QGraphicsLinearLayout Class Reference

The QGraphicsLinearLayout class provides a horizontal or vertical layout for managing widgets in Graphics View. More...

#include <qgraphicslinearlayout.h>

Inheritance diagram for QGraphicsLinearLayout:

Collaboration diagram for QGraphicsLinearLayout:

Public Member Functions
	QGraphicsLinearLayout (QGraphicsLayoutItem *parent=nullptr)
	Constructs a QGraphicsLinearLayout instance using Qt::Horizontal orientation.
	QGraphicsLinearLayout (Qt::Orientation orientation, QGraphicsLayoutItem *parent=nullptr)
	Constructs a QGraphicsLinearLayout instance.
virtual	~QGraphicsLinearLayout ()
	Destroys the QGraphicsLinearLayout object.
void	setOrientation (Qt::Orientation orientation)
	Change the layout orientation to orientation.
Qt::Orientation	orientation () const
	Returns the layout orientation.
void	addItem (QGraphicsLayoutItem *item)
	This convenience function is equivalent to calling insertItem(-1, item).
void	addStretch (int stretch=1)
	This convenience function is equivalent to calling insertStretch(-1, stretch).
void	insertItem (int index, QGraphicsLayoutItem *item)
	Inserts item into the layout at index, or before any item that is currently at index.
void	insertStretch (int index, int stretch=1)
	Inserts a stretch of stretch at index, or before any item that is currently at index.
void	removeItem (QGraphicsLayoutItem *item)
	Removes item from the layout without destroying it.
void	removeAt (int index) override
	Removes the item at index without destroying it.
void	setSpacing (qreal spacing)
	Sets the layout's spacing to spacing.
qreal	spacing () const
	Returns the layout's spacing.
void	setItemSpacing (int index, qreal spacing)
	Sets the spacing after item at index to spacing.
qreal	itemSpacing (int index) const
	Returns the spacing after item at index.
void	setStretchFactor (QGraphicsLayoutItem *item, int stretch)
	Sets the stretch factor for item to stretch.
int	stretchFactor (QGraphicsLayoutItem *item) const
	Returns the stretch factor for item.
void	setAlignment (QGraphicsLayoutItem *item, Qt::Alignment alignment)
	Sets the alignment of item to alignment.
Qt::Alignment	alignment (QGraphicsLayoutItem *item) const
	Returns the alignment for item.
void	setGeometry (const QRectF &rect) override
	\reimp
int	count () const override
	\reimp
QGraphicsLayoutItem *	itemAt (int index) const override
	\reimp When iterating from 0 and up, it will return the items in the visual arranged order.
void	invalidate () override
	\reimp
QSizeF	sizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const override
	\reimp
void	dump (int indent=0) const
Public Member Functions inherited from QGraphicsLayout
	QGraphicsLayout (QGraphicsLayoutItem *parent=nullptr)
	Constructs a QGraphicsLayout object.
	~QGraphicsLayout ()
	Destroys the QGraphicsLayout object.
void	setContentsMargins (qreal left, qreal top, qreal right, qreal bottom)
	Sets the contents margins to left, top, right and bottom.
void	getContentsMargins (qreal *left, qreal *top, qreal *right, qreal *bottom) const override
	\reimp
void	activate ()
	Activates the layout, causing all items in the layout to be immediately rearranged.
bool	isActivated () const
	Returns true if the layout is currently being activated; otherwise, returns false.
virtual void	updateGeometry () override
	\reimp
virtual void	widgetEvent (QEvent *e)
	This virtual event handler receives all events for the managed widget.
Public Member Functions inherited from QGraphicsLayoutItem
	QGraphicsLayoutItem (QGraphicsLayoutItem *parent=nullptr, bool isLayout=false)
	Constructs the QGraphicsLayoutItem object.
virtual	~QGraphicsLayoutItem ()
	Destroys the QGraphicsLayoutItem object.
void	setSizePolicy (const QSizePolicy &policy)
	Sets the size policy to policy.
void	setSizePolicy (QSizePolicy::Policy hPolicy, QSizePolicy::Policy vPolicy, QSizePolicy::ControlType controlType=QSizePolicy::DefaultType)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.This function is equivalent to calling setSizePolicy(QSizePolicy(hPolicy, vPolicy, controlType)).
QSizePolicy	sizePolicy () const
	Returns the current size policy.
void	setMinimumSize (const QSizeF &size)
	Sets the minimum size to size.
void	setMinimumSize (qreal w, qreal h)
	This convenience function is equivalent to calling setMinimumSize(QSizeF(w, h)).
QSizeF	minimumSize () const
	Returns the minimum size.
void	setMinimumWidth (qreal width)
	Sets the minimum width to width.
qreal	minimumWidth () const
	Returns the minimum width.
void	setMinimumHeight (qreal height)
	Sets the minimum height to height.
qreal	minimumHeight () const
	Returns the minimum height.
void	setPreferredSize (const QSizeF &size)
	Sets the preferred size to size.
void	setPreferredSize (qreal w, qreal h)
	This convenience function is equivalent to calling setPreferredSize(QSizeF(w, h)).
QSizeF	preferredSize () const
	Returns the preferred size.
void	setPreferredWidth (qreal width)
	Sets the preferred width to width.
qreal	preferredWidth () const
	Returns the preferred width.
void	setPreferredHeight (qreal height)
	Sets the preferred height to height.
qreal	preferredHeight () const
	Returns the preferred height.
void	setMaximumSize (const QSizeF &size)
	Sets the maximum size to size.
void	setMaximumSize (qreal w, qreal h)
	This convenience function is equivalent to calling setMaximumSize(QSizeF(w, h)).
QSizeF	maximumSize () const
	Returns the maximum size.
void	setMaximumWidth (qreal width)
	Sets the maximum width to width.
qreal	maximumWidth () const
	Returns the maximum width.
void	setMaximumHeight (qreal height)
	Sets the maximum height to height.
qreal	maximumHeight () const
	Returns the maximum height.
QRectF	geometry () const
	Returns the item's geometry (e.g., position and size) as a QRectF.
QRectF	contentsRect () const
	Returns the contents rect in local coordinates.
QSizeF	effectiveSizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const
	Returns the effective size hint for this QGraphicsLayoutItem.
virtual bool	isEmpty () const
QGraphicsLayoutItem *	parentLayoutItem () const
	Returns the parent of this QGraphicsLayoutItem, or \nullptr if there is no parent, or if the parent does not inherit from QGraphicsLayoutItem (QGraphicsLayoutItem is often used through multiple inheritance with QObject-derived classes).
void	setParentLayoutItem (QGraphicsLayoutItem *parent)
	Sets the parent of this QGraphicsLayoutItem to parent.
bool	isLayout () const
	Returns true if this QGraphicsLayoutItem is a layout (e.g., is inherited by an object that arranges other QGraphicsLayoutItem objects); otherwise returns false.
QGraphicsItem *	graphicsItem () const
	Returns the QGraphicsItem that this layout item represents.
bool	ownedByLayout () const

