input/evdevtouch/qevdevtouchhandler.cpp

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** Copyright (C) 2016 Jolla Ltd, author: <gunnar.sletta@jollamobile.com>
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#include "qevdevtouchhandler_p.h"
#include "qtouchoutputmapping_p.h"
#include <QStringList>
#include <QHash>
#include <QSocketNotifier>
#include <QGuiApplication>
#include <QTouchDevice>
#include <QLoggingCategory>
#include <QtCore/private/qcore_unix_p.h>
#include <QtGui/private/qhighdpiscaling_p.h>
#include <QtGui/private/qguiapplication_p.h>

#include <mutex>

#ifdef Q_OS_FREEBSD
#include <dev/evdev/input.h>
#else
#include <linux/input.h>
#endif

#ifndef input_event_sec
#define input_event_sec time.tv_sec
#endif

#ifndef input_event_usec
#define input_event_usec time.tv_usec
#endif

#include <math.h>

#if QT_CONFIG(mtdev)
extern "C" {
#include <mtdev.h>
}
#endif

QT_BEGIN_NAMESPACE

Q_LOGGING_CATEGORY(qLcEvdevTouch, "qt.qpa.input")
Q_LOGGING_CATEGORY(qLcEvents, "qt.qpa.input.events")

/* android (and perhaps some other linux-derived stuff) don't define everything
 * in linux/input.h, so we'll need to do that ourselves.
 */
#ifndef ABS_MT_TOUCH_MAJOR
#define ABS_MT_TOUCH_MAJOR      0x30    /* Major axis of touching ellipse */
#endif
#ifndef ABS_MT_POSITION_X
#define ABS_MT_POSITION_X       0x35    /* Center X ellipse position */
#endif
#ifndef ABS_MT_POSITION_Y
#define ABS_MT_POSITION_Y       0x36    /* Center Y ellipse position */
#endif
#ifndef ABS_MT_SLOT
#define ABS_MT_SLOT 0x2f
#endif
#ifndef ABS_CNT
#define ABS_CNT                 (ABS_MAX+1)
#endif
#ifndef ABS_MT_TRACKING_ID
#define ABS_MT_TRACKING_ID      0x39    /* Unique ID of initiated contact */
#endif
#ifndef ABS_MT_PRESSURE
#define ABS_MT_PRESSURE         0x3a
#endif
#ifndef SYN_MT_REPORT
#define SYN_MT_REPORT           2
#endif

class QEvdevTouchScreenData
{
public:
    QEvdevTouchScreenData(QEvdevTouchScreenHandler *q_ptr, const QStringList &args);

    void processInputEvent(input_event *data);
    void assignIds();

    QEvdevTouchScreenHandler *q;
    int m_lastEventType;
    QList<QWindowSystemInterface::TouchPoint> m_touchPoints;
    QList<QWindowSystemInterface::TouchPoint> m_lastTouchPoints;

    struct Contact {
        int trackingId = -1;
        int x = 0;
        int y = 0;
        int maj = -1;
        int pressure = 0;
        Qt::TouchPointState state = Qt::TouchPointPressed;
        QTouchEvent::TouchPoint::InfoFlags flags;
    };
    QHash<int, Contact> m_contacts; // The key is a tracking id for type A, slot number for type B.
    QHash<int, Contact> m_lastContacts;
    Contact m_currentData;
    int m_currentSlot;

    double m_timeStamp;
    double m_lastTimeStamp;

    int findClosestContact(const QHash<int, Contact> &contacts, int x, int y, int *dist);
    void addTouchPoint(const Contact &contact, Qt::TouchPointStates *combinedStates);
    void reportPoints();
    void loadMultiScreenMappings();

    QRect screenGeometry() const;

    int hw_range_x_min;
    int hw_range_x_max;
    int hw_range_y_min;
    int hw_range_y_max;
    int hw_pressure_min;
    int hw_pressure_max;
    QString hw_name;
    QString deviceNode;
    bool m_forceToActiveWindow;
    bool m_typeB;
    QTransform m_rotate;
    bool m_singleTouch;
    QString m_screenName;
    mutable QPointer<QScreen> m_screen;

    // Touch filtering and prediction are part of the same thing. The default
    // prediction is 0ms, but sensible results can be achieved by setting it
    // to, for instance, 16ms.
    // For filtering to work well, the QPA plugin should provide a dead-steady
    // implementation of QPlatformWindow::requestUpdate().
    bool m_filtered;
    int m_prediction;

    // When filtering is enabled, protect the access to current and last
    // timeStamp and touchPoints, as these are being read on the gui thread.
    QMutex m_mutex;
};

