#include <qquickpointhandler_p.h>

Inheritance diagram for QQuickPointHandler:

Collaboration diagram for QQuickPointHandler:

Signals
void	translationChanged ()

Signals inherited from QQuickSinglePointHandler
void	pointChanged ()

Signals inherited from QQuickPointerDeviceHandler
void	acceptedDevicesChanged ()

void	acceptedPointerTypesChanged ()

void	acceptedButtonsChanged ()

void	acceptedModifiersChanged ()

Signals inherited from QQuickPointerHandler
void	enabledChanged ()

void	activeChanged ()

void	targetChanged ()

void	marginChanged ()

	Q_REVISION (2, 15) void dragThresholdChanged()

void	grabChanged (QPointingDevice::GrabTransition transition, QEventPoint point)

void	grabPermissionChanged ()

void	canceled (QEventPoint point)

	Q_REVISION (6, 3) void parentChanged()

Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.

void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Public Member Functions
	QQuickPointHandler (QQuickItem *parent=nullptr)
	\qmltype PointHandler \instantiates QQuickPointHandler \inherits SinglePointHandler \inqmlmodule QtQuick

QVector2D	translation () const

Public Member Functions inherited from QQuickSinglePointHandler
	QQuickSinglePointHandler (QQuickItem *parent=nullptr)
	\qmltype SinglePointHandler \qmlabstract \preliminary \instantiates QQuickSinglePointHandler \inherits PointerDeviceHandler \inqmlmodule QtQuick

QQuickHandlerPoint	point () const

Public Member Functions inherited from QQuickPointerDeviceHandler
	QQuickPointerDeviceHandler (QQuickItem *parent=nullptr)
	\qmltype PointerDeviceHandler \qmlabstract

QInputDevice::DeviceTypes	acceptedDevices () const

QPointingDevice::PointerTypes	acceptedPointerTypes () const

Qt::MouseButtons	acceptedButtons () const
	\qmlproperty flags QtQuick::PointerDeviceHandler::acceptedButtons

Qt::KeyboardModifiers	acceptedModifiers () const

Public Member Functions inherited from QQuickPointerHandler
	QQuickPointerHandler (QQuickItem *parent=nullptr)
	\qmltype PointerHandler \qmlabstract

	~QQuickPointerHandler ()

bool	enabled () const
	\qmlproperty bool QtQuick::PointerHandler::enabled

void	setEnabled (bool enabled)

bool	active () const
	\readonly \qmlproperty bool QtQuick::PointerHandler::active

QQuickItem *	target () const
	\qmlproperty Item QtQuick::PointerHandler::target

void	setTarget (QQuickItem *target)

QQuickItem *	parentItem () const
	\qmlproperty Item QtQuick::PointerHandler::parent

void	setParentItem (QQuickItem *p)

void	handlePointerEvent (QPointerEvent *event)

GrabPermissions	grabPermissions () const
	\qmlproperty flags QtQuick::PointerHandler::grabPermissions

void	setGrabPermissions (GrabPermissions grabPermissions)

qreal	margin () const
	\qmlproperty real PointerHandler::margin

void	setMargin (qreal pointDistanceThreshold)

int	dragThreshold () const
	\qmlproperty int PointerHandler::dragThreshold

void	setDragThreshold (int t)

void	resetDragThreshold ()

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.

virtual	~QObject ()
	Destroys the object, deleting all its child objects.

virtual bool	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.

virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.

QString	objectName () const

Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.

void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const
	Returns `true` if the object is a widget; otherwise returns `false`.

bool	isWindowType () const
	Returns `true` if the object is a window; otherwise returns `false`.

bool	isQuickItemType () const
	Returns `true` if the object is a QQuickItem; otherwise returns `false`.

bool	signalsBlocked () const noexcept
	Returns `true` if signals are blocked; otherwise returns `false`.

bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).

QThread *	thread () const
	Returns the thread in which the object lives.

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.

int	startTimer (std::chrono::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.

template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

const QObjectList &	children () const
	Returns a list of child objects.

void	setParent (QObject *parent)
	Makes the object a child of parent.

void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.

void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const

bool	disconnect (const QObject receiver, const char member=nullptr) const

void	dumpObjectTree () const
	Dumps a tree of children to the debug output.

void	dumpObjectInfo () const
	Dumps information about signal connections, etc.

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.

bool	setProperty (const char *name, QVariant &&value)

QVariant	property (const char *name) const
	Returns the value of the object's name property.

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const
	Returns a pointer to the parent object.

bool	inherits (const char *classname) const
	Returns `true` if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns `false`.

