lc::geo::Arc Class Reference

#include <geoarc.h>

Inheritance diagram for lc::geo::Arc:

Collaboration diagram for lc::geo::Arc:

Public Member Functions
	Arc (const Coordinate &center, double radius, double startAngle, double endAngle)
	Arc (const Coordinate &center, double radius, double startAngle, double endAngle, bool CCW)
	Arc (const Arc &c)
	Arc (Arc &&c) noexcept
Arc &	operator= (Arc &&c) noexcept
const Coordinate	center () const
	Returns center of Arc. More...
double	radius () const
	Returns the radius of Arc. More...
double	startAngle () const
	Returns the startAngle. More...
double	endAngle () const
	Returns the EndAngle. More...
double	length () const
Coordinate	startP () const
Coordinate	endP () const
Area	boundingBox () const
bool	CCW () const
	Returns of the arc is in reversed direction. More...
Coordinate	nearestPointOnPath (const Coordinate &coord) const
Coordinate	nearestPointOnEntity (const Coordinate &coord) const
const maths::Equation	equation () const
bool	isAngleBetween (double angle) const
virtual void	accept (GeoEntityVisitor &v) const override
double	angle () const
double	bulge () const
Public Member Functions inherited from lc::geo::Base
virtual	~Base ()=default
Public Member Functions inherited from lc::Visitable
virtual	~Visitable ()=default

Static Public Member Functions
static Arc	createArc3P (const Coordinate &p1, const Coordinate &p2, const Coordinate &p3)
static Arc	createArcBulge (const Coordinate &p1, const Coordinate &p2, const double bulge)

Private Attributes
Coordinate	_center
	Coordinate center of Arc. More...
double	_radius
	Double _Radius of Arc. More...
double	_startAngle
	Double startAngle of Arc. More...
double	_endAngle
	Double endAngle of Arc. More...
bool	_CCW

Friends
std::ostream &	operator<< (std::ostream &os, const Arc &a)

Detailed Description

Definition at line 13 of file geoarc.h.

Constructor & Destructor Documentation

Arc::Arc	(	const Coordinate &	center,
		double	radius,
		double	startAngle,
		double	endAngle
	)

Create a new Arc center center location radius radius of the arc startAngle, will be corrected to 0..2*PI endAngle, will be corrected to 0..2*PI

Arc will always be setup such that startAngle will increase or decrease to endAngle So it's perfectly possible to have a startAngle > endAngle

Definition at line 8 of file geoarc.cpp.

        : Base(), _center(center), _radius(radius), _startAngle(Math::correctAngle(startAngle)), _endAngle(Math::correctAngle(endAngle)), _CCW(true) {
    /*
    if (startAngle<0.0 || startAngle>PI2 || startAngle<endAngle) {
        throw "Invalid start angle";
    }
    if (endAngle<0.0 || endAngle> PI2) {
        throw "Invalid end angle";
    }
    if (radius<0.0) {
        throw "Invalid radius";
    }*/

}

Arc::Arc	(	const Coordinate &	center,
		double	radius,
		double	startAngle,
		double	endAngle,
		bool	CCW
	)

Create a new Arc center center location radius radius of the arc startAngle, will be corrected to 0..2*PI endAngle, will be corrected to 0..2*PI CCW, setup arc to be drawn ClockWise or counter clockwise

Definition at line 23 of file geoarc.cpp.

        : Base(), _center(center), _radius(radius), _startAngle(Math::correctAngle(startAngle)), _endAngle(Math::correctAngle(endAngle)), _CCW(isCCW) {
}

lc::geo::Arc::Arc ( const Arc &  c )

inline

Definition at line 40 of file geoarc.h.

: _center(c._center), _radius(c._radius), _startAngle(c._startAngle), _endAngle(c._endAngle), _CCW(c._CCW) {}

lc::geo::Arc::Arc ( Arc &&  c )

inlinenoexcept

Definition at line 41 of file geoarc.h.

                                      {
                    std::swap(_center, c._center);
                    std::swap(_radius, c._radius);
                    std::swap(_startAngle, c._startAngle);
                    std::swap(_endAngle, c._endAngle);
                    std::swap(_CCW, c._CCW);
                }

Member Function Documentation

virtual void lc::geo::Arc::accept ( GeoEntityVisitor &  v ) const

inlineoverridevirtual

Implements lc::Visitable.

