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Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
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Public Types | Public Member Functions | Properties | Friends | List of all members
QPinchGesture Class Reference

The QPinchGesture class describes a pinch gesture made by the user.\inmodule QtWidgets. More...

#include <qgesture.h>

+ Inheritance diagram for QPinchGesture:
+ Collaboration diagram for QPinchGesture:

Public Types

enum  ChangeFlag { ScaleFactorChanged = 0x1 , RotationAngleChanged = 0x2 , CenterPointChanged = 0x4 }
 This enum describes the changes that can occur to the properties of the gesture object. More...
 
- Public Types inherited from QGesture
enum  GestureCancelPolicy { CancelNone = 0 , CancelAllInContext }
 This enum describes how accepting a gesture can cancel other gestures automatically. More...
 

Public Member Functions

 QPinchGesture (QObject *parent=nullptr)
 
 ~QPinchGesture ()
 Destructor.
 
ChangeFlags totalChangeFlags () const
 
void setTotalChangeFlags (ChangeFlags value)
 
ChangeFlags changeFlags () const
 
void setChangeFlags (ChangeFlags value)
 
QPointF startCenterPoint () const
 
QPointF lastCenterPoint () const
 
QPointF centerPoint () const
 
void setStartCenterPoint (const QPointF &value)
 
void setLastCenterPoint (const QPointF &value)
 
void setCenterPoint (const QPointF &value)
 
qreal totalScaleFactor () const
 
qreal lastScaleFactor () const
 
qreal scaleFactor () const
 
void setTotalScaleFactor (qreal value)
 
void setLastScaleFactor (qreal value)
 
void setScaleFactor (qreal value)
 
qreal totalRotationAngle () const
 
qreal lastRotationAngle () const
 
qreal rotationAngle () const
 
void setTotalRotationAngle (qreal value)
 
void setLastRotationAngle (qreal value)
 
void setRotationAngle (qreal value)
 
- Public Member Functions inherited from QGesture
 QGesture (QObject *parent=nullptr)
 
 ~QGesture ()
 Destroys the gesture object.
 
Qt::GestureType gestureType () const
 
Qt::GestureState state () const
 
QPointF hotSpot () const
 
void setHotSpot (const QPointF &value)
 
bool hasHotSpot () const
 
void unsetHotSpot ()
 
void setGestureCancelPolicy (GestureCancelPolicy policy)
 
GestureCancelPolicy gestureCancelPolicy () const
 
- 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.
 
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.
 

Properties

ChangeFlags totalChangeFlags
 the property of the gesture that has change
 
ChangeFlags changeFlags
 the property of the gesture that has changed in the current step
 
qreal totalScaleFactor
 the total scale factor
 
qreal lastScaleFactor
 the last scale factor recorded for this gesture
 
qreal scaleFactor
 the current scale factor
 
qreal totalRotationAngle
 the total angle covered by the gesture
 
qreal lastRotationAngle
 the last reported angle covered by the gesture motion
 
qreal rotationAngle
 the angle covered by the gesture motion
 
QPointF startCenterPoint
 the starting position of the center point
 
QPointF lastCenterPoint
 the last position of the center point recorded for this gesture
 
QPointF centerPoint
 the current center point
 
- Properties inherited from QGesture
Qt::GestureState state
 the current state of the gesture
 
Qt::GestureType gestureType
 the type of the gesture
 
QGesture::GestureCancelPolicy gestureCancelPolicy
 the policy for deciding what happens on accepting a gesture
 
QPointF hotSpot
 The point that is used to find the receiver for the gesture event.
 
bool hasHotSpot
 whether the gesture has a hot-spot
 
- Properties inherited from QObject
QString objectName
 the name of this object
 

Friends

class QPinchGestureRecognizer
 

Additional Inherited Members

- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 
- 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.
 
- 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 Member Functions inherited from QGesture
 QGesture (QGesturePrivate &dd, QObject *parent)
 
- 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)
 
- Protected Attributes inherited from QObject
QScopedPointer< QObjectData > d_ptr
 
- Related Symbols inherited from QObject
 Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
 
 
 
 \macro Q_CLASSINFO(Name, Value)
 

Detailed Description

The QPinchGesture class describes a pinch gesture made by the user.

\inmodule QtWidgets.

Since
4.6

A pinch gesture is a form of touch user input in which the user typically touches two points on the input device with a thumb and finger, before moving them closer together or further apart to change the scale factor, zoom, or level of detail of the user interface.

