ON_Curve is a pure virtual class for curve objects More...

#include <opennurbs_curve.h>

Inheritance diagram for ON_Curve:

Public Member Functions
	ON_Curve () ON_NOEXCEPT

	ON_Curve (const ON_Curve &)

virtual	~ON_Curve ()

virtual bool	ChangeClosedCurveSeam (double t)
	If this curve is closed, then modify it so that the start/end point is at curve parameter t. More...

virtual bool	ChangeDimension (int desired_dimension)
	Change the dimension of a curve. More...

ON_3dVector	CurvatureAt (double t) const
	Evaluate the curvature vector at a parameter. More...

virtual int	Degree () const =0
	Returns maximum algebraic degree of any span or a good estimate if curve spans are not algebraic. More...

ON_3dVector	DerivativeAt (double t) const
	Evaluate first derivative at a parameter. More...

void	DestroyCurveTree ()
	Destroys the runtime curve tree used to speed closest point and intersection calcuations. More...

void	DestroyRuntimeCache (bool bDelete=true) override
	virtual ON_Object::DestroyRuntimeCache override More...

virtual ON_Interval	Domain () const =0

virtual ON_Curve *	DuplicateCurve () const
	Get a duplicate of the curve. More...

bool	Ev1Der (double t, ON_3dPoint &point, ON_3dVector &first_derivative, int side=0, int *hint=0) const
	Evaluate first derivative at a parameter with error checking. More...

bool	Ev2Der (double t, ON_3dPoint &point, ON_3dVector &first_derivative, ON_3dVector &second_derivative, int side=0, int *hint=0) const
	Evaluate second derivative at a parameter with error checking. More...

virtual bool	Evaluate (double t, int der_count, int v_stride, double v, int side=0, int hint=0) const =0
	This evaluator actually does all the work. The other ON_Curve evaluation tools call this virtual function. More...

bool	EvaluatePoint (const class ON_ObjRef &objref, ON_3dPoint &P) const override
	virtual ON_Geometry override More...

bool	EvCurvature (double t, ON_3dPoint &point, ON_3dVector &tangent, ON_3dVector &kappa, int side=0, int *hint=0) const
	Evaluate unit tangent and curvature at a parameter with error checking. More...

bool	EvPoint (double t, ON_3dPoint &point, int side=0, int *hint=0) const
	Evaluate point at a parameter with error checking. More...

bool	EvTangent (double t, ON_3dPoint &point, ON_3dVector &tangent, int side=0, int *hint=0) const
	Evaluate unit tangent at a parameter with error checking. More...

virtual bool	Extend (const ON_Interval &domain)
	Pure virtual function. Default returns false. Where possible, analytically extends curve to include domain. More...

bool	FirstSpanIsLinear (double min_length, double tolerance) const

bool	FirstSpanIsLinear (double min_length, double tolerance, ON_Line *span_line) const

bool	FrameAt (double t, ON_Plane &plane) const
	Return a 3d frame at a parameter. More...

virtual bool	GetCurveParameterFromNurbFormParameter (double nurbs_t, double *curve_t) const
	Convert a NURBS curve parameter to a curve parameter More...

bool	GetDomain (double t0, double t1) const
	curve interface More...

virtual bool	GetNextDiscontinuity (ON::continuity c, double t0, double t1, double t, int hint=nullptr, int *dtype=nullptr, double cos_angle_tolerance=ON_DEFAULT_ANGLE_TOLERANCE_COSINE, double curvature_tolerance=ON_SQRT_EPSILON) const
	Search for a derivatitive, tangent, or curvature discontinuity. More...

virtual int	GetNurbForm (ON_NurbsCurve &nurbs_curve, double tolerance=0.0, const ON_Interval *subdomain=nullptr) const
	Get a NURBS curve representation of this curve. More...

virtual bool	GetNurbFormParameterFromCurveParameter (double curve_t, double *nurbs_t) const
	Convert a curve parameter to a NURBS curve parameter. More...

virtual bool	GetParameterTolerance (double t, double tminus, double tplus) const
	Returns maximum algebraic degree of any span or a good estimate if curve spans are not algebraic. More...

virtual bool	GetSpanVector (double *knots) const =0
	Get number of parameters of "knots". More...

virtual bool	GetSpanVectorIndex (double t, int side, int span_vector_index, ON_Interval span_domain) const

bool	GetTightBoundingBox (class ON_BoundingBox &tight_bbox, bool bGrowBox=false, const class ON_Xform *xform=nullptr) const override
	virtual ON_Geometry GetTightBoundingBox override More...

virtual int	HasNurbForm () const
	Does a NURBS curve representation of this curve. More...

virtual bool	IsArc (const ON_Plane plane=nullptr, ON_Arc arc=nullptr, double tolerance=ON_ZERO_TOLERANCE) const
	Test a curve to see if the locus if its points is an arc or circle. More...

bool	IsArcAt (double t, const ON_Plane plane=0, ON_Arc arc=0, double tolerance=ON_ZERO_TOLERANCE, double t0=0, double t1=0) const

bool	IsClosable (double tolerance, double min_abs_size=0.0, double min_rel_size=10.0) const
	Decide if it makes sense to close off this curve by moving the endpoint to the start based on start-end gap size and length of curve as approximated by chord defined by 6 points. More...

virtual bool	IsClosed () const
	Test a curve to see if it is closed. More...

virtual bool	IsContinuous (ON::continuity c, double t, int *hint=nullptr, double point_tolerance=ON_ZERO_TOLERANCE, double d1_tolerance=ON_ZERO_TOLERANCE, double d2_tolerance=ON_ZERO_TOLERANCE, double cos_angle_tolerance=ON_DEFAULT_ANGLE_TOLERANCE_COSINE, double curvature_tolerance=ON_SQRT_EPSILON) const
	Test continuity at a curve parameter value. More...

virtual bool	IsEllipse (const ON_Plane plane=nullptr, ON_Ellipse ellipse=nullptr, double tolerance=ON_ZERO_TOLERANCE) const

virtual bool	IsInPlane (const ON_Plane &test_plane, double tolerance=ON_ZERO_TOLERANCE) const =0
	Test a curve to see if it lies in a specific plane. More...

virtual bool	IsLinear (double tolerance=ON_ZERO_TOLERANCE) const
	Test a curve to see if the locus if its points is a line segment. More...

virtual bool	IsPeriodic () const
	Test a curve to see if it is periodic. More...

virtual bool	IsPlanar (ON_Plane *plane=nullptr, double tolerance=ON_ZERO_TOLERANCE) const
	Test a curve to see if it is planar. More...

virtual int	IsPolyline (ON_SimpleArray< ON_3dPoint > pline_points=nullptr, ON_SimpleArray< double > pline_t=nullptr) const
	Several types of ON_Curve can have the form of a polyline including a degree 1 ON_NurbsCurve, an ON_PolylineCurve, and an ON_PolyCurve all of whose segments are some form of polyline. IsPolyline tests a curve to see if it can be represented as a polyline. More...

bool	LastSpanIsLinear (double min_length, double tolerance) const

bool	LastSpanIsLinear (double min_length, double tolerance, ON_Line *span_line) const

ON_NurbsCurve *	NurbsCurve (ON_NurbsCurve pNurbsCurve=nullptr, double tolerance=0.0, const ON_Interval subdomain=nullptr) const
	Get a NURBS curve representation of this curve. More...

