1f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin/*
2f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * Copyright (C) 2010 The Android Open Source Project
3f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin *
4f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * Licensed under the Apache License, Version 2.0 (the "License");
5f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * you may not use this file except in compliance with the License.
6f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * You may obtain a copy of the License at
7f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin *
8f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin *      http://www.apache.org/licenses/LICENSE-2.0
9f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin *
10f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * Unless required by applicable law or agreed to in writing, software
11f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * distributed under the License is distributed on an "AS IS" BASIS,
12f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * See the License for the specific language governing permissions and
14f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin * limitations under the License.
15f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin */
16f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
17f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Linpackage com.android.gallery3d.anim;
18f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
19f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Linimport com.android.gallery3d.common.Utils;
20a4eae1abb4f2547dfbda84301ee764ce35464881John Reckimport com.android.gallery3d.glrenderer.GLCanvas;
21f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
22f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Linpublic class AlphaAnimation extends CanvasAnimation {
23f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    private final float mStartAlpha;
24f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    private final float mEndAlpha;
25f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    private float mCurrentAlpha;
26f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
27f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    public AlphaAnimation(float from, float to) {
28f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        mStartAlpha = from;
29f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        mEndAlpha = to;
30f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        mCurrentAlpha = from;
31f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    }
32f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
33f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    @Override
34f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    public void apply(GLCanvas canvas) {
35f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        canvas.multiplyAlpha(mCurrentAlpha);
36f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    }
37f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
38f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    @Override
39f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    public int getCanvasSaveFlags() {
40f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        return GLCanvas.SAVE_FLAG_ALPHA;
41f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    }
42f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin
43f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    @Override
44f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    protected void onCalculate(float progress) {
45f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin        mCurrentAlpha = Utils.clamp(mStartAlpha
46f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin                + (mEndAlpha - mStartAlpha) * progress, 0f, 1f);
47f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin    }
48f9a0a4306d589b4a4e20554fed512a603426bfa1Owen Lin}
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