Pixels.h

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/******************************************************************************************************
 * (C) 2018 markummitchell@github.com. This file is part of Engauge Digitizer, which is released      *
 * under GNU General Public License version 2 (GPLv2) or (at your option) any later version. See file *
 * LICENSE or go to gnu.org/licenses for details. Distribution requires prior written permission.     *
 ******************************************************************************************************/
 
#ifndef PIXELS_H
#define PIXELS_H
 
#include <QMap>
#include <QPoint>
#include <QQueue>
#include <QStack>
#include <QString>
 
class QImage;

typedef QMap<QString, bool> HashLookup;
 
typedef QQueue<QPoint> QueuedPoints;

enum PixelFillState {
  PIXEL_FILL_STATE_UNPROCESSED,
  PIXEL_FILL_STATE_IN_PROCESS,
  PIXEL_FILL_STATE_PROCESSED
};

class Pixels
{
public:
  Pixels();

  int countBlackPixelsAroundPoint (const QImage &image,
                                   int x,
                                   int y,
                                   int stopCountAt);

  void fillHole (QImage &image,
                 int row,
                 int col,
                 int thresholdCount) const;

  void fillHoles (QImage &image,
                  int thresholdCount);

  void fillIsolatedWhitePixels (QImage &image);

  static bool pixelIsBlack (const QImage &image,
                            int x,
                            int y);
  
private:
 
  enum FillIt {
    NO_FILL,
    YES_FILL
  };
 
  // Multiple pass algorithm
  int fillPass (QImage &image,
                QVector<PixelFillState> &states,
                int row,
                int col,
                PixelFillState stateFrom,
                PixelFillState stateTo,
                FillIt fillit);
  QString hashForCoordinates (int x,
                              int y) const;
  int indexCollapse (int row,
                     int col,
                     int width) const;
};
 
#endif // PIXELS_H