Go::ParamCurve Class Reference
['geometry' - a spline library]

Base class for parametric curves in Go. More...

#include <ParamCurve.h>

Inheritance diagram for Go::ParamCurve:

List of all members.

Public Member Functions
virtual	~ParamCurve ()
	virtual destructor - ensures safe inheritance
virtual void	point (Point &pt, double tpar) const=0
	Evaluate the curve's position at a given parameter.
virtual void	point (std::vector< Point > &pts, double tpar, int derivs, bool from_right=true) const=0
	Evaluate the curve's position and a certain number of derivatives at a given parameter.
Point	point (double tpar) const
	Evaluate the curve's position at a certain parameter.
std::vector< Point >	point (double tpar, int derivs, bool from_right=true) const
	Evaluate the curve's position and a certain number of derivatives at a given parameter.
virtual double	startparam () const=0
	Query the start parameter of the curve.
virtual double	endparam () const=0
	Query the end parameter of the curve.
virtual void	reverseParameterDirection (bool switchparam=false)=0
	Set the parameter direction of the curve.
virtual SplineCurve *	geometryCurve ()=0
	If the definition of this ParamCurve contains a SplineCurve describing its spatial shape, then this function will return a pointer to this SplineCurve.
virtual bool	isDegenerate (double degenerate_epsilon)=0
	Query whether the curve is degenerate (collapsed into a single point).
virtual ParamCurve *	subCurve (double from_par, double to_par, double fuzzy=DEFAULT_PARAMETER_EPSILON) const=0
	Returns a curve which is a part of this curve.
virtual ParamCurve *	clone () const=0
	The clone-function is herited from GeomObject, but overridden here to get a covariant return type (for those compilers that allow this).
virtual DirectionCone	directionCone () const=0
	Creates a DirectionCone which covers all tangent directions of this curve.
virtual CompositeBox	compositeBox () const
	Creates a composite box enclosing the curve.
virtual void	appendCurve (ParamCurve *cv, bool reparam=true)=0
	append a curve to this curve, with eventual reparametrization NB: This virtual member function currently only works for SplineCurves and CurveOnSurfaces.
virtual void	appendCurve (ParamCurve *cv, int continuity, double &dist, bool reparam=true)=0
	append a curve to this curve, with eventual reparmetrization
double	estimatedCurveLength (int numpts=4) const
	Estimate the length of the curve, by sampling it at a certain number of points and calculating the linear approximation to the curve through these points.
double	estimatedCurveLength (double tmin, double tmax, int numpts=4) const
	Estimate the length of an interval of the curve, by sampling it at a certain number of points in the interval and calculating the linear approximation through these points.
virtual void	closestPoint (const Point &pt, double tmin, double tmax, double &clo_t, Point &clo_pt, double &clo_dist, double const *seed=0) const=0
	Compute the closest point from an interval of this curve to a specified point.
void	closestPoint (const Point &pt, double &clo_t, Point &clo_pt, double &clo_dist) const
	Compute the closest point from this curve to a specified point, taking the whole curve into account (not just an interval of it).
virtual double	nextSegmentVal (double par, bool forward, double tol) const
	If the ParamCurve is divided up into logical segments, this function will return the parameter value of the "next segment", starting from a parameter given by the user.

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Detailed Description

Base class for parametric curves in Go.

Definition at line 57 of file ParamCurve.h.

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Member Function Documentation

virtual void Go::ParamCurve::point	(	Point &	pt,
		double	tpar
	)			const [pure virtual]

Evaluate the curve's position at a given parameter.

Parameters:

	pt	the evaluated position will be written to this Point
	tpar	the parameter for which we wish to evaluate the curve

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual void Go::ParamCurve::point	(	std::vector< Point > &	pts,
		double	tpar,
		int	derivs,
		bool	from_right = true
	)			const [pure virtual]

Evaluate the curve's position and a certain number of derivatives at a given parameter.