QEvdevTouchScreenData::QEvdevTouchScreenData(QEvdevTouchScreenHandler *q_ptr, const QStringList &args)
    : q(q_ptr),
      m_lastEventType(-1),
      m_currentSlot(0),
      m_timeStamp(0), m_lastTimeStamp(0),
      hw_range_x_min(0), hw_range_x_max(0),
      hw_range_y_min(0), hw_range_y_max(0),
      hw_pressure_min(0), hw_pressure_max(0),
      m_forceToActiveWindow(false), m_typeB(false), m_singleTouch(false),
      m_filtered(false), m_prediction(0)
{
    for (const QString &arg : args) {
        if (arg == QStringLiteral("force_window"))
            m_forceToActiveWindow = true;
        else if (arg == QStringLiteral("filtered"))
            m_filtered = true;
        else if (arg.startsWith(QStringLiteral("prediction=")))
            m_prediction = arg.mid(11).toInt();
    }
}

#define LONG_BITS (sizeof(long) << 3)
#define NUM_LONGS(bits) (((bits) + LONG_BITS - 1) / LONG_BITS)

#if !QT_CONFIG(mtdev)
static inline bool testBit(long bit, const long *array)
{
    return (array[bit / LONG_BITS] >> bit % LONG_BITS) & 1;
}
#endif

QEvdevTouchScreenHandler::QEvdevTouchScreenHandler(const QString &device, const QString &spec, QObject *parent)
    : QObject(parent), m_notify(nullptr), m_fd(-1), d(nullptr), m_device(nullptr)
#if QT_CONFIG(mtdev)
      , m_mtdev(nullptr)
#endif
{
    setObjectName(QLatin1String("Evdev Touch Handler"));

    const QStringList args = spec.split(QLatin1Char(':'));
    int rotationAngle = 0;
    bool invertx = false;
    bool inverty = false;
    for (int i = 0; i < args.count(); ++i) {
        if (args.at(i).startsWith(QLatin1String("rotate"))) {
            QString rotateArg = args.at(i).section(QLatin1Char('='), 1, 1);
            bool ok;
            uint argValue = rotateArg.toUInt(&ok);
            if (ok) {
                switch (argValue) {
                case 90:
                case 180:
                case 270:
                    rotationAngle = argValue;
                default:
                    break;
                }
            }
        } else if (args.at(i) == QLatin1String("invertx")) {
            invertx = true;
        } else if (args.at(i) == QLatin1String("inverty")) {
            inverty = true;
        }
    }

    qCDebug(qLcEvdevTouch, "evdevtouch: Using device %ls", qUtf16Printable(device));

    m_fd = QT_OPEN(device.toLocal8Bit().constData(), O_RDONLY | O_NDELAY, 0);

    if (m_fd >= 0) {
        m_notify = new QSocketNotifier(m_fd, QSocketNotifier::Read, this);
        connect(m_notify, &QSocketNotifier::activated, this, &QEvdevTouchScreenHandler::readData);
    } else {
        qErrnoWarning("evdevtouch: Cannot open input device %ls", qUtf16Printable(device));
        return;
    }

#if QT_CONFIG(mtdev)
    m_mtdev = static_cast<mtdev *>(calloc(1, sizeof(mtdev)));
    int mtdeverr = mtdev_open(m_mtdev, m_fd);
    if (mtdeverr) {
        qWarning("evdevtouch: mtdev_open failed: %d", mtdeverr);
        QT_CLOSE(m_fd);
        free(m_mtdev);
        return;
    }
#endif

    d = new QEvdevTouchScreenData(this, args);

#if QT_CONFIG(mtdev)
    const char *mtdevStr = "(mtdev)";
    d->m_typeB = true;
#else
    const char *mtdevStr = "";
    long absbits[NUM_LONGS(ABS_CNT)];
    if (ioctl(m_fd, EVIOCGBIT(EV_ABS, sizeof(absbits)), absbits) >= 0) {
        d->m_typeB = testBit(ABS_MT_SLOT, absbits);
        d->m_singleTouch = !testBit(ABS_MT_POSITION_X, absbits);
    }
#endif

    d->deviceNode = device;
    qCDebug(qLcEvdevTouch,
            "evdevtouch: %ls: Protocol type %c %s (%s), filtered=%s",
            qUtf16Printable(d->deviceNode),
            d->m_typeB ? 'B' : 'A', mtdevStr,
            d->m_singleTouch ? "single" : "multi",
            d->m_filtered ? "yes" : "no");
    if (d->m_filtered)
        qCDebug(qLcEvdevTouch, " - prediction=%d", d->m_prediction);

