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

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

New Member Functions

Class QGraphicsScale:

Class QIconEngineV2:

Class QPlainTextEdit:

  • QString anchorAt ( const QPoint & pos ) const

Class QState:

Class QGLShaderProgram:

Class QGLShader:

Class QAudioFormat:

Class QGraphicsObject:

Class QScriptEngine:

Class QFileSystemModel:

Class VideoWidget:

Class QDBusMessage:

Class QNetworkRequest:

Class QWizard:

Class QWebFrame:

Class QAuthenticator:

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

Class QAudioDeviceInfo:

Class QNetworkAccessManager:

Class QGraphicsItem:

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

Notes provided by the Qt Community

No notes