The QGraphicsLayout class provides the base class for all layouts in Graphics View. More...

#include <qgraphicslayout.h>

Inheritance diagram for QGraphicsLayout:

Collaboration diagram for QGraphicsLayout:

Public Member Functions
	QGraphicsLayout (QGraphicsLayoutItem *parent=nullptr)

	~QGraphicsLayout ()

void	setContentsMargins (qreal left, qreal top, qreal right, qreal bottom)

void	getContentsMargins (qreal left, qreal top, qreal right, qreal bottom) const override

void	activate ()

bool	isActivated () const

virtual void	invalidate ()

virtual void	updateGeometry () override

virtual void	widgetEvent (QEvent *e)

virtual int	count () const =0

virtual QGraphicsLayoutItem *	itemAt (int i) const =0

virtual void	removeAt (int index)=0

Public Member Functions inherited from QGraphicsLayoutItem
	QGraphicsLayoutItem (QGraphicsLayoutItem *parent=nullptr, bool isLayout=false)

virtual	~QGraphicsLayoutItem ()

void	setSizePolicy (const QSizePolicy &policy)

void	setSizePolicy (QSizePolicy::Policy hPolicy, QSizePolicy::Policy vPolicy, QSizePolicy::ControlType controlType=QSizePolicy::DefaultType)

QSizePolicy	sizePolicy () const

void	setMinimumSize (const QSizeF &size)

void	setMinimumSize (qreal w, qreal h)

QSizeF	minimumSize () const

void	setMinimumWidth (qreal width)

qreal	minimumWidth () const

void	setMinimumHeight (qreal height)

qreal	minimumHeight () const

void	setPreferredSize (const QSizeF &size)

void	setPreferredSize (qreal w, qreal h)

QSizeF	preferredSize () const

void	setPreferredWidth (qreal width)

qreal	preferredWidth () const

void	setPreferredHeight (qreal height)

qreal	preferredHeight () const

void	setMaximumSize (const QSizeF &size)

void	setMaximumSize (qreal w, qreal h)

QSizeF	maximumSize () const

void	setMaximumWidth (qreal width)

qreal	maximumWidth () const

void	setMaximumHeight (qreal height)

qreal	maximumHeight () const

virtual void	setGeometry (const QRectF &rect)

QRectF	geometry () const

QRectF	contentsRect () const

QSizeF	effectiveSizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const

virtual bool	isEmpty () const

QGraphicsLayoutItem *	parentLayoutItem () const

void	setParentLayoutItem (QGraphicsLayoutItem *parent)

bool	isLayout () const

QGraphicsItem *	graphicsItem () const

bool	ownedByLayout () const

Static Public Member Functions
static void	setInstantInvalidatePropagation (bool enable)

static bool	instantInvalidatePropagation ()

Protected Member Functions
	QGraphicsLayout (QGraphicsLayoutPrivate &, QGraphicsLayoutItem *)

void	addChildLayoutItem (QGraphicsLayoutItem *layoutItem)

Protected Member Functions inherited from QGraphicsLayoutItem
void	setGraphicsItem (QGraphicsItem *item)

void	setOwnedByLayout (bool ownedByLayout)

	QGraphicsLayoutItem (QGraphicsLayoutItemPrivate &dd)

virtual QSizeF	sizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const =0

Friends
class	QGraphicsWidget

Additional Inherited Members
Protected Attributes inherited from QGraphicsLayoutItem
QScopedPointer< QGraphicsLayoutItemPrivate >	d_ptr

Detailed Description

The QGraphicsLayout class provides the base class for all layouts in Graphics View.

Since: 4.4

\inmodule QtWidgets

QGraphicsLayout is an abstract class that defines a virtual API for arranging QGraphicsWidget children and other QGraphicsLayoutItem objects for a QGraphicsWidget. QGraphicsWidget assigns responsibility to a QGraphicsLayout through QGraphicsWidget::setLayout(). As the widget is resized, the layout will automatically arrange the widget's children. QGraphicsLayout inherits QGraphicsLayoutItem, so, it can be managed by any layout, including its own subclasses.

