#include <qquickpinchhandler_p.h>

Inheritance diagram for QQuickPinchHandler:

Collaboration diagram for QQuickPinchHandler:

Signals
void	minimumScaleChanged ()

void	maximumScaleChanged ()

void	minimumRotationChanged ()

void	maximumRotationChanged ()

void	updated ()

void	scaleChanged (qreal delta)

void	rotationChanged (qreal delta)

void	translationChanged (QVector2D delta)

Signals inherited from QQuickMultiPointHandler
void	minimumPointCountChanged ()

void	maximumPointCountChanged ()

void	centroidChanged ()

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
	QQuickPinchHandler (QQuickItem *parent=nullptr)
	\qmltype PinchHandler \instantiates QQuickPinchHandler \inherits MultiPointHandler \inqmlmodule QtQuick

QQuickDragAxis *	xAxis ()

QQuickDragAxis *	yAxis ()

QPointF	activeTranslation () const

QPointF	persistentTranslation () const

void	setPersistentTranslation (const QPointF &trans)
	\qmlsignal QtQuick::PinchHandler::translationChanged(QVector2D delta)

QQuickDragAxis *	scaleAxis ()

qreal	activeScale () const

void	setActiveScale (qreal scale)
	\readonly \qmlproperty real QtQuick::PinchHandler::activeScale

qreal	persistentScale () const

void	setPersistentScale (qreal scale)
	\qmlsignal QtQuick::PinchHandler::scaleChanged(qreal delta)

QQuickDragAxis *	rotationAxis ()

qreal	activeRotation () const

void	setActiveRotation (qreal rot)
	\qmlsignal QtQuick::PinchHandler::rotationChanged(qreal delta)

qreal	persistentRotation () const

void	setPersistentRotation (qreal rot)
	\qmlproperty real QtQuick::PinchHandler::persistentRotation

Public Member Functions inherited from QQuickMultiPointHandler
	QQuickMultiPointHandler (QQuickItem *parent=nullptr, int minimumPointCount=2, int maximumPointCount=-1)
	\qmltype MultiPointHandler

int	minimumPointCount () const
	\qmlproperty int MultiPointHandler::minimumPointCount

void	setMinimumPointCount (int c)

int	maximumPointCount () const
	\qmlproperty int MultiPointHandler::maximumPointCount

void	setMaximumPointCount (int maximumPointCount)

const QQuickHandlerPoint &	centroid () const
	\readonly \qmlproperty QtQuick::handlerPoint QtQuick::MultiPointHandler::centroid

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	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.

bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.

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::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

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

void	killTimer (Qt::TimerId id)

template<typename T >
T	findChild (QAnyStringView aName, 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 (QAnyStringView 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 >
T	findChild (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.

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 ()

Protected Member Functions
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	onActiveChanged () override
	\qmlpropertygroup QtQuick::PinchHandler::xAxis \qmlproperty real QtQuick::PinchHandler::xAxis.minimum \qmlproperty real QtQuick::PinchHandler::xAxis.maximum \qmlproperty bool QtQuick::PinchHandler::xAxis.enabled \qmlproperty real QtQuick::PinchHandler::xAxis.activeValue

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

Protected Member Functions inherited from QQuickMultiPointHandler
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.

QList< QQuickHandlerPoint > &	currentPoints ()

QQuickHandlerPoint &	mutableCentroid ()
	Returns a modifiable reference to the point that will be returned by the \l centroid property.

bool	hasCurrentPoints (QPointerEvent *event)

QVector< QEventPoint >	eligiblePoints (QPointerEvent *event)

qreal	averageTouchPointDistance (const QPointF &ref)

qreal	averageStartingDistance (const QPointF &ref)

qreal	averageTouchPointAngle (const QPointF &ref)

qreal	averageStartingAngle (const QPointF &ref)

QVector< PointData >	angles (const QPointF &ref) const

void	acceptPoints (const QVector< QEventPoint > &points)

bool	grabPoints (QPointerEvent *event, const QVector< QEventPoint > &points)

void	moveTarget (QPointF pos)

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	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.

void	setActive (bool active)

virtual void	onTargetChanged (QQuickItem *oldTarget)

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
QQuickDragAxis *	scaleAxis

qreal	activeScale

qreal	persistentScale

QQuickDragAxis *	rotationAxis

qreal	activeRotation

qreal	persistentRotation

QQuickDragAxis *	xAxis

QQuickDragAxis *	yAxis

QPointF	activeTranslation

QPointF	persistentTranslation

Properties inherited from QQuickMultiPointHandler
int	minimumPointCount

int	maximumPointCount

QQuickHandlerPoint	centroid

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)

Static Protected Member Functions inherited from QQuickMultiPointHandler
static qreal	averageAngleDelta (const QVector< PointData > &old, const QVector< PointData > &newAngles)

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 29 of file qquickpinchhandler_p.h.

