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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.gallery3d.ui;
     18 
     19 import android.view.animation.AccelerateDecelerateInterpolator;
     20 import android.view.animation.AccelerateInterpolator;
     21 import android.view.animation.DecelerateInterpolator;
     22 import android.view.animation.Interpolator;
     23 
     24 public class CaptureAnimation {
     25     // The amount of change for zooming out.
     26     private static final float ZOOM_DELTA = 0.2f;
     27     // Pre-calculated value for convenience.
     28     private static final float ZOOM_IN_BEGIN = 1f - ZOOM_DELTA;
     29 
     30     private static final Interpolator sZoomOutInterpolator =
     31             new DecelerateInterpolator();
     32     private static final Interpolator sZoomInInterpolator =
     33             new AccelerateInterpolator();
     34     private static final Interpolator sSlideInterpolator =
     35         new AccelerateDecelerateInterpolator();
     36 
     37     // Calculate the slide factor based on the give time fraction.
     38     public static float calculateSlide(float fraction) {
     39         return sSlideInterpolator.getInterpolation(fraction);
     40     }
     41 
     42     // Calculate the scale factor based on the given time fraction.
     43     public static float calculateScale(float fraction) {
     44         float value;
     45         if (fraction <= 0.5f) {
     46             // Zoom in for the beginning.
     47             value = 1f - ZOOM_DELTA *
     48                     sZoomOutInterpolator.getInterpolation(fraction * 2);
     49         } else {
     50             // Zoom out for the ending.
     51             value = ZOOM_IN_BEGIN + ZOOM_DELTA *
     52                     sZoomInInterpolator.getInterpolation((fraction - 0.5f) * 2f);
     53         }
     54         return value;
     55     }
     56 }
     57