Definition at line 54 of file qgraphicslayout.h.

Constructor & Destructor Documentation

◆ QGraphicsLayout() [1/2]

QGraphicsLayout::QGraphicsLayout ( QGraphicsLayoutItem * parent = nullptr )

Constructs a QGraphicsLayout object.

parent is passed to QGraphicsLayoutItem's constructor and the QGraphicsLayoutItem's isLayout argument is set to true.

If parent is a QGraphicsWidget the layout will be installed on that widget. (Note that installing a layout will delete the old one installed.)

Definition at line 158 of file qgraphicslayout.cpp.

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◆ ~QGraphicsLayout()

QGraphicsLayout::~QGraphicsLayout ( )

Destroys the QGraphicsLayout object.

Definition at line 200 of file qgraphicslayout.cpp.

◆ QGraphicsLayout() [2/2]

QGraphicsLayout::QGraphicsLayout	(	QGraphicsLayoutPrivate &	dd,
		QGraphicsLayoutItem *	parent
	)

protected

Definition at line 179 of file qgraphicslayout.cpp.

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Member Function Documentation

◆ activate()

void QGraphicsLayout::activate ( )

Activates the layout, causing all items in the layout to be immediately rearranged. This function is based on calling count() and itemAt(), and then calling setGeometry() on all items sequentially. When activated, the layout will adjust its geometry to its parent's contentsRect(). The parent will then invalidate any layout of its own.

If called in sequence or recursively, e.g., by one of the arranged items in response to being resized, this function will do nothing.

Note that the layout is free to use geometry caching to optimize this process. To forcefully invalidate any such cache, you can call invalidate() before calling activate().

See also: invalidate()

Definition at line 257 of file qgraphicslayout.cpp.

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◆ addChildLayoutItem()

void QGraphicsLayout::addChildLayoutItem ( QGraphicsLayoutItem * layoutItem )

protected

Since: 4.6

This function is a convenience function provided for custom layouts, and will go through all items in the layout and reparent their graphics items to the closest QGraphicsWidget ancestor of the layout.

If layoutItem is already in a different layout, it will be removed from that layout.

If custom layouts want special behaviour they can ignore to use this function, and implement their own behaviour.

See also: graphicsItem()

Definition at line 472 of file qgraphicslayout.cpp.

◆ count()

int QGraphicsLayout::count ( ) const

pure virtual

This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to return the number of items in the layout.

The subclass is free to decide how to store the items.

See also: itemAt(), removeAt()

Implemented in CustomLayout, Layout, QGraphicsLinearLayout, QGraphicsGridLayout, QGraphicsAnchorLayout, FlowLayout, and FlowLayout.

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◆ getContentsMargins()

void QGraphicsLayout::getContentsMargins	(	qreal *	left,
		qreal *	top,
		qreal *	right,
		qreal *	bottom
	)		const

overridevirtual

\reimp

Reimplemented from QGraphicsLayoutItem.

Definition at line 232 of file qgraphicslayout.cpp.

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◆ instantInvalidatePropagation()

bool QGraphicsLayout::instantInvalidatePropagation ( )

static

Definition at line 517 of file qgraphicslayout.cpp.

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◆ invalidate()

void QGraphicsLayout::invalidate ( )

virtual

Clears any cached geometry and size hint information in the layout, and posts a \l{QEvent::LayoutRequest}{LayoutRequest} event to the managed parent QGraphicsLayoutItem.

See also: activate(), setGeometry()

Reimplemented in TestLayout, TestLayout, QGraphicsLinearLayout, QGraphicsGridLayout, and QGraphicsAnchorLayout.

Definition at line 311 of file qgraphicslayout.cpp.

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◆ isActivated()

bool QGraphicsLayout::isActivated ( ) const

Returns true if the layout is currently being activated; otherwise, returns false. If the layout is being activated, this means that it is currently in the process of rearranging its items (i.e., the activate() function has been called, and has not yet returned).

