qquicktaphandler.cpp

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// Copyright (C) 2019 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qquicktaphandler_p.h"
#include "qquicksinglepointhandler_p_p.h"
#include <QtQuick/private/qquickdeliveryagent_p_p.h>
#include <QtQuick/qquickwindow.h>
#include <qpa/qplatformtheme.h>
#include <private/qguiapplication_p.h>
#include <QtGui/qstylehints.h>
 
QT_BEGIN_NAMESPACE
 
Q_LOGGING_CATEGORY(lcTapHandler, "qt.quick.handler.tap")
 
quint64 QQuickTapHandler::m_multiTapInterval(0);
// single tap distance is the same as the drag threshold
int QQuickTapHandler::m_mouseMultiClickDistanceSquared(-1);
int QQuickTapHandler::m_touchMultiTapDistanceSquared(-1);
 
QQuickTapHandler::QQuickTapHandler(QQuickItem *parent)
    : QQuickSinglePointHandler(parent)
{
    if (m_mouseMultiClickDistanceSquared < 0) {
        m_multiTapInterval = qApp->styleHints()->mouseDoubleClickInterval();
        m_mouseMultiClickDistanceSquared = qApp->styleHints()->mouseDoubleClickDistance();
        m_mouseMultiClickDistanceSquared *= m_mouseMultiClickDistanceSquared;
        m_touchMultiTapDistanceSquared = qApp->styleHints()->touchDoubleTapDistance();
        m_touchMultiTapDistanceSquared *= m_touchMultiTapDistanceSquared;
    }
}
 
bool QQuickTapHandler::wantsEventPoint(const QPointerEvent *event, const QEventPoint &point)
{
    if (!QQuickDeliveryAgentPrivate::isMouseEvent(event) &&
            !QQuickDeliveryAgentPrivate::isTouchEvent(event) &&
            !QQuickDeliveryAgentPrivate::isTabletEvent(event))
        return false;
    // If the user has not violated any constraint, it could be a tap.
    // Otherwise we want to give up the grab so that a competing handler
    // (e.g. DragHandler) gets a chance to take over.
    // Don't forget to emit released in case of a cancel.
    bool ret = false;
    bool overThreshold = d_func()->dragOverThreshold(point);
    if (overThreshold && m_gesturePolicy != DragWithinBounds) {
        m_longPressTimer.stop();
        m_holdTimer.invalidate();
    }
    switch (point.state()) {
    case QEventPoint::Pressed:
    case QEventPoint::Released:
        ret = parentContains(point);
        break;
    case QEventPoint::Updated:
        ret = point.id() == this->point().id();
        switch (m_gesturePolicy) {
        case DragThreshold:
            ret = ret && !overThreshold && parentContains(point);
            break;
        case WithinBounds:
        case DragWithinBounds:
            ret = ret && parentContains(point);
            break;
        case ReleaseWithinBounds:
            // no change to ret: depends only whether it's the already-tracking point ID
            break;
        }
        break;
    case QEventPoint::Stationary:
        // If the point hasn't moved since last time, the return value should be the same as last time.
        // If we return false here, QQuickPointerHandler::handlePointerEvent() will call setActive(false).
        ret = point.id() == this->point().id();
        break;
    case QEventPoint::Unknown:
        break;
    }
    // If this is the grabber, returning false from this function will cancel the grab,
    // so onGrabChanged(this, CancelGrabExclusive, point) and setPressed(false) will be called.
    // But when m_gesturePolicy is DragThreshold, we don't get an exclusive grab, but
    // we still don't want to be pressed anymore.
    if (!ret && point.id() == this->point().id())
        setPressed(false, true, const_cast<QPointerEvent *>(event), const_cast<QEventPoint &>(point));
    return ret;
}
 
void QQuickTapHandler::handleEventPoint(QPointerEvent *event, QEventPoint &point)
{
    const bool isTouch = QQuickDeliveryAgentPrivate::isTouchEvent(event);
    switch (point.state()) {
    case QEventPoint::Pressed:
        setPressed(true, false, event, point);
        break;
    case QEventPoint::Released: {
        if (isTouch || (static_cast<const QSinglePointEvent *>(event)->buttons() & acceptedButtons()) == Qt::NoButton)
            setPressed(false, false, event, point);
        break;
    }
    default:
        break;
    }
 