ON::object_type	ObjectType () const override
	overrides virtual ON_Object::ObjectType. More...

ON_Curve &	operator= (const ON_Curve &)

ON_3dPoint	PointAt (double t) const
	Evaluate point at a parameter. More...

ON_3dPoint	PointAtEnd () const
	Evaluate point at the end of the curve. More...

ON_3dPoint	PointAtStart () const
	Evaluate point at the start of the curve. More...

virtual bool	Reverse ()=0
	Reverse the direction of the curve. More...

bool	SetDomain (ON_Interval domain)
	Set the domain of the curve. More...

virtual bool	SetDomain (double t0, double t1)
	Set the domain of the curve More...

virtual bool	SetEndPoint (ON_3dPoint end_point)
	Force the curve to end at a specified point. More...

virtual bool	SetStartPoint (ON_3dPoint start_point)
	Force the curve to start at a specified point. More...

unsigned int	SizeOf () const override
	virtual ON_Object::SizeOf override More...

virtual int	SpanCount () const =0
	Get number of nonempty smooth (c-infinity) spans in curve More...

virtual bool	Split (double t, ON_Curve &left_side, ON_Curve &right_side) const
	Splits (divides) the curve at the specified parameter. The parameter must be in the interior of the curve's domain. The pointers passed to Split must either be nullptr or point to an ON_Curve object of the same type. If the pointer is nullptr, then a curve will be created in Split(). You may pass "this" as left_side or right_side. More...

ON_3dVector	TangentAt (double t) const
	Evaluate unit tangent vector at a parameter. More...

bool	Transform (const ON_Xform &xform) override
	overrides virtual ON_Geometry::Transform(). ON_Curve::Transform() calls ON_Geometry::Transform(xform), which calls ON_Object::TransformUserData(xform), and then calls this->DestroyCurveTree(). More...

virtual bool	Trim (const ON_Interval &domain)
	Removes portions of the curve outside the specified interval. More...

Public Member Functions inherited from ON_Geometry
	ON_Geometry ()=default

	ON_Geometry (const ON_Geometry &)=default

	~ON_Geometry ()=default

ON_BoundingBox	BoundingBox () const
	Get object's 3d axis aligned bounding box. More...

virtual class ON_Brep *	BrepForm (class ON_Brep *brep=nullptr) const
	If possible, BrepForm() creates a brep form of the ON_Geometry. More...

virtual void	ClearBoundingBox ()
	Some objects cache bounding box information. If you modify an object, then call ClearBoundingBox() to inform the object that any cached bounding boxes are invalid. More...

virtual ON_COMPONENT_INDEX	ComponentIndex () const
	If this piece of geometry is a component in something larger, like an ON_BrepEdge in an ON_Brep, then this function returns the component index. More...

virtual int	Dimension () const
	Dimension of the object. More...

virtual bool	GetBBox (double boxmin, double boxmax, bool bGrowBox=false) const
	This is the virtual function that actually calculates axis aligned bounding boxes. More...

bool	GetBoundingBox (ON_BoundingBox &bbox, bool bGrowBox=false) const
	Get object's 3d axis aligned bounding box or the union of the input box with the object's bounding box. More...

bool	GetBoundingBox (ON_3dPoint &bbox_min, ON_3dPoint &bbox_max, bool bGrowBox=false) const
	Get corners of object's 3d axis aligned bounding box or the union of the input box with the object's bounding box. More...

virtual bool	HasBrepForm () const
	Query an object to see if it has an ON_Brep form. Result: Returns true if the virtual ON_Geometry::BrepForm can compute an ON_Brep representation of this object. More...

virtual bool	IsDeformable () const

bool	IsValid (class ON_TextLog *text_log=nullptr) const override
	Tests an object to see if its data members are correctly initialized. More...

virtual bool	MakeDeformable ()
	If possible, converts the object into a form that can be accuratly modified with "squishy" transformations like projections, shears, an non-uniform scaling. More...

ON_Geometry &	operator= (const ON_Geometry &)=default

bool	Rotate (double sin_angle, double cos_angle, const ON_3dVector &rotation_axis, const ON_3dPoint &rotation_center)
	Rotates the object about the specified axis. A positive rotation angle results in a counter-clockwise rotation about the axis (right hand rule). More...

bool	Rotate (double rotation_angle, const ON_3dVector &rotation_axis, const ON_3dPoint &rotation_center)
	Rotates the object about the specified axis. A positive rotation angle results in a counter-clockwise rotation about the axis (right hand rule). More...

bool	Scale (double scale_factor)
	Scales the object by the specified facotor. The scale is centered at the origin. More...

virtual bool	SwapCoordinates (int i, int j)
	Swaps object coordinate values with indices i and j. More...

bool	Translate (const ON_3dVector &translation_vector)
	Translates the object along the specified vector. More...

Public Member Functions inherited from ON_Object
	ON_Object () ON_NOEXCEPT

	ON_Object (const ON_Object &)

virtual	~ON_Object ()

virtual ON_AggregateComponentStatus	AggregateComponentStatus () const
	Call whenever a component status setting is modifed by directly changing it on a component in a way that will result in any saved information about the parent object's aggretate component status becoming invalid. More...

bool	AttachUserData (class ON_UserData *pUserData)
	Attach user data to an object. More...

unsigned int	ClearAllComponentStates () const
	Set all active level component states to ON_ComponentStatus::NoneSet. More...

virtual unsigned int	ClearComponentStates (ON_ComponentStatus states_to_clear) const
	Clear the specified states on every component. More...

virtual unsigned int	ClearComponentStates (ON_COMPONENT_INDEX component_index, ON_ComponentStatus states_to_clear) const
	Clear states on an individual component. More...

unsigned int	CopyUserData (const ON_Object &source_object, ON_UUID source_userdata_item_id, ON_Object::UserDataConflictResolution userdata_conflict_resolution)
	Expert user tool that copies user data items with positive values of ON_UserData.m_userdata_copycount from source_object to "this. More...

void	CopyUserData (const ON_Object &source_object)
	Calls CopyUserData(source_object,ON_Object::UserDataConflictResolution::source_object). More...

virtual ON__UINT32	DataCRC (ON__UINT32 current_remainder) const
	Returns a CRC calculated from the information that defines the object. This CRC can be used as a quick way to see if two objects are not identical. More...