Constructor & Destructor Documentation

◆ QQuickPinchHandler()

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

explicit

\qmltype PinchHandler \instantiates QQuickPinchHandler \inherits MultiPointHandler \inqmlmodule QtQuick

Handler for pinch gestures.

PinchHandler is a handler that interprets a multi-finger gesture to interactively rotate, zoom, and drag an Item. Like other Input Handlers, by default it is fully functional, and manipulates its \l target, which is the Item within which it is declared.

import QtQuick
 
Rectangle {
    width: 400
    height: 300
    color: "lightsteelblue"
    PinchHandler { }
}

It has properties to restrict the range of dragging, rotation, and zoom.

If it is declared within one Item but is assigned a different \l target, it handles events within the bounds of the outer Item but manipulates the target Item instead:

import QtQuick
 
Item {
    width: 640
    height: 480
 
    Rectangle {
        id: map
        color: "aqua"
        width: 400
        height: 300
    }
 
    PinchHandler {
        target: map
    }
}

A third way to use it is to set \l target to null and react to property changes in some other way:

import QtQuick
 
Window {
    width: 320; height: 240
    visible: true
    title: handler.persistentRotation.toFixed(1) + "° " +
           handler.persistentTranslation.x.toFixed(1) + ", " +
           handler.persistentTranslation.y.toFixed(1) + " " +
           (handler.persistentScale * 100).toFixed(1) + "%"
 
    PinchHandler {
        id: handler
        target: null
        persistentScale: 0.25
        onTranslationChanged: (delta) => {
            image.x -= delta.x
            image.y -= delta.y
        }
    }
 
    Image {
        id: image
        source: "images/album-cover.jpg"
        scale: handler.persistentScale
        x: -600; y: -450
    }
}

Note: The pinch begins when the number of fingers pressed is between \l {MultiPointHandler::minimumPointCount}{minimumPointCount} and \l {MultiPointHandler::maximumPointCount}{maximumPointCount}, inclusive. Until then, PinchHandler tracks the positions of any pressed fingers, but if it's a disallowed number, it does not scale or rotate its \l target, and the \l active property remains false.

See also: PinchArea, QPointerEvent::pointCount(), QNativeGestureEvent::fingerCount(), {Qt Quick Examples - Pointer Handlers}

Definition at line 62 of file qquickpinchhandler.cpp.

References QQuickPointerDeviceHandler::acceptedButtons, and Qt::NoButton.

Member Function Documentation

◆ activeRotation()

qreal QQuickPinchHandler::activeRotation ( ) const

inline

Definition at line 95 of file qquickpinchhandler_p.h.

◆ activeScale()

qreal QQuickPinchHandler::activeScale ( ) const

inline

Definition at line 82 of file qquickpinchhandler_p.h.

◆ activeTranslation()

QPointF QQuickPinchHandler::activeTranslation ( ) const

inline

Definition at line 70 of file qquickpinchhandler_p.h.

◆ handlePointerEventImpl()

void QQuickPinchHandler::handlePointerEventImpl ( QPointerEvent * event )

overrideprotectedvirtual

This function can be overridden to implement whatever behavior a specific subclass is intended to have: \list.

Handle all the event's QPointerEvent::points() for which wantsEventPoint() already returned true.
Call setPassiveGrab() setExclusiveGrab() or cancelAllGrabs() as necessary.
Call QEvent::accept() to stop propagation, or ignore() to allow it to keep going. \endlist

Reimplemented from QQuickMultiPointHandler.

Definition at line 497 of file qquickpinchhandler.cpp.

