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
17package com.android.gallery3d.glrenderer;
18
19import com.android.gallery3d.common.Utils;
20import com.android.gallery3d.ui.AnimationTime;
21
22// FadeTexture is a texture which fades the given texture along the time.
23public 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