QGraphicsLayout Class Reference

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

#include <qgraphicslayout.h>

Inheritance diagram for QGraphicsLayout:

Public Functions
void	activate ()
	Activates the layout, causing all items in the layout to be immediately rearranged. More...
virtual int	count () const =0
	This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to return the number of items in the layout. More...
void	getContentsMargins (qreal *left, qreal *top, qreal *right, qreal *bottom) const
	Reimplemented Function More...
virtual void	invalidate ()
	Clears any cached geometry and size hint information in the layout, and posts a LayoutRequest event to the managed parent QGraphicsLayoutItem. More...
bool	isActivated () const
	Returns true if the layout is currently being activated; otherwise, returns false. More...
virtual QGraphicsLayoutItem *	itemAt (int i) const =0
	This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to return a pointer to the item at index i. More...
	QGraphicsLayout (QGraphicsLayoutItem *parent=0)
	Contructs a QGraphicsLayout object. More...
virtual void	removeAt (int index)=0
	This pure virtual function must be reimplemented in a subclass of QGraphicsLayout to remove the item at index. More...
void	setContentsMargins (qreal left, qreal top, qreal right, qreal bottom)
	Sets the contents margins to left, top, right and bottom. More...
virtual void	updateGeometry ()
	Reimplemented Function More...
virtual void	widgetEvent (QEvent *e)
	This virtual event handler receives all events for the managed widget. More...
	~QGraphicsLayout ()
	Destroys the QGraphicsLayout object. More...
Public Functions inherited from QGraphicsLayoutItem
QRectF	contentsRect () const
	Returns the contents rect in local coordinates. More...
QSizeF	effectiveSizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const
	Returns the effective size hint for this QGraphicsLayoutItem. More...
QRectF	geometry () const
	Returns the item's geometry (e. More...
QGraphicsItem *	graphicsItem () const
	Returns the QGraphicsItem that this layout item represents. More...
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. More...
qreal	maximumHeight () const
	Returns the maximum height. More...
QSizeF	maximumSize () const
	Returns the maximum size. More...
qreal	maximumWidth () const
	Returns the maximum width. More...
qreal	minimumHeight () const
	Returns the minimum height. More...
QSizeF	minimumSize () const
	Returns the minimum size. More...
qreal	minimumWidth () const
	Returns the minimum width. More...
bool	ownedByLayout () const
	Returns whether a layout should delete this item in its destructor. More...
QGraphicsLayoutItem *	parentLayoutItem () const
	Returns the parent of this QGraphicsLayoutItem, or 0 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). More...
qreal	preferredHeight () const
	Returns the preferred height. More...
QSizeF	preferredSize () const
	Returns the preferred size. More...
qreal	preferredWidth () const
	Returns the preferred width. More...
	QGraphicsLayoutItem (QGraphicsLayoutItem *parent=0, bool isLayout=false)
	Constructs the QGraphicsLayoutItem object. More...
virtual void	setGeometry (const QRectF &rect)
	This virtual function sets the geometry of the QGraphicsLayoutItem to rect, which is in parent coordinates (e. More...
void	setMaximumHeight (qreal height)
	Sets the maximum height to height. More...
void	setMaximumSize (const QSizeF &size)
	Sets the maximum size to size. More...
void	setMaximumSize (qreal w, qreal h)
	This convenience function is equivalent to calling setMaximumSize(QSizeF(w, h)). More...
void	setMaximumWidth (qreal width)
	Sets the maximum width to width. More...
void	setMinimumHeight (qreal height)
	Sets the minimum height to height. More...
void	setMinimumSize (const QSizeF &size)
	Sets the minimum size to size. More...
void	setMinimumSize (qreal w, qreal h)
	This convenience function is equivalent to calling setMinimumSize(QSizeF(w, h)). More...
void	setMinimumWidth (qreal width)
	Sets the minimum width to width. More...
void	setParentLayoutItem (QGraphicsLayoutItem *parent)
	Sets the parent of this QGraphicsLayoutItem to parent. More...
void	setPreferredHeight (qreal height)
	Sets the preferred height to height. More...
void	setPreferredSize (const QSizeF &size)
	Sets the preferred size to size. More...
void	setPreferredSize (qreal w, qreal h)
	This convenience function is equivalent to calling setPreferredSize(QSizeF(w, h)). More...
void	setPreferredWidth (qreal width)
	Sets the preferred width to width. More...
void	setSizePolicy (const QSizePolicy &policy)
	Sets the size policy to policy. More...
void	setSizePolicy (QSizePolicy::Policy hPolicy, QSizePolicy::Policy vPolicy, QSizePolicy::ControlType controlType=QSizePolicy::DefaultType)
	This function is equivalent to calling setSizePolicy(QSizePolicy(hPolicy, vPolicy, controlType)). More...
QSizePolicy	sizePolicy () const
	Returns the current size policy. More...
virtual	~QGraphicsLayoutItem ()
	Destroys the QGraphicsLayoutItem object. More...