Reimplemented in lc::entity::Arc.

Definition at line 120 of file geoarc.h.

{ v.visit(*this); }

double Arc::angle

(

)

const

Returns the angle between start and end points

Returns

double angle

Definition at line 167 of file geoarc.cpp.

                        {
    return Math::correctAngle(std::abs(_endAngle - _startAngle));
}

Area Arc::boundingBox

(

)

const

Tight bounding box for the area

Definition at line 138 of file geoarc.cpp.

                            {
    geo::Area area(startP(), endP());

    const double startAngle = _startAngle;
    const double endAngle = _endAngle;
    const double p0 = 0.0 * M_PI;
    const double p1 = 0.5 * M_PI;
    const double p2 = 1.0 * M_PI;
    const double p3 = 1.5 * M_PI;

    if ((Math::isAngleBetween(p0, startAngle, endAngle, _CCW))) {
        area = area.merge(Coordinate(_center.x() + _radius, _center.y()));
    }
    if ((Math::isAngleBetween(p1, startAngle, endAngle, _CCW))) {
        area = area.merge(Coordinate(_center.x(), _center.y() + _radius));
    }
    if ((Math::isAngleBetween(p2, startAngle, endAngle, _CCW))) {
        area = area.merge(Coordinate(_center.x() - _radius, _center.y()));
    }
    if ((Math::isAngleBetween(p3, startAngle, endAngle, _CCW))) {
        area = area.merge(Coordinate(_center.x(), _center.y() - _radius));
    }
    return area;
}

double Arc::bulge

(

)

const

Returns arc bulge

Returns

double bulge

Definition at line 171 of file geoarc.cpp.

                        {
    double bulge = std::tan(angle()/4.0);

    if(!CCW()) {
        bulge *= -1;
    }

    return bulge;
}

bool Arc::CCW

(

)

const

Returns of the arc is in reversed direction.

Returns

Double reversed.

Definition at line 126 of file geoarc.cpp.

                    {
    return _CCW;
}

const Coordinate Arc::center

(

)

const

Returns center of Arc.

Returns

geo::Coordinate Center

Definition at line 91 of file geoarc.cpp.

                                   {
    return _center;
}

Arc Arc::createArc3P ( const Coordinate &  p1, const Coordinate &  p2, const Coordinate &  p3  )

static

Definition at line 27 of file geoarc.cpp.

                                                                                     {

    geo::Coordinate vra = p2 - p1;
    geo::Coordinate vrb = p3 - p1;
    double ra2 = vra.squared() * 0.5;
    double rb2 = vrb.squared() * 0.5;
    double crossp = vra.x() * vrb.y() - vra.y() * vrb.x();
    if (std::abs(crossp) <= 0.0) {
        // "Cannot create a arc with radius 0.0.");
        // TODO add exception handling of some sort
//        throw;
        return Arc(geo::Coordinate(0., 0.), 0., 0., 0.);
    }
    crossp = 1. / crossp;

    auto center = geo::Coordinate((ra2 * vrb.y() - rb2 * vra.y()) * crossp, (rb2 * vra.x() - ra2 * vrb.x()) * crossp);
    auto radius = center.magnitude();
    center = center + p1;
    auto angle1 = center.angleTo(p1);
    auto angle2 = center.angleTo(p3);

    return Arc(center, radius, angle1, angle2, false);
}

Arc Arc::createArcBulge ( const Coordinate &  p1, const Coordinate &  p2, const double  bulge  )

static

Definition at line 51 of file geoarc.cpp.

                                                                                      {
    auto isCCW = bulge>0.;
    auto delta = atan(bulge) * 4.0;

    auto middle = p1.mid(p2);
    auto dist = p1.distanceTo(p2)/2.0;

    auto radius = std::abs(dist / std::sin(delta/2.0));

    auto wu = std::abs(std::pow(radius, 2.0) - std::pow(dist, 2.0));
    auto h = std::sqrt(wu);
    auto angle = p1.angleTo(p2);

    if (isCCW) {
        angle-=M_PI/2.0;
    } else {
        angle+=M_PI/2.0;
    }

    if (std::abs(delta)<M_PI) {
        h*=-1.0;
    }

    auto center = geo::Coordinate(angle) * h + middle;

    return Arc(center, radius, center.angleTo(p1), center.angleTo(p2), isCCW);
}

double Arc::endAngle

(

)

const

Returns the EndAngle.

