d1b6bf5fac
QDoc now has support for Doxygen style commands for italics, bold and list items. This change applies that change in QDoc to the actual documentation. Task-number: QTBUG-24578 Change-Id: Iec1c616e0d9a915a31a661916805916e19495dc9 Reviewed-by: Michael Goddard <michael.goddard@nokia.com>
148 lines
5.0 KiB
Plaintext
148 lines
5.0 KiB
Plaintext
/****************************************************************************
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**
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** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
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** Contact: http://www.qt-project.org/
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:FDL$
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** GNU Free Documentation License
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** Alternatively, this file may be used under the terms of the GNU Free
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** Documentation License version 1.3 as published by the Free Software
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** Foundation and appearing in the file included in the packaging of
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** this file.
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**
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** Other Usage
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** Alternatively, this file may be used in accordance with the terms
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** and conditions contained in a signed written agreement between you
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** and Nokia.
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*!
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\example video/qmlvideo
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\title QML Video Example
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\brief The QML Video Example demonstrates the various manipulations (move;
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resize; rotate; change aspect ratio) which can be applied to QML \l{VideoOutput}
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items.
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\section1 Overview
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This example demonstrates the various manipulations (move; resize; rotate;
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change aspect ratio) which can be applied to QML \l{VideoOutput} items.
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It also shows how native code can be combined with QML to implement more
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advanced functionality - in this case, C++ code is used to calculate the QML
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frame rate. This value is rendered in QML in a semi-transparent item
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overlaid on the video content.
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The following image shows the application executing the video-overlay scene,
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which creates a dummy overlay item (just a semi-transparent \l{Rectangle}),
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which moves across the \l{VideoOutput} item.
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\image qmlvideo-overlay.png
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\section1 Application structure
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The \l{video/qmlvideo/qml/qmlvideo/main.qml} file creates a UI which includes
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the following elements:
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\list
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\li Two \l{video/qmlvideo/qml/qmlvideo/Button.qml}{Button} elements, each
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of which displays a filename, and can be used to launch a
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\l{video/qmlvideo/qml/qmlvideo/FileBrowser.qml}{FileBrowser}
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\li An exit \l{video/qmlvideo/qml/qmlvideo/Button.qml}{Button}
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\li A \l{video/qmlvideo/qml/qmlvideo/SceneSelectionPanel.qml}{SceneSelectionPanel},
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which is a flickable list displaying the available scenes
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\li At the lower left, an item which displays the QML repainting rate - the
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upper number is the instantaneous frame rate and the lower number is the
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average over the past second.
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\endlist
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\image qmlvideo-menu.png
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Each scene in the flickable list is implemented in its own QML file - for
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example the video-basic scene (which just displays a static \l{VideoOutput} element
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in the center of the screen) is implemented in the
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\l{video/qmlvideo/qml/qmlvideo/VideoBasic.qml}{VideoBasic.qml} file. As you
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can see from the code, this makes use of a type of inheritance: a
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\l{video/qmlvideo/qml/qmlvideo/VideoBasic.qml}{VideoBasic} element ...
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\quotefromfile video/qmlvideo/qml/qmlvideo/VideoBasic.qml
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\skipto import
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\printuntil /^\}/
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... is-a
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\l{video/qmlvideo/qml/qmlvideo/SceneBasic.qml}{SceneBasic} ...
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\quotefromfile examples/video/qmlvideo/qml/qmlvideo/SceneBasic.qml
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\skipto import
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\printuntil contentType
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\dots
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\skipto Content
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\printuntil content
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\dots
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\skipto }
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\printuntil /^\}/
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... which is-a
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\l{video/qmlvideo/qml/qmlvideo/Scene.qml}{Scene}:
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\quotefromfile video/qmlvideo/qml/qmlvideo/Scene.qml
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\skipto import
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\printuntil root
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\dots
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\skipto property QtObject content
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\printuntil content
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\dots
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\skipto Button
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\printuntil /^\}/
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\l{video/qmlvideo/qml/qmlvideo/SceneBasic.qml}{SceneBasic} describes the
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structure and behaviour of the scene, but is agnostic of the type of content
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which will be displayed - this is abstracted by the
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\l{video/qmlvideo/qml/qmlvideo/Content.qml}{Content} element.
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This pattern allows us to define a particular use case (in this case, simply
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display a static piece of content), and then instantiate that use case for
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both video content
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(\l{video/qmlvideo/qml/qmlvideo/VideoBasic.qml}{VideoBasic}) and cameracontent
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(\l{video/qmlvideo/qml/qmlvideo/CameraBasic.qml}{CameraBasic}). This approach
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is used to implement many of the other scenes - for example, "repeatedly slide
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the content from left to right and back again" is implemented by
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\l{video/qmlvideo/qml/qmlvideo/SceneMove.qml}{SceneMove}, on which
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\l{video/qmlvideo/qml/qmlvideo/VideoMove.qml}{VideoMove} and
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\l{video/qmlvideo/qml/qmlvideo/CameraMove.qml}{CameraMove} are based.
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Depending on the value of the contentType property in the top-level scene
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element, the embedded
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\l{video/qmlvideo/qml/qmlvideo/Content.qml}{Content} item creates either a
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\l{MediaPlayer} or a \l{Camera} item.
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\section1 Calculating and displaying QML painting rate
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\include examples/video-qml-paint-rate.qdocinc
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All that remains is to connect the afterRendering() signal of the QQuickView
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object to a JavaScript function, which will eventually call frequencyItem.notify():
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\quotefromfile video/qmlvideo/main.cpp
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\skipto QmlApplicationViewer
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\printuntil ;
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\dots
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\skipto QQuickItem
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\printuntil ;
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\dots
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\skipto QObject::connect
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\printuntil SLOT(qmlFramePainted()));
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*/
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