/*
 * Copyright (C) 2017 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 com.google.android.material.canvas;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import androidx.annotation.RestrictTo;

/**
 * Compat methods for Canvas.
 *
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public class CanvasCompat {

  private CanvasCompat() {}

  /**
   * Convenience for {@link Canvas#saveLayer(RectF, Paint)} but instead of taking a entire Paint
   * object it takes only the {@code alpha} parameter.
   */
  public static int saveLayerAlpha(Canvas canvas, RectF bounds, int alpha) {
    if (VERSION.SDK_INT > VERSION_CODES.LOLLIPOP) {
      return canvas.saveLayerAlpha(bounds, alpha);
    } else {
      return canvas.saveLayerAlpha(bounds, alpha, Canvas.ALL_SAVE_FLAG);
    }
  }

  /**
   * Convenience for {@link #saveLayerAlpha(Canvas, RectF, int)} that takes the four float
   * coordinates of the bounds rectangle.
   */
  public static int saveLayerAlpha(
      Canvas canvas, float left, float top, float right, float bottom, int alpha) {
    if (VERSION.SDK_INT > VERSION_CODES.LOLLIPOP) {
      return canvas.saveLayerAlpha(left, top, right, bottom, alpha);
    } else {
      return canvas.saveLayerAlpha(left, top, right, bottom, alpha, Canvas.ALL_SAVE_FLAG);
    }
  }
}

@@ -892,16 +892,89 @@
 _CODES;%0A
+import androidx.annotation.NonNull;%0Aimport androidx.annotation.Nullable;%0A
 import a
@@ -1004,16 +1004,16 @@
 rictTo;%0A
-
 %0A/**%0A * 
@@ -1335,24 +1335,33 @@
 eLayerAlpha(
+@NonNull 
 Canvas canva
@@ -1358,24 +1358,34 @@
 nvas canvas,
+ @Nullable
  RectF bound
@@ -1781,22 +1781,31 @@
 rAlpha(%0A
-
       
+@NonNull 
 Canvas c

Add @NonNull and @Nullable annotations