/****************************************************************************

**

** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** 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.

**

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

/*!

    \page qt-overview.html

    \title Qt Features Overview

    This document provides a summary of the most important features of Qt,

    providing links to other pages in the documentation that cover these

    features in more detail. It is not intended to be a comprehensive

    guide to Qt's features.

    \section1 Fundamental Technologies in Qt

    Qt is built upon a set of core technologies, provided by the \l QtCore

    and \l QtGui modules. These include the following:

    \list

    \o \l{The Tulip Container Classes}, a set of template container classes.

    \o \l{The Arthur Paint System}, the Qt 4 painting framework.

    \o \l{The Interview Framework}, a model/view architecture for item views

       and the \l{QtSQL Module}, which also uses this architecture.

    \o \l{The Scribe Classes}, a framework for creating text documents,

        performing low-level text layout and writing OpenDocument files.

    \o A collection of \l{Qt Widget Gallery}{common desktop widgets}, styled

       to fit in on each supported platform.

    \o \l{The Qt 4 Main Window Classes}, a main window, toolbar, menu, and

       docking architecture.

    \o The \l{Graphics View} framework provides a canvas for producing

       interactive graphics.

    \o The \l{QtNetwork Module} provides support for TCP, UDP and local

       sockets that are integrated with Qt's event model, including support

       for Secure Socket Layer (SSL) communications,

       \l{QNetworkProxy}{network proxy} servers and

       \l{Bearer Management}{network bearer management}.

    \o Enhanced \l{qt4-threads.html}{thread support} allows

    \l{Signals & Slots}{signal-slot} connections across threads and

       per-thread event loops.

       Additionally, \l{Thread Support in Qt}{a framework for concurrent programming}

       using Qt paradigms makes common threading tasks easier.

    \o A \l{resource system} for embedding images and other resource files

       into executable files makes it easier to deploy applications.

    \o A \l{QTestLib Manual}{unit testing framework} for Qt applications and

       libraries.

    \endlist

    The mature classes provided by these technologies have been used to build

    robust, cross-platform desktop applications. They are augmented by a number

    of additional technologies and improvements that have appeared over the

    lifetime of Qt 4.

    \section1 Graphical User Interfaces

    \div{class="float-right"}

    \inlineimage gtk-tabwidget.png

    \enddiv

    \div{class="float-right"}

    \inlineimage gtk-progressbar.png

    \br

    \inlineimage gtk-checkbox.png

    \br

    \inlineimage plastique-combobox.png

    \br

    \inlineimage plastique-radiobutton.png

    \enddiv

    Alongside the support for traditional desktop user interfaces, Qt includes

    support for declarative UI development with \l{Qt Quick}, a set of

    technologies for creating fluid, dynamic user interfaces. A starting point

    for exploring this approach can be found in the \l{Introduction to Qt Quick}

    guide.

    Qt provides a range of standard user interface elements, called widgets,

    for each supported platform. Widgets can be used as containers for other

    widgets, as windows, and as regular controls that the user interacts with.

    Where the platform supports it, widgets can be made to appear partially

    transparent, and may be styled with \l{Qt Style Sheets}.

    Support for \l{QTouchEvent}{touch input} and \l{Gestures Programming}{gestures}

    enable widgets to be used to create intuitive user interfaces for

    touch-enabled devices.

    User interfaces can also be created dynamically at run-time with the

    features provided by the \l{QtUiTools} module.

    A selection of available widgets are shown in the \l{Qt Widget Gallery}.

    An introduction to the concepts behind widgets can be found in the

    \l{Widgets Tutorial}.

    \clearfloat

    \section1 Painting, Printing and Rendering

    \div{class="float-left"}

    \inlineimage qpainter-affinetransformations.png

    \enddiv

    Widgets are just one of many kinds of paint device that Qt can render onto.

    This support for unified painting makes it possible for applications to use

    the same painting code for different tasks, as well as allowing Qt to be

    extended to support additional file formats.

    Qt provides support for common bitmap image formats,

    \l{QtSvg Module}{Scalable Vector Graphics} (SVG) drawings and animations,

    Postscript and Portable Document Format (PDF) files. Postscript and PDF are

    integrated with \l{Printing with Qt}{Qt's printing system}, which also

    allows printed output to be previewed.

    Interactive graphics can be created with the

    \l{The Animation Framework}{animation framework}, allowing animations to be

    used with both widgets and graphics items. Animations can be used with the

    \l{The State Machine Framework}{state machine framework}, which provides a

    way to express application logic and integrate it with the user interface.

    Animations can be enhanced with a collection of

    \l{QGraphicsEffect}{graphics effects} that operate on graphics items and

    can be applied individually or combined to create more complex effects.

    Qt supports integration with \l{QtOpenGL}{OpenGL} on a number of levels,

    providing convenience functions for handling textures and colors, as well

    as providing support for pixel and sample buffers. Future support for

    higher level 3D integration is provided by Qt3D enablers which include

    \l{QMatrix4x4}{matrix multiplication}, \l{QQuaternion}{quaternions}, and an

    API for \l{QGLShader}{vertex and fragment shaders}.

    Two APIs are provided for multimedia. The

    \l{Phonon Overview}{Phonon Multimedia Framework} has traditionally been

    used on desktop platforms. A set of

    \l{QtMultimedia Module}{multimedia services} provides low-level access to

    the system's audio system and is often used on mobile devices.

    \clearfloat

    \section1 Infrastructure

    \div{class="float-right"}

    \inlineimage qtscript-context2d.png

    \enddiv

    Facilities for Inter-Process Communication (IPC) and Remote Procedure

    Calling (RPC) mechanisms are available on platforms that support the

    \l{intro-to-dbus.html}{D-Bus} message bus system.

    An \l{Undo Framework}{Undo framework} based on the

    \l{Books about GUI Design#Design Patterns}{Command pattern} is designed to

    enable a consistent approach to handling data in editing applications.

    The \l{QtScript} and \l{QtScriptTools} modules provide support for

    application scripting and debugging using the ECMAScript language.

    The \l{QtHelp Module} provides the foundations of an interactive help

    system that can be used in conjunction with Qt Creator or integrated into

    applications directly.

    XML handling is supported in a number of places in Qt. The \l QtCore module

    provides classes for reading and writing XML streams. The \l QtXmlPatterns

    module includes XQuery, XPath and XSLT support, providing facilities for

    XML processing beyond that supported by the QtXml module, which contains

    SAX and DOM parsers. XML schema validation in the QtXmlPatterns module

    covers large parts of version 1.0 of the specification.

    \clearfloat

    \section1 Web Client Integration

    Integration between \l{Webkit in Qt}{Qt and WebKit} makes it possible for

    developers to use a fully-featured Web browser engine to display documents

    and access online services. Developers can access the browser's environment

    to create documents and run scripts within one or more browser widgets.

    A \l{QWebElement}{DOM access API} for QtWebKit provides a cleaner and safer

    way to access elements and structures of Web pages without the use of

    JavaScript.

    \section1 Further Reading

    Many of the technologies mentioned here, as well as other, more specific

    features, are listed in the \l{What's New in Qt 4} document. A complete

    list of Qt's modules can be found on the \l{All Modules} page, which

    also includes more domain-specific technologies.

    The tools that are supplied with Qt are covered by the listing in the

    \l{Qt's Tools} document.

*/