09fea23419
The correct paths are relative to: - <reporoot>/examples/<module>, or - <reporoot>/src/<module> Removing the module specifier fixes these links/quotes. Change-Id: I6be4f28c44bd26361b60a394158b0e6cc46b1ec0 Reviewed-by: Laszlo Papp <lpapp@kde.org> Reviewed-by: Yoann Lopes <yoann.lopes@digia.com> Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
149 lines
5.4 KiB
Plaintext
149 lines
5.4 KiB
Plaintext
/****************************************************************************
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**
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** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
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** Contact: http://www.qt-project.org/legal
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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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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and Digia. For licensing terms and
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** conditions see http://qt.digia.com/licensing. For further information
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** use the contact form at http://qt.digia.com/contact-us.
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**
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** GNU Free Documentation License Usage
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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. Please review the following information to ensure
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** the GNU Free Documentation License version 1.3 requirements
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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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\ingroup multimedia_examples
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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 items:
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\list
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\li Two \l{video/qmlvideo/qml/qmlvideo/Button.qml}{Button} instances, 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}
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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} item ...
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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 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
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\l{video/qmlvideo/qml/qmlvideo/Content.qml}{Content}.
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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 camera content
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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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instance, 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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\input multimedia/doc/src/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 QGuiApplication
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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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