Android6.0 亮屏灭屏流程(DisplayPowerControler、WMS)(二)亮度设置

1、Android6.0 亮屏灭屏流程（DisplayPowerControler、WMS）（二）亮度设置从这个函数开始分析，主要分析下亮度的设置流程。cpp view plain copy 在CODE上查看代码片派生到我的代码片public void setScreenState(int state) if (mScreenState != state) if (DEBUG) Slog.d(TAG, "setScreenState: state=" + state); mScreenState = state; mScreenReady = false; scheduleSc

2、reenUpdate(); scheduleScreenUpdate主要通过消息方式，最后调用到下面函数。当我们屏幕刚要点亮，这个时候mScreenBrightness为0，所以这个时候调用mPhotonicModulator.setState设置state是点亮，但是brightness是0的。cpp view plain copy 在CODE上查看代码片派生到我的代码片private final Runnable mScreenUpdateRunnable = new Runnable() Override public void run() mScreenUpdatePending =

3、false; int brightness = mScreenState != Display.STATE_OFF && mColorFadeLevel > 0f ? mScreenBrightness : 0; if (mPhotonicModulator.setState(mScreenState, brightness) if (DEBUG) Slog.d(TAG, "Screen ready"); mScreenReady = true; invokeCleanListenerIfNeeded(); else if (DEBUG) Slog.d

4、(TAG, "Screen not ready"); ; DisplayPowerState的设置亮度状态逻辑分析mPhotonicModulator.setState应该要PhotonicModulator的run函数结合一起看。cpp view plain copy 在CODE上查看代码片派生到我的代码片public boolean setState(int state, int backlight) synchronized (mLock) boolean stateChanged = state != mPendingState; boolean backlight

5、Changed = backlight != mPendingBacklight; if (stateChanged | backlightChanged) if (DEBUG) Slog.d(TAG, "Requesting new screen state: state=" + Display.stateToString(state) + ", backlight=" + backlight); mPendingState = state; mPendingBacklight = backlight; boolean changeInProgress

6、 = mStateChangeInProgress | mBacklightChangeInProgress; mStateChangeInProgress = stateChanged; mBacklightChangeInProgress = backlightChanged; if (!changeInProgress) Slog.d(TAG,"notify set backlight thread run"); mLock.notifyAll(); return !mStateChangeInProgress; 两者结合看先setState设置了状态，只有状态改变时

7、，我们才能重新设置状态（设置到mpendingState和mPendingBacklight）。而在run函数中，当设置的状态mPendingState、mPendingBacklight和mActualState、mActualBacklight（真正设置到背光的状态、亮度）不一样时，才会调用mBlanker.requestDisplayState设置亮度。否则状态没有改变，就会把mStateChangeInProgress 和mBacklightChangeInProgress 设置为false，然后线程就wait住。而此时setState重新设置下来的话，这个时候把亮度和状态设置到mPe

8、ndingState 和mPendingBacklight 。然后这时mStateChangeInProgress 和 mBacklightChangeInProgress都是false。这样就可以调用mLock的notifyAll函数重新唤醒线程，这样就把把前面setState设置下来的mPendingState和mPendingBacklight再通过mBlanker.requestDisplayState设置到背光设备中去。cpp view plain copy 在CODE上查看代码片派生到我的代码片Override public void run() for (;) / Get pen

9、ding change. final int state; final boolean stateChanged; final int backlight; final boolean backlightChanged; synchronized (mLock) state = mPendingState; stateChanged = (state != mActualState); backlight = mPendingBacklight; backlightChanged = (backlight != mActualBacklight); if (!stateChanged) / S

10、tate changed applied, notify outer class. postScreenUpdateThreadSafe(); mStateChangeInProgress = false; if (!backlightChanged) mBacklightChangeInProgress = false; if (!stateChanged && !backlightChanged) try mLock.wait(); catch (InterruptedException ex) continue; mActualState = state; mActual

