1 /* 2 * Copyright (C) 2010 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.anim; 18 19 import com.android.gallery3d.common.Utils; 20 import com.android.gallery3d.ui.GLCanvas; 21 22 public class AlphaAnimation extends CanvasAnimation { 23 private final float mStartAlpha; 24 private final float mEndAlpha; 25 private float mCurrentAlpha; 26 27 public AlphaAnimation(float from, float to) { 28 mStartAlpha = from; 29 mEndAlpha = to; 30 mCurrentAlpha = from; 31 } 32 33 @Override 34 public void apply(GLCanvas canvas) { 35 canvas.multiplyAlpha(mCurrentAlpha); 36 } 37 38 @Override 39 public int getCanvasSaveFlags() { 40 return GLCanvas.SAVE_FLAG_ALPHA; 41 } 42 43 @Override 44 protected void onCalculate(float progress) { 45 mCurrentAlpha = Utils.clamp(mStartAlpha 46 + (mEndAlpha - mStartAlpha) * progress, 0f, 1f); 47 } 48 } 49
