FrameConverter.hpp

/*
 *  LiveFit
 *  Copyright (C) 2016 The University of Georgia
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef FRAMECONVERTER_HPP
#define FRAMECONVERTER_HPP

#include <QBasicTimer>
#include <QObject>
#include <QSize>

#include "ColorSpace.hpp"

#include <opencv2/core/mat.hpp>

/**
 * @brief Recieves frames (as cv::Mat), processes them (ideally asynchronously)
 * and emits them as a QImage (i.e. for use in a QWidget)
 */
class FrameConverter : public QObject
{
  Q_OBJECT

  /** Process a frame at each tick of this timer */
  QBasicTimer mTimer;
  /** The current frame to process into a QImage */
  cv::Mat currentFrame;
  /** The current ColorSpace of the frame we are processing */
  ColorSpace currentCS;
  /** Whether we should process all frames, or drop some to keep framerate */
  bool processAll = true;
  /** The resolution of the frames that we are processing */
  QSize frameSize;

  /** Delete a cv::Mat object */
  static void matDeleter(void *mat) { delete static_cast<cv::Mat*>(mat); }

public:
  explicit FrameConverter(QObject *parent = 0);

  /** Set whether we should process all frames, or drop some */
  void setProcessAll(bool all) { processAll = all; }

  ~FrameConverter();
signals:
  /** Emitted when we have a QImage from processing ready for display */
  void imageReady(const QImage &);

public slots:
  /** Add a new frame to be processed; if not processAll this frame may yet be dropped. */
  void processFrame(const cv::Mat &frame, enum ColorSpace);
  /** Set the resolution of the frames we are processing */
  void setFrameSize(QSize size);
  /** Stop processing frames */
  void stop();
private:
  /** Queue a new frame to be processed (depends on processAll if it gets processed). */
  void queue(const cv::Mat & frame, ColorSpace cs);
  /** Actually process a frame. Resultant QImage gets emitted by imageReady() */
  void process(cv::Mat frame, ColorSpace cs);
  /** Called each time that mTimer ticks... we call process on the queue in here. */
  void timerEvent(QTimerEvent *ev);
};

#endif // FRAMECONVERTER_HPP