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      1 /*
      2  * Copyright (C) 2011 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 com.android.gallery3d.common.Utils;
     20 
     21 // FadeTexture is a texture which fades the given texture along the time.
     22 public abstract class FadeTexture implements Texture {
     23     @SuppressWarnings("unused")
     24     private static final String TAG = "FadeTexture";
     25 
     26     // The duration of the fading animation in milliseconds
     27     public static final int DURATION = 180;
     28 
     29     private final long mStartTime;
     30     private final int mWidth;
     31     private final int mHeight;
     32     private final boolean mIsOpaque;
     33     private boolean mIsAnimating;
     34 
     35     public FadeTexture(int width, int height, boolean opaque) {
     36         mWidth = width;
     37         mHeight = height;
     38         mIsOpaque = opaque;
     39         mStartTime = now();
     40         mIsAnimating = true;
     41     }
     42 
     43     @Override
     44     public void draw(GLCanvas canvas, int x, int y) {
     45         draw(canvas, x, y, mWidth, mHeight);
     46     }
     47 
     48     @Override
     49     public boolean isOpaque() {
     50         return mIsOpaque;
     51     }
     52 
     53     @Override
     54     public int getWidth() {
     55         return mWidth;
     56     }
     57 
     58     @Override
     59     public int getHeight() {
     60         return mHeight;
     61     }
     62 
     63     public boolean isAnimating() {
     64         if (mIsAnimating) {
     65             if (now() - mStartTime >= DURATION) {
     66                 mIsAnimating = false;
     67             }
     68         }
     69         return mIsAnimating;
     70     }
     71 
     72     protected float getRatio() {
     73         float r = (float)(now() - mStartTime) / DURATION;
     74         return Utils.clamp(1.0f - r, 0.0f, 1.0f);
     75     }
     76 
     77     private long now() {
     78         return AnimationTime.get();
     79     }
     80 }
     81