Additional Inherited Members
Static Public Member Functions inherited from QGraphicsLayout
static void	setInstantInvalidatePropagation (bool enable)
static bool	instantInvalidatePropagation ()
Protected Member Functions inherited from QGraphicsLayout
	QGraphicsLayout (QGraphicsLayoutPrivate &, QGraphicsLayoutItem *)
void	addChildLayoutItem (QGraphicsLayoutItem *layoutItem)
Protected Member Functions inherited from QGraphicsLayoutItem
void	setGraphicsItem (QGraphicsItem *item)
	If the QGraphicsLayoutItem represents a QGraphicsItem, and it wants to take advantage of the automatic reparenting capabilities of QGraphicsLayout it should set this value.
void	setOwnedByLayout (bool ownedByLayout)
	QGraphicsLayoutItem (QGraphicsLayoutItemPrivate &dd)
Protected Attributes inherited from QGraphicsLayoutItem
QScopedPointer< QGraphicsLayoutItemPrivate >	d_ptr

Detailed Description

The QGraphicsLinearLayout class provides a horizontal or vertical layout for managing widgets in Graphics View.

Since

4.4

\inmodule QtWidgets

The default orientation for a linear layout is Qt::Horizontal. You can choose a vertical orientation either by calling setOrientation(), or by passing Qt::Vertical to QGraphicsLinearLayout's constructor.

The most common way to use QGraphicsLinearLayout is to construct an object on the heap, passing a parent widget to the constructor, then add widgets and layouts by calling addItem().

QGraphicsScene scene;
QGraphicsWidget *textEdit = scene.addWidget(new QTextEdit);
QGraphicsWidget *pushButton = scene.addWidget(new QPushButton);
 
QGraphicsWidget *form = new QGraphicsWidget;
scene.addItem(form);
 
QGraphicsLinearLayout *layout = new QGraphicsLinearLayout(form);
layout->addItem(textEdit);
layout->addItem(pushButton);

Alternatively, if you do not pass a parent widget to the layout's constructor, you will need to call QGraphicsWidget::setLayout() to set this layout as the top-level layout for that widget, the widget will take ownership of the layout.

You can add widgets, layouts, stretches (addStretch(), insertStretch() or setStretchFactor()), and spacings (setItemSpacing()) to a linear layout. The layout takes ownership of the items. In some cases when the layout item also inherits from QGraphicsItem (such as QGraphicsWidget) there will be a ambiguity in ownership because the layout item belongs to two ownership hierarchies. See the documentation of QGraphicsLayoutItem::setOwnedByLayout() how to handle this. You can access each item in the layout by calling count() and itemAt(). Calling removeAt() or removeItem() will remove an item from the layout, without destroying it.

