The QGraphicsItemGroup class provides a container that treats a group of items as a single item. More...

#include <qgraphicsitem.h>

Inheritance diagram for QGraphicsItemGroup:

Collaboration diagram for QGraphicsItemGroup:

Public Types
enum	{ Type = 10 }

Public Types inherited from QGraphicsItem
enum	GraphicsItemFlag { ItemIsMovable = 0x1 , ItemIsSelectable = 0x2 , ItemIsFocusable = 0x4 , ItemClipsToShape = 0x8 , ItemClipsChildrenToShape = 0x10 , ItemIgnoresTransformations = 0x20 , ItemIgnoresParentOpacity = 0x40 , ItemDoesntPropagateOpacityToChildren = 0x80 , ItemStacksBehindParent = 0x100 , ItemUsesExtendedStyleOption = 0x200 , ItemHasNoContents = 0x400 , ItemSendsGeometryChanges = 0x800 , ItemAcceptsInputMethod = 0x1000 , ItemNegativeZStacksBehindParent = 0x2000 , ItemIsPanel = 0x4000 , ItemIsFocusScope = 0x8000 , ItemSendsScenePositionChanges = 0x10000 , ItemStopsClickFocusPropagation = 0x20000 , ItemStopsFocusHandling = 0x40000 , ItemContainsChildrenInShape = 0x80000 }
	This enum describes different flags that you can set on an item to toggle different features in the item's behavior. More...

enum	GraphicsItemChange { ItemPositionChange , ItemVisibleChange = 2 , ItemEnabledChange , ItemSelectedChange , ItemParentChange , ItemChildAddedChange , ItemChildRemovedChange , ItemTransformChange , ItemPositionHasChanged , ItemTransformHasChanged , ItemSceneChange , ItemVisibleHasChanged , ItemEnabledHasChanged , ItemSelectedHasChanged , ItemParentHasChanged , ItemSceneHasChanged , ItemCursorChange , ItemCursorHasChanged , ItemToolTipChange , ItemToolTipHasChanged , ItemFlagsChange , ItemFlagsHaveChanged , ItemZValueChange , ItemZValueHasChanged , ItemOpacityChange , ItemOpacityHasChanged , ItemScenePositionHasChanged , ItemRotationChange , ItemRotationHasChanged , ItemScaleChange , ItemScaleHasChanged , ItemTransformOriginPointChange , ItemTransformOriginPointHasChanged }
	This enum describes the state changes that are notified by QGraphicsItem::itemChange(). More...

enum	CacheMode { NoCache , ItemCoordinateCache , DeviceCoordinateCache }

enum	PanelModality { NonModal , PanelModal , SceneModal }

enum	{ Type = 1 , UserType = 65536 }

Public Member Functions
	QGraphicsItemGroup (QGraphicsItem *parent=nullptr)
	Constructs a QGraphicsItemGroup.

	~QGraphicsItemGroup ()
	Destroys the QGraphicsItemGroup.

void	addToGroup (QGraphicsItem *item)
	Adds the given item and item's child items to this item group.

void	removeFromGroup (QGraphicsItem *item)
	Removes the specified item from this group.

QRectF	boundingRect () const override
	\reimp

void	paint (QPainter painter, const QStyleOptionGraphicsItem option, QWidget *widget=nullptr) override
	\reimp

bool	isObscuredBy (const QGraphicsItem *item) const override
	\reimp

QPainterPath	opaqueArea () const override
	\reimp

int	type () const override
	\reimp

Public Member Functions inherited from QGraphicsItem
	QGraphicsItem (QGraphicsItem *parent=nullptr)
	Constructs a QGraphicsItem with the given parent item.

virtual	~QGraphicsItem ()
	Destroys the QGraphicsItem and all its children.

QGraphicsScene *	scene () const
	Returns the current scene for the item, or \nullptr if the item is not stored in a scene.

QGraphicsItem *	parentItem () const
	Returns a pointer to this item's parent item.