For an overview of gesture handling in Qt and information on using gestures in your applications, see the \l{Gestures in Widgets and Graphics View} document.

Instead of repeatedly applying the same pinching gesture, the user may continue to touch the input device in one place, and apply a second touch to a new point, continuing the gesture. When this occurs, gesture events will continue to be delivered to the target object, containing an instance of QPinchGesture in the Qt::GestureUpdated state.

See also
QPanGesture, QSwipeGesture

Definition at line 102 of file qgesture.h.

Member Enumeration Documentation

◆ ChangeFlag

enum QPinchGesture::ChangeFlag

This enum describes the changes that can occur to the properties of the gesture object.

\value ScaleFactorChanged The scale factor held by scaleFactor changed. \value RotationAngleChanged The rotation angle held by rotationAngle changed. \value CenterPointChanged The center point held by centerPoint changed.

See also
changeFlags, totalChangeFlags
Enumerator
ScaleFactorChanged 
RotationAngleChanged 
CenterPointChanged 

Definition at line 108 of file qgesture.h.

Constructor & Destructor Documentation

◆ QPinchGesture()

QPinchGesture::QPinchGesture ( QObject * parent = nullptr)
explicit

Definition at line 461 of file qgesture.cpp.

References QGesture::gestureType, and Qt::PinchGesture.

◆ ~QPinchGesture()

QPinchGesture::~QPinchGesture ( )

Destructor.

Definition at line 470 of file qgesture.cpp.

Member Function Documentation

◆ centerPoint()

QPointF QPinchGesture::centerPoint ( ) const

Definition at line 504 of file qgesture.cpp.

◆ changeFlags()

QPinchGesture::ChangeFlags QPinchGesture::changeFlags ( ) const

Definition at line 484 of file qgesture.cpp.

◆ lastCenterPoint()

QPointF QPinchGesture::lastCenterPoint ( ) const

Definition at line 499 of file qgesture.cpp.

◆ lastRotationAngle()

qreal QPinchGesture::lastRotationAngle ( ) const

Definition at line 561 of file qgesture.cpp.

◆ lastScaleFactor()

qreal QPinchGesture::lastScaleFactor ( ) const

Definition at line 530 of file qgesture.cpp.

◆ rotationAngle()

qreal QPinchGesture::rotationAngle ( ) const

Definition at line 566 of file qgesture.cpp.

◆ scaleFactor()

qreal QPinchGesture::scaleFactor ( ) const

Definition at line 535 of file qgesture.cpp.

◆ setCenterPoint()

void QPinchGesture::setCenterPoint ( const QPointF & value)

Definition at line 519 of file qgesture.cpp.

◆ setChangeFlags()

void QPinchGesture::setChangeFlags ( ChangeFlags value)

Definition at line 489 of file qgesture.cpp.

Referenced by QMacPinchGestureRecognizer::reset().

+ Here is the caller graph for this function:

◆ setLastCenterPoint()

void QPinchGesture::setLastCenterPoint ( const QPointF & value)

Definition at line 514 of file qgesture.cpp.

◆ setLastRotationAngle()

void QPinchGesture::setLastRotationAngle ( qreal value)

Definition at line 576 of file qgesture.cpp.

◆ setLastScaleFactor()

void QPinchGesture::setLastScaleFactor ( qreal value)

Definition at line 545 of file qgesture.cpp.

◆ setRotationAngle()

void QPinchGesture::setRotationAngle ( qreal value)

Definition at line 581 of file qgesture.cpp.

◆ setScaleFactor()

void QPinchGesture::setScaleFactor ( qreal value)

Definition at line 550 of file qgesture.cpp.

◆ setStartCenterPoint()

void QPinchGesture::setStartCenterPoint ( const QPointF & value)

Definition at line 509 of file qgesture.cpp.

◆ setTotalChangeFlags()

void QPinchGesture::setTotalChangeFlags ( ChangeFlags value)

Definition at line 479 of file qgesture.cpp.

◆ setTotalRotationAngle()

void QPinchGesture::setTotalRotationAngle ( qreal value)

Definition at line 571 of file qgesture.cpp.

◆ setTotalScaleFactor()

void QPinchGesture::setTotalScaleFactor ( qreal value)

Definition at line 540 of file qgesture.cpp.

◆ startCenterPoint()

QPointF QPinchGesture::startCenterPoint ( ) const

Definition at line 494 of file qgesture.cpp.