Public Member Functions inherited from QQmlParserStatus
	QQmlParserStatus ()

virtual	~QQmlParserStatus ()

virtual void	classBegin ()=0
	Invoked after class creation, but before any properties have been set.

virtual void	componentComplete ()=0
	Invoked after the root component that caused this instantiation has completed construction.

Protected Member Functions
bool	wantsEventPoint (const QPointerEvent *event, const QEventPoint &point) override
	Returns `true` if the given point (as part of event) could be relevant at all to this handler, as a preliminary check.

void	handleEventPoint (QPointerEvent *event, QEventPoint &point) override

Protected Member Functions inherited from QQuickSinglePointHandler
	QQuickSinglePointHandler (QQuickSinglePointHandlerPrivate &dd, QQuickItem *parent)

bool	wantsPointerEvent (QPointerEvent *event) override
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

void	handlePointerEventImpl (QPointerEvent *event) override
	This function can be overridden to implement whatever behavior a specific subclass is intended to have:

virtual void	handleEventPoint (QPointerEvent *event, QEventPoint &point)

QEventPoint &	currentPoint (QPointerEvent *ev)

void	onGrabChanged (QQuickPointerHandler grabber, QPointingDevice::GrabTransition transition, QPointerEvent event, QEventPoint &point) override
	Notification that the grab has changed in some way which is relevant to this handler.

void	setIgnoreAdditionalPoints (bool v=true)

void	moveTarget (QPointF pos, QEventPoint &point)

void	setPointId (int id)

Protected Member Functions inherited from QQuickPointerDeviceHandler
	QQuickPointerDeviceHandler (QQuickPointerDeviceHandlerPrivate &dd, QQuickItem *parent=nullptr)

bool	wantsPointerEvent (QPointerEvent *event) override
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

Protected Member Functions inherited from QQuickPointerHandler
	QQuickPointerHandler (QQuickPointerHandlerPrivate &dd, QQuickItem *parent)

void	classBegin () override
	Overridden only because QQmlParserStatus requires it.

void	componentComplete () override
	Overridden from QQmlParserStatus to ensure that parentItem() sets its cursor if this handler's \l cursorShape property has been set.

bool	event (QEvent *) override

QPointerEvent *	currentEvent ()

virtual bool	wantsPointerEvent (QPointerEvent *event)
	It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

virtual bool	wantsEventPoint (const QPointerEvent *event, const QEventPoint &point)
	Returns `true` if the given point (as part of event) could be relevant at all to this handler, as a preliminary check.

virtual void	handlePointerEventImpl (QPointerEvent *event)
	This function can be overridden to implement whatever behavior a specific subclass is intended to have:

void	setActive (bool active)

virtual void	onTargetChanged (QQuickItem *oldTarget)

virtual void	onActiveChanged ()

virtual void	onGrabChanged (QQuickPointerHandler grabber, QPointingDevice::GrabTransition transition, QPointerEvent event, QEventPoint &point)
	Notification that the grab has changed in some way which is relevant to this handler.

virtual bool	canGrab (QPointerEvent *event, const QEventPoint &point)
	Check whether it's OK to take an exclusive grab of the point.

virtual bool	approveGrabTransition (QPointerEvent event, const QEventPoint &point, QObject proposedGrabber)
	Check this handler's rules to see if \l proposedGrabber will be allowed to take the exclusive grab.

void	setPassiveGrab (QPointerEvent *event, const QEventPoint &point, bool grab=true)
	Acquire or give up a passive grab of the given point, according to the grab state.

bool	setExclusiveGrab (QPointerEvent *ev, const QEventPoint &point, bool grab=true)
	Acquire or give up the exclusive grab of the given point, according to the grab state, and subject to the rules: canGrab(), and the rule not to relinquish another handler's grab.

void	cancelAllGrabs (QPointerEvent *event, QEventPoint &point)
	Cancel any existing grab of the given point.

QPointF	eventPos (const QEventPoint &point) const

bool	parentContains (const QEventPoint &point) const
	Returns `true` if margin() > 0 and point is within the margin beyond QQuickItem::boundingRect(), or else returns QQuickItem::contains() QEventPoint::position() effectively (because parentContains(scenePosition) calls QQuickItem::mapFromScene()).

bool	parentContains (const QPointF &scenePosition) const
	Returns `true` if scenePosition is within the margin() beyond QQuickItem::boundingRect() (if margin > 0), or parentItem() contains scenePosition according to QQuickItem::contains().

Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.

int	senderSignalIndex () const

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.

virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.

virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Properties
QVector2D	translation

Properties inherited from QQuickSinglePointHandler
QQuickHandlerPoint	point

Properties inherited from QQuickPointerDeviceHandler
QInputDevice::DeviceTypes	acceptedDevices

QPointingDevice::PointerTypes	acceptedPointerTypes

Qt::MouseButtons	acceptedButtons

Qt::KeyboardModifiers	acceptedModifiers

Properties inherited from QQuickPointerHandler
bool	enabled

bool	active

QQuickItem *	target

QQuickItem *	parent

GrabPermissions	grabPermissions

qreal	margin

int	dragThreshold

Properties inherited from QObject
QString	objectName
	the name of this object

Additional Inherited Members
Public Types inherited from QQuickPointerHandler
enum	GrabPermission { TakeOverForbidden = 0x0 , CanTakeOverFromHandlersOfSameType = 0x01 , CanTakeOverFromHandlersOfDifferentType = 0x02 , CanTakeOverFromItems = 0x04 , CanTakeOverFromAnything = 0x0F , ApprovesTakeOverByHandlersOfSameType = 0x10 , ApprovesTakeOverByHandlersOfDifferentType = 0x20 , ApprovesTakeOverByItems = 0x40 , ApprovesCancellation = 0x80 , ApprovesTakeOverByAnything = 0xF0 }

Public Slots inherited from QQuickPointerDeviceHandler
void	setAcceptedDevices (QInputDevice::DeviceTypes acceptedDevices)
	\qmlproperty flags PointerDeviceHandler::acceptedDevices

void	setAcceptedPointerTypes (QPointingDevice::PointerTypes acceptedPointerTypes)
	\qmlproperty flags PointerDeviceHandler::acceptedPointerTypes

void	setAcceptedButtons (Qt::MouseButtons buttons)

void	setAcceptedModifiers (Qt::KeyboardModifiers acceptedModifiers)
	\qmlproperty flags PointerDeviceHandler::acceptedModifiers

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe

static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	\threadsafe

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.

template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)

template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

Definition at line 22 of file qquickpointhandler_p.h.

Constructor & Destructor Documentation

◆ QQuickPointHandler()

QT_BEGIN_NAMESPACE QQuickPointHandler::QQuickPointHandler ( QQuickItem * parent = nullptr )

explicit

\qmltype PointHandler \instantiates QQuickPointHandler \inherits SinglePointHandler \inqmlmodule QtQuick

Handler for reacting to a single touchpoint.

PointHandler can be used to show feedback about a touchpoint or the mouse position, or to otherwise react to pointer events.

When a press event occurs, each instance of PointHandler chooses a single point which is not yet "taken" at that moment: if the press occurs within the bounds of the \l {PointerHandler::parent}, and no sibling PointHandler within the same \l {PointerHandler::parent} has yet acquired a passive grab on that point, and if the other constraints such as \l {PointerDeviceHandler::acceptedButtons}{acceptedButtons}, \l {PointerDeviceHandler::acceptedDevices}{acceptedDevices} etc. are satisfied, it's eligible, and the PointHandler then acquires a passive grab. In this way, the \l {PointerHandler::parent} acts like an exclusive group: there can be multiple instances of PointHandler, and the set of pressed touchpoints will be distributed among them. Each PointHandler which has chosen a point to track has its \l active property true. It then continues to track its chosen point until release: the properties of the \l point will be kept up-to-date. Any Item can bind to these properties, and thereby follow the point's movements.

By being only a passive grabber, it has the ability to keep independent oversight of all movements. The passive grab cannot be stolen or overridden even when other gestures are detected and exclusive grabs occur.

If your goal is orthogonal surveillance of eventpoints, an older alternative was QObject::installEventFilter(), but that has never been a built-in QtQuick feature: it requires some C++ code, such as a QQuickItem subclass. PointHandler is more efficient than that, because only pointer events will be delivered to it, during the course of normal event delivery in QQuickWindow; whereas an event filter needs to filter all QEvents of all types, and thus sets itself up as a potential event delivery bottleneck.