QGraphicsItem *	topLevelItem () const
	Returns this item's top-level item.

QGraphicsObject *	parentObject () const

QGraphicsWidget *	parentWidget () const

QGraphicsWidget *	topLevelWidget () const

QGraphicsWidget *	window () const

QGraphicsItem *	panel () const

void	setParentItem (QGraphicsItem *parent)
	Sets this item's parent item to newParent.

QList< QGraphicsItem * >	childItems () const

bool	isWidget () const

bool	isWindow () const

bool	isPanel () const

QGraphicsObject *	toGraphicsObject ()

const QGraphicsObject *	toGraphicsObject () const

QGraphicsItemGroup *	group () const
	Returns a pointer to this item's item group, or \nullptr if this item is not member of a group.

void	setGroup (QGraphicsItemGroup *group)
	Adds this item to the item group group.

GraphicsItemFlags	flags () const
	Returns this item's flags.

void	setFlag (GraphicsItemFlag flag, bool enabled=true)
	If enabled is true, the item flag flag is enabled; otherwise, it is disabled.

void	setFlags (GraphicsItemFlags flags)
	Sets the item flags to flags.

CacheMode	cacheMode () const

void	setCacheMode (CacheMode mode, const QSize &cacheSize=QSize())

PanelModality	panelModality () const

void	setPanelModality (PanelModality panelModality)

bool	isBlockedByModalPanel (QGraphicsItem **blockingPanel=nullptr) const

QCursor	cursor () const
	Returns the current cursor shape for the item.

void	setCursor (const QCursor &cursor)
	Sets the current cursor shape for the item to cursor.

bool	hasCursor () const
	Returns `true` if this item has a cursor set; otherwise, false is returned.

void	unsetCursor ()
	Clears the cursor from this item.

bool	isVisible () const
	Returns `true` if the item is visible; otherwise, false is returned.

bool	isVisibleTo (const QGraphicsItem *parent) const

void	setVisible (bool visible)
	If visible is true, the item is made visible.

void	hide ()
	Hides the item (items are visible by default).

void	show ()
	Shows the item (items are visible by default).

bool	isEnabled () const
	Returns `true` if the item is enabled; otherwise, false is returned.

void	setEnabled (bool enabled)
	If enabled is true, the item is enabled; otherwise, it is disabled.

bool	isSelected () const
	Returns `true` if this item is selected; otherwise, false is returned.

void	setSelected (bool selected)
	If selected is true and this item is selectable, this item is selected; otherwise, it is unselected.

bool	acceptDrops () const
	Returns `true` if this item can accept drag and drop events; otherwise, returns `false`.

void	setAcceptDrops (bool on)
	If on is true, this item will accept drag and drop events; otherwise, it is transparent for drag and drop events.

qreal	opacity () const

qreal	effectiveOpacity () const

void	setOpacity (qreal opacity)

Qt::MouseButtons	acceptedMouseButtons () const
	Returns the mouse buttons that this item accepts mouse events for.

void	setAcceptedMouseButtons (Qt::MouseButtons buttons)
	Sets the mouse buttons that this item accepts mouse events for.

bool	acceptHoverEvents () const

void	setAcceptHoverEvents (bool enabled)

bool	acceptTouchEvents () const

void	setAcceptTouchEvents (bool enabled)

bool	filtersChildEvents () const

void	setFiltersChildEvents (bool enabled)

bool	handlesChildEvents () const

void	setHandlesChildEvents (bool enabled)

bool	isActive () const

void	setActive (bool active)

bool	hasFocus () const
	Returns `true` if this item is active, and it or its \l{focusProxy()}{focus proxy} has keyboard input focus; otherwise, returns `false`.

void	setFocus (Qt::FocusReason focusReason=Qt::OtherFocusReason)
	Gives keyboard input focus to this item.

void	clearFocus ()
	Takes keyboard input focus from the item.

