grab.cpp

#include "grab.h"

#include "tasks.h"

#include <vdr/device.h>

namespace vdrlive {

const unsigned int GrabMinIntervalMs = 500;
const unsigned int GrabPauseIntervalMs = GrabMinIntervalMs * 20;

class GrabImageTask: public StickyTask
{
public:
  explicit GrabImageTask( int quality = 80, int width = 729, int height = 480 )
    : m_firstTime( 0 )
    , m_lastTime( 0 )
    , m_quality( quality )
    , m_width( width )
    , m_height( height )
    {}

  void Activate() { m_firstTime = 0; }
  bool IsActive();

private:
  uint64_t m_firstTime;
  uint64_t m_lastTime;
  int m_quality;
  int m_width;
  int m_height;

  bool GrabImage();

  virtual void Action();
};

bool GrabImageTask::IsActive()
{
  cMutexLock lock( &LiveTaskManager() );
  return GrabImage();
}

bool GrabImageTask::GrabImage()
{
  cDevice* device = cDevice::PrimaryDevice();
  if ( device == 0 ) {
    SetError( tr("Couldn't acquire primary device") );
    return false;
  }

  int size = 0;
  uchar* image = device->GrabImage( size, true, m_quality, m_width, m_height );
  if ( image == 0 ) {
    SetError( tr("Couldn't grab image from primary device") );
    return false;
  }

  LiveGrabImageManager().PutImage( reinterpret_cast<char*>( image ), size );
  return true;
}

void GrabImageTask::Action()
{
  uint64_t now = cTimeMs::Now();

  if ( m_firstTime == 0 )
    m_firstTime = now;

  if ( now - m_lastTime < GrabMinIntervalMs || now - m_firstTime > GrabPauseIntervalMs )
    return;

  if ( !GrabImage() )
    return;

  m_lastTime = now;
}

GrabImageManager::GrabImageManager()
    : m_task( new GrabImageTask )
    , m_size( 0 )
{
}

GrabImageInfo GrabImageManager::GetImage() const
{
  cMutexLock lock( &LiveTaskManager() );
  m_task->Activate();
  return std::make_pair( m_image, m_size );
}

bool GrabImageManager::CanGrab() const
{
  return m_task->IsActive();
}

void GrabImageManager::PutImage( char* image, int size )
{
  m_image.reset( image, &free );
  m_size = size;
}

GrabImageManager& LiveGrabImageManager()
{
  static GrabImageManager instance;
  return instance;
}

} // namespace vdrlive