What's New in Qt 4.6

Qt 4.6 provides many improvements and enhancements over the previous releases in the Qt 4 series. This document covers the most important features in this release, separated by category.

A list of other Qt 4 features can be found on the What's New in Qt 4 page.

Support for Symbian

Qt 4.6 is the first release to include support for the Symbian platform, with integration into the S60 framework. The port to Symbian and S60 provides all functionality required to develop rich end-user applications for devices running S60 3.1 and later.

See the The Symbian platform - Introduction to Qt for more information.

Animation Framework

The animation framework helps build highly animated, high-performance GUIs without the hassle of managing complex structures, timers, and easing curves, not to mention the large state graphs that all animated GUIs tend to be full of.

The framework makes it easy to animate QObjects, including QWidgets, by allowing Qt properties to be animated. It also allows creating custom animations and interpolation functions. Graphics views are not left out; one can animate QGraphicsWidgets and new QGraphicsObjects which inherit from QGraphicsItem (and thereby enable properties).

Animations are controlled using easing curves and can be grouped together. This enables animations of arbitrary complexity.

The API is easy to grasp with functions such as start(), stop(), pause(), and currentTime(). Here is an image from one of the examples that come with the framework:

The animation framework also plugs into the new Qt Statemachine by allowing an animation to be played when transitions are triggered. The state machine framework is introduced in 4.6 and is described below.

See The Animation Framework documentation for more information.

State Machine Framework

The state machine framework provides a robust state chart implementation based on Harel statecharts and SCXML. Qt's API lets you construct such state graphs and execute them. The key benefits of a state machine are:

• Simplify complex application semantics.
• Use of states to reduce code bloat.
• Use states to improve maintainability.
• Makes event-driven programming robust and more reusable.

It is especially the last item here that makes using a state machine worthwhile. A key characteristic of event-driven systems (such as Qt applications) is that behavior often depends not only on the last or current event, but also the events that preceded it. With statecharts, this information is easy to express.

The framework fits neatly into Qt by allowing transitions to trigger on signals and QEvents. By inserting animations into the state machine, it is also easier to use the framework for animating GUIs, for instance.

See The State Machine Framework documentation for more information.

Touch and Gestures

Support for touch input enables users to interact with many parts of a user interface at the same time, and provides the basis for gestures. Additional infrastructure for gesture recognition allows a sequence of touch inputs to be combined to create gestures that can be used to activate features and trigger actions in an application.

This new functionality brings a number of benefits:

• Allows users to interact with applications in more natural ways.
• Simplifies finger-based interaction with UI components.
• Combines support for common basic gestures and touch gestures in a single general framework.
• Enables extensibility by design.

See the QTouchEvent class documentation for more information on touch input and QGestureEvent for gestures.

DOM Access API

Web pages and XML both have very complex document object models. The W3C selector API provides a very simple way to access and manipulate such structures. This API makes it intuitive to access DOM, helps reuse CSS selector knowledge, and gives little maintenance or footprint overhead.

     QWebElement document = frame->documentElement();
     /* Assume the document has the following structure:

        <p class=intro>
          <span>Intro</span>
          <span>Snippets</span>
        </p>
        <p>
          <span>Content</span>
          <span>Here</span>
        </p>
     */

     QWebElementCollection allSpans = document.findAll("span");
     QWebElementCollection introSpans = document.findAll("p.intro span");

See the QWebElement class documentation for more information.

Performance Optimizations

As always, Qt continuously strive to optimize its performance. For this release, we have:

• Rewritten the QGraphicsView rendering algorithm.
• Made QPixmapCache support efficient Key data structure.
• Reduced overhead in QNetworkAccessManager.
• Added the QContiguousCache class, which provides efficient caching of contiguous data.
• Added support for hardware-accelerated rendering through OpenVG
• Removed Win9x support.

Graphics Effects

Effects can be used to alter the appearance of UI elements such as QGraphicsItems and QWidgets. A couple of standard effects such as blurring, colorizing and drop shadow are provided, and it is possible to implement custom effects.

See the QGraphicsEffect class documentation for more information.

XML Schema Validation

The QtXmlPatterns module can now be used to validate schemas, either through C++ APIs in the Qt application, or using the xmlpatternsvalidator command line utility. The implementation of XML Schema Validation supports the specification version 1.0 in large parts.

See the XML Processing and QXmlSchema class documentation for more information.

Qt3D Enablers

As more of Qt, and more of the applications built on Qt go 3D, API's should be provided to simplify this. Mainly, the new API aims to make it more easy to create 3D applications with OpenGL. It will also unify the Qt OpenGL codebase, and enable cross-platform 3D codebase.

The main features of the Qt3D enablers are currently: Math primitives for matrix multiplication, vectors, quaternions (client-side), and an API for vertex and fragment shaders, GLSL/ES. Future research will, among other things include stencils, scissors, vertex buffers and arrays, texture manipulation, and geometry shaders.