    input_absinfo absInfo;
    memset(&absInfo, 0, sizeof(input_absinfo));
    bool has_x_range = false, has_y_range = false;

    if (ioctl(m_fd, EVIOCGABS((d->m_singleTouch ? ABS_X : ABS_MT_POSITION_X)), &absInfo) >= 0) {
        qCDebug(qLcEvdevTouch, "evdevtouch: %ls: min X: %d max X: %d", qUtf16Printable(device),
                absInfo.minimum, absInfo.maximum);
        d->hw_range_x_min = absInfo.minimum;
        d->hw_range_x_max = absInfo.maximum;
        has_x_range = true;
    }

    if (ioctl(m_fd, EVIOCGABS((d->m_singleTouch ? ABS_Y : ABS_MT_POSITION_Y)), &absInfo) >= 0) {
        qCDebug(qLcEvdevTouch, "evdevtouch: %ls: min Y: %d max Y: %d", qUtf16Printable(device),
                absInfo.minimum, absInfo.maximum);
        d->hw_range_y_min = absInfo.minimum;
        d->hw_range_y_max = absInfo.maximum;
        has_y_range = true;
    }

    if (!has_x_range || !has_y_range)
        qWarning("evdevtouch: %ls: Invalid ABS limits, behavior unspecified", qUtf16Printable(device));

    if (ioctl(m_fd, EVIOCGABS(ABS_PRESSURE), &absInfo) >= 0) {
        qCDebug(qLcEvdevTouch, "evdevtouch: %ls: min pressure: %d max pressure: %d", qUtf16Printable(device),
                absInfo.minimum, absInfo.maximum);
        if (absInfo.maximum > absInfo.minimum) {
            d->hw_pressure_min = absInfo.minimum;
            d->hw_pressure_max = absInfo.maximum;
        }
    }

    char name[1024];
    if (ioctl(m_fd, EVIOCGNAME(sizeof(name) - 1), name) >= 0) {
        d->hw_name = QString::fromLocal8Bit(name);
        qCDebug(qLcEvdevTouch, "evdevtouch: %ls: device name: %s", qUtf16Printable(device), name);
    }

    // Fix up the coordinate ranges for am335x in case the kernel driver does not have them fixed.
    if (d->hw_name == QLatin1String("ti-tsc")) {
        if (d->hw_range_x_min == 0 && d->hw_range_x_max == 4095) {
            d->hw_range_x_min = 165;
            d->hw_range_x_max = 4016;
        }
        if (d->hw_range_y_min == 0 && d->hw_range_y_max == 4095) {
            d->hw_range_y_min = 220;
            d->hw_range_y_max = 3907;
        }
        qCDebug(qLcEvdevTouch, "evdevtouch: found ti-tsc, overriding: min X: %d max X: %d min Y: %d max Y: %d",
                d->hw_range_x_min, d->hw_range_x_max, d->hw_range_y_min, d->hw_range_y_max);
    }

    bool grabSuccess = !ioctl(m_fd, EVIOCGRAB, (void *) 1);
    if (grabSuccess)
        ioctl(m_fd, EVIOCGRAB, (void *) 0);
    else
        qWarning("evdevtouch: The device is grabbed by another process. No events will be read.");

    if (rotationAngle)
        d->m_rotate = QTransform::fromTranslate(0.5, 0.5).rotate(rotationAngle).translate(-0.5, -0.5);

    if (invertx)
        d->m_rotate *= QTransform::fromTranslate(0.5, 0.5).scale(-1.0, 1.0).translate(-0.5, -0.5);

    if (inverty)
        d->m_rotate *= QTransform::fromTranslate(0.5, 0.5).scale(1.0, -1.0).translate(-0.5, -0.5);

    QTouchOutputMapping mapping;
    if (mapping.load()) {
        d->m_screenName = mapping.screenNameForDeviceNode(d->deviceNode);
        if (!d->m_screenName.isEmpty())
            qCDebug(qLcEvdevTouch, "evdevtouch: Mapping device %ls to screen %ls",
                    qUtf16Printable(d->deviceNode), qUtf16Printable(d->m_screenName));
    }

    registerTouchDevice();
}

QEvdevTouchScreenHandler::~QEvdevTouchScreenHandler()
{
#if QT_CONFIG(mtdev)
    if (m_mtdev) {
        mtdev_close(m_mtdev);
        free(m_mtdev);
    }
#endif

    if (m_fd >= 0)
        QT_CLOSE(m_fd);

    delete d;

    unregisterTouchDevice();
}

bool QEvdevTouchScreenHandler::isFiltered() const
{
    return d && d->m_filtered;
}