QGraphicsItem *	focusProxy () const

void	setFocusProxy (QGraphicsItem *item)

QGraphicsItem *	focusItem () const

QGraphicsItem *	focusScopeItem () const

void	grabMouse ()

void	ungrabMouse ()

void	grabKeyboard ()

void	ungrabKeyboard ()

QPointF	pos () const
	Returns the position of the item in parent coordinates.

qreal	x () const
	This convenience function is equivalent to calling pos().x().

void	setX (qreal x)

qreal	y () const
	This convenience function is equivalent to calling pos().y().

void	setY (qreal y)

QPointF	scenePos () const
	Returns the item's position in scene coordinates.

void	setPos (const QPointF &pos)
	Sets the position of the item to pos, which is in parent coordinates.

void	setPos (qreal x, qreal y)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling setPos(QPointF(x, y)).

void	moveBy (qreal dx, qreal dy)
	Moves the item by dx points horizontally, and dy point vertically.

void	ensureVisible (const QRectF &rect=QRectF(), int xmargin=50, int ymargin=50)
	If this item is part of a scene that is viewed by a QGraphicsView, this convenience function will attempt to scroll the view to ensure that rect is visible inside the view's viewport.

void	ensureVisible (qreal x, qreal y, qreal w, qreal h, int xmargin=50, int ymargin=50)
	This convenience function is equivalent to calling ensureVisible(QRectF(x, y, w, h), xmargin, ymargin).

QTransform	transform () const

QTransform	sceneTransform () const

QTransform	deviceTransform (const QTransform &viewportTransform) const

QTransform	itemTransform (const QGraphicsItem other, bool ok=nullptr) const

void	setTransform (const QTransform &matrix, bool combine=false)

void	resetTransform ()

void	setRotation (qreal angle)

qreal	rotation () const

void	setScale (qreal scale)

qreal	scale () const

QList< QGraphicsTransform * >	transformations () const

void	setTransformations (const QList< QGraphicsTransform * > &transformations)

QPointF	transformOriginPoint () const

void	setTransformOriginPoint (const QPointF &origin)

void	setTransformOriginPoint (qreal ax, qreal ay)

virtual void	advance (int phase)
	This virtual function is called twice for all items by the QGraphicsScene::advance() slot.

qreal	zValue () const
	Returns the Z-value of the item.

void	setZValue (qreal z)
	Sets the Z-value of the item to z.

void	stackBefore (const QGraphicsItem *sibling)

virtual QRectF	boundingRect () const =0
	This pure virtual function defines the outer bounds of the item as a rectangle; all painting must be restricted to inside an item's bounding rect.

QRectF	childrenBoundingRect () const
	Returns the bounding rect of this item's descendants (i.e., its children, their children, etc.) in local coordinates.

QRectF	sceneBoundingRect () const
	Returns the bounding rect of this item in scene coordinates, by combining sceneTransform() with boundingRect().

virtual QPainterPath	shape () const
	Returns the shape of this item as a QPainterPath in local coordinates.

bool	isClipped () const
	Returns `true` if this item is clipped.

QPainterPath	clipPath () const

virtual bool	contains (const QPointF &point) const
	Returns `true` if this item contains point, which is in local coordinates; otherwise, false is returned.

virtual bool	collidesWithItem (const QGraphicsItem *other, Qt::ItemSelectionMode mode=Qt::IntersectsItemShape) const
	Returns `true` if this item collides with other; otherwise returns `false`.

virtual bool	collidesWithPath (const QPainterPath &path, Qt::ItemSelectionMode mode=Qt::IntersectsItemShape) const
	Returns `true` if this item collides with path.

QList< QGraphicsItem * >	collidingItems (Qt::ItemSelectionMode mode=Qt::IntersectsItemShape) const
	Returns a list of all items that collide with this item.

bool	isObscured (const QRectF &rect=QRectF()) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

bool	isObscured (qreal x, qreal y, qreal w, qreal h) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

virtual bool	isObscuredBy (const QGraphicsItem *item) const
	Returns `true` if this item's bounding rect is completely obscured by the opaque shape of item.

virtual QPainterPath	opaqueArea () const
	This virtual function returns a shape representing the area where this item is opaque.