virtual bool	DeleteComponents (const ON_COMPONENT_INDEX *ci_list, size_t ci_count)
	Delete the portions of the object identified in ci_list[]. More...

bool	DetachUserData (class ON_UserData *pUserData)
	Remove user data from an object. More...

virtual void	Dump (ON_TextLog &) const
	Creates a text dump of the object. More...

void	EmergencyDestroy ()
	Sets m_user_data_list = 0. More...

class ON_UserData *	FirstUserData () const
	User data is stored as a linked list of ON_UserData classes. FirstUserData gets the first item in the linked list. This is the most recent item attached using AttachUserData(). Remark: To iterate through all the user data on an object, call FirstUserData() and then use ON_UserData::Next() to traverse the list. More...

virtual unsigned int	GetComponentsWithSetStates (ON_ComponentStatus states_filter, bool bAllEqualStates, ON_SimpleArray< ON_COMPONENT_INDEX > &components) const

class ON_UserData *	GetUserData (const ON_UUID &userdata_uuid) const
	Get a pointer to user data. More...

bool	GetUserString (const wchar_t *key, ON_wString &string_value) const
	Get user string from the object. More...

int	GetUserStringKeys (ON_ClassArray< ON_wString > &user_string_keys) const
	Get a list of all user string keys on the object. More...

int	GetUserStrings (ON_ClassArray< ON_UserString > &user_strings) const
	Get a list of all user strings on the object. More...

bool	IsKindOf (const ON_ClassId *pClassId) const
	Low level tool to test if an object is derived from a specified class. More...

virtual void	MarkAggregateComponentStatusAsNotCurrent () const
	Call whenever a component status setting is modifed by directly changing it on a component in a way that will result in any saved information about the parent object's aggretate component status becoming invalid. More...

virtual void	MemoryRelocate ()
	The MemoryRelocate() function is called when an object's location in memory is changed. For example, if an object resides in a chunk of memory that is grown by calling a realloc that has to allocate a new chunk and copy the contents of the old chunk to the new chunk, then the location of the object's memory changes. In practice this happens when classes derived from ON_Object are stored in dynamic arrays, like the default implementation of ON_ObjectArray<>'s that use realloc to grow the dynamic array. More...

virtual ON_UUID	ModelObjectId () const
	All objects in an opennurbs model have an id ( ON_Layer.m_layer_id, ON_Font.m_font_id, ON_Material.m_material_id, ON_3dmObjectAttributes.m_uuid ). More...

unsigned int	MoveUserData (ON_Object &source_object, ON_UUID source_userdata_item_id, ON_Object::UserDataConflictResolution userdata_conflict_resolution, bool bDeleteAllSourceItems)
	Expert user tool that moves user data items from source_object to "this. More...

void	MoveUserData (ON_Object &source_object)
	Calls MoveUserData(source_object,ON_Object::UserDataConflictResolution::source_object,true). More...

ON_Object &	operator= (const ON_Object &)

void	PurgeUserData ()
	PurgeUserData() removes all user data from object. More...

virtual bool	Read (ON_BinaryArchive &binary_archive)
	Low level archive writing tool used by ON_BinaryArchive::ReadObject(). More...

virtual unsigned int	SetComponentStates (ON_COMPONENT_INDEX component_index, ON_ComponentStatus states_to_set) const
	Set states on an individual component. More...

virtual unsigned int	SetComponentStatus (ON_COMPONENT_INDEX component_index, ON_ComponentStatus status_to_copy) const
	Copy status settings to an individual component. More...

bool	SetUserString (const wchar_t key, const wchar_t string_value)
	Attach a user string to the object. This information will perisist through copy construction, operator=, and file IO. More...

int	SetUserStrings (int count, const ON_UserString *user_strings, bool bReplace)
	Append entries to the user string list More...

void	TransformUserData (const class ON_Xform &xform)
	Objects derived from ON_Geometry must call TransformUserData() in their Transform() member function. More...

virtual bool	UpdateReferencedComponents (const class ON_ComponentManifest &source_manifest, const class ON_ComponentManifest &destination_manifest, const class ON_ManifestMap &manifest_map)
	Uses the destination_manifest to update references to other components. This is typically done when a component's references came from a "source" context and are being updated to the "destination" context. For example, inserting one model into another when index, id, and name conflicts need to be resolved at the time of insertion. More...

int	UserStringCount () const

virtual bool	Write (ON_BinaryArchive &binary_archive) const
	Low level archive writing tool used by ON_BinaryArchive::WriteObject(). More...

Protected Member Functions
bool	ParameterSearch (double t, int &index, bool bEnableSnap, const ON_SimpleArray< double > &m_t, double RelTol=ON_SQRT_EPSILON) const
	Lookup a parameter in the m_t array, optionally using a built in snap tolerance to snap a parameter value to an element of m_t. This function is used by some types derived from ON_Curve to snap parameter values More...

Additional Inherited Members
Public Types inherited from ON_Object
enum	UserDataConflictResolution : unsigned char { UserDataConflictResolution::destination_object = 0, UserDataConflictResolution::source_object = 1, UserDataConflictResolution::source_copycount_gt = 2, UserDataConflictResolution::source_copycount_ge = 3, UserDataConflictResolution::destination_copycount_gt = 4, UserDataConflictResolution::destination_copycount_ge = 5, UserDataConflictResolution::delete_item = 6 }
	When a userdata item is copied or moved from a source object to a destination object, the ON_Object::UserDataConflictResolution enum values specify how conficts are resolved. Remark: A userdata item "conflict" occurs when both the destination and source object have a user data item with the same value of ON_UserData::m_userdata_uuid. More...

Static Public Attributes inherited from ON_Geometry
static const ON_Geometry	Unset

Detailed Description

ON_Curve is a pure virtual class for curve objects

Any class derived from ON_Curve should have a ON_OBJECT_DECLARE(ON_...); at the beginning of its class definition and a ON_OBJECT_IMPLEMENT( ON_..., ON_Curve ); in a .cpp file.

- See the definition of ON_NurbsCurve for an example.

Constructor & Destructor Documentation

◆ ON_Curve() [1/2]

ON_Curve::ON_Curve ( )

◆ ~ON_Curve()

virtual ON_Curve::~ON_Curve ( )

virtual

◆ ON_Curve() [2/2]

ON_Curve::ON_Curve ( const ON_Curve & )

Member Function Documentation

◆ ChangeClosedCurveSeam()

virtual bool ON_Curve::ChangeClosedCurveSeam ( double t )

virtual

If this curve is closed, then modify it so that the start/end point is at curve parameter t.

Parameters

t	[in] curve parameter of new start/end point. The returned curves domain will start at t.

Returns: true if successful.

