content: /*
   * Copyright 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 androidx.car.app.sample.showcase.common.renderer;
  
  import android.graphics.Canvas;
  import android.graphics.Rect;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  
  /** A renderer for use on templates with a surface. */
  public interface Renderer {
      /**
       * Informs the renderer that it will receive {@link #renderFrame} calls.
       *
       * @param onChangeListener a runnable that will initiate a render pass in the controller
       */
      void enable(@NonNull Runnable onChangeListener);
  
      /** Informs the renderer that it will no longer receive {@link #renderFrame} calls. */
      void disable();
  
      /** Request that a frame should be drawn to the supplied canvas. */
      void renderFrame(@NonNull Canvas canvas, @Nullable Rect visibleArea, @Nullable Rect stableArea);
  }
  