QTouchDevice *QEvdevTouchScreenHandler::touchDevice() const
{
    return m_device;
}

void QEvdevTouchScreenHandler::readData()
{
    ::input_event buffer[32];
    int events = 0;

#if QT_CONFIG(mtdev)
    forever {
        do {
            events = mtdev_get(m_mtdev, m_fd, buffer, sizeof(buffer) / sizeof(::input_event));
            // keep trying mtdev_get if we get interrupted. note that we do not
            // (and should not) handle EAGAIN; EAGAIN means that reading would
            // block and we'll get back here later to try again anyway.
        } while (events == -1 && errno == EINTR);

        // 0 events is EOF, -1 means error, handle both in the same place
        if (events <= 0)
            goto err;

        // process our shiny new events
        for (int i = 0; i < events; ++i)
            d->processInputEvent(&buffer[i]);

        // and try to get more
    }
#else
    int n = 0;
    for (; ;) {
        events = QT_READ(m_fd, reinterpret_cast<char*>(buffer) + n, sizeof(buffer) - n);
        if (events <= 0)
            goto err;
        n += events;
        if (n % sizeof(::input_event) == 0)
            break;
    }

    n /= sizeof(::input_event);

    for (int i = 0; i < n; ++i)
        d->processInputEvent(&buffer[i]);
#endif
    return;

err:
    if (!events) {
        qWarning("evdevtouch: Got EOF from input device");
        return;
    } else if (events < 0) {
        if (errno != EINTR && errno != EAGAIN) {
            qErrnoWarning("evdevtouch: Could not read from input device");
            if (errno == ENODEV) { // device got disconnected -> stop reading
                delete m_notify;
                m_notify = nullptr;

                QT_CLOSE(m_fd);
                m_fd = -1;

                unregisterTouchDevice();
            }
            return;
        }
    }
}

void QEvdevTouchScreenHandler::registerTouchDevice()
{
    if (m_device)
        return;

    m_device = new QTouchDevice;
    m_device->setName(d->hw_name);
    m_device->setType(QTouchDevice::TouchScreen);
    m_device->setCapabilities(QTouchDevice::Position | QTouchDevice::Area);
    if (d->hw_pressure_max > d->hw_pressure_min)
        m_device->setCapabilities(m_device->capabilities() | QTouchDevice::Pressure);

    QWindowSystemInterface::registerTouchDevice(m_device);
}

void QEvdevTouchScreenHandler::unregisterTouchDevice()
{
    if (!m_device)
        return;

    // At app exit the cleanup may have already been done, avoid
    // double delete by checking the list first.
    if (QWindowSystemInterface::isTouchDeviceRegistered(m_device)) {
        QWindowSystemInterface::unregisterTouchDevice(m_device);
        delete m_device;
    }

    m_device = nullptr;
}

void QEvdevTouchScreenData::addTouchPoint(const Contact &contact, Qt::TouchPointStates *combinedStates)
{
    QWindowSystemInterface::TouchPoint tp;
    tp.id = contact.trackingId;
    tp.flags = contact.flags;
    tp.state = contact.state;
    *combinedStates |= tp.state;

    // Store the HW coordinates for now, will be updated later.
    tp.area = QRectF(0, 0, contact.maj, contact.maj);
    tp.area.moveCenter(QPoint(contact.x, contact.y));
    tp.pressure = contact.pressure;

    // Get a normalized position in range 0..1.
    tp.normalPosition = QPointF((contact.x - hw_range_x_min) / qreal(hw_range_x_max - hw_range_x_min),
                                (contact.y - hw_range_y_min) / qreal(hw_range_y_max - hw_range_y_min));

    if (!m_rotate.isIdentity())
        tp.normalPosition = m_rotate.map(tp.normalPosition);

    tp.rawPositions.append(QPointF(contact.x, contact.y));

    m_touchPoints.append(tp);
}

void QEvdevTouchScreenData::processInputEvent(input_event *data)
{
    if (data->type == EV_ABS) {