Parameters:

	pts	the evaluated position and derivatives (tangent, curvature vector, etc.) will be written to this vector. The first entry will be the position, the second entry will be the first derivative, etc. The size of this vector must be set to 'derivs'+ 1 prior to calling this function.
	tpar	the parameter for which we want to evaluate the curve
	derivs	the number of derivatives we want to have calculated
	from_right	specify whether we should calculate derivatives 'from the right' or 'from the left' (default is from the right). This matters only when the curve presents discontinuities in its derivatives.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

Point Go::ParamCurve::point

(

double

tpar

)

const

Evaluate the curve's position at a certain parameter.

Parameters:

tpar

the parameter for which we want to evaluate the curve's position

Returns:

the curve's position for the parameter 'tpar'. NB: This function is implemented in terms of the ParamCurve's virtual 'point(...)' functions, but is itself not virtual. If you make a concrete subclass and wish to make this function visible to the user, you must put a 'using ParamCurve::point' statement in the class definition.

std::vector<Point> Go::ParamCurve::point	(	double	tpar,
		int	derivs,
		bool	from_right = true
	)			const

Evaluate the curve's position and a certain number of derivatives at a given parameter.

Parameters:

	tpar	the parameter for which we want to evaluate the curve
	derivs	the number of derivatives we want to have calculated
	from_right	specify whether we should calculate derivatives 'from the right' or 'from the left' (default is from the right). This matters only when the curve presents discontinuities in its derivatives.

Returns:

a STL vector containing the evaluated position and the specified number of derivatives. The first entry will be the position, the second entry will be the first derivative, etc. The total size of the returned vector will be 'derivs' + 1. NB: This function is implemented in terms of the ParamCurve's virtual 'point(...)' functions, but is itself not virtual. If you make a concrete subclass and wish to make this function visible to the user, you must put a 'using ParamCurve::point' in the class definition.

virtual double Go::ParamCurve::startparam

(

)

const [pure virtual]

Query the start parameter of the curve.

Returns:

the curve's start parameter

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual double Go::ParamCurve::endparam

(

)

const [pure virtual]

Query the end parameter of the curve.

Returns:

the curve's end parameter

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual void Go::ParamCurve::reverseParameterDirection

(

bool

switchparam = false

)

[pure virtual]

Set the parameter direction of the curve.

The curve's parameter interval will always remain constant, but by flipping the parameter direction, the curve will be traced the opposite way when moving a parameter over the parameter interval.

Parameters:

switchparam

if true, and the curve is 2D, the x and y coordinates should be swapped. This is used when turning the orientation of bounded (trimmed) surfaces.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual SplineCurve* Go::ParamCurve::geometryCurve

(

)

[pure virtual]

If the definition of this ParamCurve contains a SplineCurve describing its spatial shape, then this function will return a pointer to this SplineCurve.

Otherwise it will return a null pointer.

Returns:

a pointer to the internal SplineCurve, if it exists. Null pointer otherwise.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual bool Go::ParamCurve::isDegenerate

(

double

degenerate_epsilon

)

[pure virtual]

Query whether the curve is degenerate (collapsed into a single point).

Parameters:

degenerate_epsilon

the tolerance used in determine whether the curve is degenerate. A curve is considered degenerate if its total length is shorter than this value.

Returns:

'true' if the curve is degenerate, 'false' otherwise.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual ParamCurve* Go::ParamCurve::subCurve	(	double	from_par,
		double	to_par,
		double	fuzzy = DEFAULT_PARAMETER_EPSILON
	)			const [pure virtual]

Returns a curve which is a part of this curve.

The result is NEWed, so the user is responsible for deleting it. NB: This function only work for derived classes of ParamCurve, namely those who are spline-based.

Parameters:

	from_par	start value of parameter interval that will define the subcurve
	to_par	end value of parameter interval that will define the subcurve
	fuzzy	since subCurve works on those curves who are spline-based, this tolerance defines how close the start and end parameter must be to an existing knot in order to be considered on the knot.

Returns:

a pointer to a new subcurve which represents the part of the curve between 'from_par' and 'to_par'. It will be spline-based and have a k-regular knotvector. The user is responsible for deleting this subcurve when it is no longer needed.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual DirectionCone Go::ParamCurve::directionCone

(

)

const [pure virtual]

Creates a DirectionCone which covers all tangent directions of this curve.

Returns:

the smallest DirectionCone containing all tangent directions of this curve.

