IMS:MotionEvent 坐标点（上）

Posted 2022-04-25 xhBruce

IMS:MotionEvent 坐标点（上）

android12-security-release
主要查看获取hal底层原始坐标，并通过InputChannel发送流程，其中只关注坐标点

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Android屏幕x、y轴

屏幕的左上角作为坐标原点，X轴向右为正，Y轴向下为正。

开发者选项中指针位置、ViewRootImpl坐标

打开IMS:开发者选项中指针位置开关，比较直观查看：


X:640.9 Y:1250.9这个就是坐标点（640.9，1250.9），这里(ps.mCoords.x,ps.mCoords.y)通过PointerEventDispatcher/InputChannel传递上来的MotionEvent

ViewRootImpl是通过WindowInputEventReceiver\\InputChannel传递上来的MotionEvent，实质都是InputEventReceiver\\InputChannel

InputEventReceiver传递MotionEvent

IMS:InputChannel通过socket发送Input给App

frameworks/base/core/java/android/view/InputEventReceiver.java

frameworks/base/core/jni/android_view_InputEventReceiver.cpp

绕不开的JNI

frameworks/base/core/java/android/view/MotionEvent.java
frameworks/base/core/jni/android_view_MotionEvent.cpp
frameworks/native/include/input/Input.h
对象PointerCoords中：

InputDispatcher分发时坐标点

IMS:InputDispatcher线程分发事件
frameworks/native/libs/input/InputTransport.cpp
frameworks/native/services/inputflinger/dispatcher/InputDispatcher.cpp

（motionEntry.xCursorPosition,motionEntry.yCursorPosition）
InputDispatcher.cpp中对象传递：（建议倒着查看流程）

–mInboundQueue.push_back(std::move(newEntry));【enqueueInboundEventLocked(std::move(newEntry));】
–mPendingEvent = mInboundQueue.front();
–std::shared_ptr<MotionEntry> motionEntry = std::static_pointer_cast<MotionEntry>(mPendingEvent);
–connection->outboundQueue.push_back(dispatchEntry.release());【enqueueDispatchEntryLocked(…)】
–DispatchEntry* dispatchEntry = connection->outboundQueue.front();
–EventEntry& eventEntry = *(dispatchEntry->eventEntry);
–MotionEntry& motionEntry = static_cast<const MotionEntry&>(eventEntry);

InputReader获取处理MotionEvent

IMS:InputReader线程获取输入事件

frameworks/native/services/inputflinger/InputListener.cpp
frameworks/native/services/inputflinger/reader/InputReader.cpp
frameworks/native/services/inputflinger/reader/InputDevice.cpp
–size_t count = mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE);
–processEventsLocked(mEventBuffer, count);
–processEventsForDeviceLocked(deviceId, rawEvent, batchSize);
–device->process(rawEvents, count);
–mapper.process(rawEvent);

// --- NotifyMotionArgs ---

NotifyMotionArgs::NotifyMotionArgs(
        int32_t id, nsecs_t eventTime, nsecs_t readTime, int32_t deviceId, uint32_t source,
        int32_t displayId, uint32_t policyFlags, int32_t action, int32_t actionButton,
        int32_t flags, int32_t metaState, int32_t buttonState, MotionClassification classification,
        int32_t edgeFlags, uint32_t pointerCount, const PointerProperties* pointerProperties,
        const PointerCoords* pointerCoords, float xPrecision, float yPrecision,
        float xCursorPosition, float yCursorPosition, nsecs_t downTime,
        const std::vector<TouchVideoFrame>& videoFrames)
      : NotifyArgs(id, eventTime),
        deviceId(deviceId),
        source(source),
        displayId(displayId),
        policyFlags(policyFlags),
        action(action),
        actionButton(actionButton),
        flags(flags),
        metaState(metaState),
        buttonState(buttonState),
        classification(classification),
        edgeFlags(edgeFlags),
        pointerCount(pointerCount),
        xPrecision(xPrecision),
        yPrecision(yPrecision),
        xCursorPosition(xCursorPosition),
        yCursorPosition(yCursorPosition),
        downTime(downTime),
        readTime(readTime),
        videoFrames(videoFrames) 
    for (uint32_t i = 0; i < pointerCount; i++) 
        this->pointerProperties[i].copyFrom(pointerProperties[i]);
        this->pointerCoords[i].copyFrom(pointerCoords[i]);
    

//... ...
void NotifyMotionArgs::notify(const sp<InputListenerInterface>& listener) const 
    listener->notifyMotion(this);

SingleTouchInputMapper\\MultiTouchInputMapper处理

1. EventHub连接硬件设备\\外部设备时，匹配添加相应InputMapper
   
2. ......TouchInputMapper::process处理–processRawTouches–cookAndDispatch–dispatch...–dispatchMotion
   
3. NotifyMotionArgs 初始化参数xPrecision, yPrecision–mOrientedXPrecision, mOrientedYPrecision

void TouchInputMapper::dispatchMotion(nsecs_t when, nsecs_t readTime, uint32_t policyFlags,
                                      uint32_t source, int32_t action, int32_t actionButton,
                                      int32_t flags, int32_t metaState, int32_t buttonState,
                                      int32_t edgeFlags, const PointerProperties* properties,
                                      const PointerCoords* coords, const uint32_t* idToIndex,
                                      BitSet32 idBits, int32_t changedId, float xPrecision,
                                      float yPrecision, nsecs_t downTime) 
    // ... ...
    NotifyMotionArgs args(getContext()->getNextId(), when, readTime, deviceId, source, displayId,
                          policyFlags, action, actionButton, flags, metaState, buttonState,
                          MotionClassification::NONE, edgeFlags, pointerCount, pointerProperties,
                          pointerCoords, xPrecision, yPrecision, xCursorPosition, yCursorPosition,
                          downTime, std::move(frames));
    getListener()->notifyMotion(&args);

4. RawPointerAxes
   

EventHub获取屏幕硬件上报

IMS:EventHub设备底层上报Input事件对象处理