        if (data->code == ABS_MT_POSITION_X || (m_singleTouch && data->code == ABS_X)) {
            m_currentData.x = qBound(hw_range_x_min, data->value, hw_range_x_max);
            if (m_singleTouch)
                m_contacts[m_currentSlot].x = m_currentData.x;
            if (m_typeB) {
                m_contacts[m_currentSlot].x = m_currentData.x;
                if (m_contacts[m_currentSlot].state == Qt::TouchPointStationary)
                    m_contacts[m_currentSlot].state = Qt::TouchPointMoved;
            }
        } else if (data->code == ABS_MT_POSITION_Y || (m_singleTouch && data->code == ABS_Y)) {
            m_currentData.y = qBound(hw_range_y_min, data->value, hw_range_y_max);
            if (m_singleTouch)
                m_contacts[m_currentSlot].y = m_currentData.y;
            if (m_typeB) {
                m_contacts[m_currentSlot].y = m_currentData.y;
                if (m_contacts[m_currentSlot].state == Qt::TouchPointStationary)
                    m_contacts[m_currentSlot].state = Qt::TouchPointMoved;
            }
        } else if (data->code == ABS_MT_TRACKING_ID) {
            m_currentData.trackingId = data->value;
            if (m_typeB) {
                if (m_currentData.trackingId == -1) {
                    m_contacts[m_currentSlot].state = Qt::TouchPointReleased;
                } else {
                    m_contacts[m_currentSlot].state = Qt::TouchPointPressed;
                    m_contacts[m_currentSlot].trackingId = m_currentData.trackingId;
                }
            }
        } else if (data->code == ABS_MT_TOUCH_MAJOR) {
            m_currentData.maj = data->value;
            if (data->value == 0)
                m_currentData.state = Qt::TouchPointReleased;
            if (m_typeB)
                m_contacts[m_currentSlot].maj = m_currentData.maj;
        } else if (data->code == ABS_PRESSURE || data->code == ABS_MT_PRESSURE) {
            if (Q_UNLIKELY(qLcEvents().isDebugEnabled()))
                qCDebug(qLcEvents, "EV_ABS code 0x%x: pressure %d; bounding to [%d,%d]",
                        data->code, data->value, hw_pressure_min, hw_pressure_max);
            m_currentData.pressure = qBound(hw_pressure_min, data->value, hw_pressure_max);
            if (m_typeB || m_singleTouch)
                m_contacts[m_currentSlot].pressure = m_currentData.pressure;
        } else if (data->code == ABS_MT_SLOT) {
            m_currentSlot = data->value;
        }

    } else if (data->type == EV_KEY && !m_typeB) {
        if (data->code == BTN_TOUCH && data->value == 0)
            m_contacts[m_currentSlot].state = Qt::TouchPointReleased;
    } else if (data->type == EV_SYN && data->code == SYN_MT_REPORT && m_lastEventType != EV_SYN) {

        // If there is no tracking id, one will be generated later.
        // Until that use a temporary key.
        int key = m_currentData.trackingId;
        if (key == -1)
            key = m_contacts.count();

        m_contacts.insert(key, m_currentData);
        m_currentData = Contact();

    } else if (data->type == EV_SYN && data->code == SYN_REPORT) {

        // Ensure valid IDs even when the driver does not report ABS_MT_TRACKING_ID.
        if (!m_contacts.isEmpty() && m_contacts.constBegin().value().trackingId == -1)
            assignIds();

        std::unique_lock<QMutex> locker;
        if (m_filtered)
            locker = std::unique_lock<QMutex>{m_mutex};

        // update timestamps
        m_lastTimeStamp = m_timeStamp;
        m_timeStamp = data->input_event_sec + data->input_event_usec / 1000000.0;

        m_lastTouchPoints = m_touchPoints;
        m_touchPoints.clear();
        Qt::TouchPointStates combinedStates;
        bool hasPressure = false;

        for (auto i = m_contacts.begin(), end = m_contacts.end(); i != end; /*erasing*/) {
            auto it = i++;

            Contact &contact(it.value());

            if (!contact.state)
                continue;

            int key = m_typeB ? it.key() : contact.trackingId;
            if (!m_typeB && m_lastContacts.contains(key)) {
                const Contact &prev(m_lastContacts.value(key));
                if (contact.state == Qt::TouchPointReleased) {
                    // Copy over the previous values for released points, just in case.
                    contact.x = prev.x;
                    contact.y = prev.y;
                    contact.maj = prev.maj;
                } else {
                    contact.state = (prev.x == contact.x && prev.y == contact.y)
                            ? Qt::TouchPointStationary : Qt::TouchPointMoved;
                }
            }

