1/*
2 * Copyright (C) 2013 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.systemui.recent;
18
19import android.animation.Animator;
20import android.animation.AnimatorListenerAdapter;
21import android.animation.ValueAnimator;
22import android.util.Log;
23import android.view.View;
24import android.view.ViewPropertyAnimator;
25import android.view.ViewTreeObserver;
26
27/*
28 *  This is a helper class that listens to updates from the corresponding animation.
29 *  For the first two frames, it adjusts the current play time of the animation to
30 *  prevent jank at the beginning of the animation
31 */
32public class FirstFrameAnimatorHelper extends AnimatorListenerAdapter
33    implements ValueAnimator.AnimatorUpdateListener {
34    private static final boolean DEBUG = false;
35    private static final int MAX_DELAY = 1000;
36    private static final int IDEAL_FRAME_DURATION = 16;
37    private View mTarget;
38    private long mStartFrame;
39    private long mStartTime = -1;
40    private boolean mHandlingOnAnimationUpdate;
41    private boolean mAdjustedSecondFrameTime;
42
43    private static ViewTreeObserver.OnDrawListener sGlobalDrawListener;
44    private static long sGlobalFrameCounter;
45
46    public FirstFrameAnimatorHelper(ValueAnimator animator, View target) {
47        mTarget = target;
48        animator.addUpdateListener(this);
49    }
50
51    public FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target) {
52        mTarget = target;
53        vpa.setListener(this);
54    }
55
56    // only used for ViewPropertyAnimators
57    public void onAnimationStart(Animator animation) {
58        final ValueAnimator va = (ValueAnimator) animation;
59        va.addUpdateListener(FirstFrameAnimatorHelper.this);
60        onAnimationUpdate(va);
61    }
62
63    public static void initializeDrawListener(View view) {
64        if (sGlobalDrawListener != null) {
65            view.getViewTreeObserver().removeOnDrawListener(sGlobalDrawListener);
66        }
67        sGlobalDrawListener = new ViewTreeObserver.OnDrawListener() {
68                private long mTime = System.currentTimeMillis();
69                public void onDraw() {
70                    sGlobalFrameCounter++;
71                    if (DEBUG) {
72                        long newTime = System.currentTimeMillis();
73                        Log.d("FirstFrameAnimatorHelper", "TICK " + (newTime - mTime));
74                        mTime = newTime;
75                    }
76                }
77            };
78        view.getViewTreeObserver().addOnDrawListener(sGlobalDrawListener);
79    }
80
81    public void onAnimationUpdate(final ValueAnimator animation) {
82        final long currentTime = System.currentTimeMillis();
83        if (mStartTime == -1) {
84            mStartFrame = sGlobalFrameCounter;
85            mStartTime = currentTime;
86        }
87
88        if (!mHandlingOnAnimationUpdate &&
89            // If the current play time exceeds the duration, the animation
90            // will get finished, even if we call setCurrentPlayTime -- therefore
91            // don't adjust the animation in that case
92            animation.getCurrentPlayTime() < animation.getDuration()) {
93            mHandlingOnAnimationUpdate = true;
94            long frameNum = sGlobalFrameCounter - mStartFrame;
95            // If we haven't drawn our first frame, reset the time to t = 0
96            // (give up after MAX_DELAY ms of waiting though - might happen, for example, if we
97            // are no longer in the foreground and no frames are being rendered ever)
98            if (frameNum == 0 && currentTime < mStartTime + MAX_DELAY) {
99                // The first frame on animations doesn't always trigger an invalidate...
100                // force an invalidate here to make sure the animation continues to advance
101                mTarget.getRootView().invalidate();
102                animation.setCurrentPlayTime(0);
103
104            // For the second frame, if the first frame took more than 16ms,
105            // adjust the start time and pretend it took only 16ms anyway. This
106            // prevents a large jump in the animation due to an expensive first frame
107            } else if (frameNum == 1 && currentTime < mStartTime + MAX_DELAY &&
108                       !mAdjustedSecondFrameTime &&
109                       currentTime > mStartTime + IDEAL_FRAME_DURATION) {
110                animation.setCurrentPlayTime(IDEAL_FRAME_DURATION);
111                mAdjustedSecondFrameTime = true;
112            } else {
113                if (frameNum > 1) {
114                    mTarget.post(new Runnable() {
115                            public void run() {
116                                animation.removeUpdateListener(FirstFrameAnimatorHelper.this);
117                            }
118                        });
119                }
120                if (DEBUG) print(animation);
121            }
122            mHandlingOnAnimationUpdate = false;
123        } else {
124            if (DEBUG) print(animation);
125        }
126    }
127
128    public void print(ValueAnimator animation) {
129        float flatFraction = animation.getCurrentPlayTime() / (float) animation.getDuration();
130        Log.d("FirstFrameAnimatorHelper", sGlobalFrameCounter +
131              "(" + (sGlobalFrameCounter - mStartFrame) + ") " + mTarget + " dirty? " +
132              mTarget.isDirty() + " " + flatFraction + " " + this + " " + animation);
133    }
134}
135