Here is the call graph for this function:

◆ maximumRotationChanged

void QQuickPinchHandler::maximumRotationChanged ( )

signal

◆ maximumScaleChanged

void QQuickPinchHandler::maximumScaleChanged ( )

signal

◆ minimumRotationChanged

void QQuickPinchHandler::minimumRotationChanged ( )

signal

◆ minimumScaleChanged

void QQuickPinchHandler::minimumScaleChanged ( )

signal

◆ onActiveChanged()

void QQuickPinchHandler::onActiveChanged ( )

overrideprotectedvirtual

\qmlpropertygroup QtQuick::PinchHandler::xAxis \qmlproperty real QtQuick::PinchHandler::xAxis.minimum \qmlproperty real QtQuick::PinchHandler::xAxis.maximum \qmlproperty bool QtQuick::PinchHandler::xAxis.enabled \qmlproperty real QtQuick::PinchHandler::xAxis.activeValue

xAxis controls the constraints for horizontal translation of the \l target item.

minimum is the minimum acceptable x coordinate of the translation. maximum is the maximum acceptable x coordinate of the translation. If enabled is true, horizontal dragging is allowed.

The activeValueChanged signal is emitted when activeValue changes, to provide the increment by which it changed. This is intended for incrementally adjusting one property via multiple handlers.

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"; antialiasing: true
 
    PinchHandler {
        id: handler
        target: null
        xAxis.onActiveValueChanged: (delta) => parent.radius -= delta
        yAxis.onActiveValueChanged: (delta) => parent.border.width += delta
        rotationAxis.onActiveValueChanged: (delta) => parent.rotation += delta // add
        scaleAxis.onActiveValueChanged: (delta) => parent.scale *= delta // multiply
    }
 
    WheelHandler {
        acceptedModifiers: Qt.NoModifier
        property: "rotation"
    }
 
    WheelHandler {
        acceptedModifiers: Qt.ControlModifier
        property: "scale"
    }
}

Note: The snippet is contrived: PinchHandler already knows how to move, scale and rotate its parent item, but this code achieves different behavior in a less-declarative way, to illustrate how to use activeValueChanged in special cases.

\qmlpropertygroup QtQuick::PinchHandler::yAxis \qmlproperty real QtQuick::PinchHandler::yAxis.minimum \qmlproperty real QtQuick::PinchHandler::yAxis.maximum \qmlproperty bool QtQuick::PinchHandler::yAxis.enabled \qmlproperty real QtQuick::PinchHandler::yAxis.activeValue

yAxis controls the constraints for vertical translation of the \l target item.

minimum is the minimum acceptable y coordinate of the translation. maximum is the maximum acceptable y coordinate of the translation. If enabled is true, vertical dragging is allowed.

The activeValueChanged signal is emitted when activeValue changes, to provide the increment by which it changed. This is intended for incrementally adjusting one property via multiple handlers.

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"; antialiasing: true
 
    PinchHandler {
        id: handler
        target: null
        xAxis.onActiveValueChanged: (delta) => parent.radius -= delta
        yAxis.onActiveValueChanged: (delta) => parent.border.width += delta
        rotationAxis.onActiveValueChanged: (delta) => parent.rotation += delta // add
        scaleAxis.onActiveValueChanged: (delta) => parent.scale *= delta // multiply
    }
 
    WheelHandler {
        acceptedModifiers: Qt.NoModifier
        property: "rotation"
    }
 
    WheelHandler {
        acceptedModifiers: Qt.ControlModifier
        property: "scale"
    }
}

Note: The snippet is contrived: PinchHandler already knows how to move, scale and rotate its parent item, but this code achieves different behavior in a less-declarative way, to illustrate how to use activeValueChanged in special cases.

\qmlpropertygroup QtQuick::PinchHandler::scaleAxis \qmlproperty real QtQuick::PinchHandler::scaleAxis.minimum \qmlproperty real QtQuick::PinchHandler::scaleAxis.maximum \qmlproperty bool QtQuick::PinchHandler::scaleAxis.enabled \qmlproperty real QtQuick::PinchHandler::scaleAxis.activeValue

scaleAxis controls the constraints for setting the \l {QtQuick::Item::scale}{scale} of the \l target item according to the distance between the touchpoints.

minimum is the minimum acceptable scale. maximum is the maximum acceptable scale. If enabled is true, scaling is allowed. activeValue is the same as \l {QtQuick::PinchHandler::activeScale}.

The activeValueChanged signal is emitted when activeValue changes, to provide the multiplier for the incremental change. This is intended for incrementally adjusting one property via multiple handlers.

