- Qt 5.3
- Qt Multimedia Widgets
- Video Graphics Item Example
- videoplayer.cpp Example File
- Qt 5.3.2 Reference Documentation

# videoplayer.cpp Example File

videographicsitem/videoplayer.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
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    **   * Redistributions of source code must retain the above copyright
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    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
    **     of its contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
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    #include "videoplayer.h"

    #include <QtWidgets>
    #include <QVideoSurfaceFormat>
    #include <QGraphicsVideoItem>

    VideoPlayer::VideoPlayer(QWidget *parent)
        : QWidget(parent)
        , mediaPlayer(0, QMediaPlayer::VideoSurface)
        , videoItem(0)
        , playButton(0)
        , positionSlider(0)
    {
        videoItem = new QGraphicsVideoItem;
        videoItem->setSize(QSizeF(640, 480));

        QGraphicsScene *scene = new QGraphicsScene(this);
        QGraphicsView *graphicsView = new QGraphicsView(scene);

        scene->addItem(videoItem);

        QSlider *rotateSlider = new QSlider(Qt::Horizontal);
        rotateSlider->setRange(-180,  180);
        rotateSlider->setValue(0);

        connect(rotateSlider, SIGNAL(valueChanged(int)),
                this, SLOT(rotateVideo(int)));

        QAbstractButton *openButton = new QPushButton(tr("Open..."));
        connect(openButton, SIGNAL(clicked()), this, SLOT(openFile()));

        playButton = new QPushButton;
        playButton->setEnabled(false);
        playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

        connect(playButton, SIGNAL(clicked()),
                this, SLOT(play()));

        positionSlider = new QSlider(Qt::Horizontal);
        positionSlider->setRange(0, 0);

        connect(positionSlider, SIGNAL(sliderMoved(int)),
                this, SLOT(setPosition(int)));

        QBoxLayout *controlLayout = new QHBoxLayout;
        controlLayout->setMargin(0);
        controlLayout->addWidget(openButton);
        controlLayout->addWidget(playButton);
        controlLayout->addWidget(positionSlider);

        QBoxLayout *layout = new QVBoxLayout;
        layout->addWidget(graphicsView);
        layout->addWidget(rotateSlider);
        layout->addLayout(controlLayout);

        setLayout(layout);

        mediaPlayer.setVideoOutput(videoItem);
        connect(&mediaPlayer, SIGNAL(stateChanged(QMediaPlayer::State)),
                this, SLOT(mediaStateChanged(QMediaPlayer::State)));
        connect(&mediaPlayer, SIGNAL(positionChanged(qint64)), this, SLOT(positionChanged(qint64)));
        connect(&mediaPlayer, SIGNAL(durationChanged(qint64)), this, SLOT(durationChanged(qint64)));
    }

    VideoPlayer::~VideoPlayer()
    {
    }

    void VideoPlayer::openFile()
    {
        QString fileName = QFileDialog::getOpenFileName(this, tr("Open Movie"),QDir::homePath());

        if (!fileName.isEmpty()) {
            mediaPlayer.setMedia(QUrl::fromLocalFile(fileName));

            playButton->setEnabled(true);
        }
    }

    void VideoPlayer::play()
    {
        switch(mediaPlayer.state()) {
        case QMediaPlayer::PlayingState:
            mediaPlayer.pause();
            break;
        default:
            mediaPlayer.play();
            break;
        }
    }

    void VideoPlayer::mediaStateChanged(QMediaPlayer::State state)
    {
        switch(state) {
        case QMediaPlayer::PlayingState:
            playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
            break;
        default:
            playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
            break;
        }
    }

    void VideoPlayer::positionChanged(qint64 position)
    {
        positionSlider->setValue(position);
    }

    void VideoPlayer::durationChanged(qint64 duration)
    {
        positionSlider->setRange(0, duration);
    }

    void VideoPlayer::setPosition(int position)
    {
        mediaPlayer.setPosition(position);
    }

    void VideoPlayer::rotateVideo(int angle)
    {
        //rotate around the center of video element
        qreal x = videoItem->boundingRect().width() / 2.0;
        qreal y = videoItem->boundingRect().height() / 2.0;
        videoItem->setTransform(QTransform().translate(x, y).rotate(angle).translate(-x, -y));
    }