The QGraphicsSceneIndex class provides a base class to implement a custom indexing algorithm for discovering items in QGraphicsScene. More...

#include <qgraphicssceneindex_p.h>

Inheritance diagram for QGraphicsSceneIndex:

Collaboration diagram for QGraphicsSceneIndex:

Public Member Functions
	QGraphicsSceneIndex (QGraphicsScene *scene=nullptr)
	Constructs an abstract scene index for a given scene.

virtual	~QGraphicsSceneIndex ()
	Destroys the scene index.

QGraphicsScene *	scene () const
	Returns the scene of this index.

virtual QList< QGraphicsItem * >	items (Qt::SortOrder order=Qt::DescendingOrder) const =0
	This pure virtual function all items in the index and sort them using order.

virtual QList< QGraphicsItem * >	items (const QPointF &pos, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform &deviceTransform=QTransform()) const
	Returns all visible items that, depending on mode, are at the specified pos and return a list sorted using order.

virtual QList< QGraphicsItem * >	items (const QRectF &rect, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform &deviceTransform=QTransform()) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns all visible items that, depending on mode, are either inside or intersect with the specified rect and return a list sorted using order.

virtual QList< QGraphicsItem * >	items (const QPolygonF &polygon, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform &deviceTransform=QTransform()) const

virtual QList< QGraphicsItem * >	items (const QPainterPath &path, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform &deviceTransform=QTransform()) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns all visible items that, depending on mode, are either inside or intersect with the specified path and return a list sorted using order.

virtual QList< QGraphicsItem * >	estimateItems (const QPointF &point, Qt::SortOrder order) const
	This virtual function return an estimation of items at position point.

virtual QList< QGraphicsItem * >	estimateItems (const QRectF &rect, Qt::SortOrder order) const =0

virtual QList< QGraphicsItem * >	estimateTopLevelItems (const QRectF &, Qt::SortOrder order) 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.

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`.

Protected Slots
virtual void	updateSceneRect (const QRectF &rect)
	Notifies the index that the scene's scene rect has changed.

Protected Member Functions
virtual void	clear ()
	This virtual function removes all items in the scene index.

virtual void	addItem (QGraphicsItem *item)=0
	This pure virtual function inserts an item to the scene index.

virtual void	removeItem (QGraphicsItem *item)=0
	This pure virtual function removes an item to the scene index.

virtual void	deleteItem (QGraphicsItem *item)
	This method is called when an item has been deleted.

virtual void	itemChange (const QGraphicsItem item, QGraphicsItem::GraphicsItemChange, const void const value)
	This virtual function is called by QGraphicsItem to notify the index that some part of the item 's state changes.

virtual void	prepareBoundingRectChange (const QGraphicsItem *item)
	Notify the index for a geometry change of an item.

	QGraphicsSceneIndex (QGraphicsSceneIndexPrivate &dd, QGraphicsScene *scene)

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)

Friends
class	QGraphicsScene

class	QGraphicsScenePrivate

class	QGraphicsItem

class	QGraphicsItemPrivate

class	QGraphicsSceneBspTreeIndex

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 Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object

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 QGraphicsSceneIndex class provides a base class to implement a custom indexing algorithm for discovering items in QGraphicsScene.

Since: 4.6

The QGraphicsSceneIndex class provides a base class to implement a custom indexing algorithm for discovering items in QGraphicsScene. You need to subclass it and reimplement addItem, removeItem, estimateItems and items in order to have an functional indexing.

See also: QGraphicsScene, QGraphicsView

Definition at line 38 of file qgraphicssceneindex_p.h.

Constructor & Destructor Documentation

◆ QGraphicsSceneIndex() [1/2]

QGraphicsSceneIndex::QGraphicsSceneIndex ( QGraphicsScene * scene = nullptr )

Constructs an abstract scene index for a given scene.

Definition at line 312 of file qgraphicssceneindex.cpp.

◆ ~QGraphicsSceneIndex()

QGraphicsSceneIndex::~QGraphicsSceneIndex ( )

virtual

Destroys the scene index.

Definition at line 330 of file qgraphicssceneindex.cpp.

◆ QGraphicsSceneIndex() [2/2]

QGraphicsSceneIndex::QGraphicsSceneIndex	(	QGraphicsSceneIndexPrivate &	dd,
		QGraphicsScene *	scene
	)

protected

Definition at line 321 of file qgraphicssceneindex.cpp.

Member Function Documentation

◆ addItem()

void QGraphicsSceneIndex::addItem ( QGraphicsItem * item )

protectedpure virtual

This pure virtual function inserts an item to the scene index.

See also: removeItem(), deleteItem()

Implemented in QGraphicsSceneBspTreeIndex, and QGraphicsSceneLinearIndex.