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"; antialiasing: true
 
    PinchHandler {
        id: handler
        target: null
        xAxis.onActiveValueChanged: (delta) => parent.radius -= delta
        yAxis.onActiveValueChanged: (delta) => parent.border.width += delta
        rotationAxis.onActiveValueChanged: (delta) => parent.rotation += delta // add
        scaleAxis.onActiveValueChanged: (delta) => parent.scale *= delta // multiply
    }
 
    WheelHandler {
        acceptedModifiers: Qt.NoModifier
        property: "rotation"
    }
 
    WheelHandler {
        acceptedModifiers: Qt.ControlModifier
        property: "scale"
    }
}

Note: The snippet is contrived: PinchHandler already knows how to move, scale and rotate its parent item, but this code achieves different behavior in a less-declarative way, to illustrate how to use activeValueChanged in special cases.

\qmlpropertygroup QtQuick::PinchHandler::rotationAxis \qmlproperty real QtQuick::PinchHandler::rotationAxis.minimum \qmlproperty real QtQuick::PinchHandler::rotationAxis.maximum \qmlproperty bool QtQuick::PinchHandler::rotationAxis.enabled \qmlproperty real QtQuick::PinchHandler::rotationAxis.activeValue

rotationAxis controls the constraints for setting the \l {QtQuick::Item::rotation}{rotation} of the \l target item according to the rotation of the group of touchpoints.

minimum is the minimum acceptable rotation. maximum is the maximum acceptable rotation. If enabled is true, rotation is allowed. activeValue is the same as \l {QtQuick::PinchHandler::activeRotation}.

The activeValueChanged signal is emitted when activeValue changes, to provide the increment by which it changed. This is intended for incrementally adjusting one property via multiple handlers.

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"; antialiasing: true
 
    PinchHandler {
        id: handler
        target: null
        xAxis.onActiveValueChanged: (delta) => parent.radius -= delta
        yAxis.onActiveValueChanged: (delta) => parent.border.width += delta
        rotationAxis.onActiveValueChanged: (delta) => parent.rotation += delta // add
        scaleAxis.onActiveValueChanged: (delta) => parent.scale *= delta // multiply
    }
 
    WheelHandler {
        acceptedModifiers: Qt.NoModifier
        property: "rotation"
    }
 
    WheelHandler {
        acceptedModifiers: Qt.ControlModifier
        property: "scale"
    }
}

Note: The snippet is contrived: PinchHandler already knows how to move, scale and rotate its parent item, but this code achieves different behavior in a less-declarative way, to illustrate how to use activeValueChanged in special cases.

\readonly \qmlproperty bool QtQuick::PinchHandler::active

This property is true when all the constraints (epecially \l {MultiPointHandler::minimumPointCount}{minimumPointCount} and \l {MultiPointHandler::maximumPointCount}{maximumPointCount}) are satisfied and the \l target, if any, is being manipulated.

Reimplemented from QQuickMultiPointHandler.

Definition at line 475 of file qquickpinchhandler.cpp.

References QQuickPointerHandler::active, QQuickMultiPointHandler::angles(), QQuickMultiPointHandler::averageTouchPointDistance(), QQuickMultiPointHandler::centroid, QQuickMultiPointHandler::onActiveChanged(), QQuickDragAxis::onActiveChanged(), QQuickItem::position(), qCDebug, and QQuickPointerHandler::target.

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◆ persistentRotation()

qreal QQuickPinchHandler::persistentRotation ( ) const

inline

Definition at line 97 of file qquickpinchhandler_p.h.

◆ persistentScale()

qreal QQuickPinchHandler::persistentScale ( ) const

inline

Definition at line 84 of file qquickpinchhandler_p.h.

◆ persistentTranslation()

QPointF QQuickPinchHandler::persistentTranslation ( ) const

inline

Definition at line 71 of file qquickpinchhandler_p.h.

◆ rotationAxis()

QQuickDragAxis * QQuickPinchHandler::rotationAxis ( )

inline

Definition at line 87 of file qquickpinchhandler_p.h.

◆ rotationChanged

void QQuickPinchHandler::rotationChanged ( qreal delta )

signal

Referenced by setActiveRotation(), and setPersistentRotation().

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◆ scaleAxis()

QQuickDragAxis * QQuickPinchHandler::scaleAxis ( )

inline

Definition at line 74 of file qquickpinchhandler_p.h.