Reimplemented in ON_NurbsCurve, ON_PolyCurve, ON_PolylineCurve, ON_ArcCurve, and ON_PolyEdgeCurve.

◆ ChangeDimension()

virtual bool ON_Curve::ChangeDimension ( int desired_dimension )

virtual

Change the dimension of a curve.

Parameters

desired_dimension [in]

Returns: true if the curve's dimension was already desired_dimension or if the curve's dimension was successfully changed to desired_dimension.

Reimplemented in ON_NurbsCurve, ON_PolyCurve, ON_PolylineCurve, ON_ArcCurve, and ON_LineCurve.

◆ CurvatureAt()

ON_3dVector ON_Curve::CurvatureAt ( double t ) const

Evaluate the curvature vector at a parameter.

Parameters

t	[in] evaluation parameter

Returns: curvature vector of the curve at the parameter t.

No error handling.

See also: ON_Curve::EvCurvature

◆ Degree()

virtual int ON_Curve::Degree ( ) const

pure virtual

Returns maximum algebraic degree of any span or a good estimate if curve spans are not algebraic.

Returns: degree

Implemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ DerivativeAt()

ON_3dVector ON_Curve::DerivativeAt ( double t ) const

Evaluate first derivative at a parameter.

Parameters

t	[in] evaluation parameter

Returns: First derivative of the curve at the parameter t.

No error handling.

See also: ON_Curve::Ev1Der

◆ DestroyCurveTree()

void ON_Curve::DestroyCurveTree ( )

Destroys the runtime curve tree used to speed closest point and intersection calcuations.

If the geometry of the curve is modified in any way, then call DestroyCurveTree(); The curve tree is created as needed.

◆ DestroyRuntimeCache()

void ON_Curve::DestroyRuntimeCache ( bool bDelete = true )

overridevirtual

virtual ON_Object::DestroyRuntimeCache override

Reimplemented from ON_Object.

Reimplemented in ON_PolyEdgeSegment, ON_CurveProxy, ON_PolyCurve, and ON_PolyEdgeCurve.

◆ Domain()

virtual ON_Interval ON_Curve::Domain ( ) const

pure virtual

Returns: domain of the curve.

Implemented in ON_NurbsCurve, ON_CurveProxy, ON_ArcCurve, ON_PolyCurve, ON_PolylineCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ DuplicateCurve()

virtual ON_Curve* ON_Curve::DuplicateCurve ( ) const

virtual

Get a duplicate of the curve.

Returns: A duplicate of the curve.

The caller must delete the returned curve. For non-ON_CurveProxy objects, this simply duplicates the curve using ON_Object::Duplicate. For ON_CurveProxy objects, this duplicates the actual proxy curve geometry and, if necessary, trims and reverse the result to that the returned curve's parameterization and locus match the proxy curve's.

Reimplemented in ON_CurveProxy, ON_PolyEdgeSegment, ON_PolyCurve, and ON_PolyEdgeCurve.

◆ Ev1Der()

bool ON_Curve::Ev1Der	(	double	t,
		ON_3dPoint &	point,
		ON_3dVector &	first_derivative,
		int	side = `0`,
		int *	hint = `0`
	)		const

Evaluate first derivative at a parameter with error checking.

Parameters

t	[in] evaluation parameter
point	[out] value of curve at t
first_derivative	[out] value of first derivative at t
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::EvPoint, ON_Curve::Ev2Der, ON_Curve::EvTangent, ON_Curve::Evaluate

◆ Ev2Der()

bool ON_Curve::Ev2Der	(	double	t,
		ON_3dPoint &	point,
		ON_3dVector &	first_derivative,
		ON_3dVector &	second_derivative,
		int	side = `0`,
		int *	hint = `0`
	)		const

Evaluate second derivative at a parameter with error checking.

Parameters

t	[in] evaluation parameter
point	[out] value of curve at t
first_derivative	[out] value of first derivative at t
second_derivative	[out] value of second derivative at t
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::Ev1Der, ON_Curve::EvCurvature, ON_Curve::Evaluate

◆ Evaluate()

virtual bool ON_Curve::Evaluate	(	double	t,
		int	der_count,
		int	v_stride,
		double *	v,
		int	side = `0`,
		int *	hint = `0`
	)		const

pure virtual

This evaluator actually does all the work. The other ON_Curve evaluation tools call this virtual function.

Parameters

t	[in] evaluation parameter ( usually in Domain() ).
der_count	[in] (>=0) number of derivatives to evaluate
v_stride	[in] (>=Dimension()) stride to use for the v[] array
v	[out] array of length (der_count+1)v_stride curve(t) is returned in (v[0],...,v[m_dim-1]), curve'(t) is retuned in (v[v_stride],...,v[v_stride+m_dim-1]), curve"(t) is retuned in (v[2v_stride],...,v[2*v_stride+m_dim-1]), etc.
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::EvPoint, ON_Curve::Ev1Der, ON_Curve::Ev2Der

Implemented in ON_NurbsCurve, ON_PolylineCurve, ON_CurveProxy, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ EvaluatePoint()

bool ON_Curve::EvaluatePoint	(	const class ON_ObjRef &	objref,
		ON_3dPoint &	P
	)		const

overridevirtual

virtual ON_Geometry override

Reimplemented from ON_Geometry.

Reimplemented in ON_PolyCurve.

◆ EvCurvature()

bool ON_Curve::EvCurvature	(	double	t,
		ON_3dPoint &	point,
		ON_3dVector &	tangent,
		ON_3dVector &	kappa,
		int	side = `0`,
		int *	hint = `0`
	)		const

Evaluate unit tangent and curvature at a parameter with error checking.

Parameters

t	[in] evaluation parameter
point	[out] value of curve at t
tangent	[out] value of unit tangent
kappa	[out] value of curvature vector
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::CurvatureAt, ON_Curve::Ev2Der, ON_EvCurvature

◆ EvPoint()

bool ON_Curve::EvPoint	(	double	t,
		ON_3dPoint &	point,
		int	side = `0`,
		int *	hint = `0`
	)		const

Evaluate point at a parameter with error checking.

Parameters

t	[in] evaluation parameter
point	[out] value of curve at t
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::PointAt, ON_Curve::EvTangent, ON_Curve::Evaluate

◆ EvTangent()

bool ON_Curve::EvTangent	(	double	t,
		ON_3dPoint &	point,
		ON_3dVector &	tangent,
		int	side = `0`,
		int *	hint = `0`
	)		const

Evaluate unit tangent at a parameter with error checking.

Parameters

t	[in] evaluation parameter
point	[out] value of curve at t
tangent	[out] value of unit tangent
side	[in] optional - determines which side to evaluate from =0 default <0 to evaluate from below, >0 to evaluate from above
hint	[in/out] optional evaluation hint used to speed repeated evaluations

Returns: false if unable to evaluate.