◆ clear()

void QGraphicsSceneIndex::clear ( )

protectedvirtual

This virtual function removes all items in the scene index.

Reimplemented in QGraphicsSceneBspTreeIndex, and QGraphicsSceneLinearIndex.

Definition at line 523 of file qgraphicssceneindex.cpp.

References QList< T >::at(), i, items, removeItem(), and QList< T >::size().

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◆ deleteItem()

void QGraphicsSceneIndex::deleteItem ( QGraphicsItem * item )

protectedvirtual

This method is called when an item has been deleted.

The default implementation calls removeItem. Be careful, if your implementation of removeItem use pure virtual method of QGraphicsItem like boundingRect(), then you should reimplement this method.

See also: addItem(), removeItem()

Definition at line 555 of file qgraphicssceneindex.cpp.

References item, and removeItem().

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◆ estimateItems() [1/2]

QList< QGraphicsItem * > QGraphicsSceneIndex::estimateItems	(	const QPointF &	point,
		Qt::SortOrder	order
	)		const

virtual

This virtual function return an estimation of items at position point.

This method return a list sorted using order.

Definition at line 479 of file qgraphicssceneindex.cpp.

References estimateItems().

Referenced by estimateItems().

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◆ estimateItems() [2/2]

virtual QList< QGraphicsItem * > QGraphicsSceneIndex::estimateItems	(	const QRectF &	rect,
		Qt::SortOrder	order
	)		const

pure virtual

Implemented in QGraphicsSceneBspTreeIndex, and QGraphicsSceneLinearIndex.

◆ estimateTopLevelItems()

QList< QGraphicsItem * > QGraphicsSceneIndex::estimateTopLevelItems	(	const QRectF &	rect,
		Qt::SortOrder	order
	)		const

virtual

Reimplemented in QGraphicsSceneBspTreeIndex.

Definition at line 484 of file qgraphicssceneindex.cpp.

References QList< T >::at(), d, Qt::DescendingOrder, QGraphicsScenePrivate::ensureSortedTopLevelItems(), i, Q_UNUSED, rect, QList< T >::reserve(), QList< T >::size(), and QGraphicsScenePrivate::topLevelItems.

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◆ itemChange()

void QGraphicsSceneIndex::itemChange	(	const QGraphicsItem *	item,
		QGraphicsItem::GraphicsItemChange	change,
		const void *const	value
	)

protectedvirtual

This virtual function is called by QGraphicsItem to notify the index that some part of the item 's state changes.

By reimplementing this function, your can react to a change, and in some cases, (depending on change,) adjustments in the index can be made.

change is the parameter of the item that is changing. value is the value that changed; the type of the value depends on change.

The default implementation does nothing.

See also: QGraphicsItem::GraphicsItemChange

Reimplemented in QGraphicsSceneBspTreeIndex.

Definition at line 573 of file qgraphicssceneindex.cpp.

References item, and Q_UNUSED.

◆ items() [1/5]

QList< QGraphicsItem * > QGraphicsSceneIndex::items	(	const QPainterPath &	path,
		Qt::ItemSelectionMode	mode,
		Qt::SortOrder	order,
		const QTransform &	deviceTransform = `QTransform()`
	)		const

virtual

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns all visible items that, depending on mode, are either inside or intersect with the specified path and return a list sorted using order.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with or is contained by path are returned.

deviceTransform is the transformation apply to the view.

This method use the estimation of the index (estimateItems) and refine the list to get an exact result. If you want to implement your own refinement algorithm you can reimplement this method.

See also: estimateItems()

Definition at line 464 of file qgraphicssceneindex.cpp.

References _q_adjustRect(), d, deviceTransform(), and QtPrivate::intersect_path().

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◆ items() [2/5]

QList< QGraphicsItem * > QGraphicsSceneIndex::items	(	const QPointF &	pos,
		Qt::ItemSelectionMode	mode,
		Qt::SortOrder	order,
		const QTransform &	deviceTransform = `QTransform()`
	)		const

virtual

Returns all visible items that, depending on mode, are at the specified pos and return a list sorted using order.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with pos are returned.

deviceTransform is the transformation apply to the view.

This method use the estimation of the index (estimateItems) and refine the list to get an exact result. If you want to implement your own refinement algorithm you can reimplement this method.

See also: estimateItems()

Definition at line 364 of file qgraphicssceneindex.cpp.

References d, deviceTransform(), QtPrivate::intersect_point(), and pos.

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◆ items() [3/5]

QList< QGraphicsItem * > QGraphicsSceneIndex::items	(	const QPolygonF &	polygon,
		Qt::ItemSelectionMode	mode,
		Qt::SortOrder	order,
		const QTransform &	deviceTransform = `QTransform()`
	)		const

virtual

Definition at line 429 of file qgraphicssceneindex.cpp.

