Qt 4.8: What's New in Qt 4.7

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# What's New in Qt 4.7

Qt 4.7 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.

## Declarative UI Development with Qt Quick

Qt 4.7 introduces Qt Quick, the Qt UI Creation Kit. that enables the creation of dynamic user interfaces, easier and more effective than possible with existing UI technologies. This UI Creation Kit consists of three technologies:

- QML is a declarative language oriented on JavaScript that utilizes Qt's Meta-Object capabilities to enable designers and developers to collaborate tightly and create animated and fluid user experiences, using existing knowledge in script language and design.
- Qt Declarative is a C++ library that provides the underlying engine, which translates the declarative description of the UI in QML into items on a QGraphicsScene. The library also provides APIs to bind custom C++ types and elements to QML, and to connect the QML UI with the underlying application logic written in C++.
- Qt Creator has been improved to support interactive editing of QML UIs through drag-and-drop. The text editor supports the QML syntax and provides authoring assistance such as auto-completion, error lookup, help lookup and easy preview of QML UI's. The Qt Quick features in Qt Creator will be released with Qt Creator 2.1

## Network Bearer Management

Bearer Management controls the connectivity state of the system. The new Bearer Management API in the QtNetwork module allows the application to identify whether the system is online and how many interfaces there are, as well as start and stop interfaces, or roam transparently between access points.

QNetworkAccessManager uses this API for HTTP level roaming.

## Feature Improvements in QtWebKit

The QGraphicsWebView class has a new tiled backing store, which improves scrolling and zooming performance. You can even create animated zoom-in or zoom-out effects (see QWebSettings::TiledBackingStoreEnabled).

On mobile platforms, it is often useful to avoid displaying separate scrollbars for iframes and framesets. If you switch on frame flattening, QtWebKit will resize frames to fit their content to avoid separate scrollbars (see QWebSettings::FrameFlatteningEnabled).

Qt 4.7 adds support for accelerated compositing, which enhances the performance of CSS animations and transitions. Read more in this blog.

For hybrid QtWebKit and C++ projects, Qt 4.7 has added support for transporting QPixmaps between Qt C++ and WebKit. We have also improved the documentation for hybrid development. Read more here: The QtWebKit Bridge.

## QtWebKit Performance Benchmarks

We have introduced a set of performance benchmarks for QtWebKit, and made numerous improvements in rendering performance, page loading performance, scrolling performance and CSS performance. Here are some examples from the benchmarks run on a 64-bit Linux workstation with the raster graphics system.

In a benchmark that measures the scrolling performance on popular websites, we found out that Qt 4.7.0 on this platform is 350% faster than Qt 4.6.0, thanks to several rendering related improvements.

Our page loading benchmark shows an improvement of 16% in Qt 4.7.0 from Qt 4.6.0. This is due to improvements in text layout speed, image decoding, resource loading and event handling.

Several CSS animation benchmarks indicate a speed improvement of 31% from Qt 4.6.0 to Qt 4.7.0. These benchmarks are effectively showing the improvement we get from accelerated compositing (see above).

## Other Performance Related Improvements

In addition to the QtWebKit module, performance has been a focus area in Qt 4.7 throughout the Qt framework. Here are a couple of examples about performance related feature improvements.

On Mac OS X, Qt now uses a different widget implementation (called "alien widgets"), which improves the responsiveness of applications that have complex user interfaces with several widgets.

Qt 4.7 introduces the QStaticText class, which can be used to improve text rendering performance. More info is available from this blog.

The QPainter class has a new API for rendering pixmap fragments (QPainter::drawPixmapFragments), which can improve the rendering performance of applications that need to render pixmap fragments.

Qt 4.7 has an updated version of the JavaScriptCore engine for the QtScript module, which improves JavaScript execution performance.

## New Classes, Functions, Macros, etc.

Links to new classes, elements, functions, macros, and other items introduced in Qt 4.7.

- New Classes
- New Member Functions
- New Global Functions
- New QML Elements

### New Classes

A
  AudioDataOutput (Phonon)

D
  QDeclarativeComponent
  QDeclarativeContext
  QDeclarativeEngine
  QDeclarativeError
  QDeclarativeExpression
  QDeclarativeExtensionPlugin
  QDeclarativeImageProvider
  QDeclarativeItem
  QDeclarativeListProperty
  QDeclarativeListReference
  QDeclarativeNetworkAccessManagerFactory
  QDeclarativeParserStatus
  QDeclarativeProperty
  QDeclarativePropertyMap
  QDeclarativeScriptString
  QDeclarativeView

E
  QElapsedTimer

G
  QGLBuffer

N
  QNetworkConfiguration
  QNetworkConfigurationManager
  QNetworkSession

S
  QScriptProgram
  QStaticText

V
  VideoWidgetInterface44 (Phonon)
  ViewportAttributes (QWebPage)

