**
+     * Consume the passed in transaction, and request the ViewRoot to apply it with the
+     * next draw. This transaction will be merged with the buffer transaction from the ViewRoot
+     * and they will show up on-screen atomically synced.
+     *
+     * This will not cause a draw to be scheduled, and if there are no other changes
+     * to the View hierarchy you may need to call {@link android.view.View#invalidate}
+     */
+    boolean applyTransactionOnDraw(@NonNull SurfaceControl.Transaction t);
+}