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/****************************************************************************
**
** Copyright (C) 2016 Pelagicore AG
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QmlLive tool.
**
** $QT_BEGIN_LICENSE:GPL-QTAS$
** Commercial License Usage
** Licensees holding valid commercial Qt Automotive Suite 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 https://www.qt.io/terms-conditions.
** For further information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
** SPDX-License-Identifier: GPL-3.0
**
****************************************************************************/
/*!
\example contentplugin
\title ContentPlugin Example
\brief Demonstrates how to write a Content Plugin for QmlLive
\image contentplugin-example.png Screenshot of the Plugin in Action
The plugin written in this example displays images like the
built-in Imageviewer in QmlLive, but it shows the content rotated
only works on *.png files.
We will start by reviewing the interface defined in \c
contentadapterinterface.h in the QmlLive source code. This
interface can be used to add a new ContentAdapter to QmlLive.
The ContentAdapter will be used to display any content that shouldn't be
handled by the QmlLive Runtime, like displaying an image.
\snippet contentadapterinterface.h 0
The \c ContentAdapterInterface class declares four functions. The first
function \c canAdapt(const QUrl&) returns whether the plugin can display the
given file or directory.
The second function \c adapt(const QUrl& url, QDeclarativeContext* context)
returns a custom QUrl which will be used by QmlLive to display the given QUrl.
The returned QUrl always has to point to a QML file used to display the content.
To be able to control the returned QML file, \c context can be used to set custom
properties which will be exported to the QML file.
canPreview() and preview() are used for generating preview thumbnails.
We use the easiest implementation for these two methods.
\section1 MyContentAdapterPlugin
\snippet contentplugin/mycontentadapterplugin.h 0
The MyContentAdapterPlugin implements the interface to QmlLive. It subclasses
QObject and the required \c ContentAdapterInterface.
\snippet contentplugin/mycontentadapterplugin.h 1
The \c Q_INTERFACES macro will be used to register the plugin to Qt's plugin
system.
We have to overload the \c canAdapt(const QUrl&) function if we want it to be
called for the right file type: \e *.png." That's why we check the file
ending on the given url and return true when it's a png file.
\snippet contentplugin/mycontentadapterplugin.cpp 0
If the plugin accepts the file, \c adapt(const QUrl& url, QDeclarativeContext* context)
will be called. Here we export the path to the image as a special property in the
context to be able to access the fileName from within our QML file.
Afterwards we return a QUrl pointing to our QML file which is inside a ResourceFile.
\snippet contentplugin/mycontentadapterplugin.cpp 1
Now only the implementation of canPreview() and preview() are missing. Here we just
add some dummy implementation because we don't want to add this functionality.
\snippet contentplugin/mycontentadapterplugin.cpp 2
\section1 plugin.qml
The plugin.qml file is our ImageViewer. In it we create an \c {Image Element} and
set the source to our exported property \c imageSource. The rotation property
will be set to 180.
\snippet contentplugin/plugin.qml 0
\section1 The Resource File
Because we don't want to fiddle around with paths, we include our QML file into
a resource file. It is important to use a unique prefix in the resource file in
order to avoid conflicts with QmlLive, which also uses resource files. The best
approach is to use the plugin name as a prefix.
*/
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