### New Member Functions

Class QWizard:

void | pageAdded ( int id )
void | pageRemoved ( int id )
void | setSideWidget ( QWidget * widget )
QWidget * | sideWidget () const

Class QNetworkAccessManager:

QNetworkConfiguration | activeConfiguration () const
QNetworkConfiguration | configuration () const
NetworkAccessibility | networkAccessible () const
QNetworkReply * | sendCustomRequest ( const QNetworkRequest & request, const QByteArray & verb, QIODevice * data = 0 )
void | setConfiguration ( const QNetworkConfiguration & config )
void | setNetworkAccessible ( NetworkAccessibility accessible )

Class QAudioDeviceInfo:

QList<int> | supportedChannelCounts () const
QList<int> | supportedSampleRates () const

Class QAudioFormat:

int | channelCount () const
int | sampleRate () const
void | setChannelCount ( int channels )
void | setSampleRate ( int samplerate )

Class QGLShader:

bool | hasOpenGLShaders ( ShaderType type, const QGLContext * context = 0 )

Class QGLShaderProgram:

GLenum | geometryInputType () const
GLenum | geometryOutputType () const
int | geometryOutputVertexCount () const
int | maxGeometryOutputVertices () const
void | setAttributeArray ( int location, GLenum type, const void * values, int tupleSize, int stride = 0 )
void | setAttributeArray ( const char * name, GLenum type, const void * values, int tupleSize, int stride = 0 )
void | setAttributeBuffer ( int location, GLenum type, int offset, int tupleSize, int stride = 0 )
void | setAttributeBuffer ( const char * name, GLenum type, int offset, int tupleSize, int stride = 0 )
void | setGeometryOutputType ( GLenum outputType )
void | setGeometryOutputVertexCount ( int count )
void | setUniformValue ( int location, const GLfloat[2][2] value )
void | setUniformValue ( int location, const GLfloat[3][3] value )
void | setUniformValue ( const char * name, const GLfloat[2][2] value )
void | setUniformValue ( const char * name, const GLfloat[3][3] value )

Class QIconEngineV2:

QString | iconName ()

Class VideoWidget:

QImage | snapshot () const

Class QScriptEngine:

QScriptValue | evaluate ( const QScriptProgram & program )
void | reportAdditionalMemoryCost ( int size )

Class QFileSystemModel:

void | directoryLoaded ( const QString & path )

Class QNetworkRequest:

Priority | priority () const
void | setPriority ( Priority priority )

Class QDBusMessage:

bool | autoStartService () const
void | setAutoStartService ( bool enable )

Class QWebFrame:

void | pageChanged ()
void | scrollToAnchor ( const QString & anchor )

Class QPlainTextEdit:

QString | anchorAt ( const QPoint & pos ) const

Class QAuthenticator:

QVariant | option ( const QString & opt ) const
QVariantHash | options () const
void | setOption ( const QString & opt, const QVariant & value )

Class QState:

QList<QAbstractTransition *> | transitions () const

Class QGraphicsItem:

void | updateMicroFocus ()

Class QGraphicsObject:

void | updateMicroFocus ()

Class QGraphicsScale:

void | xScaleChanged ()
void | yScaleChanged ()
void | zScaleChanged ()

### New Global Functions

uint | qHash ( const QUrl & url )

### New QML Elements

A
  AnchorAnimation
  AnimatedImage
  Animation

B
  Behavior
  Binding
  BorderImage

C
  ColorAnimation
  Column
  Component
  Connections

F
  Flickable
  Flipable
  Flow
  FocusPanel
  FocusScope
  FontLoader

G
  Gradient
  GradientStop
  Grid
  GridView

I
  Image
  Item

K
  KeyEvent
  KeyNavigation
  Keys

L
  LayoutItem
  ListElement
  ListModel
  ListView
  Loader

M
  QML:QtObject
  MouseArea
  MouseEvent

N
  NumberAnimation

P
  ParallelAnimation
  ParentAnimation
  ParticleMotionGravity
  ParticleMotionLinear
  ParticleMotionWander
  Particles
  Path
  PathAttribute
  PathCubic
  PathElement
  PathLine
  PathPercent
  PathQuad
  PathView
  PauseAnimation
  PropertyAction
  PropertyAnimation
  PropertyChanges

R
  Rectangle
  Repeater
  Rotation
  RotationAnimation
  Row

S
  Scale
  ScriptAction
  SequentialAnimation
  SmoothedAnimation
  SpringAnimation
  State
  StateGroup
  SystemPalette

T
  Text
  TextEdit
  TextInput
  Timer
  Transform
  Transition
  Translate

V
  Vector3dAnimation
  VisualItemModel

W
  WebView

X
  XmlListModel
  XmlRole