    QQuickSinglePointHandler::handleEventPoint(event, point);
 
    // If TapHandler only needs a passive grab, it should not block other items and handlers from reacting.
    // If the point is accepted, QQuickItemPrivate::localizedTouchEvent() would skip it.
    if (isTouch && m_gesturePolicy == DragThreshold)
        point.setAccepted(false);
}
 
qreal QQuickTapHandler::longPressThreshold() const
{
    return longPressThresholdMilliseconds() / 1000.0;
}
 
void QQuickTapHandler::setLongPressThreshold(qreal longPressThreshold)
{
    int ms = qRound(longPressThreshold * 1000);
    if (m_longPressThreshold == ms)
        return;
 
    m_longPressThreshold = ms;
    emit longPressThresholdChanged();
}
 
int QQuickTapHandler::longPressThresholdMilliseconds() const
{
    return (m_longPressThreshold < 0 ? QGuiApplication::styleHints()->mousePressAndHoldInterval() : m_longPressThreshold);
}
 
void QQuickTapHandler::timerEvent(QTimerEvent *event)
{
    if (event->timerId() == m_longPressTimer.timerId()) {
        m_longPressTimer.stop();
        qCDebug(lcTapHandler) << objectName() << "longPressed";
        emit longPressed();
    } else if (event->timerId() == m_doubleTapTimer.timerId()) {
        m_doubleTapTimer.stop();
        qCDebug(lcTapHandler) << objectName() << "double-tap timer expired; taps:" << m_tapCount;
        Q_ASSERT(m_exclusiveSignals == (SingleTap | DoubleTap));
        if (m_tapCount == 1)
            emit singleTapped(m_singleTapReleasedPoint, m_singleTapReleasedButton);
        else if (m_tapCount == 2)
            emit doubleTapped(m_singleTapReleasedPoint, m_singleTapReleasedButton);
    }
}
 
void QQuickTapHandler::setGesturePolicy(QQuickTapHandler::GesturePolicy gesturePolicy)
{
    if (m_gesturePolicy == gesturePolicy)
        return;
 
    m_gesturePolicy = gesturePolicy;
    emit gesturePolicyChanged();
}
 
void QQuickTapHandler::setExclusiveSignals(QQuickTapHandler::ExclusiveSignals exc)
{
    if (m_exclusiveSignals == exc)
        return;
 