Static Public Functions
static bool	instantInvalidatePropagation ()
static void	setInstantInvalidatePropagation (bool enable)

Protected Functions
void	addChildLayoutItem (QGraphicsLayoutItem *layoutItem)
	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. More...
	QGraphicsLayout (QGraphicsLayoutPrivate &, QGraphicsLayoutItem *)
Protected Functions inherited from QGraphicsLayoutItem
	QGraphicsLayoutItem (QGraphicsLayoutItemPrivate &dd)
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. More...
void	setOwnedByLayout (bool ownedByLayout)
	Sets whether a layout should delete this item in its destructor or not. More...
virtual QSizeF	sizeHint (Qt::SizeHint which, const QSizeF &constraint=QSizeF()) const =0
	This pure virtual function returns the size hint for which of the QGraphicsLayoutItem, using the width or height of constraint to constrain the output. More...

Friends
class	QGraphicsWidget

Additional Inherited Members
Protected Variables 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

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.

Writing a Custom Layout

You can use QGraphicsLayout as a base to write your own custom layout (e.g., a flowlayout), but it is more common to use one of its subclasses instead - QGraphicsLinearLayout or QGraphicsGridLayout. When creating a custom layout, the following functions must be reimplemented as a bare minimum:

Function	Description
QGraphicsLayoutItem::setGeometry()	Notifies you when the geometry of the layout is set. You can store the geometry in your own layout class in a reimplementation of this function.
QGraphicsLayoutItem::sizeHint()	Returns the layout's size hints.
QGraphicsLayout::count()	Returns the number of items in your layout.
QGraphicsLayout::itemAt()	Returns a pointer to an item in your layout.
QGraphicsLayout::removeAt()	Removes an item from your layout without destroying it.

For more details on how to implement each function, refer to the individual function documentation.

Each layout defines its own API for arranging widgets and layout items. For example, with a grid layout, you require a row and a column index with optional row and column spans, alignment, spacing, and more. A linear layout, however, requires a single row or column index to position its items. For a grid layout, the order of insertion does not affect the layout in any way, but for a linear layout, the order is essential. When writing your own layout subclass, you are free to choose the API that best suits your layout.

For adding layout items to the custom layout, the QGraphicsLayout provides convenience function addChildLayoutItem(). The function will take care of automatically reparenting graphics items, if needed.

Activating the Layout

When the layout's geometry changes, QGraphicsLayout immediately rearranges all of its managed items by calling setGeometry() on each item. This rearrangement is called activating the layout.

QGraphicsLayout updates its own geometry to match the contentsRect() of the QGraphicsLayoutItem it is managing. Thus, it will automatically rearrange all its items when the widget is resized. QGraphicsLayout caches the sizes of all its managed items to avoid calling setGeometry() too often.

Note

A QGraphicsLayout will have the same geometry as the contentsRect() of the widget (not the layout) it is assigned to.

Activating the Layout Implicitly

The layout can be activated implicitly using one of two ways: by calling activate() or by calling invalidate(). Calling activate() activates the layout immediately. In contrast, calling invalidate() is delayed, as it posts a LayoutRequest event to the managed widget. Due to event compression, the activate() will only be called once after control has returned to the event loop. This is referred to as invalidating the layout. Invalidating the layout also invalidates any cached information. Also, the invalidate() function is a virtual function. So, you can invalidate your own cache in a subclass of QGraphicsLayout by reimplementing this function.