Returns

Double EndAngle.

Definition at line 87 of file geoarc.cpp.

                           {
    return _endAngle;
}

Coordinate Arc::endP

(

)

const

Coordinate of the end point

Definition at line 134 of file geoarc.cpp.

                           {
    return _center + Coordinate(_endAngle) * _radius;
}

const maths::Equation lc::geo::Arc::equation ( ) const

inline

Definition at line 112 of file geoarc.h.

                                                     {
                    return maths::Equation(1., 0.,1., 0., 0., -_radius* _radius).move(_center);
                }

bool Arc::isAngleBetween

(

double

angle

)

const

Definition at line 163 of file geoarc.cpp.

                                           {
    return Math::isAngleBetween(angle, _startAngle, _endAngle, _CCW);
}

double Arc::length

(

)

const

Calculates arc length This assumes that startAngle and endAngle are between -M_PI and M_PI and the difference is not bigger then 2.*M_PI TODO: Should we make this more reliable, for example to have angle is 4*MPI it's still correctly calculated?

Definition at line 118 of file geoarc.cpp.

                         {
    if (_startAngle > _endAngle) {
        return std::abs((2. * M_PI + endAngle() - startAngle()) * radius());
    } else {
        return std::abs((endAngle() - startAngle()) * radius());
    }
}

Coordinate Arc::nearestPointOnEntity

(

const Coordinate &

coord

)

const

Definition at line 98 of file geoarc.cpp.

                                                                  {
    const auto angle = (coord - center()).angle();

    // if the angle is between start and stop then calculate the nearest point
    // on it's entity
    if (isAngleBetween(angle)) {
        return center() + angle * radius();
    }

    // Find out if angle is closer to start or end and return the appropriate coordinate
    const auto ad1 = std::abs(angle - _startAngle);
    const auto ad2 = std::abs(angle - _endAngle);

    if (ad1<=ad2) {
        return startP();
    } else {
        return endP();
    }
}

Coordinate Arc::nearestPointOnPath

(

const Coordinate &

coord

)

const

Definition at line 95 of file geoarc.cpp.

                                                                {
    return center() + Coordinate((coord - center()).angle()) * radius();
}

Arc& lc::geo::Arc::operator= ( Arc &&  c )

inlinenoexcept

Definition at line 49 of file geoarc.h.

                                                   {
                    std::swap(_center, c._center);
                    std::swap(_radius, c._radius);
                    std::swap(_startAngle, c._startAngle);
                    std::swap(_endAngle, c._endAngle);
                    std::swap(_CCW, c._CCW);
                    return *this;
                }

double Arc::radius

(

)

const

Returns the radius of Arc.

Returns

Double Radius.

Definition at line 79 of file geoarc.cpp.

                         {
    return _radius;
}

double Arc::startAngle

(

)

const

Returns the startAngle.

Returns

Double startAngle.

Definition at line 83 of file geoarc.cpp.

                             {
    return _startAngle;
}

Coordinate Arc::startP

(

)

const

Coordinate of the start point

Definition at line 130 of file geoarc.cpp.

                             {
    return _center + Coordinate(_startAngle) * _radius;
}

Friends And Related Function Documentation

std::ostream& operator<< ( std::ostream &  os, const Arc &  a  )

friend

Definition at line 134 of file geoarc.h.

                                                                            {
                    os << "Arc(center=" << a._center << " radius=" << a._radius << " startAngle=" << a._startAngle << " endAngle=" << a._endAngle << " ccw=" << a._CCW << ")";
                    return os;
                }

Member Data Documentation

bool lc::geo::Arc::_CCW

private

Definition at line 144 of file geoarc.h.

Coordinate lc::geo::Arc::_center

private

Coordinate center of Arc.

Definition at line 140 of file geoarc.h.

double lc::geo::Arc::_endAngle

private

Double endAngle of Arc.

Definition at line 143 of file geoarc.h.

double lc::geo::Arc::_radius

private

Double _Radius of Arc.

Definition at line 141 of file geoarc.h.

double lc::geo::Arc::_startAngle

private

Double startAngle of Arc.

Definition at line 142 of file geoarc.h.

---

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

• lckernel/cad/geometry/geoarc.h
• lckernel/cad/geometry/geoarc.cpp