            // Avoid reporting a contact in released state more than once.
            if (!m_typeB && contact.state == Qt::TouchPointReleased
                    && !m_lastContacts.contains(key)) {
                m_contacts.erase(it);
                continue;
            }

            if (contact.pressure)
                hasPressure = true;

            addTouchPoint(contact, &combinedStates);
        }

        // Now look for contacts that have disappeared since the last sync.
        for (auto it = m_lastContacts.begin(), end = m_lastContacts.end(); it != end; ++it) {
            Contact &contact(it.value());
            int key = m_typeB ? it.key() : contact.trackingId;
            if (m_typeB) {
                if (contact.trackingId != m_contacts[key].trackingId && contact.state) {
                    contact.state = Qt::TouchPointReleased;
                    addTouchPoint(contact, &combinedStates);
                }
            } else {
                if (!m_contacts.contains(key)) {
                    contact.state = Qt::TouchPointReleased;
                    addTouchPoint(contact, &combinedStates);
                }
            }
        }

        // Remove contacts that have just been reported as released.
        for (auto i = m_contacts.begin(), end = m_contacts.end(); i != end; /*erasing*/) {
            auto it = i++;

            Contact &contact(it.value());

            if (!contact.state)
                continue;

            if (contact.state == Qt::TouchPointReleased) {
                if (m_typeB)
                    contact.state = static_cast<Qt::TouchPointState>(0);
                else
                    m_contacts.erase(it);
            } else {
                contact.state = Qt::TouchPointStationary;
            }
        }

        m_lastContacts = m_contacts;
        if (!m_typeB && !m_singleTouch)
            m_contacts.clear();


        if (!m_touchPoints.isEmpty() && (hasPressure || combinedStates != Qt::TouchPointStationary))
            reportPoints();
    }

    m_lastEventType = data->type;
}

int QEvdevTouchScreenData::findClosestContact(const QHash<int, Contact> &contacts, int x, int y, int *dist)
{
    int minDist = -1, id = -1;
    for (QHash<int, Contact>::const_iterator it = contacts.constBegin(), ite = contacts.constEnd();
         it != ite; ++it) {
        const Contact &contact(it.value());
        int dx = x - contact.x;
        int dy = y - contact.y;
        int dist = dx * dx + dy * dy;
        if (minDist == -1 || dist < minDist) {
            minDist = dist;
            id = contact.trackingId;
        }
    }
    if (dist)
        *dist = minDist;
    return id;
}

void QEvdevTouchScreenData::assignIds()
{
    QHash<int, Contact> candidates = m_lastContacts, pending = m_contacts, newContacts;
    int maxId = -1;
    QHash<int, Contact>::iterator it, ite, bestMatch;
    while (!pending.isEmpty() && !candidates.isEmpty()) {
        int bestDist = -1, bestId = 0;
        for (it = pending.begin(), ite = pending.end(); it != ite; ++it) {
            int dist;
            int id = findClosestContact(candidates, it->x, it->y, &dist);
            if (id >= 0 && (bestDist == -1 || dist < bestDist)) {
                bestDist = dist;
                bestId = id;
                bestMatch = it;
            }
        }
        if (bestDist >= 0) {
            bestMatch->trackingId = bestId;
            newContacts.insert(bestId, *bestMatch);
            candidates.remove(bestId);
            pending.erase(bestMatch);
            if (bestId > maxId)
                maxId = bestId;
        }
    }
    if (candidates.isEmpty()) {
        for (it = pending.begin(), ite = pending.end(); it != ite; ++it) {
            it->trackingId = ++maxId;
            newContacts.insert(it->trackingId, *it);
        }
    }
    m_contacts = newContacts;
}

QRect QEvdevTouchScreenData::screenGeometry() const
{
    if (m_forceToActiveWindow) {
        QWindow *win = QGuiApplication::focusWindow();
        return win ? QHighDpi::toNativePixels(win->geometry(), win) : QRect();
    }

    // Now it becomes tricky. Traditionally we picked the primaryScreen()
    // and were done with it. But then, enter multiple screens, and
    // suddenly it was all broken.
    //
    // For now we only support the display configuration of the KMS/DRM
    // backends of eglfs. See QTouchOutputMapping.
    //
    // The good news it that once winRect refers to the correct screen
    // geometry in the full virtual desktop space, there is nothing else
    // left to do since qguiapp will handle the rest.
    QScreen *screen = QGuiApplication::primaryScreen();
    if (!m_screenName.isEmpty()) {
        if (!m_screen) {
            const QList<QScreen *> screens = QGuiApplication::screens();
            for (QScreen *s : screens) {
                if (s->name() == m_screenName) {
                    m_screen = s;
                    break;
                }
            }
        }
        if (m_screen)
            screen = m_screen;
    }
    return QHighDpi::toNativePixels(screen->geometry(), screen);
}

void QEvdevTouchScreenData::reportPoints()
{
    QRect winRect = screenGeometry();
    if (winRect.isNull())
        return;

    const int hw_w = hw_range_x_max - hw_range_x_min;
    const int hw_h = hw_range_y_max - hw_range_y_min;

