/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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package com.android.internal.view;
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import android.os.Handler;
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import android.os.Message;
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import android.view.Choreographer;
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import android.view.Display;
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/**
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* Utility class to schedule things at vsync-sf instead of vsync-app
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* @hide
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*/
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public class SurfaceFlingerVsyncChoreographer {
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private static final long ONE_MS_IN_NS = 1000000;
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private static final long ONE_S_IN_NS = ONE_MS_IN_NS * 1000;
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private final Handler mHandler;
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private final Choreographer mChoreographer;
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/**
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* The offset between vsync-app and vsync-surfaceflinger. See
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* {@link #calculateAppSurfaceFlingerVsyncOffsetMs} why this is necessary.
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*/
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private long mSurfaceFlingerOffsetMs;
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public SurfaceFlingerVsyncChoreographer(Handler handler, Display display,
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Choreographer choreographer) {
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mHandler = handler;
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mChoreographer = choreographer;
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mSurfaceFlingerOffsetMs = calculateAppSurfaceFlingerVsyncOffsetMs(display);
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}
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public long getSurfaceFlingerOffsetMs() {
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return mSurfaceFlingerOffsetMs;
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}
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/**
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* This method calculates the offset between vsync-surfaceflinger and vsync-app. If vsync-app
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* is a couple of milliseconds before vsync-sf, a touch or animation event that causes a surface
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* flinger transaction are sometimes processed before the vsync-sf tick, and sometimes after,
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* which leads to jank. Figure out this difference here and then post all the touch/animation
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* events to start being processed at vsync-sf.
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*
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* @return The offset between vsync-app and vsync-sf, or 0 if vsync app happens after vsync-sf.
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*/
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private long calculateAppSurfaceFlingerVsyncOffsetMs(Display display) {
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// Calculate vsync offset from SurfaceFlinger.
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// See frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp:getDisplayConfigs
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long vsyncPeriod = (long) (ONE_S_IN_NS / display.getRefreshRate());
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long sfVsyncOffset = vsyncPeriod - (display.getPresentationDeadlineNanos() - ONE_MS_IN_NS);
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return Math.max(0, (sfVsyncOffset - display.getAppVsyncOffsetNanos()) / ONE_MS_IN_NS);
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}
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public void scheduleAtSfVsync(Runnable r) {
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final long delay = calculateDelay();
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if (delay <= 0) {
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r.run();
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} else {
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mHandler.postDelayed(r, delay);
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}
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}
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public void scheduleAtSfVsync(Handler h, Message m) {
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final long delay = calculateDelay();
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if (delay <= 0) {
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h.handleMessage(m);
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} else {
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m.setAsynchronous(true);
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h.sendMessageDelayed(m, delay);
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}
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}
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private long calculateDelay() {
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final long sinceFrameStart = System.nanoTime() - mChoreographer.getLastFrameTimeNanos();
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return mSurfaceFlingerOffsetMs - sinceFrameStart / 1000000;
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}
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}
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