content: /*
   * Copyright (C) 2016 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.exoplayer2.ui;
  
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.support.annotation.IntDef;
  import android.util.AttributeSet;
  import android.widget.FrameLayout;
  
  import com.example.exoplayer.R;
  
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  
  /**
   * A {@link FrameLayout} that resizes itself to match a specified aspect ratio.
   */
  public final class AspectRatioFrameLayout extends FrameLayout {
  
    // LINT.IfChange
    /** Resize modes for {@link AspectRatioFrameLayout}. */
    @Retention(RetentionPolicy.SOURCE)
    @IntDef({
      RESIZE_MODE_FIT,
      RESIZE_MODE_FIXED_WIDTH,
      RESIZE_MODE_FIXED_HEIGHT,
      RESIZE_MODE_FILL,
      RESIZE_MODE_ZOOM
    })
    public @interface ResizeMode {}
  
    /**
     * Either the width or height is decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIT = 0;
    /**
     * The width is fixed and the height is increased or decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIXED_WIDTH = 1;
    /**
     * The height is fixed and the width is increased or decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIXED_HEIGHT = 2;
    /**
     * The specified aspect ratio is ignored.
     */
    public static final int RESIZE_MODE_FILL = 3;
    /**
     * Either the width or height is increased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_ZOOM = 4;
    // LINT.ThenChange(../../../../../../res/values/attrs.xml)
  
    /**
     * The {@link FrameLayout} will not resize itself if the fractional difference between its natural
     * aspect ratio and the requested aspect ratio falls below this threshold.
     *
     * <p>This tolerance allows the view to occupy the whole of the screen when the requested aspect
     * ratio is very close, but not exactly equal to, the aspect ratio of the screen. This may reduce
     * the number of view layers that need to be composited by the underlying system, which can help
     * to reduce power consumption.
     */
    private static final float MAX_ASPECT_RATIO_DEFORMATION_FRACTION = 0.01f;
  
    private float videoAspectRatio;
    private int resizeMode;
  
    public AspectRatioFrameLayout(Context context) {
      this(context, null);
    }
  
    public AspectRatioFrameLayout(Context context, AttributeSet attrs) {
      super(context, attrs);
      resizeMode = RESIZE_MODE_FIT;
      if (attrs != null) {
        TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
            R.styleable.AspectRatioFrameLayout, 0, 0);
        try {
          resizeMode = a.getInt(R.styleable.AspectRatioFrameLayout_resize_mode, RESIZE_MODE_FIT);
        } finally {
          a.recycle();
        }
      }
    }
  
    /**
     * Sets the aspect ratio that this view should satisfy.
     *
     * @param widthHeightRatio The width to height ratio.
     */
    public void setAspectRatio(float widthHeightRatio) {
      if (this.videoAspectRatio != widthHeightRatio) {
        this.videoAspectRatio = widthHeightRatio;
        requestLayout();
      }
    }
  
    /**
     * Returns the resize mode.
     */
    public @ResizeMode int getResizeMode() {
      return resizeMode;
    }
  
    /**
     * Sets the resize mode.
     *
     * @param resizeMode The resize mode.
     */
    public void setResizeMode(@ResizeMode int resizeMode) {
      if (this.resizeMode != resizeMode) {
        this.resizeMode = resizeMode;
        requestLayout();
      }
    }
  
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      super.onMeasure(widthMeasureSpec, heightMeasureSpec);
      if (resizeMode == RESIZE_MODE_FILL || videoAspectRatio <= 0) {
        // Aspect ratio not set.
        return;
      }
  
      int width = getMeasuredWidth();
      int height = getMeasuredHeight();
      float viewAspectRatio = (float) width / height;
      float aspectDeformation = videoAspectRatio / viewAspectRatio - 1;
      if (Math.abs(aspectDeformation) <= MAX_ASPECT_RATIO_DEFORMATION_FRACTION) {
        // We're within the allowed tolerance.
        return;
      }
  
      switch (resizeMode) {
        case RESIZE_MODE_FIXED_WIDTH:
          height = (int) (width / videoAspectRatio);
          break;
        case RESIZE_MODE_FIXED_HEIGHT:
          width = (int) (height * videoAspectRatio);
          break;
        case RESIZE_MODE_ZOOM:
          if (aspectDeformation > 0) {
            width = (int) (height * videoAspectRatio);
          } else {
            height = (int) (width / videoAspectRatio);
          }
          break;
        default:
          if (aspectDeformation > 0) {
            height = (int) (width / videoAspectRatio);
          } else {
            width = (int) (height * videoAspectRatio);
          }
          break;
      }
      super.onMeasure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
          MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
    }
  
  }
  