    // Map the coordinates based on the normalized position. QPA expects 'area'
    // to be in screen coordinates.
    const int pointCount = m_touchPoints.count();
    for (int i = 0; i < pointCount; ++i) {
        QWindowSystemInterface::TouchPoint &tp(m_touchPoints[i]);

        // Generate a screen position that is always inside the active window
        // or the primary screen.  Even though we report this as a QRectF, internally
        // Qt uses QRect/QPoint so we need to bound the size to winRect.size() - QSize(1, 1)
        const qreal wx = winRect.left() + tp.normalPosition.x() * (winRect.width() - 1);
        const qreal wy = winRect.top() + tp.normalPosition.y() * (winRect.height() - 1);
        const qreal sizeRatio = (winRect.width() + winRect.height()) / qreal(hw_w + hw_h);
        if (tp.area.width() == -1) // touch major was not provided
            tp.area = QRectF(0, 0, 8, 8);
        else
            tp.area = QRectF(0, 0, tp.area.width() * sizeRatio, tp.area.height() * sizeRatio);
        tp.area.moveCenter(QPointF(wx, wy));

        // Calculate normalized pressure.
        if (!hw_pressure_min && !hw_pressure_max)
            tp.pressure = tp.state == Qt::TouchPointReleased ? 0 : 1;
        else
            tp.pressure = (tp.pressure - hw_pressure_min) / qreal(hw_pressure_max - hw_pressure_min);

        if (Q_UNLIKELY(qLcEvents().isDebugEnabled()))
            qCDebug(qLcEvents) << "reporting" << tp;
    }

    // Let qguiapp pick the target window.
    if (m_filtered)
        emit q->touchPointsUpdated();
    else
        QWindowSystemInterface::handleTouchEvent(nullptr, q->touchDevice(), m_touchPoints);
}

QEvdevTouchScreenHandlerThread::QEvdevTouchScreenHandlerThread(const QString &device, const QString &spec, QObject *parent)
    : QDaemonThread(parent), m_device(device), m_spec(spec), m_handler(nullptr), m_touchDeviceRegistered(false)
    , m_touchUpdatePending(false)
    , m_filterWindow(nullptr)
    , m_touchRate(-1)
{
    start();
}

QEvdevTouchScreenHandlerThread::~QEvdevTouchScreenHandlerThread()
{
    quit();
    wait();
}

void QEvdevTouchScreenHandlerThread::run()
{
    m_handler = new QEvdevTouchScreenHandler(m_device, m_spec);

    if (m_handler->isFiltered())
        connect(m_handler, &QEvdevTouchScreenHandler::touchPointsUpdated, this, &QEvdevTouchScreenHandlerThread::scheduleTouchPointUpdate);

    // Report the registration to the parent thread by invoking the method asynchronously
    QMetaObject::invokeMethod(this, "notifyTouchDeviceRegistered", Qt::QueuedConnection);

    exec();

    delete m_handler;
    m_handler = nullptr;
}

bool QEvdevTouchScreenHandlerThread::isTouchDeviceRegistered() const
{
    return m_touchDeviceRegistered;
}

void QEvdevTouchScreenHandlerThread::notifyTouchDeviceRegistered()
{
    m_touchDeviceRegistered = true;
    emit touchDeviceRegistered();
}

void QEvdevTouchScreenHandlerThread::scheduleTouchPointUpdate()
{
    QWindow *window = QGuiApplication::focusWindow();
    if (window != m_filterWindow) {
        if (m_filterWindow)
            m_filterWindow->removeEventFilter(this);
        m_filterWindow = window;
        if (m_filterWindow)
            m_filterWindow->installEventFilter(this);
    }
    if (m_filterWindow) {
        m_touchUpdatePending = true;
        m_filterWindow->requestUpdate();
    }
}

bool QEvdevTouchScreenHandlerThread::eventFilter(QObject *object, QEvent *event)
{
    if (m_touchUpdatePending && object == m_filterWindow && event->type() == QEvent::UpdateRequest) {
        m_touchUpdatePending = false;
        filterAndSendTouchPoints();
    }
    return false;
}

void QEvdevTouchScreenHandlerThread::filterAndSendTouchPoints()
{
    QRect winRect = m_handler->d->screenGeometry();
    if (winRect.isNull())
        return;

    float vsyncDelta = 1.0f / QGuiApplication::primaryScreen()->refreshRate();

