- Qt 5.5
- Qt Multimedia
- QML Video Shader Effects Example
- main.cpp Example File
- Qt 5.5.1 Reference Documentation

# main.cpp Example File

video/qmlvideofx/main.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the Qt Mobility Components.
    **
    ** $QT_BEGIN_LICENSE:LGPL21$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
    ** accordance with the commercial license agreement provided with the
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    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 2.1 or version 3 as published by the Free
    ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
    ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
    ** following information to ensure the GNU Lesser General Public License
    ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
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    #include <QtCore/QStandardPaths>
    #include <QtCore/QStringList>
    #include <QtQml/QQmlContext>
    #include <QtGui/QGuiApplication>
    #include <QtQuick/QQuickItem>
    #include <QtQuick/QQuickView>
    #include "filereader.h"
    #include "trace.h"

    #ifdef PERFORMANCEMONITOR_SUPPORT
    #include "performancemonitordeclarative.h"
    #endif

    int main(int argc, char *argv[])
    {
        QGuiApplication app(argc, argv);

    #ifdef PERFORMANCEMONITOR_SUPPORT
        PerformanceMonitor::qmlRegisterTypes();
    #endif

        QUrl fileName;
        qreal volume = 0.5;
        QStringList args = app.arguments();
    #ifdef PERFORMANCEMONITOR_SUPPORT
        PerformanceMonitor::State performanceMonitorState;
    #endif
        for (int i = 1; i < args.size(); ++i) {
            const QByteArray arg = args.at(i).toUtf8();
            if (arg.startsWith('-')) {
                if ("-volume" == arg) {
                    if (i + 1 < args.size())
                        volume = 0.01 * args.at(++i).toInt();
                    else
                        qtTrace() << "Option \"-volume\" takes a value";
                }
    #ifdef PERFORMANCEMONITOR_SUPPORT
                else if (performanceMonitorState.parseArgument(arg)) {
                    // Do nothing
                }
    #endif
                else {
                    qtTrace() << "Option" << arg << "ignored";
                }
            } else {
                if (fileName.isEmpty())
                    fileName = QUrl::fromLocalFile(arg);
                else
                    qtTrace() << "Argument" << arg << "ignored";
            }
        }

        QQuickView viewer;

        viewer.setSource(QUrl(QLatin1String("qrc:///qml/qmlvideofx/Main.qml")));
        QQuickItem *rootObject = viewer.rootObject();
        rootObject->setProperty("fileName", fileName);
        viewer.rootObject()->setProperty("volume", volume);

    #ifdef PERFORMANCEMONITOR_SUPPORT
        if (performanceMonitorState.valid) {
            rootObject->setProperty("perfMonitorsLogging", performanceMonitorState.logging);
            rootObject->setProperty("perfMonitorsVisible", performanceMonitorState.visible);
        }
        QObject::connect(&viewer, SIGNAL(afterRendering()),
                         rootObject, SLOT(qmlFramePainted()));
    #endif

        FileReader fileReader;
        viewer.rootContext()->setContextProperty("fileReader", &fileReader);

        const QUrl appPath(QUrl::fromLocalFile(app.applicationDirPath()));
        const QStringList picturesLocation = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);
        const QUrl imagePath = picturesLocation.isEmpty() ? appPath : QUrl::fromLocalFile(picturesLocation.first());
        viewer.rootContext()->setContextProperty("imagePath", imagePath);

        const QStringList moviesLocation = QStandardPaths::standardLocations(QStandardPaths::MoviesLocation);
        const QUrl videoPath = moviesLocation.isEmpty() ? appPath : QUrl::fromLocalFile(moviesLocation.first());
        viewer.rootContext()->setContextProperty("videoPath", videoPath);

        viewer.setTitle("qmlvideofx");
        viewer.setFlags(Qt::Window | Qt::WindowSystemMenuHint | Qt::WindowTitleHint |
                              Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint);
        viewer.setMinimumSize(QSize(1280, 720));
        viewer.setResizeMode(QQuickView::SizeRootObjectToView);

        viewer.show();

        // Delay invocation of init until the event loop has started, to work around
        // a GL context issue on Harmattan: without this, we get the following error
        // when the first ShaderEffectItem is created:
        // "QGLShaderProgram::addShader: Program and shader are not associated with same context"
        QMetaObject::invokeMethod(viewer.rootObject(), "init", Qt::QueuedConnection);

        return app.exec();
    }