Definition at line 17 of file qgraphicslinearlayout.h.

Constructor & Destructor Documentation

QGraphicsLinearLayout() [1/2]

QGraphicsLinearLayout::QGraphicsLinearLayout

(

QGraphicsLayoutItem *

parent = nullptr

)

Constructs a QGraphicsLinearLayout instance using Qt::Horizontal orientation.

parent is passed to QGraphicsLayout's constructor.

Definition at line 165 of file qgraphicslinearlayout.cpp.

QGraphicsLinearLayout() [2/2]

QGraphicsLinearLayout::QGraphicsLinearLayout	(	Qt::Orientation	orientation,
		QGraphicsLayoutItem *	parent = nullptr )

Constructs a QGraphicsLinearLayout instance.

You can pass the orientation for the layout, either horizontal or vertical, and parent is passed to QGraphicsLayout's constructor.

Definition at line 156 of file qgraphicslinearlayout.cpp.

~QGraphicsLinearLayout()

QGraphicsLinearLayout::~QGraphicsLinearLayout ( )

virtual

Destroys the QGraphicsLinearLayout object.

Definition at line 173 of file qgraphicslinearlayout.cpp.

References count(), i, item, itemAt(), and removeAt().

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Member Function Documentation

addItem()

void QGraphicsLinearLayout::addItem ( QGraphicsLayoutItem * item )

inline

This convenience function is equivalent to calling insertItem(-1, item).

Definition at line 27 of file qgraphicslinearlayout.h.

References item.

addStretch()

void QGraphicsLinearLayout::addStretch ( int stretch = 1 )

inline

This convenience function is equivalent to calling insertStretch(-1, stretch).

Definition at line 28 of file qgraphicslinearlayout.h.

alignment()

Qt::Alignment QGraphicsLinearLayout::alignment

(

QGraphicsLayoutItem *

item

)

const

Returns the alignment for item.

The default alignment is Qt::AlignTop | Qt::AlignLeft.

The alignment decides how the item is positioned within its assigned space in the case where there's more space available in the layout than the widgets can occupy.

See also

setAlignment()

Definition at line 423 of file qgraphicslinearlayout.cpp.

References d, and item.

count()

int QGraphicsLinearLayout::count ( ) const

overridevirtual

\reimp

Implements QGraphicsLayout.

Definition at line 439 of file qgraphicslinearlayout.cpp.

References d.

Referenced by ~QGraphicsLinearLayout().

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dump()

void QGraphicsLinearLayout::dump

(

int

indent = 0

)

const

Definition at line 520 of file qgraphicslinearlayout.cpp.

References d, Qt::Horizontal, Q_UNUSED, and qDebug.

Referenced by setGeometry().

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insertItem()

void QGraphicsLinearLayout::insertItem	(	int	index,
		QGraphicsLayoutItem *	item )

Inserts item into the layout at index, or before any item that is currently at index.

See also

addItem(), itemAt(), insertStretch(), setItemSpacing()

Definition at line 235 of file qgraphicslinearlayout.cpp.

References d, invalidate(), item, Q_ASSERT, and qWarning.

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insertStretch()

void QGraphicsLinearLayout::insertStretch	(	int	index,
		int	stretch = 1 )

Inserts a stretch of stretch at index, or before any item that is currently at index.

See also

addStretch(), setStretchFactor(), setItemSpacing(), insertItem()

Definition at line 262 of file qgraphicslinearlayout.cpp.

References d, and invalidate().

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invalidate()

void QGraphicsLinearLayout::invalidate ( )

overridevirtual

\reimp

Reimplemented from QGraphicsLayout.

Definition at line 508 of file qgraphicslinearlayout.cpp.

References d, and QGraphicsLayout::invalidate().

Referenced by insertItem(), insertStretch(), removeAt(), removeItem(), setAlignment(), setItemSpacing(), setOrientation(), setSpacing(), and setStretchFactor().

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itemAt()

QGraphicsLayoutItem * QGraphicsLinearLayout::itemAt ( int index ) const

overridevirtual

\reimp When iterating from 0 and up, it will return the items in the visual arranged order.

Implements QGraphicsLayout.

Definition at line 449 of file qgraphicslinearlayout.cpp.

References d, item, and qWarning.

Referenced by ~QGraphicsLinearLayout().

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itemSpacing()

qreal QGraphicsLinearLayout::itemSpacing

(

int

index

)

const

Returns the spacing after item at index.

Definition at line 352 of file qgraphicslinearlayout.cpp.