See also: ON_Curve::TangentAt, ON_Curve::Ev1Der

◆ Extend()

virtual bool ON_Curve::Extend ( const ON_Interval & domain )

virtual

Pure virtual function. Default returns false. Where possible, analytically extends curve to include domain.

Parameters

domain [in] if domain is not included in curve domain, curve will be extended so that its domain includes domain. Will not work if curve is closed. Original curve is identical to the restriction of the resulting curve to the original curve domain,

Returns: true if successful.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, and ON_LineCurve.

◆ FirstSpanIsLinear() [1/2]

bool ON_Curve::FirstSpanIsLinear	(	double	min_length,
		double	tolerance
	)		const

Parameters

min_length	[in] minimum length of a linear span
tolerance	[in] distance tolerance to use when checking linearity. Returns true if the span is a non-degenrate line. This means: dimension = 2 or 3 The length of the the line segment from the span's initial point to the span's control point is >= min_length. The maximum distance from the line segment to the span is <= tolerance and the span increases monotonically in the direction of the line segment.

◆ FirstSpanIsLinear() [2/2]

bool ON_Curve::FirstSpanIsLinear	(	double	min_length,
		double	tolerance,
		ON_Line *	span_line
	)		const

◆ FrameAt()

bool ON_Curve::FrameAt	(	double	t,
		ON_Plane &	plane
	)		const

Return a 3d frame at a parameter.

Parameters

t	[in] evaluation parameter
plane	[out] the frame is returned here

Returns: true if successful

See also: ON_Curve::PointAt, ON_Curve::TangentAt,, ON_Curve::Ev1Der, Ev2Der

◆ GetCurveParameterFromNurbFormParameter()

virtual bool ON_Curve::GetCurveParameterFromNurbFormParameter	(	double	nurbs_t,
		double *	curve_t
	)		const

virtual

Convert a NURBS curve parameter to a curve parameter

Parameters

nurbs_t	[in] nurbs form parameter
curve_t	[out] curve parameter

If GetNurbForm returns 2, this function converts the curve parameter to the NURBS curve parameter.

See also: ON_Curve::GetNurbForm, ON_Curve::GetNurbFormParameterFromCurveParameter

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_CurveProxy, ON_LineCurve, and ON_ArcCurve.

◆ GetDomain()

bool ON_Curve::GetDomain	(	double *	t0,
		double *	t1
	)		const

curve interface

Gets domain of the curve

Parameters

t0	[out]
t1	[out] domain is [t0, t1]

Returns: true if successful.

◆ GetNextDiscontinuity()

virtual bool ON_Curve::GetNextDiscontinuity	(	ON::continuity	c,
		double	t0,
		double	t1,
		double *	t,
		int *	hint = `nullptr`,
		int *	dtype = `nullptr`,
		double	cos_angle_tolerance = `ON_DEFAULT_ANGLE_TOLERANCE_COSINE`,
		double	curvature_tolerance = `ON_SQRT_EPSILON`
	)		const

virtual

Search for a derivatitive, tangent, or curvature discontinuity.

Parameters

c	[in] type of continity to test for.
t0	[in] Search begins at t0. If there is a discontinuity at t0, it will be ignored. This makes it possible to repeatedly call GetNextDiscontinuity and step through the discontinuities.
t1	[in] (t0 != t1) If there is a discontinuity at t1 is will be ingored unless c is a locus discontinuity type and t1 is at the start or end of the curve.
t	[out] if a discontinuity is found, then *t reports the parameter at the discontinuity.
hint	[in/out] if GetNextDiscontinuity will be called repeatedly, passing a "hint" with initial value *hint=0 will increase the speed of the search.
dtype	[out] if not nullptr, dtype reports the kind of discontinuity found at t. A value of 1 means the first derivative or unit tangent was discontinuous. A value of 2 means the second derivative or curvature was discontinuous. A value of 0 means teh curve is not closed, a locus discontinuity test was applied, and t1 is at the start of end of the curve. If 'c', the type of continuity to test for is ON::continuity::Gsmooth_continuous and the curvature changes from curved to 0 or 0 to curved and there is no tangency kink dtype is returns 3
cos_angle_tolerance	[in] default = cos(1 degree) Used only when c is ON::continuity::G1_continuous or ON::continuity::G2_continuous. If the cosine of the angle between two tangent vectors is <= cos_angle_tolerance, then a G1 discontinuity is reported.
curvature_tolerance	[in] (default = ON_SQRT_EPSILON) Used only when c is ON::continuity::G2_continuous. If K0 and K1 are curvatures evaluated from above and below and \|K0 - K1\| > curvature_tolerance, then a curvature discontinuity is reported.

Returns

Parametric continuity tests c = (C0_continuous, ..., G2_continuous):

true if a parametric discontinuity was found strictly
between t0 and t1. Note well that all curves are
parametrically continuous at the ends of their domains.

Locus continuity tests c = (C0_locus_continuous, ...,G2_locus_continuous):

true if a locus discontinuity was found strictly between
t0 and t1 or at t1 is the at the end of a curve.
Note well that all open curves (IsClosed()=false) are locus
discontinuous at the ends of their domains.  All closed
curves (IsClosed()=true) are at least C0_locus_continuous at
the ends of their domains.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_CurveProxy, and ON_PolyCurve.

◆ GetNurbForm()

virtual int ON_Curve::GetNurbForm	(	ON_NurbsCurve &	nurbs_curve,
		double	tolerance = `0.0`,
		const ON_Interval *	subdomain = `nullptr`
	)		const

virtual

Get a NURBS curve representation of this curve.

Parameters

nurbs_curve	[out] NURBS representation returned here
tolerance	[in] tolerance to use when creating NURBS representation.
subdomain	[in] if not nullptr, then the NURBS representation for this portion of the curve is returned.

Returns: 0 unable to create NURBS representation with desired accuracy. 1 success - returned NURBS parameterization matches the curve's to wthe desired accuracy 2 success - returned NURBS point locus matches the curve's to the desired accuracy and the domain of the NURBS curve is correct. On However, This curve's parameterization and the NURBS curve parameterization may not match to the desired accuracy. This situation happens when getting NURBS representations of curves that have a transendental parameterization like circles

This is a low-level virtual function. If you do not need the parameterization information provided by the return code, then ON_Curve::NurbsCurve may be easier to use.

See also: ON_Curve::NurbsCurve

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_CurveProxy, ON_LineCurve, ON_ArcCurve, and ON_CurveOnSurface.

◆ GetNurbFormParameterFromCurveParameter()

virtual bool ON_Curve::GetNurbFormParameterFromCurveParameter	(	double	curve_t,
		double *	nurbs_t
	)		const

virtual

Convert a curve parameter to a NURBS curve parameter.

