Merge "Check whether pointer has stopped at liftoff" (55b2c0b5) · Commits · e / os / android_frameworks_native

libs/input/VelocityTracker.cpp

+56 −41

Original line number	Diff line number	Diff line
		@@ -27,6 +27,8 @@
		#include <utils/BitSet.h>
		#include <utils/Timers.h>

		using std::literals::chrono_literals::operator""ms;

		namespace android {

		/**
		@@ -57,8 +59,14 @@ static const nsecs_t NANOS_PER_MS = 1000000;
		// Some input devices do not send ACTION_MOVE events in the case where a pointer has
		// stopped. We need to detect this case so that we can accurately predict the
		// velocity after the pointer starts moving again.
		static const nsecs_t ASSUME_POINTER_STOPPED_TIME = 40 * NANOS_PER_MS;
		static const std::chrono::duration ASSUME_POINTER_STOPPED_TIME = 40ms;

		static std::string toString(std::chrono::nanoseconds t) {
		std::stringstream stream;
		stream.precision(1);
		stream << std::fixed << std::chrono::duration<float, std::milli>(t).count() << " ms";
		return stream.str();
		}

		static float vectorDot(const float* a, const float* b, uint32_t m) {
		float r = 0;
		@@ -146,18 +154,14 @@ std::unique_ptr<VelocityTrackerStrategy> VelocityTracker::createStrategy(
		VelocityTracker::Strategy strategy) {
		switch (strategy) {
		case VelocityTracker::Strategy::IMPULSE:
		if (DEBUG_STRATEGY) {
		ALOGI("Initializing impulse strategy");
		}
		ALOGI_IF(DEBUG_STRATEGY, "Initializing impulse strategy");
		return std::make_unique<ImpulseVelocityTrackerStrategy>();

		case VelocityTracker::Strategy::LSQ1:
		return std::make_unique<LeastSquaresVelocityTrackerStrategy>(1);

		case VelocityTracker::Strategy::LSQ2:
		if (DEBUG_STRATEGY && !DEBUG_IMPULSE) {
		ALOGI("Initializing lsq2 strategy");
		}
		ALOGI_IF(DEBUG_STRATEGY && !DEBUG_IMPULSE, "Initializing lsq2 strategy");
		return std::make_unique<LeastSquaresVelocityTrackerStrategy>(2);

		case VelocityTracker::Strategy::LSQ3:
		@@ -221,12 +225,11 @@ void VelocityTracker::addMovement(nsecs_t eventTime, BitSet32 idBits,
		idBits.clearLastMarkedBit();
		}

		if ((mCurrentPointerIdBits.value & idBits.value)
		&& eventTime >= mLastEventTime + ASSUME_POINTER_STOPPED_TIME) {
		if (DEBUG_VELOCITY) {
		ALOGD("VelocityTracker: stopped for %0.3f ms, clearing state.",
		(eventTime - mLastEventTime) * 0.000001f);
		}
		if ((mCurrentPointerIdBits.value & idBits.value) &&
		std::chrono::nanoseconds(eventTime - mLastEventTime) > ASSUME_POINTER_STOPPED_TIME) {
		ALOGD_IF(DEBUG_VELOCITY, "VelocityTracker: stopped for %s, clearing state.",
		toString(std::chrono::nanoseconds(eventTime - mLastEventTime)).c_str());

		// We have not received any movements for too long. Assume that all pointers
		// have stopped.
		mStrategy->clear();
		@@ -281,8 +284,18 @@ void VelocityTracker::addMovement(const MotionEvent* event) {
		case AMOTION_EVENT_ACTION_MOVE:
		case AMOTION_EVENT_ACTION_HOVER_MOVE:
		break;
		default:
		// Ignore all other actions because they do not convey any new information about
		case AMOTION_EVENT_ACTION_POINTER_UP:
		case AMOTION_EVENT_ACTION_UP: {
		std::chrono::nanoseconds delaySinceLastEvent(event->getEventTime() - mLastEventTime);
		if (delaySinceLastEvent > ASSUME_POINTER_STOPPED_TIME) {
		ALOGD_IF(DEBUG_VELOCITY,
		"VelocityTracker: stopped for %s, clearing state upon pointer liftoff.",
		toString(delaySinceLastEvent).c_str());
		// We have not received any movements for too long. Assume that all pointers
		// have stopped.
		mStrategy->clear();
		}
		// These actions because they do not convey any new information about
		// pointer movement. We also want to preserve the last known velocity of the pointers.
		// Note that ACTION_UP and ACTION_POINTER_UP always report the last known position
		// of the pointers that went up. ACTION_POINTER_UP does include the new position of
		@@ -292,6 +305,10 @@ void VelocityTracker::addMovement(const MotionEvent* event) {
		// before adding the movement.
		return;
		}
		default:
		// Ignore all other actions.
		return;
		}

		size_t pointerCount = event->getPointerCount();
		if (pointerCount > MAX_POINTERS) {
		@@ -438,10 +455,10 @@ void LeastSquaresVelocityTrackerStrategy::addMovement(
		static bool solveLeastSquares(const std::vector<float>& x, const std::vector<float>& y,
		const std::vector<float>& w, uint32_t n, float* outB, float* outDet) {
		const size_t m = x.size();
		if (DEBUG_STRATEGY) {
		ALOGD("solveLeastSquares: m=%d, n=%d, x=%s, y=%s, w=%s", int(m), int(n),

