Video Graphics Item Example

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#include "videoplayer.h"

#include <QtWidgets>
#include <QGraphicsVideoItem>

VideoPlayer::VideoPlayer(QWidget *parent)
    : QWidget(parent)
{
    m_mediaPlayer = new QMediaPlayer(this, QMediaPlayer::VideoSurface);
    const QRect screenGeometry = QApplication::desktop()->screenGeometry(this);
    m_videoItem = new QGraphicsVideoItem;
    m_videoItem->setSize(QSizeF(screenGeometry.width() / 3, screenGeometry.height() / 2));

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

    scene->addItem(m_videoItem);

    QSlider *rotateSlider = new QSlider(Qt::Horizontal);
    rotateSlider->setToolTip(tr("Rotate Video"));
    rotateSlider->setRange(-180,  180);
    rotateSlider->setValue(0);

    connect(rotateSlider, &QAbstractSlider::valueChanged,
            this, &VideoPlayer::rotateVideo);

    QAbstractButton *openButton = new QPushButton(tr("Open..."));
    connect(openButton, &QAbstractButton::clicked, this, &VideoPlayer::openFile);

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

    connect(m_playButton, &QAbstractButton::clicked, this, &VideoPlayer::play);

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

    connect(m_positionSlider, &QAbstractSlider::sliderMoved,
            this, &VideoPlayer::setPosition);

    QBoxLayout *controlLayout = new QHBoxLayout;
    controlLayout->setMargin(0);
    controlLayout->addWidget(openButton);
    controlLayout->addWidget(m_playButton);
    controlLayout->addWidget(m_positionSlider);

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

    m_mediaPlayer->setVideoOutput(m_videoItem);
    connect(m_mediaPlayer, &QMediaPlayer::stateChanged,
            this, &VideoPlayer::mediaStateChanged);
    connect(m_mediaPlayer, &QMediaPlayer::positionChanged, this, &VideoPlayer::positionChanged);
    connect(m_mediaPlayer, &QMediaPlayer::durationChanged, this, &VideoPlayer::durationChanged);
}

VideoPlayer::~VideoPlayer()
{
}

QSize VideoPlayer::sizeHint() const
{
    return (m_videoItem->size() * qreal(3) / qreal(2)).toSize();
}

bool VideoPlayer::isPlayerAvailable() const
{
    return m_mediaPlayer->isAvailable();
}

void VideoPlayer::openFile()
{
    QFileDialog fileDialog(this);
    fileDialog.setAcceptMode(QFileDialog::AcceptOpen);
    fileDialog.setWindowTitle(tr("Open Movie"));
    const QStringList supportedMimeTypes = m_mediaPlayer->supportedMimeTypes();
    if (!supportedMimeTypes.isEmpty())
        fileDialog.setMimeTypeFilters(supportedMimeTypes);
    fileDialog.setDirectory(QStandardPaths::standardLocations(QStandardPaths::MoviesLocation).value(0, QDir::homePath()));
    if (fileDialog.exec() == QDialog::Accepted)
        load(fileDialog.selectedUrls().constFirst());
}

void VideoPlayer::load(const QUrl &url)
{
    m_mediaPlayer->setMedia(url);
    m_playButton->setEnabled(true);
}

void VideoPlayer::play()
{
    switch (m_mediaPlayer->state()) {
    case QMediaPlayer::PlayingState:
        m_mediaPlayer->pause();
        break;
    default:
        m_mediaPlayer->play();
        break;
    }
}

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

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

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

void VideoPlayer::setPosition(int position)
{
    m_mediaPlayer->setPosition(position);
}

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