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whatsnew.qdoc
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whatsnew.qdoc
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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms
** and conditions contained in a signed written agreement between you
** and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\title What's New in Qt Quick 2
\page qtquick2-whatsnew.html
\inqmlmodule QtQuick 2
\section1 Qt 5.0.0 includes QtQuick 2.0
QtQuick 2.0 is a major update.
\section2 SceneGraph renderer
QtQuick 2 is based on an OpenGL scenegraph. The following
classes replace their equivalents in QtQuick 1:
\list
\li QQuickView
\li QQuickCanvas
\li QQuickItem
\li QQuickPaintedItem
\endlist
\section2 QML Engine/Language Improvements
JS engine changed to V8. For most QML users this should not make a visible difference beyond performance improvements, however a lot of undefined behavior semantics may have changed as well. As always, it is recommended not to rely on undefined behavior.
Parser and compiler optimizations.
New binding optimizer.
ValueType improvements:
- QColor is now a value type. The red, green, blue and alpha channels can be accessed via "r", "g", "b" and "a" properties
- Improved support for QVector4D, now constructible in QML via Qt.vector4d()
Arbitrary functionality may be provided in a namespace through a Module API. See \l{qmlRegisterModuleApi()} for more information.
JavaScript (.js) files may now import QML modules and other JavaScript files. See \l{Importing One JavaScript File From Another} for more information.
A new property type "var" has been added which obsoletes the old "variant" property type.
Properties of the "var" type may hold JavaScript references. See \l{QML Basic Types} for more information.
QML properties of type \c var and \c variant can now hold pixmaps. See \l{Scarce Resources in JavaScript} for more information
QQmlExpression can now be directly (and more efficiently) constructed from a
QQmlScriptString.
Support for certain sequence types (QList<int>, QList<qreal>, QList<bool>, QList<QUrl>, QList<QString> and QStringList) has been improved.
QObjects can define Q_PROPERTYs of these types which can be accessed transparently from JavaScript. See the section on
sequences in \l{Extending QML Functionalities using C++} for more information.
\section2 Canvas Item
The new \l Canvas item provides a HTML5 canvas like API, with some enhancements:
1) Supports 2 render targets: Canvas.Image and Canvas.FramebufferObject
2) Supports background thread rendering
3) Supports tiled canvas rendering
The Canvas item supports most of the HTML5 context2d APIs, the API details please look at the canvas item documentation.
\section2 Particle System
The \l{QtQuick.Particles 2}{QtQuick.Particles} module contains elements that can be composed to form 2D particle system.
\section2 Element API/Behavior Changes
New \l SpriteImage element renders animated sprites and can transition between animations.
It uses the \l Sprite element to represent each animation.
MouseArea now propagates clicked, doubleClicked and pressAndHold differently to pressed.
These will now be propagated to the highest-stacking-order enabled MouseArea which has a handler for them.
You can still ignore these events in the handler to let them pass through.
This behavior is triggered with the new property propagateComposedEvents.
The Binding element can now be used as a value source, and will also restore any previously
set binding when its \e when clause becomes false.
Flickable: added dragging, draggingHorizontally and draggingVerically properties.
Added topMargin, bottomMargin, leftMargin, rightMargin, xOrigin, yOrigin properties.
Image has two new properties: horizontalAlignment and verticalAlignment. It also has a new value for
fillMode (Image.Pad) that does not transform the image.
Setting Image sourceSize.width and sourceSize.height will now fit the image to the size, maintaining aspect.
Grid now has rowSpacing and columnSpacing properties. Spacing properties on positioners are now real numbers instead
of integers.
Positioner (Row, Column, Grid, Flow) improvements:
\list
\li Transitions used for \c add and \c move now have improved features: they can access a ViewTransition attached property (see the ViewTransition documentation for examples) and can now animate arbitrary item properties (instead of being restricted to animating an item's position).
\li Items in a positioner now have attached properties that can be used to determine a subitem's location: Positioner.index, Positioner.isFirstItem, Positioner.isLastItem.
\endlist
Loader improvements:
- "active" property added to Loader, to allow delaying instantiation of a Loader element's item property
- "setSource(JSObject)" method added to Loader to allow initial property values to be specified (similar to Component.createObject())
- now only emits the \c sourceChanged signal when the source is changed and the
\c sourceComponentChanged signal when the sourceComponent is changed. It used to emit both signals when one of the properties was changed.
Text improvements:
- a \c onLineLaidOut handler is called for every line during the layout process. This gives the opportunity to position and resize a line as it is being laid out.
- a \c doLayout method was added to trigger the layout from Javascript.
- now automatically switch to StyledText instead of RichText if textFormat is set to AutoText.
TextEdit:
- the default value of the textFormat property is now PlainText instead of AutoText.
TextInput has new wrapMode and verticalAlignment properties, and the positionAt function now takes
a y parameter.
PathView now has a \c currentItem property
ListView and GridView:
- Can now apply specified transitions whenever items are added, removed or moved in a view.
See the documentation for ViewTransition and ListView.add, ListView.addDisplaced,
GridView.add, GridView.addDisplaced etc. for details.
- These now have headerItem and footerItem properties (the instantiated header and footer items).
- In RightToLeft layout the preferredHighlightBegin/End are now also reversed.
ListView section.labelPositioning property added to allow keeping the current section label
at the start and/or next section label at the end of the view.
A new property type ("var") has been introduced which obsoletes "variant" properties in QML.
Properties of this type are equivalent to regular JavaScript variables. See the documentation
on \l{QML Basic Types} for more information about "var" properties.
New elements have been added for contructing paths: PathArc, PathCurve, PathSvg.
\section2 QtQuick 1 is now a separate library and module
Writing C++ applications using QtQuick 1 specific API, i.e. QDeclarativeView or QDeclarativeItem
requires adding the "quick1" module to the .pro file, e.g. QT += quick1
QDeclarativeView and QDeclarativeItem headers are now in the QtQuick 1 module, i.e.
#include <QtQuick1/QDeclarativeView>
#include <QtQuick1/QDeclarativeItem>
\sa {What's New in Qt Quick 1}{What's New in Qt Quick 1}
*/