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual CompositeBox Go::ParamCurve::compositeBox

(

)

const [virtual]

Creates a composite box enclosing the curve.

The composite box consists of an inner and an edge box. The inner box is supposed to be made from the interior of the curve, while the edge box is made from the start and end points. The default implementation simply makes both boxes identical to the regular bounding box.

Returns:

the CompositeBox enclosing the curve.

Reimplemented in Go::SplineCurve.

virtual void Go::ParamCurve::appendCurve	(	ParamCurve *	cv,
		bool	reparam = true
	)			[pure virtual]

append a curve to this curve, with eventual reparametrization NB: This virtual member function currently only works for SplineCurves and CurveOnSurfaces.

Moreover, 'this' curve and the 'cv' curve must be of the same type.

Parameters:

	cv	the curve to append to 'this' curve.
	reparam	specify whether or not there should be reparametrization

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

virtual void Go::ParamCurve::appendCurve	(	ParamCurve *	cv,
		int	continuity,
		double &	dist,
		bool	reparam = true
	)			[pure virtual]

append a curve to this curve, with eventual reparmetrization

Parameters:

	cv	the curve to append to 'this' curve.
	continuity	the required continuity at the transition. Can be G^(-1) and upwards.
	dist	a measure of the local distorsion around the transition in order to achieve the specified continuity.
	reparam	specify whether or not there should be reparametrization

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

double Go::ParamCurve::estimatedCurveLength

(

int

numpts = 4

)

const

Estimate the length of the curve, by sampling it at a certain number of points and calculating the linear approximation to the curve through these points.

Parameters:

numpts

number of sample points used

Returns:

the estimated curve length

double Go::ParamCurve::estimatedCurveLength	(	double	tmin,
		double	tmax,
		int	numpts = 4
	)			const

Estimate the length of an interval of the curve, by sampling it at a certain number of points in the interval and calculating the linear approximation through these points.

Parameters:

	tmin	parameter at start of interval
	tmax	parameter at end of interval
	numpts	number of sample points used

Returns:

the estimated curve length

virtual void Go::ParamCurve::closestPoint	(	const Point &	pt,
		double	tmin,
		double	tmax,
		double &	clo_t,
		Point &	clo_pt,
		double &	clo_dist,
		double const *	seed = 0
	)			const [pure virtual]

Compute the closest point from an interval of this curve to a specified point.

Parameters:

	pt	point we want to find the closest point to
	tmin	start parameter of search interval
	tmax	end parameter of search interval
	clo_t	upon function return, 'clo_t' will contain the parameter value of the closest point found.
	clo_pt	upon function return, 'clo_pt' will contain the position of the closest point found.
	clo_dist	upon function return, 'clo_dist' will containn the distance between 'pt' and the closest point found.
	seed	pointer to initial guess value, provided by the user (can be 0, for which the algorithm will determine a (hopefully) reasonable choice).

Implemented in Go::CurveOnSurface, and Go::SplineCurve.

void Go::ParamCurve::closestPoint	(	const Point &	pt,
		double &	clo_t,
		Point &	clo_pt,
		double &	clo_dist
	)			const

Compute the closest point from this curve to a specified point, taking the whole curve into account (not just an interval of it).

Parameters:

	pt	point we want to find the closest point to
	clo_t	upon function return, 'clo_t' will contain the parameter value of the closest point found.
	clo_pt	upon function return, 'clo_pt' will contain the position of the closest point found.
	clo_dist	upon function return, 'clo_dist' will containn the distance between 'pt' and the closest point found.

virtual double Go::ParamCurve::nextSegmentVal	(	double	par,
		bool	forward,
		double	tol
	)			const [virtual]

If the ParamCurve is divided up into logical segments, this function will return the parameter value of the "next segment", starting from a parameter given by the user.

If no division into logical segments exist, then it is the start- or end parameter that is returned.

Parameters:

	par	the parameter from which we start the search for the next segment.
	forward	whether to search forwards or backwards along the parameter domain.
	tol	the tolerance to determine or not 'par' is already located on the start of the next segment.

Returns:

the parameter value of the next segment.

Reimplemented in Go::CurveOnSurface, and Go::SplineCurve.

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

• ParamCurve.h

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