11、Backlight = backlight; / Apply pending change. if (true) Slog.d(TAG, "Updating screen state: state=" + Display.stateToString(state) + ", backlight=" + backlight); mBlanker.requestDisplayState(state, backlight); Slog.d(TAG, "kangchen Updating screen state: state="); 设置亮度

12、、状态到背光设备DisplayBlanker的requestDisplayState如下，主要调用requestGlobalDisplayStateInternal函数。cpp view plain copy 在CODE上查看代码片派生到我的代码片DisplayBlanker blanker = new DisplayBlanker() Override public void requestDisplayState(int state, int brightness) / The order of operations is important for legacy reasons. if

13、(state = Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness); callbacks.onDisplayStateChange(state); if (state != Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness); ; requestGlobalDisplayStateInternal函数先是对state和brightness的处理，然后把这个两个变量放在mGlobalDisplayState 和m

14、GlobalDisplayBrightness成员变量中。紧接着调用applyGlobalDisplayStateLocked函数mTempDisplayStateWorkQueue作为参数。最后再调用mTempDisplayStateWorkQueue各个成员的run函数（这里返回的是Runnable接口，这里就会设置状态和亮度到设备中去）。cpp view plain copy 在CODE上查看代码片派生到我的代码片private void requestGlobalDisplayStateInternal(int state, int brightness) if (state = Di

15、splay.STATE_UNKNOWN) state = Display.STATE_ON; if (state = Display.STATE_OFF) brightness = PowerManager.BRIGHTNESS_OFF; else if (brightness < 0) brightness = PowerManager.BRIGHTNESS_DEFAULT; else if (brightness > PowerManager.BRIGHTNESS_ON) brightness = PowerManager.BRIGHTNESS_ON; synchronized

16、 (mTempDisplayStateWorkQueue) try synchronized (mSyncRoot) if (mGlobalDisplayState = state && mGlobalDisplayBrightness = brightness) return; / no change mGlobalDisplayState = state; mGlobalDisplayBrightness = brightness; applyGlobalDisplayStateLocked(mTempDisplayStateWorkQueue); / Setting th

17、e display power state can take hundreds of milliseconds / to complete so we defer the most expensive part of the work until / after we have exited the critical section to avoid blocking other / threads for a long time. for (int i = 0; i < mTempDisplayStateWorkQueue.size(); i+) mTempDisplayStateWo

18、rkQueue.get(i).run();/设置亮度、状态到设备 finally mTempDisplayStateWorkQueue.clear(); applyGlobalDisplayStateLocked函数会遍历各个显示设备（多显示），然后调用updateDisplayStateLocked函数返回一个Runnable，最后把这个Runnable放入之前传入的mTempDisplayStateWorkQueue队列中。cpp view plain copy 在CODE上查看代码片派生到我的代码片private void applyGlobalDisplayStateLocked(Li

19、st<Runnable> workQueue) final int count = mDisplayDevices.size(); for (int i = 0; i < count; i+) DisplayDevice device = mDisplayDevices.get(i); Runnable runnable = updateDisplayStateLocked(device); if (runnable != null) workQueue.add(runnable); 那下面我们看下updateDisplayStateLocked函数，主要是调用了Displa

20、yDevice的requestDisplayStateLocked函数，当然mGlobalDisplayState和mGlobalDisplayBrightness作为参数。cpp view plain copy 在CODE上查看代码片派生到我的代码片private Runnable updateDisplayStateLocked(DisplayDevice device) / Blank or unblank the display immediately to match the state requested / by the display power controller (if

21、known). DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked(); if (info.flags & DisplayDeviceInfo.FLAG_NEVER_BLANK) = 0) return device.requestDisplayStateLocked(mGlobalDisplayState, mGlobalDisplayBrightness); return null; 这里的DisplayDevice的requestDisplayStateLocked函数，是在LocalDisplayAdapter中

22、实现的，这里吧state和brightness保存在mState和mBrightness中，然后返回Runnable接口，最后在Runnable接口中设置亮度和状态。cpp view plain copy 在CODE上查看代码片派生到我的代码片public Runnable requestDisplayStateLocked(final int state, final int brightness) / Assume that the brightness is off if the display is being turned off. assert state != Display.S

