QGraphicsRotation Class Reference

The QGraphicsRotation class provides a rotation transformation around a given axis. More...

#include <qgraphicstransform.h>

Inheritance diagram for QGraphicsRotation:

Collaboration diagram for QGraphicsRotation:

Signals
void	originChanged ()
	This signal is emitted whenever the origin has changed.
void	angleChanged ()
	This signal is emitted whenever the angle has changed.
void	axisChanged ()
	This signal is emitted whenever the axis of the object changes.
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
	QGraphicsRotation (QObject *parent=nullptr)
	Constructs a new QGraphicsRotation with the given parent.
	~QGraphicsRotation ()
	Destroys the graphics rotation.
QVector3D	origin () const
void	setOrigin (const QVector3D &point)
qreal	angle () const
void	setAngle (qreal)
QVector3D	axis () const
void	setAxis (const QVector3D &axis)
void	setAxis (Qt::Axis axis)
	Convenience function to set the axis to axis.
void	applyTo (QMatrix4x4 *matrix) const override
	\reimp
Public Member Functions inherited from QGraphicsTransform
	QGraphicsTransform (QObject *parent=nullptr)
	Constructs a new QGraphicsTransform with the given parent.
	~QGraphicsTransform ()
	Destroys the graphics transform.
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
QVector3D	origin
	the origin of the rotation in 3D space.
qreal	angle
	the angle for clockwise rotation, in degrees.
QVector3D	axis
	a rotation axis, specified by a vector in 3D space.
Properties inherited from QObject
QString	objectName
	the name of this object

Additional Inherited Members
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 Slots inherited from QGraphicsTransform
void	update ()
	Notifies that this transform operation has changed its parameters in such a way that applyTo() will return a different result than before.
Protected Member Functions inherited from QGraphicsTransform
	QGraphicsTransform (QGraphicsTransformPrivate &p, 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
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

The QGraphicsRotation class provides a rotation transformation around a given axis.

Since

4.6 \inmodule QtWidgets

You can provide the desired axis by assigning a QVector3D to the axis property or by passing a member if Qt::Axis to the setAxis convenience function. By default the axis is (0, 0, 1) i.e., rotation around the Z axis.

The angle property, which is provided by QGraphicsRotation, now describes the number of degrees to rotate around this axis.

QGraphicsRotation provides certain parameters to help control how the rotation should be applied.

The origin is the point that the item is rotated around (i.e., it stays fixed relative to the parent as the rest of the item is rotated). By default the origin is QPointF(0, 0).

The angle property provides the number of degrees to rotate the item clockwise around the origin. This value also be negative, indicating a counter-clockwise rotation. For animation purposes it may also be useful to provide rotation angles exceeding (-360, 360) degrees, for instance to animate how an item rotates several times.

Note: the final rotation is the combined effect of a rotation in 3D space followed by a projection back to 2D. If several rotations are performed in succession, they will not behave as expected unless they were all around the Z axis.

See also

QGraphicsTransform, QGraphicsItem::setRotation(), QTransform::rotate()

Definition at line 82 of file qgraphicstransform.h.

Constructor & Destructor Documentation

QGraphicsRotation()

QGraphicsRotation::QGraphicsRotation

(

QObject *

parent = nullptr

)

Constructs a new QGraphicsRotation with the given parent.

Definition at line 395 of file qgraphicstransform.cpp.

~QGraphicsRotation()

QGraphicsRotation::~QGraphicsRotation

(

)

Destroys the graphics rotation.

Definition at line 403 of file qgraphicstransform.cpp.

Member Function Documentation

angle()

qreal QGraphicsRotation::angle

(

)

const

Definition at line 444 of file qgraphicstransform.cpp.

References d.

angleChanged

void QGraphicsRotation::angleChanged ( )

signal

This signal is emitted whenever the angle has changed.

See also

QGraphicsRotation::angle

Referenced by setAngle().