Multimedia Services

Qt 4.6 comes with new classes for handling audio. These classes provide low-level access to the system's audio system. By specifying the audio format (QAudioFormat) and supplying audio data through a QIODevice, you get direct access to the functionality of the sound device. The API also comes with functions to query audio devices for which audio formats they support.

See the QtMultimedia Module documentation for more information.

New Classes, Functions, Macros, etc.

Links to new classes, functions, macros, and other items introduced in Qt 4.6.

• New Classes
• New Member Functions
• New Global Functions
• New Macros

New Classes

New Member Functions

Class QScriptString:

quint32

toArrayIndex ( bool * ok = 0 ) const

Class QStyleOptionGraphicsItem:

qreal

levelOfDetailFromTransform ( const QTransform & worldTransform )

Class QScriptEngineDebugger:

DebuggerState

state () const

Class QNetworkProxyFactory:

void	setUseSystemConfiguration ( bool enable )

Class QWebView:

QPainter::RenderHints	renderHints () const
void	setRenderHint ( QPainter::RenderHint hint, bool enabled = true )
void	setRenderHints ( QPainter::RenderHints hints )

Class QNetworkReply:

void	ignoreSslErrors ( const QList<QSslError> & errors )
bool	isFinished () const
bool	isRunning () const

Class QGraphicsLayout:

void	addChildLayoutItem ( QGraphicsLayoutItem * layoutItem )

Class QDBusConnection:

bool	connect ( const QString & service, const QString & path, const QString & interface, const QString & name, const QStringList & argumentMatch, const QString & signature, QObject * receiver, const char * slot )
bool	disconnect ( const QString & service, const QString & path, const QString & interface, const QString & name, const QStringList & argumentMatch, const QString & signature, QObject * receiver, const char * slot )

Class QGraphicsItem:

bool	acceptTouchEvents () const
bool	filtersChildEvents () const
QGraphicsItem *	focusItem () const
QGraphicsItem *	focusProxy () const
QGraphicsEffect *	graphicsEffect () const
Qt::InputMethodHints	inputMethodHints () const
bool	isActive () const
bool	isBlockedByModalPanel ( QGraphicsItem ** blockingPanel = 0 ) const
bool	isPanel () const
QGraphicsItem *	panel () const
PanelModality	panelModality () const
QGraphicsObject *	parentObject () const
qreal	rotation () const
qreal	scale () const
void	setAcceptTouchEvents ( bool enabled )
void	setActive ( bool active )
void	setFiltersChildEvents ( bool enabled )
void	setFocusProxy ( QGraphicsItem * item )
void	setGraphicsEffect ( QGraphicsEffect * effect )
void	setInputMethodHints ( Qt::InputMethodHints hints )
void	setPanelModality ( PanelModality panelModality )
void	setRotation ( qreal angle )
void	setScale ( qreal factor )
void	setTransformOriginPoint ( const QPointF & origin )
void	setTransformOriginPoint ( qreal x, qreal y )
void	setTransformations ( const QList<QGraphicsTransform *> & transformations )
void	setX ( qreal x )
void	setY ( qreal y )
void	stackBefore ( const QGraphicsItem * sibling )
QGraphicsObject *	toGraphicsObject ()
const QGraphicsObject *	toGraphicsObject () const
QPointF	transformOriginPoint () const
QList<QGraphicsTransform *>	transformations () const

Class QSystemLocale:

virtual QLocale

fallbackLocale () const

Class QGLFramebufferObject:

void	blitFramebuffer ( QGLFramebufferObject * target, const QRect & targetRect, QGLFramebufferObject * source, const QRect & sourceRect, GLbitfield buffers = GL_COLOR_BUFFER_BIT, GLenum filter = GL_NEAREST )
bool	hasOpenGLFramebufferBlit ()

Class QWebSecurityOrigin:

void	addLocalScheme ( const QString & scheme )
QStringList	localSchemes ()
void	removeLocalScheme ( const QString & scheme )

Class QGraphicsView:

bool	isTransformed () const

Class QNetworkCacheMetaData:

AttributesMap	attributes () const
void	setAttributes ( const AttributesMap & attributes )

Class QNetworkAccessManager:

QNetworkReply *

deleteResource ( const QNetworkRequest & request )

Class QPrintPreviewWidget:

int	pageCount () const

Class QXmlQuery:

bool	setFocus ( const QString & focus )

Class QWebPage:

QWebFrame *	frameAt ( const QPoint & pos ) const
bool	shouldInterruptJavaScript ()

