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/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** 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 The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/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 qtwebengine-features.html
\title Qt WebEngine Features
\brief Summarizes Qt WebEngine features.
Qt WebEngine supports the following features:
\list
\li \l{Audio and Video Codecs}
\li \l{Chromium DevTools}
\li \l{Drag and Drop}
\li \l{Fullscreen}
\li \l{HTML5 DRM}
\li \l{HTML5 Geolocation}
\li \l{HTTP/2 Protocol}
\li \l{Native Dialogs}
\li \l{Pepper Plugin API}
\li \l{Print to PDF}
\li \l{Spellchecker}
\li \l{Touch}
\li \l{View Source}
\li \l{WebRTC}
\endlist
\section1 Audio and Video Codecs
Qt WebEngine supports the MPEG-4 Part 14 (MP4) file format only if the
required proprietary audio and video codecs, such as H.264 and MPEG layer-3
(MP3), have been enabled. Proprietary codecs can be enabled by passing the
following option when configuring Qt:
\code
-proprietary-codecs
\endcode
\warning When distributing proprietary codec libraries, you must acquire
licenses for them.
\l FFmpeg is a cross-platform solution to record, convert, and stream audio
and video. It can be configured for use with several codecs, which rises
licensing issues during distribution with the codec libraries. For some
codecs, open source implementations, such as \l{OpenH264 Project Homepage}
{OpenH264}, are available.
\section1 Chromium DevTools
The Chromium DevTools provide the ability to inspect and debug layout and
performance issues of any web content.
This feature can be tested by launching a Qt WebEngine application with the
command line option \c {--remote-debugging-port=[your-port]} or by setting
the environment variable \c QTWEBENGINE_REMOTE_DEBUGGING, and then using a
Chromium based browser (such as \l{WebEngine Widgets Simple Browser Example}
{Simple Browser} or \l{WebEngine Quick Nano Browser}{Nano Browser}) to connect
to \c {http://localhost:[your-port]}.
For more information, see \l {Qt WebEngine Debugging and Profiling}.
\section1 Drag and Drop
Qt WebEngine supports HTML5 drag and drop.
This feature can be tested by opening an HTML5 drag and drop demo, such as
\l{HTML5 Demos - Drag and Drop}, \l{HTML5 Demos - Simple Drag and Drop}, or
\l{HTML5 Demos - Drag and Drop, Automatic Upload}, in \l{WebEngine Widgets
Simple Browser Example}{Simple Browser} or \l{WebEngine Quick Nano Browser}
{Nano Browser}.
Dragging files into the browser is not actually part of HTML5, but it is
supported. It can be tested by opening \l{HTML5 Demos - File API}.
Support for this feature was added in Qt 5.7.0.
\section1 Fullscreen
Qt WebEngine supports viewing web content in fullscreen mode. For more
information, see \l{WebEngineSettings::fullscreenSupportEnabled}
{WebEngineSettings.fullscreenSupportEnabled},
\l{WebEngineView::fullScreenRequested}{WebEngineView.fullScreenRequested},
QWebEngineSettings::FullScreenSupportEnabled, and
QWebEnginePage::fullScreenRequested.
This feature can be tested by playing a video from YouTube in \l{WebEngine
Widgets Video Player Example}{Video Player} or \l{WebEngine Quick Nano Browser}
{Nano Browser}, and clicking the full screen icon to go into fullscreen
mode.
Support for this feature was added in Qt 5.6.0.
\section1 HTML5 DRM
Qt WebEngine supports viewing DRM protected videos if the \l{Widevine DRM}
plugin has been installed.
The video format most commonly used by DRM services, H.264, requires
proprietary audio and video codecs. For more information about enabling the
codecs, see \l{Audio and Video Codecs}.
This feature can be tested by playing a video in \l{WebEngine Widgets Simple Browser
Example}{Simple Browser} or \l{WebEngine Quick Nano Browser}{Nano Browser}
from \l{castLabs}, \l{Swank Motion Pictures, Inc.}, or \l{Shaka Player}.
Support for this feature was added in Qt 5.7.0.
\section1 HTML5 Geolocation
Qt WebEngine supports JavaScript Geolocation API with \l {Qt Location} as a
backend. The application has to explicitly allow the feature by using
QWebEnginePage::Geolocation or \l{WebEngineView::Feature}
{WebEngineView.Feature}.
If Qt Location has been built before Qt WebEngine then this feature can be
tested by using \l{WebEngine Widgets Maps Example}{Maps} and allowing it to
find the current position of the user. Note that on Windows an external GPS
receiver must be connected to the application. For more information, see
\l{Qt Positioning}.
Support for this feature was added in Qt 5.5.0.
\section1 HTTP/2 Protocol
Qt WebEngine supports the Chromium implementation of the \l{HTTP/2}
protocol.
