content: /*
   * Copyright (C) 2014 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.Outline;
  import android.graphics.drawable.Drawable;
  
  /**
   * Interface by which a View builds its {@link Outline}, used for shadow casting and clipping.
   */
  public abstract class ViewOutlineProvider {
      /**
       * Default outline provider for Views, which queries the Outline from the View's background,
       * or generates a 0 alpha, rectangular Outline the size of the View if a background
       * isn't present.
       *
       * @see Drawable#getOutline(Outline)
       */
      public static final ViewOutlineProvider BACKGROUND = new ViewOutlineProvider() {
          @Override
          public void getOutline(View view, Outline outline) {
              Drawable background = view.getBackground();
              if (background != null) {
                  background.getOutline(outline);
              } else {
                  outline.setRect(0, 0, view.getWidth(), view.getHeight());
                  outline.setAlpha(0.0f);
              }
          }
      };
  
      /**
       * Maintains the outline of the View to match its rectangular bounds,
       * at <code>1.0f</code> alpha.
       *
       * This can be used to enable Views that are opaque but lacking a background cast a shadow.
       */
      public static final ViewOutlineProvider BOUNDS = new ViewOutlineProvider() {
          @Override
          public void getOutline(View view, Outline outline) {
              outline.setRect(0, 0, view.getWidth(), view.getHeight());
          }
      };
  
      /**
       * Maintains the outline of the View to match its rectangular padded bounds,
       * at <code>1.0f</code> alpha.
       *
       * This can be used to enable Views that are opaque but lacking a background cast a shadow.
       */
      public static final ViewOutlineProvider PADDED_BOUNDS = new ViewOutlineProvider() {
          @Override
          public void getOutline(View view, Outline outline) {
              outline.setRect(view.getPaddingLeft(),
                      view.getPaddingTop(),
                      view.getWidth() - view.getPaddingRight(),
                      view.getHeight() - view.getPaddingBottom());
          }
      };
  
      /**
       * Called to get the provider to populate the Outline.
       *
       * This method will be called by a View when its owned Drawables are invalidated, when the
       * View's size changes, or if {@link View#invalidateOutline()} is called
       * explicitly.
       *
       * The input outline is empty and has an alpha of <code>1.0f</code>.
       *
       * @param view The view building the outline.
       * @param outline The empty outline to be populated.
       */
      public abstract void getOutline(View view, Outline outline);
  }
  