Parameters

curve_t	[in] curve parameter
nurbs_t	[out] nurbs form parameter

If GetNurbForm returns 2, this function converts the curve parameter to the NURBS curve parameter.

See also: ON_Curve::GetNurbForm, ON_Curve::GetCurveParameterFromNurbFormParameter

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_CurveProxy, ON_LineCurve, and ON_ArcCurve.

◆ GetParameterTolerance()

virtual bool ON_Curve::GetParameterTolerance	(	double	t,
		double *	tminus,
		double *	tplus
	)		const

virtual

Returns maximum algebraic degree of any span or a good estimate if curve spans are not algebraic.

Returns: degree

Reimplemented in ON_NurbsCurve, ON_CurveProxy, and ON_CurveOnSurface.

◆ GetSpanVector()

virtual bool ON_Curve::GetSpanVector ( double * knots ) const

pure virtual

Get number of parameters of "knots".

Parameters

knots [out] an array of length SpanCount()+1 is filled in with the parameters where the curve is not smooth (C-infinity).

Returns: true if successful

Implemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ GetSpanVectorIndex()

virtual bool ON_Curve::GetSpanVectorIndex	(	double	t,
		int	side,
		int *	span_vector_index,
		ON_Interval *	span_domain
	)		const

virtual

◆ GetTightBoundingBox()

bool ON_Curve::GetTightBoundingBox	(	class ON_BoundingBox &	tight_bbox,
		bool	bGrowBox = `false`,
		const class ON_Xform *	xform = `nullptr`
	)		const

overridevirtual

virtual ON_Geometry GetTightBoundingBox override

Reimplemented from ON_Geometry.

Reimplemented in ON_PolyCurve, ON_PolylineCurve, and ON_LineCurve.

◆ HasNurbForm()

virtual int ON_Curve::HasNurbForm ( ) const

virtual

Does a NURBS curve representation of this curve.

Returns: 0 unable to create NURBS representation with desired accuracy. 1 success - NURBS parameterization matches the curve's to wthe desired accuracy 2 success - NURBS point locus matches the curve's and the domain of the NURBS curve is correct. However, This curve's parameterization and the NURBS curve parameterization may not match. This situation happens when getting NURBS representations of curves that have a transendental parameterization like circles

This is a low-level virtual function.

See also: ON_Curve::GetNurbForm, ON_Curve::NurbsCurve

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_CurveProxy, ON_LineCurve, and ON_ArcCurve.

◆ IsArc()

virtual bool ON_Curve::IsArc	(	const ON_Plane *	plane = `nullptr`,
		ON_Arc *	arc = `nullptr`,
		double	tolerance = `ON_ZERO_TOLERANCE`
	)		const

virtual

Test a curve to see if the locus if its points is an arc or circle.

Parameters

plane	[in] if not nullptr, test is performed in this plane
arc	[out] if not nullptr and true is returned, then arc parameters are filled in
tolerance	[in] tolerance to use when checking

Returns: ON_Arc.m_angle > 0 if curve locus is an arc between specified points. If ON_Arc.m_angle is 2.0*ON_PI, then the curve is a circle.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ IsArcAt()

bool ON_Curve::IsArcAt	(	double	t,
		const ON_Plane *	plane = `0`,
		ON_Arc *	arc = `0`,
		double	tolerance = `ON_ZERO_TOLERANCE`,
		double *	t0 = `0`,
		double *	t1 = `0`
	)		const

Parameters

t	[in] curve parameter
plane	[in] if not nullptr, test is performed in this plane
arc	[out] if not nullptr and true is returned, then arc parameters are filled in
tolerance	[in] tolerance to use when checking
t0	[out] if not nullptr, and then *t0 is set to the parameter at the start of the G2 curve segment that was tested.
t1	[out] if not nullptr, and then *t0 is set to the parameter at the start of the G2 curve segment that was tested.

Returns: True if the paramter t is on a arc segment of the curve.

◆ IsClosable()

bool ON_Curve::IsClosable	(	double	tolerance,
		double	min_abs_size = `0.0`,
		double	min_rel_size = `10.0`
	)		const

Decide if it makes sense to close off this curve by moving the endpoint to the start based on start-end gap size and length of curve as approximated by chord defined by 6 points.

Parameters

tolerance	[in] maximum allowable distance between start and end. if start - end gap is greater than tolerance, returns false
min_abs_size	[in] if greater than 0.0 and none of the interior sampled points are at least min_abs_size from start, returns false.
min_rel_size	[in] if greater than 1.0 and chord length is less than min_rel_size*gap, returns false.

Returns: true if start and end points are close enough based on above conditions.

◆ IsClosed()

virtual bool ON_Curve::IsClosed ( ) const

virtual

Test a curve to see if it is closed.

Returns: true if the curve is closed.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_BrepEdge, ON_ArcCurve, ON_LineCurve, ON_PolyEdgeSegment, ON_CurveOnSurface, and ON_PolyEdgeCurve.

◆ IsContinuous()

virtual bool ON_Curve::IsContinuous	(	ON::continuity	c,
		double	t,
		int *	hint = `nullptr`,
		double	point_tolerance = `ON_ZERO_TOLERANCE`,
		double	d1_tolerance = `ON_ZERO_TOLERANCE`,
		double	d2_tolerance = `ON_ZERO_TOLERANCE`,
		double	cos_angle_tolerance = `ON_DEFAULT_ANGLE_TOLERANCE_COSINE`,
		double	curvature_tolerance = `ON_SQRT_EPSILON`
	)		const

virtual

Test continuity at a curve parameter value.

Parameters

c	[in] type of continuity to test for. Read ON::continuity comments for details.
t	[in] parameter to test
hint	[in] evaluation hint
point_tolerance	[in] if the distance between two points is greater than point_tolerance, then the curve is not C0.
d1_tolerance	[in] if the difference between two first derivatives is greater than d1_tolerance, then the curve is not C1.
d2_tolerance	[in] if the difference between two second derivatives is greater than d2_tolerance, then the curve is not C2.
cos_angle_tolerance	[in] default = cos(1 degree) Used only when c is ON::continuity::G1_continuous or ON::continuity::G2_continuous. If the cosine of the angle between two tangent vectors is <= cos_angle_tolerance, then a G1 discontinuity is reported.
curvature_tolerance	[in] (default = ON_SQRT_EPSILON) Used only when c is ON::continuity::G2_continuous or ON::continuity::Gsmooth_continuous. ON::continuity::G2_continuous: If K0 and K1 are curvatures evaluated from above and below and \|K0 - K1\| > curvature_tolerance, then a curvature discontinuity is reported. ON::continuity::Gsmooth_continuous: If K0 and K1 are curvatures evaluated from above and below and the angle between K0 and K1 is at least twice angle tolerance or \|\|K0\| - \|K1\|\| > (max(\|K0\|,\|K1\|) > curvature_tolerance, then a curvature discontinuity is reported.