QRegion	boundingRegion (const QTransform &itemToDeviceTransform) const

qreal	boundingRegionGranularity () const

void	setBoundingRegionGranularity (qreal granularity)

virtual void	paint (QPainter painter, const QStyleOptionGraphicsItem option, QWidget *widget=nullptr)=0
	This function, which is usually called by QGraphicsView, paints the contents of an item in local coordinates.

void	update (const QRectF &rect=QRectF())
	Schedules a redraw of the area covered by rect in this item.

void	update (qreal x, qreal y, qreal width, qreal height)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling update(QRectF(x, y, width, height)).

void	scroll (qreal dx, qreal dy, const QRectF &rect=QRectF())

QPointF	mapToItem (const QGraphicsItem *item, const QPointF &point) const
	Maps the point point, which is in this item's coordinate system, to item's coordinate system, and returns the mapped coordinate.

QPointF	mapToParent (const QPointF &point) const
	Maps the point point, which is in this item's coordinate system, to its parent's coordinate system, and returns the mapped coordinate.

QPointF	mapToScene (const QPointF &point) const
	Maps the point point, which is in this item's coordinate system, to the scene's coordinate system, and returns the mapped coordinate.

QPolygonF	mapToItem (const QGraphicsItem *item, const QRectF &rect) const
	Maps the rectangle rect, which is in this item's coordinate system, to item's coordinate system, and returns the mapped rectangle as a polygon.

QPolygonF	mapToParent (const QRectF &rect) const
	Maps the rectangle rect, which is in this item's coordinate system, to its parent's coordinate system, and returns the mapped rectangle as a polygon.

QPolygonF	mapToScene (const QRectF &rect) const
	Maps the rectangle rect, which is in this item's coordinate system, to the scene's coordinate system, and returns the mapped rectangle as a polygon.

QRectF	mapRectToItem (const QGraphicsItem *item, const QRectF &rect) const

QRectF	mapRectToParent (const QRectF &rect) const

QRectF	mapRectToScene (const QRectF &rect) const

QPolygonF	mapToItem (const QGraphicsItem *item, const QPolygonF &polygon) const
	Maps the polygon polygon, which is in this item's coordinate system, to item's coordinate system, and returns the mapped polygon.

QPolygonF	mapToParent (const QPolygonF &polygon) const
	Maps the polygon polygon, which is in this item's coordinate system, to its parent's coordinate system, and returns the mapped polygon.

QPolygonF	mapToScene (const QPolygonF &polygon) const
	Maps the polygon polygon, which is in this item's coordinate system, to the scene's coordinate system, and returns the mapped polygon.

QPainterPath	mapToItem (const QGraphicsItem *item, const QPainterPath &path) const
	Maps the path path, which is in this item's coordinate system, to item's coordinate system, and returns the mapped path.

QPainterPath	mapToParent (const QPainterPath &path) const
	Maps the path path, which is in this item's coordinate system, to its parent's coordinate system, and returns the mapped path.

QPainterPath	mapToScene (const QPainterPath &path) const
	Maps the path path, which is in this item's coordinate system, to the scene's coordinate system, and returns the mapped path.

QPointF	mapFromItem (const QGraphicsItem *item, const QPointF &point) const
	Maps the point point, which is in item's coordinate system, to this item's coordinate system, and returns the mapped coordinate.

QPointF	mapFromParent (const QPointF &point) const
	Maps the point point, which is in this item's parent's coordinate system, to this item's coordinate system, and returns the mapped coordinate.

QPointF	mapFromScene (const QPointF &point) const
	Maps the point point, which is in this item's scene's coordinate system, to this item's coordinate system, and returns the mapped coordinate.

QPolygonF	mapFromItem (const QGraphicsItem *item, const QRectF &rect) const
	Maps the rectangle rect, which is in item's coordinate system, to this item's coordinate system, and returns the mapped rectangle as a polygon.

