[Interest] QAbstractVideoSurface as viewfinder on iOS

[Igor Mironchik]

Hi guys,

I decided to implement my custom video surface and use it as view finder 
with QCamera.

I wrote:

ViewFinderSurface::ViewFinderSurface( const QCamera & camera, QObject * 
parent )
     :    QAbstractVideoSurface( parent )
     ,    m_camera( camera )
{
}

bool
ViewFinderSurface::present( const QVideoFrame & frame )
{
     if( !isActive() )
         return false;

     qDebug() << "FRAME" << frame.bits() << frame.width() << 
frame.height() << frame.bytesPerLine();

     QImage image( frame.bits(), frame.width(), frame.height(), 
frame.bytesPerLine(),
         QVideoFrame::imageFormatFromPixelFormat( frame.pixelFormat() ) );

     qDebug() << "IMAGE is NULL" << image.isNull();

     QCameraInfo cameraInfo( m_camera );

     const QScreen * screen = QGuiApplication::primaryScreen();
     const int screenAngle = screen->angleBetween( 
screen->nativeOrientation(),
         screen->orientation() );

     int rotation = 0;

     if( cameraInfo.position() == QCamera::BackFace )
         rotation = ( cameraInfo.orientation() - screenAngle ) % 360;
     else
         rotation = ( 360 - cameraInfo.orientation() + screenAngle ) % 360;

     image = image.transformed( QTransform().rotate( rotation ) );

     emit newFrame( QPixmap::fromImage( image ) );

     return true;
}

QList< QVideoFrame::PixelFormat >
ViewFinderSurface::supportedPixelFormats( 
QAbstractVideoBuffer::HandleType type ) const
{
     Q_UNUSED( type )

     return QList< QVideoFrame::PixelFormat > ()
         << QVideoFrame::Format_ARGB32
         << QVideoFrame::Format_ARGB32_Premultiplied
         << QVideoFrame::Format_RGB32
         << QVideoFrame::Format_RGB24
         << QVideoFrame::Format_RGB565
         << QVideoFrame::Format_RGB555
         << QVideoFrame::Format_ARGB8565_Premultiplied
         << QVideoFrame::Format_BGRA32
         << QVideoFrame::Format_BGRA32_Premultiplied
         << QVideoFrame::Format_BGR32
         << QVideoFrame::Format_BGR24
         << QVideoFrame::Format_BGR565
         << QVideoFrame::Format_BGR555
         << QVideoFrame::Format_BGRA5658_Premultiplied
         << QVideoFrame::Format_AYUV444
         << QVideoFrame::Format_AYUV444_Premultiplied
         << QVideoFrame::Format_YUV444
         << QVideoFrame::Format_YUV420P
         << QVideoFrame::Format_YV12
         << QVideoFrame::Format_UYVY
         << QVideoFrame::Format_YUYV
         << QVideoFrame::Format_NV12
         << QVideoFrame::Format_NV21
         << QVideoFrame::Format_IMC1
         << QVideoFrame::Format_IMC2
         << QVideoFrame::Format_IMC3
         << QVideoFrame::Format_IMC4
         << QVideoFrame::Format_Y8
         << QVideoFrame::Format_Y16
         << QVideoFrame::Format_Jpeg
         << QVideoFrame::Format_CameraRaw
         << QVideoFrame::Format_AdobeDng;
}

But I always receive empty QVideoFrame... What's wrong?