◆ scaleChanged

void QQuickPinchHandler::scaleChanged ( qreal delta )

signal

Referenced by setActiveScale(), and setPersistentScale().

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◆ setActiveRotation()

void QQuickPinchHandler::setActiveRotation ( qreal rot )

\qmlsignal QtQuick::PinchHandler::rotationChanged(qreal delta)

The rotationChanged signal is emitted when \l activeRotation (and therefore \l persistentRotation) changes. The delta value gives the additive change in rotation. For example, if the user moves fingers to change the pinch distance so that activeRotation changes from 10 to 30 degrees, rotationChanged(20) will be emitted. You can use that to incrementally change the rotation of an item:

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"
 
    PinchHandler {
        id: handler
        target: null
        onRotationChanged: (delta) => parent.rotation += delta // add
        onScaleChanged: (delta) => parent.scale *= delta // multiply
    }
}

Note: If you set the \l persistentRotation property directly, delta is 0.

\readonly \qmlproperty QVector2D QtQuick::PinchHandler::rotation

Deprecated: [6.5] Use activeRotation

\readonly \qmlproperty real QtQuick::PinchHandler::activeRotation

The rotation of the pinch gesture in degrees, with positive values clockwise. It is 0 when the gesture begins. If \l target is not null, this will be automatically added to its \l {Item::rotation}{rotation}. Otherwise, bindings can be used to do arbitrary things with this value.

See also: QtQuick::PinchHandler::rotationAxis.activeValue

Definition at line 239 of file qquickpinchhandler.cpp.

References activeRotation, QQuickDragAxis::activeValue, emit, rotationChanged(), and QQuickDragAxis::updateValue().

Referenced by handlePointerEventImpl().

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◆ setActiveScale()

void QQuickPinchHandler::setActiveScale ( qreal scale )

\readonly \qmlproperty real QtQuick::PinchHandler::activeScale

The scale factor while the pinch gesture is being performed. It is 1.0 when the gesture begins, increases as the touchpoints are spread apart, and decreases as the touchpoints are brought together. If \l target is not null, its \l {Item::scale}{scale} will be automatically multiplied by this value. Otherwise, bindings can be used to do arbitrary things with this value.

See also: QtQuick::PinchHandler::scaleAxis.activeValue

Definition at line 117 of file qquickpinchhandler.cpp.

References activeScale, QQuickDragAxis::activeValue, emit, scaleChanged(), and QQuickDragAxis::updateValue().

Referenced by handlePointerEventImpl().

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◆ setPersistentRotation()

void QQuickPinchHandler::setPersistentRotation ( qreal rot )

\qmlproperty real QtQuick::PinchHandler::persistentRotation

The rotation to be applied to the \l target if it is not null. Otherwise, bindings can be used to do arbitrary things with this value. While the pinch gesture is being performed, \l activeRotation is continuously added; after the gesture ends, it stays the same; and when the next pinch gesture begins, it begins to be modified by activeRotation again.

It's possible to set this property, as a way of synchronizing the basis rotation with a rotation that was set in some other way, for example by another handler. If you set this property directly, activeRotation does not change, and rotationChanged(0) is emitted.

Definition at line 264 of file qquickpinchhandler.cpp.

References QQuickDragAxis::activeValue, emit, persistentRotation, rotationChanged(), and QQuickDragAxis::updateValue().

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◆ setPersistentScale()

void QQuickPinchHandler::setPersistentScale ( qreal scale )

\qmlsignal QtQuick::PinchHandler::scaleChanged(qreal delta)

The scaleChanged signal is emitted when \l activeScale (and therefore \l persistentScale) changes. The delta value gives the multiplicative change in scale. For example, if the user moves fingers to change the pinch distance so that activeScale changes from 2 to 2.5, scaleChanged(1.25) will be emitted. You can use that to incrementally change the scale of an item:

import QtQuick
 
Rectangle {
    width: 100; height: 100
    color: "lightsteelblue"
 
    PinchHandler {
        id: handler
        target: null
        onRotationChanged: (delta) => parent.rotation += delta // add
        onScaleChanged: (delta) => parent.scale *= delta // multiply
    }
}

Note: If you set the \l persistentScale property directly, delta is 1.