Class QHelpSearchEngine:

int	hitCount () const

Class QWebSettings:

void	clearMemoryCaches ()
QString	defaultTextEncoding () const
void	enablePersistentStorage ( const QString & path = QString() )
QString	localStoragePath () const
QString	offlineWebApplicationCachePath ()
qint64	offlineWebApplicationCacheQuota ()
void	setDefaultTextEncoding ( const QString & encoding )
void	setLocalStoragePath ( const QString & path )
void	setOfflineWebApplicationCachePath ( const QString & path )
void	setOfflineWebApplicationCacheQuota ( qint64 maximumSize )

Class QSyntaxHighlighter:

void	rehighlightBlock ( const QTextBlock & block )

Class QNetworkRequest:

QObject *	originatingObject () const
void	setOriginatingObject ( QObject * object )

Class QXmlStreamReader:

QString	readElementText ( ReadElementTextBehaviour behaviour )
bool	readNextStartElement ()
void	skipCurrentElement ()

Class QWebHitTestResult:

QWebElement	element () const
QWebElement	enclosingBlockElement () const
QWebElement	linkElement () const

Class QWebFrame:

void	contentsSizeChanged ( const QSize & size )
QWebElement	documentElement () const
QWebElementCollection	findAllElements ( const QString & selectorQuery ) const
QWebElement	findFirstElement ( const QString & selectorQuery ) const
void	loadFinished ( bool ok )
void	loadStarted ()
void	render ( QPainter * painter, RenderLayer layer, const QRegion & clip = QRegion() )
QRect	scrollBarGeometry ( Qt::Orientation orientation ) const
void	setFocus ()

Class QWebDatabase:

void	removeAllDatabases ()

Class QGraphicsScene:

QGraphicsItem *	activePanel () const
bool	isActive () const
QGraphicsItem *	itemAt ( const QPointF & position, const QTransform & deviceTransform ) const
QGraphicsItem *	itemAt ( qreal x, qreal y, const QTransform & deviceTransform ) const
QList<QGraphicsItem *>	items ( const QPointF & pos, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform & deviceTransform = QTransform() ) const
QList<QGraphicsItem *>	items ( const QRectF & rect, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform & deviceTransform = QTransform() ) const
QList<QGraphicsItem *>	items ( const QPolygonF & polygon, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform & deviceTransform = QTransform() ) const
QList<QGraphicsItem *>	items ( const QPainterPath & path, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform & deviceTransform = QTransform() ) const
QList<QGraphicsItem *>	items ( qreal x, qreal y, qreal w, qreal h, Qt::ItemSelectionMode mode, Qt::SortOrder order, const QTransform & deviceTransform = QTransform() ) const
bool	sendEvent ( QGraphicsItem * item, QEvent * event )
void	setActivePanel ( QGraphicsItem * item )
void	setSelectionArea ( const QPainterPath & path, const QTransform & deviceTransform )
void	setSelectionArea ( const QPainterPath & path, Qt::ItemSelectionMode mode, const QTransform & deviceTransform )

Class QSslSocket:

void	connectToHostEncrypted ( const QString & hostName, quint16 port, const QString & sslPeerName, OpenMode mode = ReadWrite )
void	ignoreSslErrors ( const QList<QSslError> & errors )
void	setSocketOption ( QAbstractSocket::SocketOption option, const QVariant & value )
QVariant	socketOption ( QAbstractSocket::SocketOption option )

Class QAbstractXmlNodeModel:

QSourceLocation

sourceLocation ( const QXmlNodeModelIndex & index ) const

Class QGraphicsLayoutItem:

bool	ownedByLayout () const
void	setOwnedByLayout ( bool ownership )

Class QSharedPointer:

QSharedPointer<X>

objectCast () const

Class QWeakPointer:

T *	data () const
QWeakPointer<T>	operator= ( const QObject * obj )

Class QProcessEnvironment:

QProcessEnvironment

systemEnvironment ()

Class QDBusPendingCall:

QDBusPendingCall	fromCompletedCall ( const QDBusMessage & msg )
QDBusPendingCall	fromError ( const QDBusError & error )

New Global Functions

QDataStream &	operator<< ( QDataStream & stream, const QWebHistory & history )
QDataStream &	operator>> ( QDataStream & stream, QWebHistory & history )
void	qDrawBorderPixmap ( QPainter * painter, const QRect & target, const QMargins & margins, const QPixmap & pixmap )
bool	qFuzzyCompare ( const QMatrix & m1, const QMatrix & m2 )
bool	qFuzzyCompare ( const QTransform & t1, const QTransform & t2 )
QSharedPointer<X>	qSharedPointerObjectCast ( const QWeakPointer<T> & other )
QSharedPointer<X>	qSharedPointerObjectCast ( const QSharedPointer<T> & other )
int	qWebKitMajorVersion ()
int	qWebKitMinorVersion ()
QString	qWebKitVersion ()
QString	qtTrId ( const char * id, int n = -1 )

New Macros

	QBENCHMARK_ONCE
	QT_TRID_NOOP ( id )