Event Handling

QGraphicsLayout listens to events for the widget it manages through the virtual widgetEvent() event handler. When the layout is assigned to a widget, all events delivered to the widget are first processed by widgetEvent(). This allows the layout to be aware of any relevant state changes on the widget such as visibility changes or layout direction changes.

Margin Handling

The margins of a QGraphicsLayout can be modified by reimplementing setContentsMargins() and getContentsMargins().

Definition at line 59 of file qgraphicslayout.h.

Constructors and Destructors

QGraphicsLayout() [1/2]

QGraphicsLayout::QGraphicsLayout

(

QGraphicsLayoutItem *

parent = 0

)

Contructs 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 163 of file qgraphicslayout.cpp.

    : QGraphicsLayoutItem(*new QGraphicsLayoutPrivate)
{
    setParentLayoutItem(parent);
    if (parent && !parent->isLayout()) {
        // If a layout has a parent that is not a layout it must be a QGraphicsWidget.
        QGraphicsItem *itemParent = parent->graphicsItem();
        if (itemParent && itemParent->isWidget()) {
            static_cast<QGraphicsWidget *>(itemParent)->d_func()->setLayout_helper(this);
        } else {
            qWarning("QGraphicsLayout::QGraphicsLayout: Attempt to create a layout with a parent that is"
                    " neither a QGraphicsWidget nor QGraphicsLayout");
        }
    }
    d_func()->sizePolicy = QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding, QSizePolicy::DefaultType);
    setOwnedByLayout(true);
}

~QGraphicsLayout()

QGraphicsLayout::~QGraphicsLayout

(

)

Destroys the QGraphicsLayout object.

Definition at line 205 of file qgraphicslayout.cpp.

{
}

QGraphicsLayout() [2/2]

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

protected

Warning

This function is not part of the public interface.

Definition at line 184 of file qgraphicslayout.cpp.

    : QGraphicsLayoutItem(dd)
{
    setParentLayoutItem(parent);
    if (parent && !parent->isLayout()) {
        // If a layout has a parent that is not a layout it must be a QGraphicsWidget.
        QGraphicsItem *itemParent = parent->graphicsItem();
        if (itemParent && itemParent->isWidget()) {
            static_cast<QGraphicsWidget *>(itemParent)->d_func()->setLayout_helper(this);
        } else {
            qWarning("QGraphicsLayout::QGraphicsLayout: Attempt to create a layout with a parent that is"
                    " neither a QGraphicsWidget nor QGraphicsLayout");
        }
    }
    d_func()->sizePolicy = QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding, QSizePolicy::DefaultType);
    setOwnedByLayout(true);
}

Functions

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 262 of file qgraphicslayout.cpp.

Referenced by widgetEvent().

{
    Q_D(QGraphicsLayout);
    if (d->activated)
        return;

    d->activateRecursive(this);

    // we don't call activate on a sublayout, but somebody might.
    // Therefore, we walk to the parentitem of the toplevel layout.
    QGraphicsLayoutItem *parentItem = this;
    while (parentItem && parentItem->isLayout())
        parentItem = parentItem->parentLayoutItem();
    if (!parentItem)
        return;
    Q_ASSERT(!parentItem->isLayout());

    setGeometry(parentItem->contentsRect());    // relayout children
    if (!QGraphicsLayout::instantInvalidatePropagation()) {
        parentLayoutItem()->updateGeometry();
    }
}

addChildLayoutItem()

void QGraphicsLayout::addChildLayoutItem ( QGraphicsLayoutItem *  layoutItem )

protected

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.

Since

4.6

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 476 of file qgraphicslayout.cpp.

{
    Q_D(QGraphicsLayout);
    d->addChildLayoutItem(layoutItem);
}

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 QGraphicsGridLayout, QGraphicsAnchorLayout, and QGraphicsLinearLayout.