Returns: true if the curve has at least the c type continuity at the parameter t.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_CurveProxy, ON_PolyCurve, and ON_ArcCurve.

◆ IsEllipse()

virtual bool ON_Curve::IsEllipse	(	const ON_Plane *	plane = `nullptr`,
		ON_Ellipse *	ellipse = `nullptr`,
		double	tolerance = `ON_ZERO_TOLERANCE`
	)		const

virtual

◆ IsInPlane()

virtual bool ON_Curve::IsInPlane	(	const ON_Plane &	test_plane,
		double	tolerance = `ON_ZERO_TOLERANCE`
	)		const

pure virtual

Test a curve to see if it lies in a specific plane.

Parameters

test_plane	[in]
tolerance	[in] tolerance to use when checking

Returns: true if the maximum distance from the curve to the test_plane is <= tolerance.

Implemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ IsLinear()

virtual bool ON_Curve::IsLinear ( double tolerance = ON_ZERO_TOLERANCE ) const

virtual

Test a curve to see if the locus if its points is a line segment.

Parameters

tolerance [in] // tolerance to use when checking linearity

Returns: true if the ends of the curve are farther than tolerance apart and the maximum distance from any point on the curve to the line segment connecting the curve's ends is <= tolerance.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ IsPeriodic()

virtual bool ON_Curve::IsPeriodic ( ) const

virtual

Test a curve to see if it is periodic.

Returns: true if the curve is closed and at least C2 at the start/end.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_CurveProxy, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ IsPlanar()

virtual bool ON_Curve::IsPlanar	(	ON_Plane *	plane = `nullptr`,
		double	tolerance = `ON_ZERO_TOLERANCE`
	)		const

virtual

Test a curve to see if it is planar.

Parameters

plane	[out] if not nullptr and true is returned, the plane parameters are filled in.
tolerance	[in] tolerance to use when checking

Returns: true if there is a plane such that the maximum distance from the curve to the plane is <= tolerance.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ IsPolyline()

virtual int ON_Curve::IsPolyline	(	ON_SimpleArray< ON_3dPoint > *	pline_points = `nullptr`,
		ON_SimpleArray< double > *	pline_t = `nullptr`
	)		const

virtual

Several types of ON_Curve can have the form of a polyline including a degree 1 ON_NurbsCurve, an ON_PolylineCurve, and an ON_PolyCurve all of whose segments are some form of polyline. IsPolyline tests a curve to see if it can be represented as a polyline.

Parameters

pline_points	[out] if not nullptr and true is returned, then the points of the polyline form are returned here.
t	[out] if not nullptr and true is returned, then the parameters of the polyline points are returned here.

Returns: table 0 curve is not some form of a polyline >=2 number of points in polyline form

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, and ON_LineCurve.

◆ LastSpanIsLinear() [1/2]

bool ON_Curve::LastSpanIsLinear	(	double	min_length,
		double	tolerance
	)		const

◆ LastSpanIsLinear() [2/2]

bool ON_Curve::LastSpanIsLinear	(	double	min_length,
		double	tolerance,
		ON_Line *	span_line
	)		const

◆ NurbsCurve()

ON_NurbsCurve* ON_Curve::NurbsCurve	(	ON_NurbsCurve *	pNurbsCurve = `nullptr`,
		double	tolerance = `0.0`,
		const ON_Interval *	subdomain = `nullptr`
	)		const

Get a NURBS curve representation of this curve.

Parameters

pNurbsCurve	[in/out] if not nullptr, this ON_NurbsCurve will be used to store the NURBS representation of the curve will be returned.
tolerance	[in] tolerance to use when creating NURBS representation.
subdomain	[in] if not nullptr, then the NURBS representation for this portion of the curve is returned.

Returns: nullptr or a NURBS representation of the curve.

See ON_Surface::GetNurbForm for important details about the NURBS surface parameterization.

See also: ON_Curve::GetNurbForm

◆ ObjectType()

ON::object_type ON_Curve::ObjectType ( ) const

overridevirtual

overrides virtual ON_Object::ObjectType.

Returns: ON::curve_object

Reimplemented from ON_Object.

◆ operator=()

ON_Curve& ON_Curve::operator= ( const ON_Curve & )

◆ ParameterSearch()

bool ON_Curve::ParameterSearch	(	double	t,
		int &	index,
		bool	bEnableSnap,
		const ON_SimpleArray< double > &	m_t,
		double	RelTol = `ON_SQRT_EPSILON`
	)		const

protected

Lookup a parameter in the m_t array, optionally using a built in snap tolerance to snap a parameter value to an element of m_t. This function is used by some types derived from ON_Curve to snap parameter values

Parameters

t	[in] parameter
index	[out] index into m_t such that if function returns false then

value condition -1 t<m_t[0] or m_t is empty 0<=i<=m_t.Count()-2 m_t[i] < t < m_t[i+1] m_t.Count()-1 t>m_t[ m_t.Count()-1]

if the function returns true then t is equal to, or is closest to and within tolerance of m_t[index].

Parameters

bEnableSnap	[in] enable snapping
m_t	[in] Array of parameter values to snap to
RelTol	[in] tolerance used in snapping

Returns: true if the t is exactly equal to (bEnableSnap==false), or within tolerance of (bEnableSnap==true) m_t[index].

◆ PointAt()

ON_3dPoint ON_Curve::PointAt ( double t ) const

Evaluate point at a parameter.

Parameters

t	[in] evaluation parameter

Returns: Point (location of curve at the parameter t).

No error handling.

See also: ON_Curve::EvPoint, ON_Curve::PointAtStart, ON_Curve::PointAtEnd

◆ PointAtEnd()

ON_3dPoint ON_Curve::PointAtEnd ( ) const

Evaluate point at the end of the curve.

Parameters

t	[in] evaluation parameter

Returns: Point (location of the end of the curve.)

No error handling.

See also: ON_Curve::PointAt

◆ PointAtStart()

ON_3dPoint ON_Curve::PointAtStart ( ) const

Evaluate point at the start of the curve.

Parameters

t	[in] evaluation parameter

Returns: Point (location of the start of the curve.)

No error handling.

See also: ON_Curve::PointAt

◆ Reverse()

virtual bool ON_Curve::Reverse ( )

pure virtual

Reverse the direction of the curve.

Returns: true if curve was reversed.

If reveresed, the domain changes from [a,b] to [-b,-a]

Implemented in ON_NurbsCurve, ON_BrepTrim, ON_PolylineCurve, ON_CurveProxy, ON_PolyCurve, ON_BrepEdge, ON_LineCurve, ON_ArcCurve, and ON_CurveOnSurface.

◆ SetDomain() [1/2]

bool ON_Curve::SetDomain ( ON_Interval domain )

Set the domain of the curve.

