QHoverEvent Class

The QHoverEvent class contains parameters that describe a mouse event. More...

Header: #include <QHoverEvent>
CMake: find_package(Qt6 REQUIRED COMPONENTS Gui)
target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake: QT += gui
Inherits: QSinglePointEvent

Public Functions

QHoverEvent(QEvent::Type type, const QPointF &scenePos, const QPointF &globalPos, const QPointF &oldPos, Qt::KeyboardModifiers modifiers = Qt::NoModifier, const QPointingDevice *device = QPointingDevice::primaryPointingDevice())
virtual ~QHoverEvent() override
QPoint oldPos() const
QPointF oldPosF() const

Reimplemented Public Functions

virtual QHoverEvent *clone() const override
virtual bool isUpdateEvent() const override

Protected Functions

QHoverEvent(const QHoverEvent &)
QHoverEvent(QHoverEvent &&)

Protected Variables

QPointF m_oldPos

Detailed Description

Mouse events occur when a mouse cursor is moved into, out of, or within a widget, and if the widget has the Qt::WA_Hover attribute.

The function pos() gives the current cursor position, while oldPos() gives the old mouse position.

There are a few similarities between the events QEvent::HoverEnter and QEvent::HoverLeave, and the events QEvent::Enter and QEvent::Leave. However, they are slightly different because we do an update() in the event handler of HoverEnter and HoverLeave.

QEvent::HoverMove is also slightly different from QEvent::MouseMove. Let us consider a top-level window A containing a child B which in turn contains a child C (all with mouse tracking enabled):

Now, if you move the cursor from the top to the bottom in the middle of A, you will get the following QEvent::MouseMove events:

  1. A::MouseMove
  2. B::MouseMove
  3. C::MouseMove

You will get the same events for QEvent::HoverMove, except that the event always propagates to the top-level regardless whether the event is accepted or not. It will only stop propagating with the Qt::WA_NoMousePropagation attribute.

In this case the events will occur in the following way:

  1. A::HoverMove
  2. A::HoverMove, B::HoverMove
  3. A::HoverMove, B::HoverMove, C::HoverMove

Member Function Documentation

QHoverEvent::QHoverEvent(QEvent::Type type, const QPointF &scenePos, const QPointF &globalPos, const QPointF &oldPos, Qt::KeyboardModifiers modifiers = Qt::NoModifier, const QPointingDevice *device = QPointingDevice::primaryPointingDevice())

Constructs a hover event object originating from device.

The type parameter must be QEvent::HoverEnter, QEvent::HoverLeave, or QEvent::HoverMove.

The scenePos is the current mouse cursor's position relative to the receiving window or scene, oldPos is its previous such position, and globalPos is the mouse position in absolute coordinates. modifiers hold the state of all keyboard modifiers at the time of the event.

[protected] QHoverEvent::QHoverEvent(const QHoverEvent &)

Copy constructor.

[protected] QHoverEvent::QHoverEvent(QHoverEvent &&)

Move-copy constructor.

[override virtual] QHoverEvent::~QHoverEvent()

Destroys the instance of QHoverEvent. The destructor is virtual.

[override virtual] QHoverEvent *QHoverEvent::clone() const

[override virtual] bool QHoverEvent::isUpdateEvent() const

QPoint QHoverEvent::oldPos() const

Returns the previous position of the mouse cursor, relative to the widget that received the event. If there is no previous position, oldPos() will return the same position as pos().

On QEvent::HoverEnter events, this position will always be QPoint(-1, -1).

See also pos().

QPointF QHoverEvent::oldPosF() const

Returns the previous position of the mouse cursor, relative to the widget that received the event. If there is no previous position, oldPosF() will return the same position as posF().

On QEvent::HoverEnter events, this position will always be QPointF(-1, -1).

See also posF().

Member Variable Documentation

QPointF QHoverEvent::m_oldPos

© 2022 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.