Referenced by QGraphicsLayoutPrivate::activateRecursive(), QGraphicsLinearLayout::addStretch(), QGraphicsLayoutItemPrivate::hasHeightForWidth(), QGraphicsLayoutItemPrivate::hasWidthForHeight(), removeLayoutItemFromLayout(), and QGraphicsLayoutItem::~QGraphicsLayoutItem().

getContentsMargins()

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

virtual

Reimplemented Function

Reimplemented from QGraphicsLayoutItem.

Definition at line 237 of file qgraphicslayout.cpp.

Referenced by QGraphicsLinearLayout::setGeometry(), QGraphicsGridLayout::setGeometry(), QGraphicsLinearLayout::sizeHint(), QGraphicsAnchorLayout::sizeHint(), and QGraphicsGridLayout::sizeHint().

{
    Q_D(const QGraphicsLayout);
    d->getMargin(left, d->left, QStyle::PM_LayoutLeftMargin);
    d->getMargin(top, d->top, QStyle::PM_LayoutTopMargin);
    d->getMargin(right, d->right, QStyle::PM_LayoutRightMargin);
    d->getMargin(bottom, d->bottom, QStyle::PM_LayoutBottomMargin);
}

instantInvalidatePropagation()

bool QGraphicsLayout::instantInvalidatePropagation ( )

static

Since

4.8

See also

setInstantInvalidatePropagation()

returns true if the complete widget/layout hierarchy is rearranged in one go.

Definition at line 519 of file qgraphicslayout.cpp.

Referenced by activate(), QGraphicsLayoutPrivate::activateRecursive(), invalidate(), QGraphicsWidget::setGeometry(), updateGeometry(), and QGraphicsWidget::updateGeometry().

{
    return g_instantInvalidatePropagation;
}

invalidate()

void QGraphicsLayout::invalidate ( )

virtual

Clears any cached geometry and size hint information in the layout, and posts a LayoutRequest event to the managed parent QGraphicsLayoutItem.

See also

activate(), setGeometry()

Reimplemented in QGraphicsGridLayout, QGraphicsAnchorLayout, and QGraphicsLinearLayout.

Definition at line 306 of file qgraphicslayout.cpp.

Referenced by QGraphicsLayoutPrivate::activateRecursive(), QGraphicsLinearLayout::addStretch(), QGraphicsLinearLayout::invalidate(), QGraphicsAnchorLayout::invalidate(), QGraphicsGridLayout::invalidate(), setContentsMargins(), QGraphicsWidget::setLayout(), updateGeometry(), and widgetEvent().

{
    if (QGraphicsLayout::instantInvalidatePropagation()) {
        updateGeometry();
    } else {
        // only mark layouts as invalid (activated = false) if we can post a LayoutRequest event.
        QGraphicsLayoutItem *layoutItem = this;
        while (layoutItem && layoutItem->isLayout()) {
            // we could call updateGeometry(), but what if that method
            // does not call the base implementation? In addition, updateGeometry()
            // does more than we need.
            layoutItem->d_func()->sizeHintCacheDirty = true;
            layoutItem->d_func()->sizeHintWithConstraintCacheDirty = true;
            layoutItem = layoutItem->parentLayoutItem();
        }
        if (layoutItem) {
            layoutItem->d_func()->sizeHintCacheDirty = true;
            layoutItem->d_func()->sizeHintWithConstraintCacheDirty = true;
        }

        bool postIt = layoutItem ? !layoutItem->isLayout() : false;
        if (postIt) {
            layoutItem = this;
            while (layoutItem && layoutItem->isLayout()
                    && static_cast<QGraphicsLayout*>(layoutItem)->d_func()->activated) {
                static_cast<QGraphicsLayout*>(layoutItem)->d_func()->activated = false;
                layoutItem = layoutItem->parentLayoutItem();
            }
            if (layoutItem && !layoutItem->isLayout()) {
                // If a layout has a parent that is not a layout it must be a QGraphicsWidget.
                QApplication::postEvent(static_cast<QGraphicsWidget *>(layoutItem), new QEvent(QEvent::LayoutRequest));
            }
        }
    }
}

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 293 of file qgraphicslayout.cpp.

Referenced by widgetEvent().