This feature can be tested by opening an HTTP/2 demo, such as the
\l{Akamai HTTP/2 Demo}, in \l{WebEngine Widgets Simple Browser Example}
{Simple Browser} or \l{WebEngine Quick Nano Browser}{Nano Browser}.
\section1 Native Dialogs
A web page might request dialogs for the following functions:
\list
\li Entering user credentials for HTTP and proxy authentication
\li Displaying JavaScript alerts, confirmation dialogs, and prompts
\li Picking colors
\li Selecting files
\li Displaying form validation messages
\endlist
Qt WebEngine provides standard dialogs for these functions. In widget-based
applications, the standard dialogs are based on QDialog, whereas in Qt Quick
applications, they can be based either on Qt Quick Controls 1 or Qt Quick
Controls 2 (since Qt 5.8). The latter are used only on \c eglfs platforms.
To explicitly force either dialogs based on Qt Quick Controls 1 or Qt Quick
Controls 2, set the \c QTWEBENGINE_DIALOG_SET environment variable to either
\c{QtQuickControls1} or \c{QtQuickControls2}.
Qt WebEngine Widgets dialogs can be customized by reimplementing the
QWebEnginePage::chooseFiles(), QWebEnginePage::javaScriptAlert(),
QWebEnginePage::javaScriptConfirm(), and QWebEnginePage::javaScriptPrompt()
functions.
Since Qt 5.8, Qt Quick dialogs can be customized by connecting to the
WebEngineView::authenticationDialogRequested(),
WebEngineView::javaScriptDialogRequested(),
WebEngineView::colorDialogRequested(),
WebEngineView::fileDialogRequested(), and
WebEngineView::formValidationMessageRequested() signals. For an example,
see \l{WebEngine Qt Quick Custom Dialogs Example}.
\section1 Pepper Plugin API
Qt WebEngine supports loading Pepper Plugin API (PPAPI) plugins if
WebEngineSettings::pluginsEnabled or QWebEngineSettings::PluginsEnabled
is set.
Except for the Adobe Flash Player plugin, the plugins must be loaded
manually using the Chromium command line syntax with the
\c --register-pepper-plugins argument. The argument value is a list of
entries, separated by commas, that contain the file path and one or several
MIME types, separated by semicolons:
\code
<file-path-plugin1>;<mime-type-plugin1>,<file-path-plugin2>;<mime-type1-plugin2>;<mime-type2-plugin2>
\endcode
For example:
\code
--register-pepper-plugins="libppapi_example.so;application/x-ppapi-example"
\endcode
The MIME type is important because it determines which embeds the plugin is
used for.
Support for this feature was added in Qt 5.6.0.
\section2 Pepper Flash Player Plugin Support
The Pepper Flash player plugin can be loaded automatically if it is
installed in one of the following locations, depending on the platform:
\list
\li Windows
\code
C:\Windows\SysWOW64\Macromed\Flash\pepflashplayer*.dll
C:\Windows\System32\Macromed\Flash\pepflashplayer*.dll
\endcode
\li OS X
\code
/Library/Internet Plug-Ins/PepperFlashPlayer/PepperFlashPlayer.plugin
\endcode
\li Linux
\code
/usr/lib/pepperflashplugin-nonfree/libpepflashplayer.so
/usr/lib/adobe-flashplugin/libpepflashplayer.so
/usr/lib/PepperFlash/libpepflashplayer.so
/usr/lib64/chromium/PepperFlash/libpepflashplayer.so
\endcode
\endlist
You can also load the Pepper Flash player from a specific location by using
command line arguments:
\code
--ppapi-flash-path=./libpepflashplayer.so
\endcode
By default, the Flash version is set to \c{11.2.999.999}. You can use the
\c{ppapi-flash-version=} argument to set another Flash version in the
format \c{major.minor.build.revision}:
\code
--ppapi-flash-version=16.0.0.235
\endcode
This feature can be tested in \l{WebEngine Widgets Simple Browser Example}{Simple Browser}
or \l{WebEngine Quick Nano Browser}{Nano Browser} if the Adobe Flash PPAPI
plugin is installed and plugins are enabled in the browser. To test the
feature, the \c https://helpx.adobe.com/flash-player.html page can be opened
in the browser.
\section1 Print to PDF
Qt WebEngine supports printing a web page to a PDF file. For more
information, see QWebEnginePage::printToPdf() and
\l{WebEngineView::printToPdf}{WebEngineView.printToPdf}.
This feature can be tested using \l{WebEngine Widgets Html2Pdf Example}
{Html2Pdf}.
Support for this feature was added in Qt 5.7.0.
\section1 Spellchecker
Qt WebEngine supports integrating spellchecking support into HTML forms to
enable users to submit spellchecked messages. When the user clicks on
an underlined misspelled word, the default context menu displays up to four
suggestions. Selecting one will replace the misspelled word.
