QDeclarativeItem Class Reference

The QDeclarativeItem class provides the most basic of all visual items in QML. More...

 #include <QDeclarativeItem>

Inherits: QGraphicsObject and QDeclarativeParserStatus.

This class was introduced in Qt 4.7.

List of all members, including inherited members

Public Types

enum	TransformOrigin { TopLeft, Top, TopRight, Left, ..., BottomRight }

Properties

baselineOffset : qreal
childrenRect : const QRectF
clip : bool
implicitHeight : const qreal

implicitWidth : const qreal
parent : QDeclarativeItem *
smooth : bool

12 properties inherited from QGraphicsObject
1 property inherited from QObject

Public Functions

	QDeclarativeItem ( QDeclarativeItem * parent = 0 )
virtual	~QDeclarativeItem ()
qreal	baselineOffset () const
QDeclarativeItem *	childAt ( qreal x, qreal y ) const
QRectF	childrenRect ()
bool	clip () const
void	forceActiveFocus ()
qreal	implicitHeight () const
qreal	implicitWidth () const
bool	keepMouseGrab () const
QScriptValue	mapFromItem ( const QScriptValue & item, qreal x, qreal y ) const
QScriptValue	mapToItem ( const QScriptValue & item, qreal x, qreal y ) const
QDeclarativeItem *	parentItem () const
void	setBaselineOffset ( qreal )
void	setClip ( bool )
void	setKeepMouseGrab ( bool keep )
void	setParentItem ( QDeclarativeItem * parent )
void	setSmooth ( bool smooth )
void	setTransformOrigin ( TransformOrigin origin )
bool	smooth () const
TransformOrigin	transformOrigin () const

2 public functions inherited from QGraphicsObject
2 public functions inherited from QDeclarativeParserStatus
29 public functions inherited from QObject
177 public functions inherited from QGraphicsItem

Signals

	Q_REVISION ()
	Q_REVISION ()

9 signals inherited from QGraphicsObject
1 signal inherited from QObject

Protected Functions

virtual void	geometryChanged ( const QRectF & newGeometry, const QRectF & oldGeometry )
bool	heightValid () const
bool	isComponentComplete () const
void	setImplicitHeight ( qreal h )
void	setImplicitWidth ( qreal w )
bool	widthValid () const

7 protected functions inherited from QObject
24 protected functions inherited from QGraphicsItem

Additional Inherited Members

1 public slot inherited from QObject
5 static public members inherited from QObject
2 static public members inherited from QGraphicsItem
1 protected slot inherited from QGraphicsObject

Detailed Description

The QDeclarativeItem class provides the most basic of all visual items in QML.

All visual items in Qt Declarative inherit from QDeclarativeItem. Although QDeclarativeItem has no visual appearance, it defines all the properties that are common across visual items - such as the x and y position, the width and height, anchoring and key handling.

You can subclass QDeclarativeItem to provide your own custom visual item that inherits these features. Note that, because it does not draw anything, QDeclarativeItem sets the QGraphicsItem::ItemHasNoContents flag. If you subclass QDeclarativeItem to create a visual item, you will need to unset this flag.

Member Type Documentation

enum QDeclarativeItem::TransformOrigin

Controls the point about which simple transforms like scale apply.

Constant	Value	Description
`QDeclarativeItem::TopLeft`	`0`	The top-left corner of the item.
`QDeclarativeItem::Top`	`1`	The center point of the top of the item.
`QDeclarativeItem::TopRight`	`2`	The top-right corner of the item.
`QDeclarativeItem::Left`	`3`	The left most point of the vertical middle.
`QDeclarativeItem::Center`	`4`	The center of the item.
`QDeclarativeItem::Right`	`5`	The right most point of the vertical middle.
`QDeclarativeItem::BottomLeft`	`6`	The bottom-left corner of the item.
`QDeclarativeItem::Bottom`	`7`	The center point of the bottom of the item.
`QDeclarativeItem::BottomRight`	`8`	The bottom-right corner of the item.

Property Documentation

baselineOffset : qreal

This property holds the position of the item's baseline in local coordinates.

The baseline of a Text item is the imaginary line on which the text sits. Controls containing text usually set their baseline to the baseline of their text.

For non-text items, a default baseline offset of 0 is used.

Access functions:

qreal	baselineOffset () const
void	setBaselineOffset ( qreal )

childrenRect : const QRectF

This property holds the geometry of an item's children.

This property holds the (collective) position and size of the item's children.

Access functions:

QRectF childrenRect ()

clip : bool

This property holds whether clipping is enabled. The default clip value is false.

If clipping is enabled, an item will clip its own painting, as well as the painting of its children, to its bounding rectangle. If you set clipping during an item's paint operation, remember to re-set it to prevent clipping the rest of your scene.

Non-rectangular clipping regions are not supported for performance reasons.

Access functions:

bool	clip () const
void	setClip ( bool )

implicitHeight : const qreal

Access functions:

qreal implicitHeight () const

implicitWidth : const qreal

Access functions:

qreal implicitWidth () const

parent : QDeclarativeItem *

This property holds the parent of the item.

Access functions:

QDeclarativeItem *	parentItem () const
void	setParentItem ( QDeclarativeItem * parent )

Notifier signal:

void	parentChanged ()

smooth : bool

This property holds whether the item is smoothly transformed.

This property is provided purely for the purpose of optimization. Turning smooth transforms off is faster, but looks worse; turning smooth transformations on is slower, but looks better.