References _q_adjustRect(), d, deviceTransform(), and QtPrivate::intersect_path().

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◆ items() [4/5]

QList< QGraphicsItem * > QGraphicsSceneIndex::items	(	const QRectF &	rect,
		Qt::ItemSelectionMode	mode,
		Qt::SortOrder	order,
		const QTransform &	deviceTransform = `QTransform()`
	)		const

virtual

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns all visible items that, depending on mode, are either inside or intersect with the specified rect and return a list sorted using order.

The default value for mode is Qt::IntersectsItemShape; all items whose exact shape intersects with or is contained by rect are returned.

deviceTransform is the transformation apply to the view.

This method use the estimation of the index (estimateItems) and refine the list to get an exact result. If you want to implement your own refinement algorithm you can reimplement this method.

See also: estimateItems()

Definition at line 396 of file qgraphicssceneindex.cpp.

References _q_adjustRect(), d, deviceTransform(), QtPrivate::intersect_rect(), and rect.

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◆ items() [5/5]

QList< QGraphicsItem * > QGraphicsSceneIndex::items ( Qt::SortOrder order = Qt::DescendingOrder ) const

pure virtual

This pure virtual function all items in the index and sort them using order.

Implemented in QGraphicsSceneBspTreeIndex, and QGraphicsSceneLinearIndex.

◆ prepareBoundingRectChange()

void QGraphicsSceneIndex::prepareBoundingRectChange ( const QGraphicsItem * item )

protectedvirtual

Notify the index for a geometry change of an item.

See also: QGraphicsItem::prepareGeometryChange()

Reimplemented in QGraphicsSceneBspTreeIndex.

Definition at line 585 of file qgraphicssceneindex.cpp.

References item, and Q_UNUSED.

Referenced by QGraphicsItem::prepareGeometryChange().

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◆ removeItem()

void QGraphicsSceneIndex::removeItem ( QGraphicsItem * item )

protectedpure virtual

This pure virtual function removes an item to the scene index.

See also: addItem(), deleteItem()

Implemented in QGraphicsSceneBspTreeIndex, and QGraphicsSceneLinearIndex.

Referenced by clear(), and deleteItem().

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◆ scene()

QGraphicsScene * QGraphicsSceneIndex::scene ( ) const

Returns the scene of this index.

Definition at line 338 of file qgraphicssceneindex.cpp.

References d.

◆ updateSceneRect

void QGraphicsSceneIndex::updateSceneRect ( const QRectF & rect )

protectedvirtualslot

Notifies the index that the scene's scene rect has changed.

rect is thew new scene rect.

See also: QGraphicsScene::sceneRect()

Definition at line 515 of file qgraphicssceneindex.cpp.

References Q_UNUSED, and rect.

Friends And Related Symbol Documentation

◆ QGraphicsItem

friend class QGraphicsItem

friend

Definition at line 77 of file qgraphicssceneindex_p.h.

◆ QGraphicsItemPrivate

friend class QGraphicsItemPrivate

friend

Definition at line 78 of file qgraphicssceneindex_p.h.

◆ QGraphicsScene

friend class QGraphicsScene

friend

Definition at line 75 of file qgraphicssceneindex_p.h.

◆ QGraphicsSceneBspTreeIndex

friend class QGraphicsSceneBspTreeIndex

friend

Definition at line 79 of file qgraphicssceneindex_p.h.

◆ QGraphicsScenePrivate

friend class QGraphicsScenePrivate

friend

Definition at line 76 of file qgraphicssceneindex_p.h.

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

qtbase/src/widgets/graphicsview/qgraphicssceneindex_p.h
qtbase/src/widgets/graphicsview/qgraphicssceneindex.cpp

Public Member Functions

Protected Slots

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QGraphicsSceneIndex() [1/2]

◆ ~QGraphicsSceneIndex()

◆ QGraphicsSceneIndex() [2/2]

Member Function Documentation

◆ addItem()

◆ clear()

◆ deleteItem()

◆ estimateItems() [1/2]

◆ estimateItems() [2/2]

◆ estimateTopLevelItems()

◆ itemChange()

◆ items() [1/5]

◆ items() [2/5]

◆ items() [3/5]

◆ items() [4/5]

◆ items() [5/5]

◆ prepareBoundingRectChange()

◆ removeItem()

◆ scene()

◆ updateSceneRect

Friends And Related Symbol Documentation

◆ QGraphicsItem

◆ QGraphicsItemPrivate

◆ QGraphicsScene

◆ QGraphicsSceneBspTreeIndex

◆ QGraphicsScenePrivate