    m_exclusiveSignals = exc;
    emit exclusiveSignalsChanged();
}
 
void QQuickTapHandler::setPressed(bool press, bool cancel, QPointerEvent *event, QEventPoint &point)
{
    if (m_pressed != press) {
        qCDebug(lcTapHandler) << objectName() << "pressed" << m_pressed << "->" << press
                              << (cancel ? "CANCEL" : "") << point << "gp" << m_gesturePolicy;
        m_pressed = press;
        connectPreRenderSignal(press);
        updateTimeHeld();
        if (press) {
            m_longPressTimer.start(longPressThresholdMilliseconds(), this);
            m_holdTimer.start();
        } else {
            m_longPressTimer.stop();
            m_holdTimer.invalidate();
        }
        if (press) {
            // on press, grab before emitting changed signals
            if (m_gesturePolicy == DragThreshold)
                setPassiveGrab(event, point, press);
            else
                setExclusiveGrab(event, point, press);
        }
        if (!cancel && !press && parentContains(point)) {
            if (point.timeHeld() < longPressThreshold()) {
                // Assuming here that pointerEvent()->timestamp() is in ms.
                const quint64 ts = event->timestamp();
                const quint64 interval = ts - m_lastTapTimestamp;
                const auto distanceSquared = QVector2D(point.scenePosition() - m_lastTapPos).lengthSquared();
                const auto singleTapReleasedButton = event->isSinglePointEvent() ? static_cast<QSinglePointEvent *>(event)->button() : Qt::NoButton;
                if ((interval < m_multiTapInterval && distanceSquared <
                        (event->device()->type() == QInputDevice::DeviceType::Mouse ?
                         m_mouseMultiClickDistanceSquared : m_touchMultiTapDistanceSquared))
                      && m_singleTapReleasedButton == singleTapReleasedButton) {
                    ++m_tapCount;
                } else {
                    m_singleTapReleasedButton = singleTapReleasedButton;
                    m_singleTapReleasedPoint = point;
                    m_tapCount = 1;
                }
                qCDebug(lcTapHandler) << objectName() << "tapped" << m_tapCount << "times; interval since last:" << interval
                                      << "sec; distance since last:" << qSqrt(distanceSquared);
                auto button = event->isSinglePointEvent() ? static_cast<QSinglePointEvent *>(event)->button() : Qt::NoButton;
                emit tapped(point, button);
                emit tapCountChanged();
                switch (m_exclusiveSignals) {
                case NotExclusive:
                    if (m_tapCount == 1)
                        emit singleTapped(point, button);
                    else if (m_tapCount == 2)
                        emit doubleTapped(point, button);
                    break;
                case SingleTap:
                    if (m_tapCount == 1)
                        emit singleTapped(point, button);
                    break;
                case DoubleTap:
                    if (m_tapCount == 2)
                        emit doubleTapped(point, button);
                    break;
                case (SingleTap | DoubleTap):
                    if (m_tapCount == 1) {
                        qCDebug(lcTapHandler) << objectName() << "waiting to emit singleTapped:" << m_multiTapInterval << "ms";
                        m_doubleTapTimer.start(m_multiTapInterval, this);
                    }
                }
                qCDebug(lcTapHandler) << objectName() << "tap" << m_tapCount << "after" << event->timestamp() - m_lastTapTimestamp << "ms";
 
                m_lastTapTimestamp = ts;
                m_lastTapPos = point.scenePosition();
            } else {
                qCDebug(lcTapHandler) << objectName() << "tap threshold" << longPressThreshold() << "exceeded:" << point.timeHeld();
            }
        }
        emit pressedChanged();
        if (!press && m_gesturePolicy != DragThreshold) {
            // on release, ungrab after emitting changed signals
            setExclusiveGrab(event, point, press);
        }
        if (cancel) {
            emit canceled(point);
            setExclusiveGrab(event, point, false);
            // In case there is a filtering parent (Flickable), we should not give up the passive grab,
            // so that it can continue to filter future events.
            d_func()->reset();
            emit pointChanged();
        }
    }
}
 
void QQuickTapHandler::onGrabChanged(QQuickPointerHandler *grabber, QPointingDevice::GrabTransition transition,
                                     QPointerEvent *ev, QEventPoint &point)
{
    QQuickSinglePointHandler::onGrabChanged(grabber, transition, ev, point);
    bool isCanceled = transition == QPointingDevice::CancelGrabExclusive || transition == QPointingDevice::CancelGrabPassive;
    if (grabber == this && (isCanceled || point.state() == QEventPoint::Released))
        setPressed(false, isCanceled, ev, point);
}
 
void QQuickTapHandler::connectPreRenderSignal(bool conn)
{
    auto par = parentItem();
    if (!par)
        return;
    if (conn)
        connect(par->window(), &QQuickWindow::beforeSynchronizing, this, &QQuickTapHandler::updateTimeHeld);
    else
        disconnect(par->window(), &QQuickWindow::beforeSynchronizing, this, &QQuickTapHandler::updateTimeHeld);
}
 
void QQuickTapHandler::updateTimeHeld()
{
    emit timeHeldChanged();
}
 
QT_END_NAMESPACE
 
#include "moc_qquicktaphandler_p.cpp"