		ALOGD_IF(DEBUG_STRATEGY, "solveLeastSquares: m=%d, n=%d, x=%s, y=%s, w=%s", int(m), int(n),
		vectorToString(x).c_str(), vectorToString(y).c_str(), vectorToString(w).c_str());
		}

		LOG_ALWAYS_FATAL_IF(m != y.size() \|\| m != w.size(), "Mismatched vector sizes");

		// Expand the X vector to a matrix A, pre-multiplied by the weights.
		@@ -452,9 +469,9 @@ static bool solveLeastSquares(const std::vector<float>& x, const std::vector<flo
		a[i][h] = a[i - 1][h] * x[h];
		}
		}
		if (DEBUG_STRATEGY) {
		ALOGD(" - a=%s", matrixToString(&a[0][0], m, n, false /rowMajor/).c_str());
		}

		ALOGD_IF(DEBUG_STRATEGY, " - a=%s",
		matrixToString(&a[0][0], m, n, false /rowMajor/).c_str());

		// Apply the Gram-Schmidt process to A to obtain its QR decomposition.
		float q[n][m]; // orthonormal basis, column-major order
		@@ -473,9 +490,7 @@ static bool solveLeastSquares(const std::vector<float>& x, const std::vector<flo
		float norm = vectorNorm(&q[j][0], m);
		if (norm < 0.000001f) {
		// vectors are linearly dependent or zero so no solution
		if (DEBUG_STRATEGY) {
		ALOGD(" - no solution, norm=%f", norm);
		}
		ALOGD_IF(DEBUG_STRATEGY, " - no solution, norm=%f", norm);
		return false;
		}

		@@ -518,9 +533,8 @@ static bool solveLeastSquares(const std::vector<float>& x, const std::vector<flo
		}
		outB[i] /= r[i][i];
		}
		if (DEBUG_STRATEGY) {
		ALOGD(" - b=%s", vectorToString(outB, n).c_str());
		}

		ALOGD_IF(DEBUG_STRATEGY, " - b=%s", vectorToString(outB, n).c_str());

		// Calculate the coefficient of determination as 1 - (SSerr / SStot) where
		// SSerr is the residual sum of squares (variance of the error),
		@@ -546,11 +560,11 @@ static bool solveLeastSquares(const std::vector<float>& x, const std::vector<flo
		sstot += w[h] * w[h] * var * var;
		}
		*outDet = sstot > 0.000001f ? 1.0f - (sserr / sstot) : 1;
		if (DEBUG_STRATEGY) {
		ALOGD(" - sserr=%f", sserr);
		ALOGD(" - sstot=%f", sstot);
		ALOGD(" - det=%f", *outDet);
		}

		ALOGD_IF(DEBUG_STRATEGY, " - sserr=%f", sserr);
		ALOGD_IF(DEBUG_STRATEGY, " - sstot=%f", sstot);
		ALOGD_IF(DEBUG_STRATEGY, " - det=%f", *outDet);

		return true;
		}

		@@ -673,11 +687,11 @@ bool LeastSquaresVelocityTrackerStrategy::getEstimator(uint32_t id,
		outEstimator->time = newestMovement.eventTime;
		outEstimator->degree = degree;
		outEstimator->confidence = xdet * ydet;
		if (DEBUG_STRATEGY) {
		ALOGD("estimate: degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f",

		ALOGD_IF(DEBUG_STRATEGY, "estimate: degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f",
		int(outEstimator->degree), vectorToString(outEstimator->xCoeff, n).c_str(),
		vectorToString(outEstimator->yCoeff, n).c_str(), outEstimator->confidence);
		}

		return true;
		}
		}
		@@ -1185,9 +1199,10 @@ bool ImpulseVelocityTrackerStrategy::getEstimator(uint32_t id,
		outEstimator->time = newestMovement.eventTime;
		outEstimator->degree = 2; // similar results to 2nd degree fit
		outEstimator->confidence = 1;
		if (DEBUG_STRATEGY) {
		ALOGD("velocity: (%.1f, %.1f)", outEstimator->xCoeff[1], outEstimator->yCoeff[1]);
		}