Parameters

domain [in] increasing interval

Returns: true if successful.

◆ SetDomain() [2/2]

virtual bool ON_Curve::SetDomain	(	double	t0,
		double	t1
	)

virtual

Set the domain of the curve

Parameters

t0	[in]
t1	[in] new domain will be [t0,t1]

Returns: true if successful.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolyCurve, ON_PolylineCurve, ON_ArcCurve, and ON_LineCurve.

◆ SetEndPoint()

virtual bool ON_Curve::SetEndPoint ( ON_3dPoint end_point )

virtual

Force the curve to end at a specified point.

Parameters

end_point [in]

Returns: true if successful.

Some end points cannot be moved. Be sure to check return code. ON_Curve::SetEndPoint() returns true if end_point is the same as the end of the curve, false otherwise.

See also: ON_Curve::SetStartPoint, ON_Curve::PointAtStart, ON_Curve::PointAtEnd

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_PolyEdgeCurve.

◆ SetStartPoint()

virtual bool ON_Curve::SetStartPoint ( ON_3dPoint start_point )

virtual

Force the curve to start at a specified point.

Parameters

start_point [in]

Returns: true if successful.

Some end points cannot be moved. Be sure to check return code. ON_Curve::SetStartPoint() returns true if start_point is the same as the start of the curve, false otherwise.

See also: ON_Curve::SetEndPoint, ON_Curve::PointAtStart, ON_Curve::PointAtEnd

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_PolyEdgeCurve.

◆ SizeOf()

unsigned int ON_Curve::SizeOf ( ) const

overridevirtual

virtual ON_Object::SizeOf override

Reimplemented from ON_Object.

Reimplemented in ON_NurbsCurve, ON_PolyCurve, ON_CurveProxy, ON_CurveOnSurface, ON_PolylineCurve, and ON_LineCurve.

◆ SpanCount()

virtual int ON_Curve::SpanCount ( ) const

pure virtual

Get number of nonempty smooth (c-infinity) spans in curve

Returns: Number of nonempty smooth (c-infinity) spans.

Implemented in ON_NurbsCurve, ON_CurveProxy, ON_PolylineCurve, ON_PolyCurve, ON_ArcCurve, ON_LineCurve, and ON_CurveOnSurface.

◆ Split()

virtual bool ON_Curve::Split	(	double	t,
		ON_Curve *&	left_side,
		ON_Curve *&	right_side
	)		const

virtual

Splits (divides) the curve at the specified parameter. The parameter must be in the interior of the curve's domain. The pointers passed to Split must either be nullptr or point to an ON_Curve object of the same type. If the pointer is nullptr, then a curve will be created in Split(). You may pass "this" as left_side or right_side.

Parameters

t	[in] parameter to split the curve at in the interval returned by Domain().
left_side	[out] left portion of curve returned here
right_side	[out] right portion of curve returned here

Returns

true - The curve was split into two pieces. false - The curve could not be split. For example if the parameter is too close to an endpoint.

For example, if crv were an ON_NurbsCurve, then
@verbatim
    ON_NurbsCurve right_side;
    crv.Split( crv.Domain().Mid() &crv, &right_side );
@endverbatim
would split crv at the parametric midpoint, put the left side
in crv, and return the right side in right_side.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_PolyCurve, ON_CurveProxy, ON_ArcCurve, and ON_LineCurve.

◆ TangentAt()

ON_3dVector ON_Curve::TangentAt ( double t ) const

Evaluate unit tangent vector at a parameter.

Parameters

t	[in] evaluation parameter

Returns: Unit tangent vector of the curve at the parameter t.

No error handling.

See also: ON_Curve::EvTangent

◆ Transform()

bool ON_Curve::Transform ( const ON_Xform & xform )

overridevirtual

overrides virtual ON_Geometry::Transform(). ON_Curve::Transform() calls ON_Geometry::Transform(xform), which calls ON_Object::TransformUserData(xform), and then calls this->DestroyCurveTree().

Parameters

xform [in] transformation to apply to object.

Classes derived from ON_Curve should call ON_Curve::Transform() to handle user data transformations and curve tree destruction and then transform their definition.

Reimplemented from ON_Geometry.

Reimplemented in ON_NurbsCurve, ON_CurveProxy, ON_PolyCurve, ON_PolylineCurve, ON_CurveOnSurface, and ON_LineCurve.

◆ Trim()

virtual bool ON_Curve::Trim ( const ON_Interval & domain )

virtual

Removes portions of the curve outside the specified interval.

Parameters

domain [in] interval of the curve to keep. Portions of the curve before curve(domain[0]) and after curve(domain[1]) are removed.

Returns: true if successful.

Reimplemented in ON_NurbsCurve, ON_PolylineCurve, ON_CurveProxy, ON_PolyCurve, ON_ArcCurve, and ON_LineCurve.

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ON_Curve() [1/2]

◆ ~ON_Curve()

◆ ON_Curve() [2/2]

Member Function Documentation

◆ ChangeClosedCurveSeam()

◆ ChangeDimension()

◆ CurvatureAt()

◆ Degree()

◆ DerivativeAt()

◆ DestroyCurveTree()

◆ DestroyRuntimeCache()

◆ Domain()

◆ DuplicateCurve()

◆ Ev1Der()

◆ Ev2Der()

◆ Evaluate()

◆ EvaluatePoint()

◆ EvCurvature()

◆ EvPoint()

◆ EvTangent()

◆ Extend()

◆ FirstSpanIsLinear() [1/2]

◆ FirstSpanIsLinear() [2/2]

◆ FrameAt()

◆ GetCurveParameterFromNurbFormParameter()

◆ GetDomain()

◆ GetNextDiscontinuity()

◆ GetNurbForm()

◆ GetNurbFormParameterFromCurveParameter()

◆ GetParameterTolerance()

◆ GetSpanVector()

◆ GetSpanVectorIndex()

◆ GetTightBoundingBox()

◆ HasNurbForm()

◆ IsArc()

◆ IsArcAt()

◆ IsClosable()

◆ IsClosed()

◆ IsContinuous()

◆ IsEllipse()

◆ IsInPlane()

◆ IsLinear()

◆ IsPeriodic()

◆ IsPlanar()

◆ IsPolyline()

◆ LastSpanIsLinear() [1/2]

◆ LastSpanIsLinear() [2/2]

◆ NurbsCurve()

◆ ObjectType()

◆ operator=()

◆ ParameterSearch()

◆ PointAt()

◆ PointAtEnd()

◆ PointAtStart()

◆ Reverse()

◆ SetDomain() [1/2]

◆ SetDomain() [2/2]

◆ SetEndPoint()

◆ SetStartPoint()

◆ SizeOf()

◆ SpanCount()

◆ Split()

◆ TangentAt()

◆ Transform()

◆ Trim()