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/****************************************************************************
**
** Copyright (C) 2013 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 topics-ui.html
\title User Interfaces
\brief Qt's features for creating user interfaces
Qt features multiple technologies for creating user interfaces. While it is
possible to mix and match these different technologies as needed, one approach
is often better suitable for a certain type of user interface than the others.
\l {Qt Creator} is a good example of an application that mixes different user
interface technologies. In fact, it uses all of the three different approaches
described below. \l {Qt Creator} uses the traditional \l {Qt Widgets} such as
menus and dialogs as a basis of the user interface, \l {Qt Quick} amongst others
for the welcome screen, and \l {Qt WebKit} for presenting the Qt reference
documentation. The following sections provide brief introductions to the
available technologies for creating user interfaces, and a comparison table
to help choosing the best suitable technology.
\section1 QML Graphical User Interfaces
QML allows developers to build user interfaces in a declarative way. User
interfaces specifically benefit from the simplicity of compounding QML objects
and configuring them using property bindings.
\l{Qt Quick} is a module which supplies QML types for creating user interfaces
such as a visual canvas with its own coordinate system and rendering engine.
Animation and transition effects are a first class concept in Qt Quick and
visual effects can be supplemented through specialized components for particle
and shader effects.
\section2 Important UI Topics for QML Applications
\list
\li \l{qtquick-usecase-visual.html}{Visual types in QML}
\li \l{qtquick-usecase-userinput.html}{Responding to User Input in QML}
\li \l{qtquick-usecase-animations.html}{Animations in QML}
\li \l{qtquick-usecase-text.html}{Displaying Text in QML}
\li \l{qtquick-usecase-layouts.html}{Layouts in QML}
\li \l{qtquick-usecase-styling.html}{Style and Theme Support}
\li \l{qtquick-usecase-integratingjs.html}{Integrating JavaScript in QML}
\endlist
\section2 Graphical Controls
The \l{Qt Quick Controls} module is new in Qt 5.1 and provides a
set of UI elements to create user interfaces using \l{Qt Quick} 2.
For more about how to create application user interfaces with QML, visit the
\l{QML User Interfaces} page.
\section1 Qt Widgets
\l {Qt Widgets} are traditional user interface elements that are typically found
in desktop environments. The widgets integrate well to the underlying platform
providing native look'n'feel on Windows, Linux and Mac OSX. The widgets are mature
and feature rich user interface elements suitable for mostly static user interfaces.
In contrast to \l {Qt Quick}, the widgets do not scale that well for touch screens
and fluid, highly animated modern user interfaces. The widgets are a good choice
for applications with traditional desktop centric user interfaces, such as office
type applications.
\section2 Important Concepts in Qt Widgets
\list
\li \l{mainwindow.html}{Application Main Window}
\li \l{desktop-integration.html}{Desktop Integration}
\li \l{dialogs.html}{Dialog Windows}
\li \l{layout.html}{Layout Management}
\li \l{model-view-programming.html}{Model/View Programming}
\li \l{richtext.html}{Rich Text Processing}
\li \l{dnd.html}{Drag and Drop}
\li \l{Internationalization with Qt}{Internationalization}
\endlist
\section1 Displaying Web Content
Qt provides a \l{http://www.webkit.org/}{WebKit}-based layout engine
with support for a wide range of standard web techologies such as HTML, CSS and
JavaScript, that make it possible to embed content from the World Wide Web into
your Qt application. Qt features both WebKit-based QML and C++ APIs.
\l{Qt WebKit} displays web content through the \l WebView QML type while the
\l{Qt WebKit Widgets} features a C++ API to render and interact with web
content.
The main difference between the two APIs is that WebView utilizes a multi-
process architecture, \l{http://trac.webkit.org/wiki/WebKit2}{WebKit2}, with a
separate web rendering process. The C++ API uses the previous version of WebKit,
which has a single-process architecture.
See also \l {Integrating Web Content}.
\section1 Comparison
Notice that choosing the appropriate technology for building an user interface
is not always black and white, but may depend on several criterias, such as other
existing technologies used in a project or even target platform constraints. To
some extent, many items in the following table can be implemented using any of
the three available technologies. The following table merely aims to help you
choose the best suited tool for the job.
\table
\header
\li
\li Qt Quick / Qt Quick Controls
\li Qt Widgets
\li Qt WebKit
\li Comments
\row
\li Used language(s)
\li QML/JS
\li C++
\li HTML/CSS/JS
\li
\row
\li Native look'n'feel
\li X
\li X
\li
\li Qt Widgets and Qt Quick Controls integrate well to the underlying
platform, providing a native look'n'feel on Windows, Linux, and Mac OS X.
\row
\li Custom look'n'feel
\li X
\li
\li (X)
\li Qt Widgets provide means for customization via style sheets,
but Qt Quick is a better performing choice for user interfaces
that do not aim to look native.
\row
\li Fluid animated UIs
\li X
\li
\li
\li Qt Widgets do not scale well for animations, and Qt WebKit's CSS3
animations are not as powerful as Qt Quick animations. Qt Quick
offers a convenient and natural way to implement animations in a
declarative manner.
\row
\li Touch screen
\li X
\li
\li
\li Qt Widgets often require a mouse cursor for good interaction, whereas
Qt Quick only provides primitive building blocks that were designed
with touch interaction in mind.
The WebView Qt Quick component has support for multi-touch gestures
to interact with web content.
\row
\li Standard industry widgets
\li
\li X
\li
\li Qt Widgets provide all the bells and whistles, developed over two
decades, needed for building standard industry type applications.
Qt WebKit Widgets provide widgets and additional classes to render
and interact with web content.
\row
\li Model/View programming
\li (X)
\li X
\li
\li Some MVC like concepts exist in Qt WebKit, Qt Quick provides convenient
views, but Qt Widgets provide more convenient and complete frameworks.
In addition to Qt Quick views, Qt Quick Controls provide a TableView.
\row
\li Rapid UI development
\li X
\li
\li (X)
\li Thanks to its superior productivity, Qt Quick is an excellent choice
for rapid UI prototyping and development.
\row
\li HW accelerated graphics
\li X
\li
\li
\li Qt Widgets provide QGLWidget for rendering OpenGL graphics,
and Qt WebKit supports WebGL, but the OpenGL ES 2.0 or OpenGL 2.0
based \l {Qt Quick Scene Graph} has proven to provide the best
performance for UIs and for integrating with OpenGL content.
\row
\li Graphical effects
\li X
\li
\li
\li The particle system and shader effects available in Qt Quick
are more flexible compared to CSS Effects and Shaders available
in Qt WebKit. Qt Widgets offer very little in this area.
\row
\li Rich text processing
\li X
\li X
\li
\li Qt Widgets currently provide the most comprehensive base for implementing
text editors. Qt's rich text document classes can also be utilized in
Qt Quick and Qt Quick Controls' TextArea, but may require some C++
implementation.
\row
\li Existing web content
\li
\li
\li X
\li Both Qt Quick and Qt Widgets prodive components for presenting
\l {richtext-html-subset.html}{simple rich text}, but Qt WebKit
is the right choice for presenting full-blown web content.
\endtable
\section1 Internationalization and Translations
Qt provides excellent support for translating applications into local languages.
Release managers, translators, and developers can use Qt translation tools to
accomplish their tasks.
\list
\li \l{Internationalization with Qt} - instructions and the process of creating
localized applications.
\li \l{Qt Linguist Manual} - manual of Qt's translation tool
\endlist
*/
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