JGEOMETRY2D::JSegment2D Class Reference

Line segment in two dimensions. More...

#include <JSegment2D.hh>

Inheritance diagram for JGEOMETRY2D::JSegment2D:

Public Member Functions
	JSegment2D ()
	Default constructor. More...
	JSegment2D (const JVector2D &A, const JVector2D &B)
	Constructor. More...
double	getLengthSquared () const
	Get length squared. More...
double	getLength () const
	Get length. More...
bool	intersects (const JSegment2D &segment) const
	Test whether two line segments intersect. More...
JVector2D	getIntersection (const JSegment2D &segment) const
	Get intersection of two line segments. More...
double	getDistanceSquared (const JVector2D &point) const
	Get squared of distance to point. More...
double	getDistance (const JVector2D &point) const
	Get distance to point. More...
double	getDot (const JSegment2D &segment) const
	Get dot product. More...

Friends
JReader &	operator>> (JReader &in, JSegment2D &segment)
	Read segment from input. More...
JWriter &	operator<< (JWriter &out, const JSegment2D &segment)
	Write segment to output. More...

Detailed Description

Line segment in two dimensions.

Definition at line 36 of file JSegment2D.hh.

Constructor & Destructor Documentation

JGEOMETRY2D::JSegment2D::JSegment2D ( )

inline

Default constructor.

Definition at line 43 of file JSegment2D.hh.

                 :
      JSegment2D_t()
    {}

JGEOMETRY2D::JSegment2D::JSegment2D ( const JVector2D &  A, const JVector2D &  B  )

inline

Constructor.

Parameters

A	start position
B	end position

Definition at line 54 of file JSegment2D.hh.

                                   :
      JSegment2D_t(A,B)
    {}

Member Function Documentation

double JGEOMETRY2D::JSegment2D::getLengthSquared ( ) const

inline

Get length squared.

Returns

square of length

Definition at line 65 of file JSegment2D.hh.

    {
      return JVector2D(this->second - this->first).getLengthSquared();
    }

double JGEOMETRY2D::JSegment2D::getLength ( ) const

inline

Get length.

Returns

length

Definition at line 76 of file JSegment2D.hh.

    {
      return sqrt(getLengthSquared());
    }

bool JGEOMETRY2D::JSegment2D::intersects ( const JSegment2D &  segment ) const

inline

Test whether two line segments intersect.

Parameters

segment

line segment

Returns

true if two line segment intersect; else false

Definition at line 88 of file JSegment2D.hh.

    {
      return (getCCW(this->first,   segment.first, this->second)   != getCCW(this->first,   segment.second, this->second) &&
              getCCW(segment.first, this->first,   segment.second) != getCCW(segment.first, this->second,   segment.second));
    }

JVector2D JGEOMETRY2D::JSegment2D::getIntersection ( const JSegment2D &  segment ) const

inline

Get intersection of two line segments.

Parameters

segment

line segment

Returns

intersection point

Definition at line 101 of file JSegment2D.hh.

    {
      JVector2D da(this->second   - this->first);
      JVector2D db(segment.second - segment.first);
      
      const double gp = JMATH::getPerpDot(da, db);

      if (gp != 0.0) {

        da.mul(JMATH::getPerpDot(segment.second, segment.first)); 
        db.mul(JMATH::getPerpDot(this->second,   this->first));

        db.sub(da);
        db.div(gp);

        return db;

      } else {
        throw JDivisionByZero("JSegment2D::getIntersection()");
      }
    }

double JGEOMETRY2D::JSegment2D::getDistanceSquared ( const JVector2D &  point ) const

inline

Get squared of distance to point.

Parameters

point

point

Returns

square of distance

Definition at line 130 of file JSegment2D.hh.

    {
      JVector2D D(this->second - this->first);

      const double gp = D.getLengthSquared();

      if (gp != 0.0) {

        const JVector2D U(point - this->first);

        double u = D.getDot(U);

        if      (u < 0.0)
          u  = 0.0;
        else if (u > gp)
          u  = 1.0;
        else
          u /= gp;

        D.mul(u);
        D.sub(U);

        return D.getLengthSquared();

      } else {

        return first.getDistanceSquared(point);
      }
    }

double JGEOMETRY2D::JSegment2D::getDistance ( const JVector2D &  point ) const

inline

Get distance to point.

Parameters

point

point

Returns

distance

Definition at line 167 of file JSegment2D.hh.

    {
      return sqrt(getDistanceSquared(point));
    }

double JGEOMETRY2D::JSegment2D::getDot ( const JSegment2D &  segment ) const

inline

Get dot product.

Parameters

segment

segment

Returns

dot product

Definition at line 179 of file JSegment2D.hh.

    {
      return JVector2D(this->second - this->first).getDot(segment.second - segment.first);
    }

Friends And Related Function Documentation

JReader& operator>> ( JReader &  in, JSegment2D &  segment  )

friend

Read segment from input.

Parameters

in	reader
segment	segment

Returns

reader

Definition at line 192 of file JSegment2D.hh.

    {
      in >> segment.first;
      in >> segment.second;

      return in;
    }

JWriter& operator<< ( JWriter &  out, const JSegment2D &  segment  )

friend

Write segment to output.

Parameters

out	writer
segment	segment

Returns

writer

Definition at line 208 of file JSegment2D.hh.

    {
      out << segment.first;
      out << segment.second;

      return out;
    }

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

• JSegment2D.hh