Segment Class Reference

Selectable piecewise-defined line that follows a filtered line in the image. More...

#include <Segment.h>

Inheritance diagram for Segment:

Collaboration diagram for Segment:

Public Slots
void	slotHover (bool hover)
	Slot for hover enter/leave events in the associated SegmentLines. More...

Signals
void	signalMouseClickOnSegment (QPointF posSegmentStart)
	Pass mouse press event, with coordinates of first point in the Segment since that info uniquely identifies the owning Segment. More...

Public Member Functions
	Segment (QGraphicsScene &scene, int yLast, bool isGnuplot)
	Single constructor. More...
	~Segment ()
void	appendColumn (int x, int y, const DocumentModelSegments &modelSegments)
	Add some more pixels in a new column to an active segment. More...
QList< QPoint >	fillPoints (const DocumentModelSegments &modelSegments)
	Create evenly spaced points along the segment. More...
QPointF	firstPoint () const
	Coordinates of first point in Segment. More...
void	forwardMousePress ()
	Forward mouse press event from a component SegmentLine that was just clicked on. More...
double	length () const
	Get method for length in pixels. More...
int	lineCount () const
	Get method for number of lines. More...
void	removeUnneededLines (int *foldedLines)
	Try to compress a segment that was just completed, by folding together line from point i to point i+1, with the line from i+1 to i+2, then the line from i+2 to i+3, until one of the points is more than a half pixel from the folded line. More...
void	updateModelSegment (const DocumentModelSegments &modelSegments)
	Update this segment given the new settings. More...

Detailed Description

Selectable piecewise-defined line that follows a filtered line in the image.

Clicking on a Segment results in the immediate creation of multiple Points along that Segment.

Definition at line 21 of file Segment.h.

Constructor & Destructor Documentation

Segment()

Segment::Segment	(	QGraphicsScene &	scene,
		int	yLast,
		bool	isGnuplot
	)

Single constructor.

Definition at line 22 of file Segment.cpp.

                                 :
  m_scene (scene),
  m_yLast (y),
  m_length (0),
  m_isGnuplot (isGnuplot)
{
}

~Segment()

Segment::~Segment

(

)

Definition at line 32 of file Segment.cpp.

{
  QList<SegmentLine*>::iterator itr;
  for (itr = m_lines.begin(); itr != m_lines.end(); itr++) {

    SegmentLine *segmentLine = *itr;
    m_scene.removeItem (segmentLine);
  }
}

Member Function Documentation

appendColumn()

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

Add some more pixels in a new column to an active segment.

Definition at line 42 of file Segment.cpp.

{
  int xOld = x - 1;
  int yOld = m_yLast;
  int xNew = x;
  int yNew = y;

  LOG4CPP_DEBUG_S ((*mainCat)) << "Segment::appendColumn"
                               << " segment=0x" << std::hex << static_cast<void*> (this) << std::dec
                               << " adding ("
                               << xOld << "," << yOld << ") to ("
                               << xNew << "," << yNew << ")";

  SegmentLine* line = new SegmentLine(m_scene,
                                      modelSegments,
                                      this);
  ENGAUGE_CHECK_PTR(line);
  line->setLine(QLineF (xOld,
                        yOld,
                        xNew,
                        yNew));

  // Do not show this line or its segment. this is handled later

  m_lines.append(line);

  // Update total length using distance formula
  m_length += qSqrt((1.0) * (1.0) + (y - m_yLast) * (y - m_yLast));

  m_yLast = y;
}

fillPoints()

QList< QPoint > Segment::fillPoints

(

const DocumentModelSegments &

modelSegments

)

Create evenly spaced points along the segment.

Definition at line 205 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::fillPoints";

  if (modelSegments.fillCorners()) {
    return fillPointsFillingCorners(modelSegments);
  } else {
    return fillPointsWithoutFillingCorners(modelSegments);
  }
}

firstPoint()

QPointF Segment::firstPoint

(

)

const

Coordinates of first point in Segment.

This info can be used to uniquely identify a Segment. This method relies on SegmentFactory::removeEmptySegments to guarantee every Segment has at least one line

Definition at line 281 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::firstPoint"
                              << " lineCount=" << m_lines.count();

  // There has to be at least one SegmentLine since this only gets called when a SegmentLine is clicked on
  ENGAUGE_ASSERT (m_lines.count () > 0);

  SegmentLine *line = m_lines.first();
  QPointF pos = line->line().p1();

  LOG4CPP_INFO_S ((*mainCat)) << "Segment::firstPoint"
                              << " pos=" << QPointFToString (pos).toLatin1().data();

  return pos;
}

forwardMousePress()

void Segment::forwardMousePress

(

)

Forward mouse press event from a component SegmentLine that was just clicked on.

Definition at line 298 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::forwardMousePress"
                              << " segmentLines=" << m_lines.count();

  emit signalMouseClickOnSegment (firstPoint ());
}

length()

double Segment::length

(

)

const

Get method for length in pixels.

Definition at line 375 of file Segment.cpp.

{
  return m_length;
}

lineCount()

int Segment::lineCount

(

)

const

Get method for number of lines.

Definition at line 380 of file Segment.cpp.

