content: package com.cjj.cartoon.viewpageranim;
  
  import android.view.View;
  import android.support.v4.view.ViewPager;
  
  public class ZoomOutPageTransformer implements ViewPager.PageTransformer {
      private static final float MIN_SCALE = 0.85f;
      private static final float MIN_ALPHA = 0.5f;
  
      public void transformPage(View view, float position) {
          int pageWidth = view.getWidth();
          int pageHeight = view.getHeight();
  
          if (position < -1) { // [-Infinity,-1)
              // This page is way off-screen to the left.
              view.setAlpha(0);
  
          } else if (position <= 1) { // [-1,1]
              // Modify the default slide transition to shrink the page as well
              float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
              float vertMargin = pageHeight * (1 - scaleFactor) / 2;
              float horzMargin = pageWidth * (1 - scaleFactor) / 2;
              if (position < 0) {
                  view.setTranslationX(horzMargin - vertMargin / 2);
              } else {
                  view.setTranslationX(-horzMargin + vertMargin / 2);
              }
  
              // Scale the page down (between MIN_SCALE and 1)
              view.setScaleX(scaleFactor);
              view.setScaleY(scaleFactor);
  
              // Fade the page relative to its size.
              view.setAlpha(MIN_ALPHA +
                      (scaleFactor - MIN_SCALE) /
                      (1 - MIN_SCALE) * (1 - MIN_ALPHA));
  
          } else { // (1,+Infinity]
              // This page is way off-screen to the right.
              view.setAlpha(0);
          }
      }
  }