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      1 /*
      2  * Copyright (C) 2016 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.server.wm.animation;
     18 
     19 import android.graphics.Rect;
     20 import android.view.animation.ClipRectAnimation;
     21 import android.view.animation.Interpolator;
     22 import android.view.animation.Transformation;
     23 import android.view.animation.TranslateAnimation;
     24 
     25 /**
     26  * Special case of ClipRectAnimation that animates only the top/bottom
     27  * dimensions of the clip, picking up the other dimensions from whatever is
     28  * set on the transform already. In addition to that, information about a vertical translation
     29  * animation can be specified so this animation simulates as the clip would be applied after instead
     30  * of before applying the translation.
     31  */
     32 public class ClipRectTBAnimation extends ClipRectAnimation {
     33 
     34     private final int mFromTranslateY;
     35     private final int mToTranslateY;
     36     private final Interpolator mTranslateInterpolator;
     37     private float mNormalizedTime;
     38 
     39     /**
     40      * Constructor. Passes in 0 for Left/Right parameters of ClipRectAnimation
     41      */
     42     public ClipRectTBAnimation(int fromT, int fromB, int toT, int toB,
     43             int fromTranslateY, int toTranslateY, Interpolator translateInterpolator) {
     44         super(0, fromT, 0, fromB, 0, toT, 0, toB);
     45         mFromTranslateY = fromTranslateY;
     46         mToTranslateY = toTranslateY;
     47         mTranslateInterpolator = translateInterpolator;
     48     }
     49 
     50     @Override
     51     public boolean getTransformation(long currentTime, Transformation outTransformation) {
     52 
     53         // Hack: Because translation animation has a different interpolator, we need to duplicate
     54         // code from Animation here and use it to calculate/store the uninterpolated normalized
     55         // time.
     56         final long startOffset = getStartOffset();
     57         final long duration = getDuration();
     58         float normalizedTime;
     59         if (duration != 0) {
     60             normalizedTime = ((float) (currentTime - (getStartTime() + startOffset))) /
     61                     (float) duration;
     62         } else {
     63             // time is a step-change with a zero duration
     64             normalizedTime = currentTime < getStartTime() ? 0.0f : 1.0f;
     65         }
     66         mNormalizedTime = normalizedTime;
     67         return super.getTransformation(currentTime, outTransformation);
     68     }
     69 
     70     /**
     71      * Calculates and sets clip rect on given transformation. It uses existing values
     72      * on the Transformation for Left/Right clip parameters.
     73      */
     74     @Override
     75     protected void applyTransformation(float it, Transformation tr) {
     76         float translationT = mTranslateInterpolator.getInterpolation(mNormalizedTime);
     77         int translation =
     78                 (int) (mFromTranslateY + (mToTranslateY - mFromTranslateY) * translationT);
     79         Rect oldClipRect = tr.getClipRect();
     80         tr.setClipRect(oldClipRect.left,
     81                 mFromRect.top - translation + (int) ((mToRect.top - mFromRect.top) * it),
     82                 oldClipRect.right,
     83                 mFromRect.bottom - translation + (int) ((mToRect.bottom - mFromRect.bottom) * it));
     84     }
     85 
     86 }
     87