{
  return m_lines.count();
}

removeUnneededLines()

void Segment::removeUnneededLines

(

int *

foldedLines

)

Try to compress a segment that was just completed, by folding together line from point i to point i+1, with the line from i+1 to i+2, then the line from i+2 to i+3, until one of the points is more than a half pixel from the folded line.

this should save memory and improve user interface responsiveness

Definition at line 421 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::removeUnneededLines";

  QFile *fileDump = nullptr;
  QTextStream *strDump = nullptr;
  if (m_isGnuplot) {

    QString filename ("segment.gnuplot");

    std::cout << GNUPLOT_FILE_MESSAGE.toLatin1().data() << filename.toLatin1().data() << "\n";

    fileDump = new QFile (filename);
    fileDump->open (QIODevice::WriteOnly | QIODevice::Text);
    strDump = new QTextStream (fileDump);

  }

  // Pathological case is y=0.001*x*x, since the small slope can fool a naive algorithm
  // into optimizing away all but one point at the origin and another point at the far right.
  // From this we see that we cannot simply throw away points that were optimized away since they
  // are needed later to see if we have diverged from the curve
  SegmentLine *linePrevious = nullptr; // Previous line which corresponds to itrPrevious
  QList<SegmentLine*>::iterator itr, itrPrevious;
  QList<QPoint> removedPoints;
  for (itr = m_lines.begin(); itr != m_lines.end(); itr++) {

    SegmentLine *line = *itr;
    ENGAUGE_CHECK_PTR(line);

    if (linePrevious != nullptr) {

      double xLeft = linePrevious->line().x1();
      double yLeft = linePrevious->line().y1();
      double xInt = linePrevious->line().x2();
      double yInt = linePrevious->line().y2();

      // If linePrevious is the last line of one Segment and line is the first line of another Segment then
      // it makes no sense to remove any point so we continue the loop
      if (linePrevious->line().p2() == line->line().p1()) {

        double xRight = line->line().x2();
        double yRight = line->line().y2();

        if (pointIsCloseToLine(xLeft, yLeft, xInt, yInt, xRight, yRight) &&
          pointsAreCloseToLine(xLeft, yLeft, removedPoints, xRight, yRight)) {

          if (m_isGnuplot) {

            // Dump
            dumpToGnuplot (*strDump,
                           qFloor (xInt),
                           qFloor (yInt),
                           linePrevious,
                           line);
          }

          // Remove intermediate point, by removing older line and stretching new line to first point
          ++(*foldedLines);

          LOG4CPP_DEBUG_S ((*mainCat)) << "Segment::removeUnneededLines"
                                       << " segment=0x" << std::hex << static_cast<void*> (this) << std::dec
                                       << " removing ("
                                       << linePrevious->line().x1() << "," << linePrevious->line().y1() << ") to ("
                                       << linePrevious->line().x2() << "," << linePrevious->line().y2() << ") "
                                       << " and modifying ("
                                       << line->line().x1() << "," << line->line().y1() << ") to ("
                                       << line->line().x2() << "," << line->line().y2() << ") into ("
                                       << xLeft << "," << yLeft << ") to ("
                                       << xRight << "," << yRight << ")";

          removedPoints.append(QPoint(qFloor (xInt),
                                      qFloor (yInt)));
          m_lines.erase (itrPrevious);
          delete linePrevious;

          // New line
          line->setLine (xLeft, yLeft, xRight, yRight);

        } else {

          // Keeping this intermediate point and clear out the removed points list
          removedPoints.clear();
        }
      }
    }

    linePrevious = line;
    itrPrevious = itr;

    // This theoretically should not be needed, but for some reason modifying the last point triggers a segfault
    if (itr == m_lines.end()) {
      break;
    }
  }

  if (strDump != nullptr) {

    // Final gnuplot processing
    *strDump << "set terminal x11 persist\n";
    fileDump->close ();
    delete strDump;
    delete fileDump;

  }
}

signalMouseClickOnSegment

void Segment::signalMouseClickOnSegment ( QPointF  posSegmentStart )

signal

Pass mouse press event, with coordinates of first point in the Segment since that info uniquely identifies the owning Segment.

slotHover

void Segment::slotHover ( bool  hover )

slot

Slot for hover enter/leave events in the associated SegmentLines.

Definition at line 528 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::slotHover";

  QList<SegmentLine*>::iterator itr, itrPrevious;
  for (itr = m_lines.begin(); itr != m_lines.end(); itr++) {

    SegmentLine *line = *itr;
    line->setHover(hover);
  }
}

updateModelSegment()

void Segment::updateModelSegment

(

const DocumentModelSegments &

modelSegments

)

Update this segment given the new settings.

Definition at line 540 of file Segment.cpp.

{
  LOG4CPP_INFO_S ((*mainCat)) << "Segment::updateModelSegment";

  QList<SegmentLine*>::iterator itr;
  for (itr = m_lines.begin(); itr != m_lines.end(); itr++) {

    SegmentLine *line = *itr;
    line->updateModelSegment (modelSegments);
  }
}

---

The documentation for this class was generated from the following files:

• Segment/Segment.h
• Segment/Segment.cpp