See also: activate(), invalidate()

Definition at line 298 of file qgraphicslayout.cpp.

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◆ itemAt()

QGraphicsLayoutItem * QGraphicsLayout::itemAt ( int i ) const

pure virtual

This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to return a pointer to the item at index i. The reimplementation can assume that i is valid (i.e., it respects the value of count()). Together with count(), it is provided as a means of iterating over all items in a layout.

The subclass is free to decide how to store the items, and the visual arrangement does not have to be reflected through this function.

See also: count(), removeAt()

Implemented in CustomLayout, Layout, QGraphicsLinearLayout, QGraphicsGridLayout, QGraphicsAnchorLayout, FlowLayout, and FlowLayout.

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◆ removeAt()

void QGraphicsLayout::removeAt ( int index )

pure virtual

This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to remove the item at index. The reimplementation can assume that index is valid (i.e., it respects the value of count()).

The implementation must ensure that the parentLayoutItem() of the removed item does not point to this layout, since the item is considered to be removed from the layout hierarchy.

If the layout is to be reused between applications, we recommend that the layout deletes the item, but the graphics view framework does not depend on this.

The subclass is free to decide how to store the items.

See also: itemAt(), count()

Implemented in CustomLayout, Layout, QGraphicsLinearLayout, QGraphicsGridLayout, QGraphicsAnchorLayout, and FlowLayout.

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◆ setContentsMargins()

void QGraphicsLayout::setContentsMargins	(	qreal	left,
		qreal	top,
		qreal	right,
		qreal	bottom
	)

Sets the contents margins to left, top, right and bottom. The default contents margins for toplevel layouts are style dependent (by querying the pixelMetric for QStyle::PM_LayoutLeftMargin, QStyle::PM_LayoutTopMargin, QStyle::PM_LayoutRightMargin and QStyle::PM_LayoutBottomMargin).

For sublayouts the default margins are 0.

Changing the contents margins automatically invalidates the layout.

See also: invalidate()

Definition at line 217 of file qgraphicslayout.cpp.

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◆ setInstantInvalidatePropagation()

void QGraphicsLayout::setInstantInvalidatePropagation ( bool enable )

static

Definition at line 505 of file qgraphicslayout.cpp.

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◆ updateGeometry()

void QGraphicsLayout::updateGeometry ( )

overridevirtual

\reimp

Reimplemented from QGraphicsLayoutItem.

Definition at line 350 of file qgraphicslayout.cpp.

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◆ widgetEvent()

void QGraphicsLayout::widgetEvent ( QEvent * e )

virtual

This virtual event handler receives all events for the managed widget. QGraphicsLayout uses this event handler to listen for layout related events such as geometry changes, layout changes or layout direction changes.

e is a pointer to the event.

You can reimplement this event handler to track similar events for your own custom layout.

See also: QGraphicsWidget::event(), QGraphicsItem::sceneEvent()

Reimplemented in SubQGraphicsLinearLayout.

Definition at line 390 of file qgraphicslayout.cpp.

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Friends And Related Function Documentation

◆ QGraphicsWidget

friend class QGraphicsWidget

friend

Definition at line 83 of file qgraphicslayout.h.

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

src/widgets/graphicsview/qgraphicslayout.h
src/widgets/graphicsview/qgraphicslayout.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QGraphicsLayout() [1/2]

◆ ~QGraphicsLayout()

◆ QGraphicsLayout() [2/2]

Member Function Documentation

◆ activate()

◆ addChildLayoutItem()

◆ count()

◆ getContentsMargins()

◆ instantInvalidatePropagation()

◆ invalidate()

◆ isActivated()

◆ itemAt()

◆ removeAt()

◆ setContentsMargins()

◆ setInstantInvalidatePropagation()

◆ updateGeometry()

◆ widgetEvent()

Friends And Related Function Documentation

◆ QGraphicsWidget