\readonly \qmlproperty QVector2D QtQuick::PinchHandler::scale

Deprecated: [6.5] Use persistentScale

\qmlproperty real QtQuick::PinchHandler::persistentScale

The scale factor that will automatically be set on the \l target if it is not null. Otherwise, bindings can be used to do arbitrary things with this value. While the pinch gesture is being performed, it is continuously multiplied by \l activeScale; after the gesture ends, it stays the same; and when the next pinch gesture begins, it begins to be multiplied by activeScale again.

It's possible to set this property, as a way of synchronizing the basis scale with a scale that was set in some other way, for example by another handler. If you set this property directly, activeScale does not change, and scaleChanged(1) is emitted.

Definition at line 163 of file qquickpinchhandler.cpp.

References QQuickDragAxis::activeValue, emit, persistentScale, scaleChanged(), and QQuickDragAxis::updateValue().

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◆ setPersistentTranslation()

void QQuickPinchHandler::setPersistentTranslation ( const QPointF & trans )

\qmlsignal QtQuick::PinchHandler::translationChanged(QVector2D delta)

The translationChanged signal is emitted when \l activeTranslation (and therefore \l persistentTranslation) changes. The delta vector gives the change in translation. You can use that to incrementally change the position of an item:

import QtQuick
 
Window {
    width: 320; height: 240
    visible: true
    title: handler.persistentRotation.toFixed(1) + "° " +
           handler.persistentTranslation.x.toFixed(1) + ", " +
           handler.persistentTranslation.y.toFixed(1) + " " +
           (handler.persistentScale * 100).toFixed(1) + "%"
 
    PinchHandler {
        id: handler
        target: null
        persistentScale: 0.25
        onTranslationChanged: (delta) => {
            image.x -= delta.x
            image.y -= delta.y
        }
    }
 
    Image {
        id: image
        source: "images/album-cover.jpg"
        scale: handler.persistentScale
        x: -600; y: -450
    }
}

Note: If you set the \l persistentTranslation property directly, delta is {0, 0}.

\readonly \qmlproperty QVector2D QtQuick::PinchHandler::translation

Deprecated: [6.5] Use activeTranslation

\readonly \qmlproperty QPointF QtQuick::PinchHandler::activeTranslation

The translation of the cluster of points while the pinch gesture is being performed. It is {0, 0} when the gesture begins, and increases as the \l {eventPoint}{eventPoint(s)} are dragged downward and to the right. After the gesture ends, it stays the same; and when the next pinch gesture begins, it is reset to {0, 0} again.

Note: On some touchpads, such as on a \macos trackpad, native gestures do not generate any translation values, and this property stays at (0, 0).

\qmlproperty QPointF QtQuick::PinchHandler::persistentTranslation

The translation to be applied to the \l target if it is not null. Otherwise, bindings can be used to do arbitrary things with this value. While the pinch gesture is being performed, \l activeTranslation is continuously added to it; after the gesture ends, it stays the same.

It's possible to set this property, as a way of synchronizing the basis translation with a translation that was set in some other way, for example by another handler. If you set this property directly, activeTranslation does not change, and translationChanged({0, 0}) is emitted.

Note: On some touchpads, such as on a \macos trackpad, native gestures do not generate any translation values, and this property stays at (0, 0).

Definition at line 323 of file qquickpinchhandler.cpp.

References QQuickDragAxis::activeValue, emit, persistentTranslation, translationChanged(), QQuickDragAxis::updateValue(), QPointF::x(), and QPointF::y().

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◆ translationChanged

void QQuickPinchHandler::translationChanged ( QVector2D delta )

signal

Referenced by handlePointerEventImpl(), and setPersistentTranslation().

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◆ updated

void QQuickPinchHandler::updated ( )

signal

Referenced by handlePointerEventImpl().

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◆ wantsPointerEvent()

bool QQuickPinchHandler::wantsPointerEvent ( QPointerEvent * event )

overrideprotectedvirtual

It is the responsibility of this function to decide whether the event could be relevant at all to this handler, as a preliminary check.

Returns true if this handler would like handlePointerEventImpl() to be called. If it returns false, the handler will be deactivated: setActive(false) will be called, and any remaining exclusive grab will be relinquished, as a fail-safe.

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. QQuickSinglePointHandler::wantsPointerEvent() and QQuickMultiPointHandler::wantsPointerEvent() call wantsEventPoint(), which is also virtual. You usually can get the behavior you want by subclassing the appropriate handler type, overriding QQuickSinglePointHandler::handleEventPoint() or handlePointerEventImpl(), and perhaps overriding wantsEventPoint() if needed.