◆ totalChangeFlags()

QPinchGesture::ChangeFlags QPinchGesture::totalChangeFlags ( ) const

Definition at line 474 of file qgesture.cpp.

◆ totalRotationAngle()

qreal QPinchGesture::totalRotationAngle ( ) const

Definition at line 556 of file qgesture.cpp.

◆ totalScaleFactor()

qreal QPinchGesture::totalScaleFactor ( ) const

Definition at line 525 of file qgesture.cpp.

Friends And Related Symbol Documentation

◆ QPinchGestureRecognizer

friend class QPinchGestureRecognizer
friend

Definition at line 163 of file qgesture.h.

Property Documentation

◆ centerPoint

QPinchGesture::centerPoint
readwrite

the current center point

The center point is the midpoint between the two input points in the gesture.

See also
startCenterPoint, lastCenterPoint

Definition at line 130 of file qgesture.h.

Referenced by operator<<().

◆ changeFlags

QPinchGesture::changeFlags
readwrite

the property of the gesture that has changed in the current step

This property indicates which of the other properties has changed since the previous gesture event included information about this gesture. You can use this information to determine which aspect of your user interface needs to be updated.

See also
totalChangeFlags, scaleFactor, rotationAngle, centerPoint

Definition at line 118 of file qgesture.h.

Referenced by operator<<().

◆ lastCenterPoint

QPinchGesture::lastCenterPoint
readwrite

the last position of the center point recorded for this gesture

See also
centerPoint, startCenterPoint

Definition at line 129 of file qgesture.h.

Referenced by operator<<().

◆ lastRotationAngle

QPinchGesture::lastRotationAngle
readwrite

the last reported angle covered by the gesture motion

The last rotation angle is the angle as reported in the \l rotationAngle property when a previous gesture event was delivered for this gesture.

See also
rotationAngle, totalRotationAngle

Definition at line 125 of file qgesture.h.

Referenced by operator<<().

◆ lastScaleFactor

QPinchGesture::lastScaleFactor
readwrite

the last scale factor recorded for this gesture

The last scale factor contains the scale factor reported in the \l scaleFactor property when a previous gesture event included information about this gesture.

If no previous event was delivered with information about this gesture (i.e., this gesture object contains information about the first movement in the gesture) then this property contains zero.

See also
scaleFactor, totalScaleFactor

Definition at line 121 of file qgesture.h.

Referenced by operator<<().

◆ rotationAngle

QPinchGesture::rotationAngle
readwrite

the angle covered by the gesture motion

See also
totalRotationAngle, lastRotationAngle

Definition at line 126 of file qgesture.h.

Referenced by operator<<().

◆ scaleFactor

QPinchGesture::scaleFactor
readwrite

the current scale factor

The scale factor measures the scale factor associated with the distance between two of the user's inputs on a touch device.

See also
totalScaleFactor, lastScaleFactor

Definition at line 122 of file qgesture.h.

Referenced by operator<<().

◆ startCenterPoint

QPinchGesture::startCenterPoint
readwrite

the starting position of the center point

See also
centerPoint, lastCenterPoint

Definition at line 128 of file qgesture.h.

Referenced by operator<<().

◆ totalChangeFlags

QPinchGesture::totalChangeFlags
readwrite

the property of the gesture that has change

This property indicates which of the other properties has changed since the gesture has started. You can use this information to determine which aspect of your user interface needs to be updated.

See also
changeFlags, scaleFactor, rotationAngle, centerPoint

Definition at line 117 of file qgesture.h.

Referenced by operator<<(), and QPinchGestureRecognizer::reset().

◆ totalRotationAngle

QPinchGesture::totalRotationAngle
readwrite

the total angle covered by the gesture

This total angle measures the complete angle covered by the gesture. Usually, this is equal to the value held by the \l rotationAngle property, except in the case where the user performs multiple rotations by removing and repositioning one of the touch points, as described above. In this case, the total angle will be the sum of the rotation angles for the multiple stages of the gesture.

See also
rotationAngle, lastRotationAngle

Definition at line 124 of file qgesture.h.

Referenced by operator<<().

◆ totalScaleFactor

QPinchGesture::totalScaleFactor
readwrite

the total scale factor

The total scale factor measures the total change in scale factor from the original value to the current scale factor.

See also
scaleFactor, lastScaleFactor

Definition at line 120 of file qgesture.h.

Referenced by operator<<().

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