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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** 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. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\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.
*/
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