QPolygonF	mapFromParent (const QRectF &rect) const
	Maps the rectangle rect, which is in this item's parent's coordinate system, to this item's coordinate system, and returns the mapped rectangle as a polygon.

QPolygonF	mapFromScene (const QRectF &rect) const
	Maps the rectangle rect, which is in this item's scene's coordinate system, to this item's coordinate system, and returns the mapped rectangle as a polygon.

QRectF	mapRectFromItem (const QGraphicsItem *item, const QRectF &rect) const

QRectF	mapRectFromParent (const QRectF &rect) const

QRectF	mapRectFromScene (const QRectF &rect) const

QPolygonF	mapFromItem (const QGraphicsItem *item, const QPolygonF &polygon) const
	Maps the polygon polygon, which is in item's coordinate system, to this item's coordinate system, and returns the mapped polygon.

QPolygonF	mapFromParent (const QPolygonF &polygon) const
	Maps the polygon polygon, which is in this item's parent's coordinate system, to this item's coordinate system, and returns the mapped polygon.

QPolygonF	mapFromScene (const QPolygonF &polygon) const
	Maps the polygon polygon, which is in this item's scene's coordinate system, to this item's coordinate system, and returns the mapped polygon.

QPainterPath	mapFromItem (const QGraphicsItem *item, const QPainterPath &path) const
	Maps the path path, which is in item's coordinate system, to this item's coordinate system, and returns the mapped path.

QPainterPath	mapFromParent (const QPainterPath &path) const
	Maps the path path, which is in this item's parent's coordinate system, to this item's coordinate system, and returns the mapped path.

QPainterPath	mapFromScene (const QPainterPath &path) const
	Maps the path path, which is in this item's scene's coordinate system, to this item's coordinate system, and returns the mapped path.

QPointF	mapToItem (const QGraphicsItem *item, qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapToItem(item, QPointF(x, y)).

QPointF	mapToParent (qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapToParent(QPointF(x, y)).

QPointF	mapToScene (qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapToScene(QPointF(x, y)).

QPolygonF	mapToItem (const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const

QPolygonF	mapToParent (qreal x, qreal y, qreal w, qreal h) const

QPolygonF	mapToScene (qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectToItem (const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectToParent (qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectToScene (qreal x, qreal y, qreal w, qreal h) const

QPointF	mapFromItem (const QGraphicsItem *item, qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapFromItem(item, QPointF(x, y)).

QPointF	mapFromParent (qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapFromParent(QPointF(x, y)).

QPointF	mapFromScene (qreal x, qreal y) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This convenience function is equivalent to calling mapFromScene(QPointF(x, y)).

QPolygonF	mapFromItem (const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const

QPolygonF	mapFromParent (qreal x, qreal y, qreal w, qreal h) const

QPolygonF	mapFromScene (qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectFromItem (const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectFromParent (qreal x, qreal y, qreal w, qreal h) const

QRectF	mapRectFromScene (qreal x, qreal y, qreal w, qreal h) const

bool	isAncestorOf (const QGraphicsItem *child) const
	Returns `true` if this item is an ancestor of child (i.e., if this item is child's parent, or one of child's parent's ancestors).

QGraphicsItem *	commonAncestorItem (const QGraphicsItem *other) const

bool	isUnderMouse () const

QVariant	data (int key) const
	Returns this item's custom data for the key key as a QVariant.

void	setData (int key, const QVariant &value)
	Sets this item's custom data for the key key to value.

Qt::InputMethodHints	inputMethodHints () const
	Returns the current input method hints of this item.

void	setInputMethodHints (Qt::InputMethodHints hints)
	Sets the current input method hints of this item to hints.

virtual int	type () const
	Returns the type of an item as an int.

void	installSceneEventFilter (QGraphicsItem *filterItem)
	Installs an event filter for this item on filterItem, causing all events for this item to first pass through filterItem's sceneEventFilter() function.

void	removeSceneEventFilter (QGraphicsItem *filterItem)
	Removes an event filter on this item from filterItem.