23、TATE_OFF | brightness = PowerManager.BRIGHTNESS_OFF; final boolean stateChanged = (mState != state); final boolean brightnessChanged = (mBrightness != brightness) && mBacklight != null; if (stateChanged | brightnessChanged) final int displayId = mBuiltInDisplayId; final IBinder token = getDi

24、splayTokenLocked(); final int oldState = mState; if (stateChanged) mState = state;/保存state updateDeviceInfoLocked(); if (brightnessChanged) mBrightness = brightness;/保存brightness / Defer actually setting the display state until after we have exited / the critical section since it can take hundreds o

25、f milliseconds / to complete. return new Runnable() /返回Runnable Override public void run() / Exit a suspended state before making any changes. int currentState = oldState; if (Display.isSuspendedState(oldState) | oldState = Display.STATE_UNKNOWN) if (!Display.isSuspendedState(state) setDisplayState(

26、state); currentState = state; else if (state = Display.STATE_DOZE_SUSPEND | oldState = Display.STATE_DOZE_SUSPEND) setDisplayState(Display.STATE_DOZE); currentState = Display.STATE_DOZE; else return; / old state and new state is off / Apply brightness changes given that we are in a non-suspended sta

27、te. if (brightnessChanged) Slog.d(TAG, "kangchen setDisplayBrightnessbrightness1=" + brightness); setDisplayBrightness(brightness); Slog.d(TAG, "kangchen setDisplayBrightnessbrightness2=" + brightness); / Enter the final desired state, possibly suspended. if (state != currentStat

28、e) setDisplayState(state); private void setDisplayState(int state) if (DEBUG) Slog.d(TAG, "setDisplayState(" + "id=" + displayId + ", state=" + Display.stateToString(state) + ")"); try final int mode = getPowerModeForState(state); SurfaceControl.setDisplayPowe

29、rMode(token, mode);/到SurfaceControl设置状态 finally Trace.traceEnd(Trace.TRACE_TAG_POWER); private void setDisplayBrightness(int brightness) try mBacklight.setBrightness(brightness);/设置亮度 finally Trace.traceEnd(Trace.TRACE_TAG_POWER); ; return null; DisplayPowerControl设置亮度逻辑（根据VSync信号将亮度慢慢变亮）上面在DisplayP

30、owerState中仅仅是设置状态，比如刚点亮屏幕这个时候其实设置的brightness为0，我们继续分析DisplayPowerState的updatePowerState函数。在updatePowerState函数中，当设置亮度时会调用如下代码：cpp view plain copy 在CODE上查看代码片派生到我的代码片if (!mPendingScreenOff) if (state = Display.STATE_ON | state = Display.STATE_DOZE) animateScreenBrightness(brightness, slowChange ? BRIG

31、HTNESS_RAMP_RATE_SLOW : BRIGHTNESS_RAMP_RATE_FAST); else animateScreenBrightness(brightness, 0); 我们注意到这里有一个BRIGHTNESS_RAMP_RATE_SLOW 和BRIGHTNESS_RAMP_RATE_FAST（这里涉及到亮度显示原理我们后面分析），先看animateScreenBrightness函数。这里函数主要调用了mScreenBrightnessRampAnimator.animateTo函数。cpp view plain copy 在CODE上查看代码片派生到我的代码片pri

32、vate void animateScreenBrightness(int target, int rate) if (mScreenBrightnessRampAnimator.animateTo(target, rate) try mBatteryStats.noteScreenBrightness(target); catch (RemoteException ex) / same process 我们再来看mScreenBrightnessRampAnimator 对象的创建cpp view plain copy 在CODE上查看代码片派生到我的代码片mScreenBrightness