		ALOGD_IF(DEBUG_STRATEGY, "velocity: (%.1f, %.1f)", outEstimator->xCoeff[1],
		outEstimator->yCoeff[1]);

		if (DEBUG_IMPULSE) {
		// TODO(b/134179997): delete this block once the switch to 'impulse' is complete.
		// Calculate the lsq2 velocity for the same inputs to allow runtime comparisons

libs/input/tests/VelocityTracker_test.cpp

+66 −7

Original line number	Diff line number	Diff line
		@@ -26,7 +26,9 @@
		#include <gui/constants.h>
		#include <input/VelocityTracker.h>

		using namespace std::chrono_literals;
		using std::literals::chrono_literals::operator""ms;
		using std::literals::chrono_literals::operator""ns;
		using std::literals::chrono_literals::operator""us;
		using android::base::StringPrintf;

		namespace android {
		@@ -149,8 +151,7 @@ static std::vector<MotionEvent> createMotionEventStream(
		if (i == 0) {
		action = AMOTION_EVENT_ACTION_DOWN;
		EXPECT_EQ(1U, pointerCount) << "First event should only have 1 pointer";
		} else if (i == motions.size() - 1) {
		EXPECT_EQ(1U, pointerCount) << "Last event should only have 1 pointer";
		} else if ((i == motions.size() - 1) && pointerCount == 1) {
		action = AMOTION_EVENT_ACTION_UP;
		} else {
		const MotionEventEntry& previousEntry = motions[i-1];
		@@ -195,7 +196,7 @@ static std::vector<MotionEvent> createMotionEventStream(

		static void computeAndCheckVelocity(const VelocityTracker::Strategy strategy,
		const std::vector<MotionEventEntry>& motions, int32_t axis,
		float targetVelocity) {
		float targetVelocity, uint32_t pointerId = DEFAULT_POINTER_ID) {
		VelocityTracker vt(strategy);
		float Vx, Vy;

		@@ -204,7 +205,7 @@ static void computeAndCheckVelocity(const VelocityTracker::Strategy strategy,
		vt.addMovement(&event);
		}

		vt.getVelocity(DEFAULT_POINTER_ID, &Vx, &Vy);
		vt.getVelocity(pointerId, &Vx, &Vy);

		switch (axis) {
		case AMOTION_EVENT_AXIS_X:
		@@ -846,12 +847,70 @@ TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_ThreeFi

		// Velocity should actually be zero, but we expect 0.016 here instead.
		// This is close enough to zero, and is likely caused by division by a very small number.
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, -0.016);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y, -0.016);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y, 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y, 0);
		}

		/**
		* ================= Pointer liftoff ===============================================================
		*/

		/**
		* The last movement of a pointer is always ACTION_POINTER_UP or ACTION_UP. If there's a short delay
		* between the last ACTION_MOVE and the next ACTION_POINTER_UP or ACTION_UP, velocity should not be
		* affected by the liftoff.
		*/
		TEST_F(VelocityTrackerTest, ShortDelayBeforeActionUp) {
		std::vector<MotionEventEntry> motions = {
		{0ms, {{10, 0}}}, {10ms, {{20, 0}}}, {20ms, {{30, 0}}}, {30ms, {{30, 0}}}, // ACTION_UP
		};
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
		1000);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 1000);
		}

		/**
		* The last movement of a single pointer is ACTION_UP. If there's a long delay between the last
		* ACTION_MOVE and the final ACTION_UP, velocity should be reported as zero because the pointer
		* should be assumed to have stopped.
		*/
		TEST_F(VelocityTrackerTest, LongDelayBeforeActionUp) {
		std::vector<MotionEventEntry> motions = {
		{0ms, {{10, 0}}},
		{10ms, {{20, 0}}},
		{20ms, {{30, 0}}},
		{3000ms, {{30, 0}}}, // ACTION_UP
		};
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 0);
		}

		/**
		* The last movement of a pointer is always ACTION_POINTER_UP or ACTION_UP. If there's a long delay
		* before ACTION_POINTER_UP event, the movement should be assumed to have stopped.
		* The final velocity should be reported as zero for all pointers.
		*/
		TEST_F(VelocityTrackerTest, LongDelayBeforeActionPointerUp) {
		std::vector<MotionEventEntry> motions = {
		{0ms, {{10, 0}}},
		{10ms, {{20, 0}, {100, 0}}},
		{20ms, {{30, 0}, {200, 0}}},
		{30ms, {{30, 0}, {300, 0}}},
		{40ms, {{30, 0}, {400, 0}}},
		{3000ms, {{30, 0}}}, // ACTION_POINTER_UP
		};
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0,
		/pointerId/ 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 0,
		/pointerId/ 0);
		computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0,
		/pointerId/ 1);
		computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 0,
		/pointerId/ 1);
		}

		/**
		* ================== Tests for least squares fitting ==============================================
		*