Additional Inherited Members
Protected Types inherited from QGraphicsItem
enum	Extension { UserExtension = 0x80000000 }

Protected Member Functions inherited from QGraphicsItem
void	updateMicroFocus ()
	Updates the item's micro focus.

virtual bool	sceneEventFilter (QGraphicsItem watched, QEvent event)
	Filters events for the item watched.

virtual bool	sceneEvent (QEvent *event)
	This virtual function receives events to this item.

virtual void	contextMenuEvent (QGraphicsSceneContextMenuEvent *event)
	This event handler can be reimplemented in a subclass to process context menu events.

virtual void	dragEnterEvent (QGraphicsSceneDragDropEvent *event)
	This event handler, for event event, can be reimplemented to receive drag enter events for this item.

virtual void	dragLeaveEvent (QGraphicsSceneDragDropEvent *event)
	This event handler, for event event, can be reimplemented to receive drag leave events for this item.

virtual void	dragMoveEvent (QGraphicsSceneDragDropEvent *event)
	This event handler, for event event, can be reimplemented to receive drag move events for this item.

virtual void	dropEvent (QGraphicsSceneDragDropEvent *event)
	This event handler, for event event, can be reimplemented to receive drop events for this item.

virtual void	focusInEvent (QFocusEvent *event)
	This event handler, for event event, can be reimplemented to receive focus in events for this item.

virtual void	focusOutEvent (QFocusEvent *event)
	This event handler, for event event, can be reimplemented to receive focus out events for this item.

virtual void	hoverEnterEvent (QGraphicsSceneHoverEvent *event)
	This event handler, for event event, can be reimplemented to receive hover enter events for this item.

virtual void	hoverMoveEvent (QGraphicsSceneHoverEvent *event)
	This event handler, for event event, can be reimplemented to receive hover move events for this item.

virtual void	hoverLeaveEvent (QGraphicsSceneHoverEvent *event)
	This event handler, for event event, can be reimplemented to receive hover leave events for this item.

virtual void	keyPressEvent (QKeyEvent *event)
	This event handler, for event event, can be reimplemented to receive key press events for this item.

virtual void	keyReleaseEvent (QKeyEvent *event)
	This event handler, for event event, can be reimplemented to receive key release events for this item.

virtual void	mousePressEvent (QGraphicsSceneMouseEvent *event)
	This event handler, for event event, can be reimplemented to receive mouse press events for this item.

virtual void	mouseMoveEvent (QGraphicsSceneMouseEvent *event)
	This event handler, for event event, can be reimplemented to receive mouse move events for this item.

virtual void	mouseReleaseEvent (QGraphicsSceneMouseEvent *event)
	This event handler, for event event, can be reimplemented to receive mouse release events for this item.

virtual void	mouseDoubleClickEvent (QGraphicsSceneMouseEvent *event)
	This event handler, for event event, can be reimplemented to receive mouse double-click events for this item.

virtual void	wheelEvent (QGraphicsSceneWheelEvent *event)
	This event handler, for event event, can be reimplemented to receive wheel events for this item.

virtual void	inputMethodEvent (QInputMethodEvent *event)
	This event handler, for event event, can be reimplemented to receive input method events for this item.

virtual QVariant	inputMethodQuery (Qt::InputMethodQuery query) const
	This method is only relevant for input items.

virtual QVariant	itemChange (GraphicsItemChange change, const QVariant &value)
	This virtual function is called by QGraphicsItem to notify custom items that some part of the item's state changes.

virtual bool	supportsExtension (Extension extension) const

virtual void	setExtension (Extension extension, const QVariant &variant)

virtual QVariant	extension (const QVariant &variant) const

	QGraphicsItem (QGraphicsItemPrivate &dd, QGraphicsItem *parent)

void	addToIndex ()

void	removeFromIndex ()

void	prepareGeometryChange ()
	Prepares the item for a geometry change.