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applyTo()

void QGraphicsRotation::applyTo ( QMatrix4x4 * matrix ) const

overridevirtual

\reimp

Implements QGraphicsTransform.

Definition at line 540 of file qgraphicstransform.cpp.

References d, and qIsNaN().

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axis()

QVector3D QGraphicsRotation::axis

(

)

const

Definition at line 487 of file qgraphicstransform.cpp.

References d.

axisChanged

void QGraphicsRotation::axisChanged ( )

signal

This signal is emitted whenever the axis of the object changes.

See also

QGraphicsRotation::axis

Referenced by setAxis().

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origin()

QVector3D QGraphicsRotation::origin

(

)

const

Definition at line 416 of file qgraphicstransform.cpp.

References d.

originChanged

QGraphicsRotation::originChanged ( )

signal

This signal is emitted whenever the origin has changed.

See also

QGraphicsRotation::origin

Referenced by setOrigin().

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setAngle()

void QGraphicsRotation::setAngle

(

qreal

angle

)

Definition at line 449 of file qgraphicstransform.cpp.

References angle, angleChanged(), d, emit, and QGraphicsTransform::update().

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setAxis() [1/2]

void QGraphicsRotation::setAxis

(

const QVector3D &

axis

)

Definition at line 492 of file qgraphicstransform.cpp.

References axis, axisChanged(), d, emit, and QGraphicsTransform::update().

Referenced by setAxis().

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setAxis() [2/2]

void QGraphicsRotation::setAxis

(

Qt::Axis

axis

)

Convenience function to set the axis to axis.

Note: the Qt::YAxis rotation for QTransform is inverted from the correct mathematical rotation in 3D space. The QGraphicsRotation class implements a correct mathematical rotation. The following two sequences of code will perform the same transformation:

QTransform t;
t.rotate(45, Qt::YAxis);
 
QGraphicsRotation r;
r.setAxis(Qt::YAxis);
r.setAngle(-45);

Definition at line 521 of file qgraphicstransform.cpp.

References axis, setAxis(), Qt::XAxis, Qt::YAxis, and Qt::ZAxis.

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setOrigin()

void QGraphicsRotation::setOrigin

(

const QVector3D &

point

)

Definition at line 421 of file qgraphicstransform.cpp.

References d, emit, originChanged(), and QGraphicsTransform::update().

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Property Documentation

angle

QGraphicsRotation::angle

readwrite

the angle for clockwise rotation, in degrees.

The angle can be any real number; the default value is 0.0. A value of 180 will rotate 180 degrees, clockwise. If you provide a negative number, the item will be rotated counter-clockwise. Normally the rotation angle will be in the range (-360, 360), but you can also provide numbers outside of this range (e.g., a angle of 370 degrees gives the same result as 10 degrees). Setting the angle to NaN results in no rotation.

See also

origin

Definition at line 87 of file qgraphicstransform.h.

Referenced by setAngle().

axis

QGraphicsRotation::axis

readwrite

a rotation axis, specified by a vector in 3D space.

This can be any axis in 3D space. By default the axis is (0, 0, 1), which is aligned with the Z axis. If you provide another axis, QGraphicsRotation will provide a transformation that rotates around this axis. For example, if you would like to rotate an item around its X axis, you could pass (1, 0, 0) as the axis.

See also

QTransform, QGraphicsRotation::angle

Definition at line 88 of file qgraphicstransform.h.

Referenced by setAxis(), and setAxis().

origin

QGraphicsRotation::origin

readwrite

the origin of the rotation in 3D space.

All rotations will be done relative to this point (i.e., this point will stay fixed, relative to the parent, when the item is rotated).

See also

angle

Definition at line 86 of file qgraphicstransform.h.

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

• qtbase/src/widgets/graphicsview/qgraphicstransform.h (05fc3aef53348fb58be6308076e000825b704e58)
• qtbase/src/widgets/graphicsview/qgraphicstransform.cpp (23bf260f10f4b507e2e19398a16574ca77fe774d)