By default smooth transformations are off.

Access functions:

bool	smooth () const
void	setSmooth ( bool smooth )

Member Function Documentation

QDeclarativeItem::QDeclarativeItem ( QDeclarativeItem * parent = 0 )

Constructs a QDeclarativeItem with the given parent.

QDeclarativeItem::~QDeclarativeItem () `[virtual]`

Destroys the QDeclarativeItem.

QDeclarativeItem::Q_REVISION () `[signal]`

QDeclarativeItem * QDeclarativeItem::childAt ( qreal x, qreal y ) const

void QDeclarativeItem::forceActiveFocus ()

void QDeclarativeItem::geometryChanged ( const QRectF & newGeometry, const QRectF & oldGeometry ) `[virtual protected]`

This function is called to handle this item's changes in geometry from oldGeometry to newGeometry. If the two geometries are the same, it doesn't do anything.

bool QDeclarativeItem::heightValid () const `[protected]`

Returns whether the height property has been set explicitly.

bool QDeclarativeItem::isComponentComplete () const `[protected]`

Returns true if construction of the QML component is complete; otherwise returns false.

It is often desirable to delay some processing until the component is completed.

See also componentComplete().

bool QDeclarativeItem::keepMouseGrab () const

Returns a value indicating whether mouse input should remain with this item exclusively.

See also setKeepMouseGrab().

QScriptValue QDeclarativeItem::mapFromItem ( const QScriptValue & item, qreal x, qreal y ) const

QScriptValue QDeclarativeItem::mapToItem ( const QScriptValue & item, qreal x, qreal y ) const

void QDeclarativeItem::setImplicitHeight ( qreal h ) `[protected]`

Sets the implied height of the item to h. This is the height implied by other properties that determine the content.

See also implicitHeight().

void QDeclarativeItem::setImplicitWidth ( qreal w ) `[protected]`

Sets the implied width of the item to w. This is the width implied by other properties that determine the content.

See also implicitWidth().

void QDeclarativeItem::setKeepMouseGrab ( bool keep )

The flag indicating whether the mouse should remain with this item is set to keep.

This is useful for items that wish to grab and keep mouse interaction following a predefined gesture. For example, an item that is interested in horizontal mouse movement may set keepMouseGrab to true once a threshold has been exceeded. Once keepMouseGrab has been set to true, filtering items will not react to mouse events.

If the item does not indicate that it wishes to retain mouse grab, a filtering item may steal the grab. For example, Flickable may attempt to steal a mouse grab if it detects that the user has begun to move the viewport.

See also keepMouseGrab().

void QDeclarativeItem::setTransformOrigin ( TransformOrigin origin )

Set the transform origin.

See also transformOrigin().

TransformOrigin QDeclarativeItem::transformOrigin () const

Returns the current transform origin.

See also setTransformOrigin().

bool QDeclarativeItem::widthValid () const `[protected]`

Returns whether the width property has been set explicitly.

Contents

QDeclarativeItem Class Reference

Public Types

Properties

Public Functions

Signals

Protected Functions

Additional Inherited Members

Detailed Description

Member Type Documentation

enum QDeclarativeItem::TransformOrigin

Property Documentation

baselineOffset : qreal

childrenRect : const QRectF

clip : bool

implicitHeight : const qreal

implicitWidth : const qreal

parent : QDeclarativeItem *

smooth : bool

Member Function Documentation

QDeclarativeItem::QDeclarativeItem ( QDeclarativeItem * parent = 0 )

QDeclarativeItem::~QDeclarativeItem () [virtual]

QDeclarativeItem::Q_REVISION () [signal]

QDeclarativeItem::Q_REVISION () [signal]

QDeclarativeItem * QDeclarativeItem::childAt ( qreal x, qreal y ) const

void QDeclarativeItem::forceActiveFocus ()

void QDeclarativeItem::geometryChanged ( const QRectF & newGeometry, const QRectF & oldGeometry ) [virtual protected]

bool QDeclarativeItem::heightValid () const [protected]

bool QDeclarativeItem::isComponentComplete () const [protected]

bool QDeclarativeItem::keepMouseGrab () const

QScriptValue QDeclarativeItem::mapFromItem ( const QScriptValue & item, qreal x, qreal y ) const

QScriptValue QDeclarativeItem::mapToItem ( const QScriptValue & item, qreal x, qreal y ) const

void QDeclarativeItem::setImplicitHeight ( qreal h ) [protected]

void QDeclarativeItem::setImplicitWidth ( qreal w ) [protected]

void QDeclarativeItem::setKeepMouseGrab ( bool keep )

void QDeclarativeItem::setTransformOrigin ( TransformOrigin origin )

TransformOrigin QDeclarativeItem::transformOrigin () const

bool QDeclarativeItem::widthValid () const [protected]

QDeclarativeItem::~QDeclarativeItem () `[virtual]`

QDeclarativeItem::Q_REVISION () `[signal]`

QDeclarativeItem::Q_REVISION () `[signal]`

void QDeclarativeItem::geometryChanged ( const QRectF & newGeometry, const QRectF & oldGeometry ) `[virtual protected]`

bool QDeclarativeItem::heightValid () const `[protected]`

bool QDeclarativeItem::isComponentComplete () const `[protected]`

void QDeclarativeItem::setImplicitHeight ( qreal h ) `[protected]`

void QDeclarativeItem::setImplicitWidth ( qreal w ) `[protected]`

bool QDeclarativeItem::widthValid () const `[protected]`