Protected Attributes inherited from QGraphicsItem
QScopedPointer< QGraphicsItemPrivate >	d_ptr

Related Symbols inherited from QGraphicsItem
T	qgraphicsitem_cast (QGraphicsItem *item)

Detailed Description

The QGraphicsItemGroup class provides a container that treats a group of items as a single item.

Since: 4.2

\inmodule QtWidgets

A QGraphicsItemGroup is a special type of compound item that treats itself and all its children as one item (i.e., all events and geometries for all children are merged together). It's common to use item groups in presentation tools, when the user wants to group several smaller items into one big item in order to simplify moving and copying of items.

If all you want is to store items inside other items, you can use any QGraphicsItem directly by passing a suitable parent to setParentItem().

The boundingRect() function of QGraphicsItemGroup returns the bounding rectangle of all items in the item group. QGraphicsItemGroup ignores the ItemIgnoresTransformations flag on its children (i.e., with respect to the geometry of the group item, the children are treated as if they were transformable).

There are two ways to construct an item group. The easiest and most common approach is to pass a list of items (e.g., all selected items) to QGraphicsScene::createItemGroup(), which returns a new QGraphicsItemGroup item. The other approach is to manually construct a QGraphicsItemGroup item, add it to the scene calling QGraphicsScene::addItem(), and then add items to the group manually, one at a time by calling addToGroup(). To dismantle ("ungroup") an item group, you can either call QGraphicsScene::destroyItemGroup(), or you can manually remove all items from the group by calling removeFromGroup().

// Group all selected items together
QGraphicsItemGroup *group = scene->createItemGroup(scene->selecteditems());
 
// Destroy the group, and delete the group item
scene->destroyItemGroup(group);

The operation of adding and removing items preserves the items' scene-relative position and transformation, as opposed to calling setParentItem(), where only the child item's parent-relative position and transformation are kept.

The addtoGroup() function reparents the target item to this item group, keeping the item's position and transformation intact relative to the scene. Visually, this means that items added via addToGroup() will remain completely unchanged as a result of this operation, regardless of the item or the group's current position or transformation; although the item's position and matrix are likely to change.

The removeFromGroup() function has similar semantics to setParentItem(); it reparents the item to the parent item of the item group. As with addToGroup(), the item's scene-relative position and transformation remain intact.

See also: QGraphicsItem, {Graphics View Framework}

Definition at line 946 of file qgraphicsitem.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Enumerator
Type

Definition at line 961 of file qgraphicsitem.h.

Constructor & Destructor Documentation

◆ QGraphicsItemGroup()

QGraphicsItemGroup::QGraphicsItemGroup ( QGraphicsItem * parent = nullptr )

explicit

Constructs a QGraphicsItemGroup.

parent is passed to QGraphicsItem's constructor.

See also: QGraphicsScene::addItem()

Definition at line 10825 of file qgraphicsitem.cpp.

References QGraphicsItem::setHandlesChildEvents().

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◆ ~QGraphicsItemGroup()

QGraphicsItemGroup::~QGraphicsItemGroup ( )

Destroys the QGraphicsItemGroup.

Definition at line 10834 of file qgraphicsitem.cpp.

Member Function Documentation

◆ addToGroup()

void QGraphicsItemGroup::addToGroup ( QGraphicsItem * item )

Adds the given item and item's child items to this item group.

The item and child items will be reparented to this group, but its position and transformation relative to the scene will stay intact.

See also: removeFromGroup(), QGraphicsScene::createItemGroup()

Definition at line 10845 of file qgraphicsitem.cpp.