{
    Q_D(const QGraphicsLayout);
    return d->activated;
}

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 QGraphicsGridLayout, QGraphicsAnchorLayout, and QGraphicsLinearLayout.

Referenced by QGraphicsLayoutPrivate::activateRecursive(), QGraphicsLinearLayout::addStretch(), QGraphicsLayoutItemPrivate::hasHeightForWidth(), QGraphicsLayoutItemPrivate::hasWidthForHeight(), removeLayoutItemFromLayout(), and QGraphicsLayoutItem::~QGraphicsLayoutItem().

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 QGraphicsGridLayout, QGraphicsAnchorLayout, and QGraphicsLinearLayout.

Referenced by QGraphicsLinearLayout::addStretch(), removeLayoutItemFromLayout(), and QGraphicsLayoutItem::~QGraphicsLayoutItem().

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 222 of file qgraphicslayout.cpp.

{
    Q_D(QGraphicsLayout);
    if (d->left == left && d->top == top && d->right == right && d->bottom == bottom)
        return;
    d->left = left;
    d->right = right;
    d->top = top;
    d->bottom = bottom;
    invalidate();
}

setInstantInvalidatePropagation()

void QGraphicsLayout::setInstantInvalidatePropagation ( bool  enable )

static

Since

4.8

See also

instantInvalidatePropagation()

Calling this function with enable set to true will enable a feature that makes propagation of invalidation up to ancestor layout items to be done in one go. It will propagate up the parentLayoutItem() hierarchy until it has reached the root. If the root item is a QGraphicsWidget, it will post a layout request to it. When the layout request is consumed it will traverse down the hierarchy of layouts and widgets and activate all layouts that is invalid (not activated). This is the recommended behaviour.

If not set it will also propagate up the parentLayoutItem() hierarchy, but it will stop at the first widget it encounters, and post a layout request to the widget. When the layout request is consumed, this might cause it to continue propagation up to the parentLayoutItem() of the widget. It will continue in this fashion until it has reached a widget with no parentLayoutItem(). This strategy might cause drawing artifacts, since it is not done in one go, and the consumption of layout requests might be interleaved by consumption of paint events, which might cause significant flicker. Note, this is not the recommended behavior, but for compatibility reasons this is the default behaviour.

Definition at line 508 of file qgraphicslayout.cpp.

{
    g_instantInvalidatePropagation = enable;
}

updateGeometry()

void QGraphicsLayout::updateGeometry ( )

virtual

Reimplemented Function

Reimplemented from QGraphicsLayoutItem.

Definition at line 345 of file qgraphicslayout.cpp.

Referenced by invalidate().

{
    Q_D(QGraphicsLayout);
    if (QGraphicsLayout::instantInvalidatePropagation()) {
        d->activated = false;
        QGraphicsLayoutItem::updateGeometry();

        QGraphicsLayoutItem *parentItem = parentLayoutItem();
        if (!parentItem)
            return;

        if (parentItem->isLayout())
            static_cast<QGraphicsLayout *>(parentItem)->invalidate();
        else
            parentItem->updateGeometry();
    } else {
        QGraphicsLayoutItem::updateGeometry();
        if (QGraphicsLayoutItem *parentItem = parentLayoutItem()) {
            if (parentItem->isLayout()) {
                parentItem->updateGeometry();
            } else {
                invalidate();
            }
        }
    }
}

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()

Definition at line 385 of file qgraphicslayout.cpp.

{
    switch (e->type()) {
    case QEvent::GraphicsSceneResize:
        if (isActivated()) {
            setGeometry(parentLayoutItem()->contentsRect());
        } else {
            activate(); // relies on that activate() will call updateGeometry()
        }
        break;
    case QEvent::LayoutRequest:
        activate();
        break;
    case QEvent::LayoutDirectionChange:
        invalidate();
        break;
    default:
        break;
    }
}

Friends and Related Functions

QGraphicsWidget

friend class QGraphicsWidget

friend

Definition at line 88 of file qgraphicslayout.h.

---

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

• /src/gui/graphicsview/qgraphicslayout.h
• /src/gui/graphicsview/qgraphicslayout.cpp