References d.

orientation()

Qt::Orientation QGraphicsLinearLayout::orientation

(

)

const

Returns the layout orientation.

See also

setOrientation()

Definition at line 209 of file qgraphicslinearlayout.cpp.

References d.

Referenced by setOrientation().

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removeAt()

void QGraphicsLinearLayout::removeAt ( int index )

overridevirtual

Removes the item at index without destroying it.

Ownership of the item is transferred to the caller.

See also

removeItem(), insertItem()

Implements QGraphicsLayout.

Definition at line 294 of file qgraphicslinearlayout.cpp.

References d, invalidate(), layoutItem(), and qWarning.

Referenced by ~QGraphicsLinearLayout().

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removeItem()

void QGraphicsLinearLayout::removeItem

(

QGraphicsLayoutItem *

item

)

Removes item from the layout without destroying it.

Ownership of item is transferred to the caller.

See also

removeAt(), insertItem()

Definition at line 277 of file qgraphicslinearlayout.cpp.

References d, invalidate(), and item.

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setAlignment()

void QGraphicsLinearLayout::setAlignment	(	QGraphicsLayoutItem *	item,
		Qt::Alignment	alignment )

Sets the alignment of item to alignment.

If item's alignment changes, the layout is automatically invalidated.

See also

alignment(), invalidate()

Definition at line 404 of file qgraphicslinearlayout.cpp.

References alignment, d, invalidate(), and item.

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setGeometry()

void QGraphicsLinearLayout::setGeometry ( const QRectF & rect )

overridevirtual

\reimp

Reimplemented from QGraphicsLayoutItem.

Definition at line 465 of file qgraphicslinearlayout.cpp.

References d, dump(), QGraphicsLayoutItem::geometry(), QGraphicsLayout::getContentsMargins(), qDebug, qSwap(), rect, Qt::RightToLeft, and QGraphicsLayoutItem::setGeometry().

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setItemSpacing()

void QGraphicsLinearLayout::setItemSpacing	(	int	index,
		qreal	spacing )

Sets the spacing after item at index to spacing.

Definition at line 343 of file qgraphicslinearlayout.cpp.

References d, invalidate(), and spacing().

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setOrientation()

void QGraphicsLinearLayout::setOrientation

(

Qt::Orientation

orientation

)

Change the layout orientation to orientation.

Changing the layout orientation will automatically invalidate the layout.

See also

orientation()

Definition at line 195 of file qgraphicslinearlayout.cpp.

References d, invalidate(), and orientation().

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setSpacing()

void QGraphicsLinearLayout::setSpacing

(

qreal

spacing

)

Sets the layout's spacing to spacing.

Spacing refers to the vertical and horizontal distances between items.

See also

setItemSpacing(), setStretchFactor(), QGraphicsGridLayout::setSpacing()

Definition at line 317 of file qgraphicslinearlayout.cpp.

References d, Qt::Horizontal, invalidate(), qWarning, spacing(), and Qt::Vertical.

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setStretchFactor()

void QGraphicsLinearLayout::setStretchFactor	(	QGraphicsLayoutItem *	item,
		int	stretch )

Sets the stretch factor for item to stretch.

If an item's stretch factor changes, this function will invalidate the layout.

Setting stretch to 0 removes the stretch factor from the item, and is effectively equivalent to setting stretch to 1.

See also

stretchFactor()

Definition at line 367 of file qgraphicslinearlayout.cpp.

References d, invalidate(), item, qWarning, and stretchFactor().

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sizeHint()

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

overridevirtual

\reimp

Implements QGraphicsLayoutItem.

Definition at line 496 of file qgraphicslinearlayout.cpp.

References d, and QGraphicsLayout::getContentsMargins().

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spacing()

qreal QGraphicsLinearLayout::spacing

(

)

const

Returns the layout's spacing.

Spacing refers to the vertical and horizontal distances between items.

See also

setSpacing()

Definition at line 334 of file qgraphicslinearlayout.cpp.

References d.

Referenced by setItemSpacing(), and setSpacing().

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stretchFactor()

int QGraphicsLinearLayout::stretchFactor

(

QGraphicsLayoutItem *

item

)

const

Returns the stretch factor for item.

The default stretch factor is 0, meaning that the item has no assigned stretch factor.

See also

setStretchFactor()

Definition at line 387 of file qgraphicslinearlayout.cpp.

References d, item, and qWarning.

Referenced by setStretchFactor().

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

• qtbase/src/widgets/graphicsview/qgraphicslinearlayout.h (05fc3aef53348fb58be6308076e000825b704e58)
• qtbase/src/widgets/graphicsview/qgraphicslinearlayout.cpp (d60aa6a8cf8b020c2ae8e6a8bb45311acce8cab9)