References QList< T >::at(), QGraphicsItem::boundingRect(), QGraphicsItem::childrenBoundingRect(), d, QTransform::fromTranslate(), i, QTransform::inverted(), QPointF::isNull(), item, QGraphicsItem::itemTransform(), QGraphicsItem::mapFromItem(), QTransform::mapRect(), ok, QGraphicsItem::pos(), QGraphicsItem::prepareGeometryChange(), qWarning, QTransform::rotate(), QGraphicsItem::rotation(), QGraphicsItem::scale(), QTransform::scale(), QGraphicsItem::setParentItem(), QGraphicsItem::setPos(), QGraphicsItem::setTransform(), QList< T >::size(), QGraphicsItem::transformations(), QGraphicsItem::transformOriginPoint(), QTransform::translate(), QGraphicsItem::update(), QGraphicsItem::x(), QPointF::x(), QGraphicsItem::y(), and QPointF::y().

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◆ boundingRect()

QRectF QGraphicsItemGroup::boundingRect ( ) const

overridevirtual

\reimp

Returns the bounding rect of this group item, and all its children.

Implements QGraphicsItem.

Definition at line 10957 of file qgraphicsitem.cpp.

References d.

◆ isObscuredBy()

bool QGraphicsItemGroup::isObscuredBy ( const QGraphicsItem * item ) const

overridevirtual

\reimp

Reimplemented from QGraphicsItem.

Definition at line 10980 of file qgraphicsitem.cpp.

References QGraphicsItem::isObscuredBy(), and item.

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◆ opaqueArea()

QPainterPath QGraphicsItemGroup::opaqueArea ( ) const

overridevirtual

\reimp

Reimplemented from QGraphicsItem.

Definition at line 10988 of file qgraphicsitem.cpp.

References QGraphicsItem::opaqueArea().

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◆ paint()

void QGraphicsItemGroup::paint	(	QPainter *	painter,
		const QStyleOptionGraphicsItem *	option,
		QWidget *	widget = `nullptr`
	)

overridevirtual

\reimp

Implements QGraphicsItem.

Definition at line 10966 of file qgraphicsitem.cpp.

References d, QPainter::drawRect(), Qt::NoBrush, painter, Q_UNUSED, QPainter::setBrush(), QStyle::State_Selected, and widget.

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◆ removeFromGroup()

void QGraphicsItemGroup::removeFromGroup ( QGraphicsItem * item )

Removes the specified item from this group.

The item will be reparented to this group's parent item, or to 0 if this group has no parent. Its position and transformation relative to the scene will stay intact.

See also: addToGroup(), QGraphicsScene::destroyItemGroup()

Definition at line 10903 of file qgraphicsitem.cpp.

References QList< T >::at(), QGraphicsItem::childrenBoundingRect(), d, QGraphicsItem::d_ptr, QTransform::fromTranslate(), QGraphicsItem::group(), i, QTransform::inverted(), QPointF::isNull(), item, QGraphicsItem::itemTransform(), QGraphicsItem::mapToItem(), ok, QGraphicsItemPrivate::parent, QGraphicsItem::pos(), QGraphicsItem::prepareGeometryChange(), qWarning, QTransform::rotate(), QGraphicsItem::rotation(), QGraphicsItem::scale(), QTransform::scale(), QGraphicsItem::sceneTransform(), QGraphicsItem::setParentItem(), QGraphicsItem::setPos(), QGraphicsItem::setTransform(), QList< T >::size(), QGraphicsItem::transformations(), QGraphicsItem::transformOriginPoint(), QTransform::translate(), QGraphicsItem::x(), QPointF::x(), QGraphicsItem::y(), and QPointF::y().

Referenced by QGraphicsItem::setGroup().

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◆ type()

int QGraphicsItemGroup::type ( ) const

overridevirtual

\reimp

Reimplemented from QGraphicsItem.

Definition at line 10996 of file qgraphicsitem.cpp.

References Type.

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

qtbase/src/widgets/graphicsview/qgraphicsitem.h
qtbase/src/widgets/graphicsview/qgraphicsitem.cpp

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ QGraphicsItemGroup()

◆ ~QGraphicsItemGroup()

Member Function Documentation

◆ addToGroup()

◆ boundingRect()

◆ isObscuredBy()

◆ opaqueArea()

◆ paint()

◆ removeFromGroup()

◆ type()