Segment.h

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/******************************************************************************************************
 * (C) 2014 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 SEGMENT_H
#define SEGMENT_H
 
#include <QList>
#include <QObject>
#include <QPointF>
 
class DocumentModelSegments;
class QGraphicsScene;
class QTextStream;
class SegmentLine;

class Segment : public QObject
{ 
  Q_OBJECT;
 
public:
  Segment(QGraphicsScene &scene,
          int yLast,
          bool isGnuplot);
  ~Segment();

  void appendColumn(int x, int y, const DocumentModelSegments &modelSegments);

  QList<QPoint> fillPoints(const DocumentModelSegments &modelSegments);

  QPointF firstPoint () const;

  void forwardMousePress ();

  double length() const;

  int lineCount() const;

  void lockHoverState ();

  void removeUnneededLines(int *foldedLines);

  void updateModelSegment(const DocumentModelSegments &modelSegments);
 
public slots:

  void slotHover (bool hover);
 
signals:

  void signalMouseClickOnSegment (QPointF posSegmentStart);
 
private:
  Segment();
 
  // While filling corners, create a point if any of the following are true:
  // -it is the first point of the any line segment
  // -it is different than the previous point
  // While not filling corners, create a point if any of the following are true:
  // -it is the first point of the first line segment
  // -it is different than the previous point
  void createAcceptablePoint(bool *pFirst,
                             QList<QPoint> *pList,
                             double *xPrev,
                             double *yPrev,
                             double x,
                             double y);

  void dumpToGnuplot (QTextStream &strDump,
                      int xInt,
                      int yInt,
                      const SegmentLine *lineOld,
                      const SegmentLine *lineNew) const;
 
  // Create evenly spaced points along the segment, with extra points to fill in corners.This algorithm is the
  // same as fillPointsWithoutFillingCorners except extra points are inserted at the corners
  QList<QPoint> fillPointsFillingCorners(const DocumentModelSegments &modelSegments);
 
  // Create evenly spaced points along the segment, without extra points in corners
  QList<QPoint> fillPointsWithoutFillingCorners(const DocumentModelSegments &modelSegments);
 
  // A corner is defined as a point where the incoming slope is positive and the outgoing slope is zero
  // or negative, or incoming slope is negative and the outgoing slope is zero or positive
  bool isCorner (double yLast,
                 double yPrev,
                 double yNext) const;
 
  // Return true if point are a half pixel or less away from a line
  bool pointIsCloseToLine(double xLeft, double yLeft, double xInt, double yInt,
    double xRight, double yRight);
 
  // Return true if points are a half pixel or less away from a line
  bool pointsAreCloseToLine(double xLeft, double yLeft, QList<QPoint> removedPoints,
    double xRight, double yRight);
 
  QGraphicsScene &m_scene;
 
  // Y value of last point which is in previous column
  int m_yLast;
 
  // Total length of lines owned by this segment, as floating point to allow fractional increments
  double m_length;
 
  // This segment is drawn as a series of line segments
  QList<SegmentLine*> m_lines;
 
  // True for gnuplot input files for debugging
  bool m_isGnuplot;
};
 
#endif // SEGMENT_H