    QHash<int, FilteredTouchPoint> filteredPoints;

    m_handler->d->m_mutex.lock();

    double time = m_handler->d->m_timeStamp;
    double lastTime = m_handler->d->m_lastTimeStamp;
    double touchDelta = time - lastTime;
    if (m_touchRate < 0 || touchDelta > vsyncDelta) {
        // We're at the very start, with nothing to go on, so make a guess
        // that the touch rate will be somewhere in the range of half a vsync.
        // This doesn't have to be accurate as we will calibrate it over time,
        // but it gives us a better starting point so calibration will be
        // slightly quicker. If, on the other hand, we already have an
        // estimate, we'll leave it as is and keep it.
        if (m_touchRate < 0)
            m_touchRate = (1.0 / QGuiApplication::primaryScreen()->refreshRate()) / 2.0;

    } else {
        // Update our estimate for the touch rate. We're making the assumption
        // that this value will be mostly accurate with the occational bump,
        // so we're weighting the existing value high compared to the update.
        const double ratio = 0.9;
        m_touchRate = sqrt(m_touchRate * m_touchRate * ratio + touchDelta * touchDelta * (1.0 - ratio));
    }

    QList<QWindowSystemInterface::TouchPoint> points = m_handler->d->m_touchPoints;
    QList<QWindowSystemInterface::TouchPoint> lastPoints = m_handler->d->m_lastTouchPoints;

    m_handler->d->m_mutex.unlock();

    for (int i=0; i<points.size(); ++i) {
        QWindowSystemInterface::TouchPoint &tp = points[i];
        QPointF pos = tp.normalPosition;
        FilteredTouchPoint f;

        QWindowSystemInterface::TouchPoint ltp;
        ltp.id = -1;
        for (int j=0; j<lastPoints.size(); ++j) {
            if (lastPoints.at(j).id == tp.id) {
                ltp = lastPoints.at(j);
                break;
            }
        }

        QPointF velocity;
        if (lastTime != 0 && ltp.id >= 0)
            velocity = (pos - ltp.normalPosition) / m_touchRate;
        if (m_filteredPoints.contains(tp.id)) {
            f = m_filteredPoints.take(tp.id);
            f.x.update(pos.x(), velocity.x(), vsyncDelta);
            f.y.update(pos.y(), velocity.y(), vsyncDelta);
            pos = QPointF(f.x.position(), f.y.position());
        } else {
            f.x.initialize(pos.x(), velocity.x());
            f.y.initialize(pos.y(), velocity.y());
            // Make sure the first instance of a touch point we send has the
            // 'pressed' state.
            if (tp.state != Qt::TouchPointPressed)
                tp.state = Qt::TouchPointPressed;
        }

        tp.velocity = QVector2D(f.x.velocity() * winRect.width(), f.y.velocity() * winRect.height());

        qreal filteredNormalizedX = f.x.position() + f.x.velocity() * m_handler->d->m_prediction / 1000.0;
        qreal filteredNormalizedY = f.y.position() + f.y.velocity() * m_handler->d->m_prediction / 1000.0;

        // Clamp to the screen
        tp.normalPosition = QPointF(qBound<qreal>(0, filteredNormalizedX, 1),
                                    qBound<qreal>(0, filteredNormalizedY, 1));

        qreal x = winRect.x() + (tp.normalPosition.x() * (winRect.width() - 1));
        qreal y = winRect.y() + (tp.normalPosition.y() * (winRect.height() - 1));

        tp.area.moveCenter(QPointF(x, y));

        // Store the touch point for later so we can release it if we've
        // missed the actual release between our last update and this.
        f.touchPoint = tp;

        // Don't store the point for future reference if it is a release.
        if (tp.state != Qt::TouchPointReleased)
            filteredPoints[tp.id] = f;
    }

    for (QHash<int, FilteredTouchPoint>::const_iterator it = m_filteredPoints.constBegin(), end = m_filteredPoints.constEnd(); it != end; ++it) {
        const FilteredTouchPoint &f = it.value();
        QWindowSystemInterface::TouchPoint tp = f.touchPoint;
        tp.state = Qt::TouchPointReleased;
        tp.velocity = QVector2D();
        points.append(tp);
    }

    m_filteredPoints = filteredPoints;

    QWindowSystemInterface::handleTouchEvent(nullptr,
                                             m_handler->touchDevice(),
                                             points);
}


QT_END_NAMESPACE