One possible use case is to add this handler to a transparent Item which is on top of the rest of the scene (by having a high \l{Item::z} {z} value), so that when a point is freshly pressed, it will be delivered to that Item and its handlers first, providing the opportunity to take the passive grab as early as possible. Such an item (like a pane of glass over the whole UI) can be a convenient parent for other Items which visualize the kind of reactive feedback which must always be on top; and likewise it can be the parent for popups, popovers, dialogs and so on. If it will be used in that way, it can be helpful for your main.cpp to use QQmlContext::setContextProperty() to make the "glass pane" accessible by ID to the entire UI, so that other Items and PointHandlers can be reparented to it.

import QtQuick
 
Window {
    width: 480
    height: 320
    visible: true
 
    Item {
        id: glassPane
        z: 10000
        anchors.fill: parent
 
        //![1]
        PointHandler {
            id: handler
            acceptedDevices: PointerDevice.TouchScreen | PointerDevice.TouchPad
            target: Rectangle {
                parent: glassPane
                color: "red"
                visible: handler.active
                x: handler.point.position.x - width / 2
                y: handler.point.position.y - height / 2
                width: 20; height: width; radius: width / 2
            }
        }
        //![1]
    }
}

Like all input handlers, a PointHandler has a \l target property, which may be used as a convenient place to put a point-tracking Item; but PointHandler will not automatically manipulate the target item in any way. You need to use bindings to make it react to the \l point.

Note: On macOS, PointHandler does not react to multiple fingers on the trackpad by default, although it does react to a pressed point (mouse position). That is because macOS can provide either native gesture recognition, or raw touchpoints, but not both. We prefer to use the native gesture event in PinchHandler, so we do not want to disable it by enabling touch. However MultiPointTouchArea does enable touch, thus disabling native gesture recognition within the entire window; so it's an alternative if you only want to react to all the touchpoints but do not require the smooth native-gesture experience.

See also: MultiPointTouchArea, HoverHandler, {Qt Quick Examples - Pointer Handlers}

Definition at line 82 of file qquickpointhandler.cpp.

References QQuickSinglePointHandler::setIgnoreAdditionalPoints().

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Member Function Documentation

◆ handleEventPoint()

void QQuickPointHandler::handleEventPoint	(	QPointerEvent *	event,
		QEventPoint &	point
	)

overrideprotectedvirtual

Reimplemented from QQuickSinglePointHandler.

Definition at line 104 of file qquickpointhandler.cpp.

References QQuickPointerDeviceHandler::acceptedButtons, emit, QQuickSinglePointHandler::handleEventPoint(), QQuickDeliveryAgentPrivate::isTouchEvent(), Qt::NoButton, QQuickSinglePointHandler::point, QEventPoint::Pressed, QEventPoint::Released, QQuickPointerHandler::setActive(), QQuickPointerHandler::setPassiveGrab(), and translationChanged().

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◆ translation()

QVector2D QQuickPointHandler::translation ( ) const

Definition at line 127 of file qquickpointhandler.cpp.

References QQuickSinglePointHandler::point, and position().

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◆ translationChanged

void QQuickPointHandler::translationChanged ( )

signal

Referenced by handleEventPoint().

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◆ wantsEventPoint()

bool QQuickPointHandler::wantsEventPoint	(	const QPointerEvent *	event,
		const QEventPoint &	point
	)

overrideprotectedvirtual

Returns true if the given point (as part of event) could be relevant at all to this handler, as a preliminary check.

If you override this function, you should call the immediate parent class implementation (and return false if it returns false); that in turn calls its parent class implementation, and so on.

In particular, the bounds checking is done here: the base class QQuickPointerHandler::wantsEventPoint() calls parentContains(point) (which allows the flexibility promised by margin(), QQuickItem::contains() and QQuickItem::containmentMask()). Pointer Handlers can receive QEventPoints that are outside the parent item's bounds: this allows some flexibility for dealing with multi-point gestures in which one or more fingers have strayed outside the bounds, and yet the gesture is still unambiguously intended for the target() item.

You should not generally react to the event or point here, but it's ok to set state to remember what needs to be done in your overridden handlePointerEventImpl() or QQuickSinglePointHandler::handleEventPoint().

Reimplemented from QQuickPointerHandler.

Definition at line 88 of file qquickpointhandler.cpp.

References QQuickHandlerPoint::id, metaObject(), QQuickPointerHandler::parent, QQuickSinglePointHandler::point, QEventPoint::Pressed, and QQuickPointerHandler::wantsEventPoint().

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Property Documentation

◆ translation

QVector2D QQuickPointHandler::translation

read

Definition at line 42 of file qquickpointhandler_p.h.

The documentation for this class was generated from the following files:

qtdeclarative/src/quick/handlers/qquickpointhandler_p.h
qtdeclarative/src/quick/handlers/qquickpointhandler.cpp

Signals

Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QQuickPointHandler()

Member Function Documentation

◆ handleEventPoint()

◆ translation()

◆ translationChanged

◆ wantsEventPoint()

Property Documentation

◆ translation