package com.hellotalk.view;

import android.annotation.SuppressLint;

import android.support.v4.view.ViewPager.PageTransformer;

import android.view.View;

/**

 *

 * @author way

 *

 */

@SuppressLint("NewApi")

public class ZoomOutPageTransformer implements PageTransformer {

	private static float MIN_SCALE = 0.85f;

	private static float MIN_ALPHA = 0.5f;

	@Override

	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);

		}

	}

}