content: /*
   * Copyright (C) 2019 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.graphics.Rect;
  import android.os.IBinder;
  
  import com.android.internal.util.Preconditions;
  
  import java.util.concurrent.Executor;
  
  /**
   * Listener for sampling the result of the screen composition.
   * {@hide}
   */
  public abstract class CompositionSamplingListener {
  
      private long mNativeListener;
      private final Executor mExecutor;
  
      public CompositionSamplingListener(Executor executor) {
          mExecutor = executor;
          mNativeListener = nativeCreate(this);
      }
  
      public void destroy() {
          if (mNativeListener == 0) {
              return;
          }
          unregister(this);
          nativeDestroy(mNativeListener);
          mNativeListener = 0;
      }
  
      @Override
      protected void finalize() throws Throwable {
          try {
              destroy();
          } finally {
              super.finalize();
          }
      }
  
      /**
       * Reports a luma sample from the registered region.
       */
      public abstract void onSampleCollected(float medianLuma);
  
      /**
       * Registers a sampling listener.
       */
      public static void register(CompositionSamplingListener listener,
              int displayId, IBinder stopLayer, Rect samplingArea) {
          if (listener.mNativeListener == 0) {
              return;
          }
          Preconditions.checkArgument(displayId == Display.DEFAULT_DISPLAY,
                  "default display only for now");
          nativeRegister(listener.mNativeListener, stopLayer, samplingArea.left, samplingArea.top,
                  samplingArea.right, samplingArea.bottom);
      }
  
      /**
       * Unregisters a sampling listener.
       */
      public static void unregister(CompositionSamplingListener listener) {
          if (listener.mNativeListener == 0) {
              return;
          }
          nativeUnregister(listener.mNativeListener);
      }
  
      /**
       * Dispatch the collected sample.
       *
       * Called from native code on a binder thread.
       */
      private static void dispatchOnSampleCollected(CompositionSamplingListener listener,
              float medianLuma) {
          listener.mExecutor.execute(() -> listener.onSampleCollected(medianLuma));
      }
  
      private static native long nativeCreate(CompositionSamplingListener thiz);
      private static native void nativeDestroy(long ptr);
      private static native void nativeRegister(long ptr, IBinder stopLayer,
              int samplingAreaLeft, int top, int right, int bottom);
      private static native void nativeUnregister(long ptr);
  }
  