CallbackPointOrdinal Class Reference

Callback for computing the ordinal for a specified point, as a function of the LineStyle and curve geometry. More...

#include <CallbackPointOrdinal.h>

Collaboration diagram for CallbackPointOrdinal:

Public Member Functions
	CallbackPointOrdinal (const LineStyle &lineStyle, const Transformation &transformation, const QPointF &posScreen)
	Single constructor. More...
CallbackSearchReturn	callback (const Point &pointStart, const Point &pointStop)
	Callback method. More...
double	ordinal () const
	Computed ordinal. More...

Detailed Description

Callback for computing the ordinal for a specified point, as a function of the LineStyle and curve geometry.

Definition at line 18 of file CallbackPointOrdinal.h.

Constructor & Destructor Documentation

CallbackPointOrdinal()

CallbackPointOrdinal::CallbackPointOrdinal	(	const LineStyle &	lineStyle,
		const Transformation &	transformation,
		const QPointF &	posScreen
	)

Single constructor.

Definition at line 15 of file CallbackPointOrdinal.cpp.

                                                                     :
  m_lineStyle (lineStyle),
  m_transformation (transformation),
  m_posScreen (posScreen),
  m_haveMinimumDistanceToLine (false),
  m_minimumDistanceToLine (0.0),
  m_minimumProjectedDistanceOutsideLine (0.0),
  m_ordinal (0)
{
}

Member Function Documentation

callback()

CallbackSearchReturn CallbackPointOrdinal::callback	(	const Point &	pointStart,
		const Point &	pointStop
	)

Callback method.

Definition at line 28 of file CallbackPointOrdinal.cpp.

{
  double xProjection, yProjection, projectedDistanceOutsideLine, distanceToLine;
 
  projectPointOntoLine(m_posScreen.x(),
                       m_posScreen.y(),
                       pointStart.posScreen().x(),
                       pointStart.posScreen().y(),
                       pointStop.posScreen().x(),
                       pointStop.posScreen().y(),
                       &xProjection,
                       &yProjection,
                       &projectedDistanceOutsideLine,
                       &distanceToLine);
 
  // Compare the best so far
  bool distancesAreEqual = (qAbs (distanceToLine - m_minimumDistanceToLine) <= 0); // Epsilon test prevents compiler warning
  if (!m_haveMinimumDistanceToLine ||
      (distanceToLine < m_minimumDistanceToLine) ||
      (distancesAreEqual && projectedDistanceOutsideLine < m_minimumProjectedDistanceOutsideLine)) {
 
    // Compute ordinal using epsilon test to prevent compiler warning
    if (qAbs (projectedDistanceOutsideLine) <= 0) {
 
      // Put new point inside the line segment
      m_ordinal = (pointStart.ordinal() + pointStop.ordinal()) / 2.0;
 
    } else {
 
      // Put new point just outside the line segment
      double distanceProjectionToStart = qSqrt ((xProjection - pointStart.posScreen().x()) * (xProjection - pointStart.posScreen().x()) +
                                                (yProjection - pointStart.posScreen().y()) * (yProjection - pointStart.posScreen().y()));
      double distanceProjectionToStop = qSqrt ((xProjection - pointStop.posScreen().x()) * (xProjection - pointStop.posScreen().x()) +
                                               (yProjection - pointStop.posScreen().y()) * (yProjection - pointStop.posScreen().y()));
      if (distanceProjectionToStart < distanceProjectionToStop) {
 
        // Before start point
        m_ordinal = pointStart.ordinal() - 0.5;
 
      } else {
 
        // After stop point
        m_ordinal = pointStop.ordinal() + 0.5;
      }
    }
 
    // Save as new 'best'
    m_haveMinimumDistanceToLine = true;
    m_minimumDistanceToLine = distanceToLine;
    m_minimumProjectedDistanceOutsideLine = projectedDistanceOutsideLine;
  }
 
  return CALLBACK_SEARCH_RETURN_CONTINUE;
}

ordinal()

double CallbackPointOrdinal::ordinal

(

)

const

Computed ordinal.

Definition at line 84 of file CallbackPointOrdinal.cpp.

{
  return m_ordinal;
}

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

• Callback/CallbackPointOrdinal.h
• Callback/CallbackPointOrdinal.cpp