To be able to check the spelling, the spellchecker needs dictionaries. It
supports dictionaries from the \l{Hunspell project}, but they have to be
compiled into a special binary format. A Hunspell dictionary consists of two
files:
\list
\li A \c .dic file that is a dictionary containing words for the
language
\li An \c .aff file that defines the meaning of special flags in the
dictionary
\endlist
These two files can be converted into the \c bdic format by using the
\c qwebengine_convert_dict tool that is shipped together with Qt.
When the Qt WebEngine spellchecker initializes, it will try to load the
\c bdict dictionaries and to check them for consistency.
If \c QTWEBENGINE_DICTIONARIES_PATH is set, the spellchecker uses the
dictionaries in the specified directory without looking anywere else.
Otherwise, it uses the \e qtwebengine_dictionaries directory relative to the
executable if it exists. If it does not exist, it will look in \c
QT_INSTALL_PREFIX/qtwebengines_dictionaries.
On macOS, depending on how Qt WebEngine is configured at build time, there
are two possibilities how spellchecking data is found:
\list
\li Hunspell dictionaries (default) - .bdic dictionaries are used, just
like on other platforms
\li Native dictionaries - the macOS spellchecking APIs are used (which
means the results will depend on the installed OS dictionaries)
\endlist
Thus, in the macOS Hunspell case, Qt WebEngine will look in the \e
qtwebengine_dictionaries subdirectory located inside the application bundle
\c Resources directory, and also in the \c Resources directory located
inside the Qt framework bundle.
To summarize, in case of Hunspell usage, the following paths are considered:
\list
\li \c QTWEBENGINE_DICTIONARIES_PATH, if set
\li QCoreApplication::applicationDirPath()/qtwebengine_dictionaries
or QCoreApplication::applicationDirPath()/../Contents/Resources/qtwebengine_dictionaries
(on macOS)
\li [QLibraryInfo::DataPath]/qtwebengine_dictionaries
or path/to/QtWebEngineCore.framework/Resources/qtwebengine_dictionaries (Qt framework
bundle on macOS)
\endlist
Spellchecking is disabled by default and can be enabled per profile by
using the QWebEngineProfile::setSpellCheckEnabled() method in widget-based
applications and the \l {QQuickWebEngineProfile::spellCheckEnabled}
{WebEngineProfile.spellCheckEnabled} property in Qt Quick applications.
The current language used for spellchecking is defined per profile, and can
be set using the QWebEngineProfile::setSpellCheckLanguages() method or the
\l {QQuickWebEngineProfile::spellCheckLanguages}
{WebEngineProfile.spellCheckLanguages} property.
This feature can be tested by building and running the
\l{WebEngine Widgets Spellchecker Example}{Spellchecker Example}.
Support for this feature was added in Qt 5.8.0.
\section1 Touch
Qt WebEngine supports touch devices for navigating and interacting with web pages.
Applications can prohibit the use of touch events in the following ways:
\list
\li Passing the flag \c --touch-events=disabled on the command line will disable touch event
support in JavaScript API (meaning \c ontouchstart and related handlers will not be present
in the \c document.window object). Touch events will still be delivered to web pages.
\li Installing an event filter object using \l {QObject::installEventFilter} on the WebEngine
view focus proxy object, and filtering out all touch events.
\endlist
\section1 View Source
Qt WebEngine supports viewing the HTML source of a web page.
This feature can be used from custom menus or assigned to custom events.
For more information, see WebEngineView::WebAction, and QWebEnginePage::WebAction.
This feature can be tested by opening a web page in \l{WebEngine Widgets
Simple Browser Example}{Simple Browser} or \l{WebEngine Quick Nano Browser}
{Nano Browser}, and then selecting \c{Page Source} in the context menu. The
\c{Page Source} context menu entry opens the source view in a new tab.
For opening the source view in the current tab, URLs with \l{view-source URI scheme}
are also supported. For example, you can type the following URL to the URL bar
to view the HTML source of the qt.io web page:
\code
view-source:https://www.qt.io/
\endcode
Auto-completion of incomplete URLs with \l{view-source URI scheme} makes the usage of
this feature more comfortable. For example, the following incomplete URL also loads
the source view of the qt.io web page:
\code
view-source:qt.io
\endcode
Support for this feature was added in Qt 5.8.0.
\section1 WebRTC
WebRTC provides browsers with Real-Time Communications (RTC) capabilities
via simple APIs. For more information, see \l{WebEngineView::Feature}
{WebEngineView.Feature} and QWebEnginePage::Feature.
This feature can be tested by setting up a webcam or microphone and then
opening \c https://test.webrtc.org/ in \l{WebEngine Widgets Simple Browser
Example}{Simple Browser} or \l{WebEngine Quick Nano Browser}{Nano Browser}.
*/
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