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Commit 58d4ff7f authored by Siarhei Vishniakou's avatar Siarhei Vishniakou Committed by android-build-merger
Browse files

Merge "Movement estimates for pointer location" am: 3803f0b5 

am: 86cf7a6b

Change-Id: I221518785b59e529fcacf78d6ca1c989fcd8561f
parents e3cc3c01 86cf7a6b

libs/input/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 


cc_library {

    name: "libinput",

    cpp_std: "c++17",

    host_supported: true,

    cflags: [

        "-Wall",

libs/input/VelocityTracker.cpp

+31 −14
Original line number Diff line number Diff line
@@ -23,9 +23,11 @@ 
// Log debug messages about the progress of the algorithm itself.

#define DEBUG_STRATEGY 0



#include <array>

#include <inttypes.h>

#include <limits.h>

#include <math.h>

#include <optional>



#include <android-base/stringprintf.h>

#include <cutils/properties.h>
@@ -564,7 +566,9 @@ static bool solveLeastSquares(const float* x, const float* y, 
 * Optimized unweighted second-order least squares fit. About 2x speed improvement compared to

 * the default implementation

 */

static float solveUnweightedLeastSquaresDeg2(const float* x, const float* y, size_t count) {

static std::optional<std::array<float, 3>> solveUnweightedLeastSquaresDeg2(

        const float* x, const float* y, size_t count) {

    // Solving y = a*x^2 + b*x + c

    float sxi = 0, sxiyi = 0, syi = 0, sxi2 = 0, sxi3 = 0, sxi2yi = 0, sxi4 = 0;



    for (size_t i = 0; i < count; i++) {
@@ -573,8 +577,8 @@ static float solveUnweightedLeastSquaresDeg2(const float* x, const float* y, siz 
        float xi2 = xi*xi;

        float xi3 = xi2*xi;

        float xi4 = xi3*xi;

        float xi2yi = xi2*yi;

        float xiyi = xi*yi;

        float xi2yi = xi2*yi;



        sxi += xi;

        sxi2 += xi2;
@@ -591,13 +595,23 @@ static float solveUnweightedLeastSquaresDeg2(const float* x, const float* y, siz 
    float Sx2y = sxi2yi - sxi2*syi / count;

    float Sx2x2 = sxi4 - sxi2*sxi2 / count;



    float numerator = Sxy*Sx2x2 - Sx2y*Sxx2;

    float denominator = Sxx*Sx2x2 - Sxx2*Sxx2;

    if (denominator == 0) {

        ALOGW("division by 0 when computing velocity, Sxx=%f, Sx2x2=%f, Sxx2=%f", Sxx, Sx2x2, Sxx2);

        return 0;

        return std::nullopt;

    }

    return numerator/denominator;

    // Compute a

    float numerator = Sx2y*Sxx - Sxy*Sxx2;

    float a = numerator / denominator;



    // Compute b

    numerator = Sxy*Sx2x2 - Sx2y*Sxx2;

    float b = numerator / denominator;



    // Compute c

    float c = syi/count - b * sxi/count - a * sxi2/count;



    return std::make_optional(std::array<float, 3>({c, b, a}));

}



bool LeastSquaresVelocityTrackerStrategy::getEstimator(uint32_t id,
@@ -640,20 +654,23 @@ bool LeastSquaresVelocityTrackerStrategy::getEstimator(uint32_t id, 
    if (degree > m - 1) {

        degree = m - 1;

    }

    if (degree >= 1) {

        if (degree == 2 && mWeighting == WEIGHTING_NONE) { // optimize unweighted, degree=2 fit



    if (degree == 2 && mWeighting == WEIGHTING_NONE) {

        // Optimize unweighted, quadratic polynomial fit

        std::optional<std::array<float, 3>> xCoeff = solveUnweightedLeastSquaresDeg2(time, x, m);

        std::optional<std::array<float, 3>> yCoeff = solveUnweightedLeastSquaresDeg2(time, y, m);

        if (xCoeff && yCoeff) {

            outEstimator->time = newestMovement.eventTime;

            outEstimator->degree = 2;

            outEstimator->confidence = 1;

            outEstimator->xCoeff[0] = 0; // only slope is calculated, set rest of coefficients = 0

            outEstimator->yCoeff[0] = 0;

            outEstimator->xCoeff[1] = solveUnweightedLeastSquaresDeg2(time, x, m);

            outEstimator->yCoeff[1] = solveUnweightedLeastSquaresDeg2(time, y, m);

            outEstimator->xCoeff[2] = 0;

            outEstimator->yCoeff[2] = 0;

            for (size_t i = 0; i <= outEstimator->degree; i++) {

                outEstimator->xCoeff[i] = (*xCoeff)[i];

                outEstimator->yCoeff[i] = (*yCoeff)[i];

            }

            return true;

        }



    } else if (degree >= 1) {

        // General case for an Nth degree polynomial fit

        float xdet, ydet;

        uint32_t n = degree + 1;

        if (solveLeastSquares(time, x, w, m, n, outEstimator->xCoeff, &xdet)