Check whether pointer has stopped at liftoff
Android uses ACTION_UP and ACTION_POINTER_UP events to signal that a
pointer has left the screen.
These events don't carry new information, and should always have the
same coordinates as the last ACTION_MOVE event.
However, these events do have a new timestamp.
Before this CL: these events are getting ignored completely by
VelocityTracker. If there's a large delay before ACTION_UP, the velocity
is still reported to be the same as the if there's no delay.
In this CL: we will check these events for timestamps. If too much time
has passed, we will clear the strategy.
Example logs:
VelocityTracker: VelocityTracker: stopped for 2970.0 ms, clearing state upon pointer liftoff.
Bug: 200900433
Test: atest libinput_tests
Change-Id: Ie3e5a61e70b6324ee4aedaf2bce58766f5598718
diff --git a/libs/input/VelocityTracker.cpp b/libs/input/VelocityTracker.cpp
index 7f427f2..76aaf61 100644
--- a/libs/input/VelocityTracker.cpp
+++ b/libs/input/VelocityTracker.cpp
@@ -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 @@
// 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 @@
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 @@
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 @@
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 @@
// before adding the movement.
return;
}
+ default:
+ // Ignore all other actions.
+ return;
+ }
size_t pointerCount = event->getPointerCount();
if (pointerCount > MAX_POINTERS) {
@@ -438,10 +455,10 @@
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),
- vectorToString(x).c_str(), vectorToString(y).c_str(), vectorToString(w).c_str());
- }
+
+ 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 @@
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 @@
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 @@
}
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 @@
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 @@
outEstimator->time = newestMovement.eventTime;
outEstimator->degree = degree;
outEstimator->confidence = xdet * ydet;
- if (DEBUG_STRATEGY) {
- ALOGD("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);
- }
+
+ 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 @@
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