See also: wantsEventPoint(), QQuickPointerDeviceHandler::wantsPointerEvent(), QQuickMultiPointHandler::wantsPointerEvent(), QQuickSinglePointHandler::wantsPointerEvent()

Reimplemented from QQuickMultiPointHandler.

Definition at line 333 of file qquickpinchhandler.cpp.

References Qt::BeginNativeGesture, Qt::EndNativeGesture, QQuickMultiPointHandler::maximumPointCount, QQuickMultiPointHandler::minimumPointCount, QEvent::NativeGesture, QQuickPointerHandler::parentContains(), Qt::RotateNativeGesture, QQuickMultiPointHandler::wantsPointerEvent(), and Qt::ZoomNativeGesture.

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◆ xAxis()

QQuickDragAxis * QQuickPinchHandler::xAxis ( )

inline

Definition at line 65 of file qquickpinchhandler_p.h.

◆ yAxis()

QQuickDragAxis * QQuickPinchHandler::yAxis ( )

inline

Definition at line 66 of file qquickpinchhandler_p.h.

Property Documentation

◆ activeRotation

qreal QQuickPinchHandler::activeRotation

read

Definition at line 48 of file qquickpinchhandler_p.h.

Referenced by setActiveRotation().

◆ activeScale

qreal QQuickPinchHandler::activeScale

read

Definition at line 39 of file qquickpinchhandler_p.h.

Referenced by handlePointerEventImpl(), and setActiveScale().

◆ activeTranslation

QPointF QQuickPinchHandler::activeTranslation

read

Definition at line 56 of file qquickpinchhandler_p.h.

Referenced by handlePointerEventImpl().

◆ persistentRotation

qreal QQuickPinchHandler::persistentRotation

readwrite

Definition at line 49 of file qquickpinchhandler_p.h.

Referenced by setPersistentRotation().

◆ persistentScale

qreal QQuickPinchHandler::persistentScale

readwrite

Definition at line 40 of file qquickpinchhandler_p.h.

Referenced by setPersistentScale().

◆ persistentTranslation

QPointF QQuickPinchHandler::persistentTranslation

readwrite

Definition at line 57 of file qquickpinchhandler_p.h.

Referenced by handlePointerEventImpl(), and setPersistentTranslation().

◆ rotationAxis

QQuickDragAxis * QQuickPinchHandler::rotationAxis

read

Definition at line 42 of file qquickpinchhandler_p.h.

◆ scaleAxis

QQuickDragAxis * QQuickPinchHandler::scaleAxis

read

Definition at line 33 of file qquickpinchhandler_p.h.

◆ xAxis

QQuickDragAxis * QQuickPinchHandler::xAxis

read

Definition at line 51 of file qquickpinchhandler_p.h.

Referenced by handlePointerEventImpl().

◆ yAxis

QQuickDragAxis * QQuickPinchHandler::yAxis

read

Definition at line 52 of file qquickpinchhandler_p.h.

Referenced by handlePointerEventImpl().

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

qtdeclarative/src/quick/handlers/qquickpinchhandler_p.h (bd131dcbf579f822ac8cee98324dc1355f7cd314)
qtdeclarative/src/quick/handlers/qquickpinchhandler.cpp (442eeba6724b2b9044822f2d4a54a81b2d6979f6)

Signals

Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QQuickPinchHandler()

Member Function Documentation

◆ activeRotation()

◆ activeScale()

◆ activeTranslation()

◆ handlePointerEventImpl()

◆ maximumRotationChanged

◆ maximumScaleChanged

◆ minimumRotationChanged

◆ minimumScaleChanged

◆ onActiveChanged()

◆ persistentRotation()

◆ persistentScale()

◆ persistentTranslation()

◆ rotationAxis()

◆ rotationChanged

◆ scaleAxis()

◆ scaleChanged

◆ setActiveRotation()

◆ setActiveScale()

◆ setPersistentRotation()

◆ setPersistentScale()

◆ setPersistentTranslation()

◆ translationChanged

◆ updated

◆ wantsPointerEvent()

◆ xAxis()

◆ yAxis()

Property Documentation

◆ activeRotation

◆ activeScale

◆ activeTranslation

◆ persistentRotation

◆ persistentScale

◆ persistentTranslation

◆ rotationAxis

◆ scaleAxis

◆ xAxis

◆ yAxis