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# videoplayer.cpp Example File
multimedia/videographicsitem/videoplayer.cpp

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     ** General Public License version 3.0 as published by the Free Software
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     #include "videoplayer.h"
     #include "videoitem.h"

     #include <QtMultimedia>

     #ifndef QT_NO_OPENGL
     # include <QtOpenGL/QGLWidget>
     #endif

     VideoPlayer::VideoPlayer(QWidget *parent, Qt::WindowFlags flags)
         : QWidget(parent, flags)
         , videoItem(0)
         , playButton(0)
         , positionSlider(0)
     {
         connect(&movie, SIGNAL(stateChanged(QMovie::MovieState)),
                 this, SLOT(movieStateChanged(QMovie::MovieState)));
         connect(&movie, SIGNAL(frameChanged(int)),
                 this, SLOT(frameChanged(int)));

         videoItem = new VideoItem;

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

     #ifndef QT_NO_OPENGL
         graphicsView->setViewport(new QGLWidget);
     #endif

         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)));

         connect(&movie, SIGNAL(frameChanged(int)),
                 positionSlider, SLOT(setValue(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);
     }

     VideoPlayer::~VideoPlayer()
     {
     }

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

         if (!fileName.isEmpty()) {
             videoItem->stop();

             movie.setFileName(fileName);

             playButton->setEnabled(true);
             positionSlider->setMaximum(movie.frameCount());

             movie.jumpToFrame(0);
         }
     }

     void VideoPlayer::play()
     {
         switch(movie.state()) {
         case QMovie::NotRunning:
             movie.start();
             break;
         case QMovie::Paused:
             movie.setPaused(false);
             break;
         case QMovie::Running:
             movie.setPaused(true);
             break;
         }
     }

     void VideoPlayer::movieStateChanged(QMovie::MovieState state)
     {
         switch(state) {
         case QMovie::NotRunning:
         case QMovie::Paused:
             playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
             break;
         case QMovie::Running:
             playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
             break;
         }
     }

     void VideoPlayer::frameChanged(int frame)
     {
         if (!presentImage(movie.currentImage())) {
             movie.stop();
             playButton->setEnabled(false);
             positionSlider->setMaximum(0);
         } else {
             positionSlider->setValue(frame);
         }
     }

     void VideoPlayer::setPosition(int frame)
     {
         movie.jumpToFrame(frame);
     }

     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));
     }

     bool VideoPlayer::presentImage(const QImage &image)
     {
         QVideoFrame frame(image);

         if (!frame.isValid())
             return false;

         QVideoSurfaceFormat currentFormat = videoItem->surfaceFormat();

         if (frame.pixelFormat() != currentFormat.pixelFormat()
                 || frame.size() != currentFormat.frameSize()) {
             QVideoSurfaceFormat format(frame.size(), frame.pixelFormat());

             if (!videoItem->start(format))
                 return false;
         }

         if (!videoItem->present(frame)) {
             videoItem->stop();

             return false;
         } else {
             return true;
         }
     }