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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.glrenderer;
     18 
     19 import com.android.gallery3d.common.Utils;
     20 import com.android.gallery3d.ui.AnimationTime;
     21 
     22 // FadeTexture is a texture which fades the given texture along the time.
     23 public abstract class FadeTexture implements Texture {
     24     @SuppressWarnings("unused")
     25     private static final String TAG = "FadeTexture";
     26 
     27     // The duration of the fading animation in milliseconds
     28     public static final int DURATION = 180;
     29 
     30     private final long mStartTime;
     31     private final int mWidth;
     32     private final int mHeight;
     33     private final boolean mIsOpaque;
     34     private boolean mIsAnimating;
     35 
     36     public FadeTexture(int width, int height, boolean opaque) {
     37         mWidth = width;
     38         mHeight = height;
     39         mIsOpaque = opaque;
     40         mStartTime = now();
     41         mIsAnimating = true;
     42     }
     43 
     44     @Override
     45     public void draw(GLCanvas canvas, int x, int y) {
     46         draw(canvas, x, y, mWidth, mHeight);
     47     }
     48 
     49     @Override
     50     public boolean isOpaque() {
     51         return mIsOpaque;
     52     }
     53 
     54     @Override
     55     public int getWidth() {
     56         return mWidth;
     57     }
     58 
     59     @Override
     60     public int getHeight() {
     61         return mHeight;
     62     }
     63 
     64     public boolean isAnimating() {
     65         if (mIsAnimating) {
     66             if (now() - mStartTime >= DURATION) {
     67                 mIsAnimating = false;
     68             }
     69         }
     70         return mIsAnimating;
     71     }
     72 
     73     protected float getRatio() {
     74         float r = (float)(now() - mStartTime) / DURATION;
     75         return Utils.clamp(1.0f - r, 0.0f, 1.0f);
     76     }
     77 
     78     private long now() {
     79         return AnimationTime.get();
     80     }
     81 }
     82