qt-everywhere-src-5.14.1/qtdeclarative/src/quick/handlers/qquickhoverhandler.cpp

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#include "qquickhoverhandler_p.h"
#include <private/qquicksinglepointhandler_p_p.h>

QT_BEGIN_NAMESPACE

Q_LOGGING_CATEGORY(lcHoverHandler, "qt.quick.handler.hover")

/*!
    \qmltype HoverHandler
    \instantiates QQuickHoverHandler
    \inherits SinglePointHandler
    \inqmlmodule QtQuick
    \ingroup qtquick-input-handlers
    \brief Handler for mouse and tablet hover.

    HoverHandler detects a hovering mouse or tablet stylus cursor.

    A binding to the \l hovered property is the easiest way to react when the
    cursor enters or leaves the \l {PointerHandler::parent}{parent} Item.
    The \l {SinglePointHandler::point}{point} property provides more detail,
    including the cursor position. The
    \l {PointerDeviceHandler::acceptedDevices}{acceptedDevices},
    \l {PointerDeviceHandler::acceptedPointerTypes}{acceptedPointerTypes},
    and \l {PointerDeviceHandler::acceptedModifiers}{acceptedModifiers}
    properties can be used to narrow the behavior to detect hovering of
    specific kinds of devices or while holding a modifier key.

    \sa MouseArea, PointHandler
*/

QQuickHoverHandler::QQuickHoverHandler(QQuickItem *parent)
    : QQuickSinglePointHandler(parent)
{
    // Tell QQuickPointerDeviceHandler::wantsPointerEvent() to ignore button state
    d_func()->acceptedButtons = Qt::NoButton;
}

QQuickHoverHandler::~QQuickHoverHandler()
{
    if (auto parent = parentItem())
        QQuickItemPrivate::get(parent)->setHasHoverInChild(false);
}

void QQuickHoverHandler::componentComplete()
{
    parentItem()->setAcceptHoverEvents(true);
    QQuickItemPrivate::get(parentItem())->setHasHoverInChild(true);
}

bool QQuickHoverHandler::wantsPointerEvent(QQuickPointerEvent *event)
{
    QQuickEventPoint *point = event->point(0);
    if (QQuickPointerDeviceHandler::wantsPointerEvent(event) && wantsEventPoint(point) && parentContains(point)) {
        // assume this is a mouse event, so there's only one point
        setPointId(point->pointId());
        return true;
    }
    setHovered(false);
    return false;
}

void QQuickHoverHandler::handleEventPoint(QQuickEventPoint *point)
{
    bool hovered = true;
    if (point->state() == QQuickEventPoint::Released &&
            point->pointerEvent()->device()->pointerType() == QQuickPointerDevice::Finger)
        hovered = false;
    setHovered(hovered);
    setPassiveGrab(point);
}

/*!
    \qmlproperty bool QtQuick::HoverHandler::hovered
    \readonly

    Holds true whenever any pointing device cursor (mouse or tablet) is within
    the bounds of the \c parent Item, extended by the
    \l {PointerHandler::margin}{margin}, if any.
*/
void QQuickHoverHandler::setHovered(bool hovered)
{
    if (m_hovered != hovered) {
        qCDebug(lcHoverHandler) << objectName() << "hovered" << m_hovered << "->" << hovered;
        m_hovered = hovered;
        emit hoveredChanged();
    }
}

QT_END_NAMESPACE