33、RampAnimator = new RampAnimator<DisplayPowerState>( mPowerState, DisplayPowerState.SCREEN_BRIGHTNESS); 我们注意一个参数是DisplayPowerState对象mPowerState，另一个参数是DisplayPowerState.SCREEN_BRIGHTNESScpp view plain copy 在CODE上查看代码片派生到我的代码片public static final IntProperty<DisplayPowerState> SCREEN_BRIGHTN

34、ESS = new IntProperty<DisplayPowerState>("screenBrightness") Override public void setValue(DisplayPowerState object, int value) object.setScreenBrightness(value); Override public Integer get(DisplayPowerState object) return object.getScreenBrightness(); ; RampAnimator的构造函数。cpp view p

35、lain copy 在CODE上查看代码片派生到我的代码片public RampAnimator(T object, IntProperty<T> property) mObject = object; mProperty = property; mChoreographer = Choreographer.getInstance(); 我们结合RampAnimator的构造函数，再来分析RampAnimator的animateTo函数。1. 当rate<=0时，这个时候，我们直接调用mProperty.setValue。就是调用DisplayPowerState的setSc

36、reenBrightness函数。这个setScreenBrightness函数我们后面分析。2. 当rate>0时，这个时候会调用postAnimationCallback函数（这个函数根据VSync信号过来，把亮度慢慢上升的一个过程），而且mAnimating置为true。cpp view plain copy 在CODE上查看代码片派生到我的代码片public boolean animateTo(int target, int rate) / Immediately jump to the target the first time. if (mFirstTime | rate &

37、lt;= 0) if (mFirstTime | target != mCurrentValue) mFirstTime = false; mRate = 0; mTargetValue = target; mCurrentValue = target; mProperty.setValue(mObject, target);/设置值 if (mAnimating) mAnimating = false; cancelAnimationCallback(); if (mListener != null) mListener.onAnimationEnd(); return true; retu

38、rn false; / Adjust the rate based on the closest target. / If a faster rate is specified, then use the new rate so that we converge / more rapidly based on he new request. / If a slower rate is specified, then use the new rate only if the current / value is somewhere in between the new and the old t

39、arget meaning that / we will be ramping in a different direction to get there. / Otherwise, continue at the previous rate. if (!mAnimating | rate > mRate | (target <= mCurrentValue && mCurrentValue <= mTargetValue) | (mTargetValue <= mCurrentValue && mCurrentValue <= t

40、arget) mRate = rate; final boolean changed = (mTargetValue != target); mTargetValue = target; / Start animating. if (!mAnimating && target != mCurrentValue) mAnimating = true; mAnimatedValue = mCurrentValue; mLastFrameTimeNanos = System.nanoTime(); postAnimationCallback(); return changed; 下面

41、我们先分析postAnimationCallback函数，这个和之前分析WMS的VSync信号类似，当VSync信号过来时，会调用mAnimationCallback函数。（可以看之前博客cpp view plain copy 在CODE上查看代码片派生到我的代码片private void postAnimationCallback() mChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, mAnimationCallback, null); 那我们继续看mAnimationCallback 的run函数，这个函数当当前值和

42、上一次值不一样，我们就调用DisplayPowerState的setScreenBrightness来设置亮度。而且当前值不是目标值，我们就继续调用postAnimationCallback函数，来设置VSync回调。最后当亮度变成目标值后，将mAnimating 置为false，代表亮度变化的动画结束了。cpp view plain copy 在CODE上查看代码片派生到我的代码片private final Runnable mAnimationCallback = new Runnable() Override / Choreographer callback public void un

43、() final long frameTimeNanos = mChoreographer.getFrameTimeNanos(); final float timeDelta = (frameTimeNanos - mLastFrameTimeNanos) * 0.000000001f; mLastFrameTimeNanos = frameTimeNanos; final float scale = ValueAnimator.getDurationScale(); if (scale = 0) / Animation off. mAnimatedValue = mTargetValue; else final float amount = timeDelta * mRate / scale; if (mTargetValue > mCurrentValue) mAnimatedValue = Math.min(mAnimatedValue + amount, mTargetValue); else mAnimatedValue = Math.max(m