Curve2D Class Reference

Superclass for 2-dimensional space curves: f(t) = ( x(t), y(t) ). More...

#include <labelingmath.h>

Inheritance diagram for Curve2D:

List of all members.

Public Member Functions
	Curve2D ()
	Default constructor.
virtual	~Curve2D ()
	Destructor. Frees all allocated resources.
bool	setCtrlPoints (std::vector< tgt::vec2 > &ctrlPoints, float curveLength=0.f)
	Sets the control points of the curve.
std::vector< tgt::vec2 >	getCtrlPoints ()
	Returns the control point array.
virtual tgt::vec2	getCurvePoint (float t)=0
	Returns the curve point at parameter t.
virtual tgt::vec2	getTangent (float t)=0
	Returns the tangent vector at parameter t.
virtual float	getTangentMagnitude (float t)=0
	Returns the magnitude of the tangent vector at parameter t.
virtual float	getSegmentLength (float t1, float t2)=0
	Returns the length of the curve segment between parameters t1 and t2.
virtual tgt::vec2	getNextPoint (float &curParam, float offset)=0
	Returns the curve point at parameter t that satisfies the following condition: getSegmentLength(curParam, t) == offset.
virtual void	shift (tgt::vec2 shiftVector)=0
	Shifts the whole curve by shiftVector.
Protected Member Functions
virtual bool	calcFunction (float curveLength=0)=0
	Calculates the curve from the prior set control points.
Protected Attributes
std::vector< tgt::vec2 >	ctrlPoints_
	The curve's control points.
float	paramScale_
	Scale and shift parameters for mapping parameter range of curve segment to [0;1].
float	paramShift_

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Detailed Description

Superclass for 2-dimensional space curves: f(t) = ( x(t), y(t) ).

The curve is determined by an array of control points.

Definition at line 137 of file labelingmath.h.

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Member Function Documentation

virtual bool calcFunction

(

float

curveLength = 0

)

[protected, pure virtual]

Calculates the curve from the prior set control points.

Parameters:

curveLength

specifies the length of the curve segment whose parameter range is mapped to [0;!]

virtual tgt::vec2 getNextPoint	(	float &	curParam,
		float	offset
	)			[pure virtual]

Returns the curve point at parameter t that satisfies the following condition:

• getSegmentLength(curParam, t) == offset.

Note:

This is just an approximation.

Parameters:

c

curParam is set to t afterwards.

Implemented in Curve2DPolynomial.

bool setCtrlPoints	(	std::vector< tgt::vec2 > &	ctrlPoints,
		float	curveLength = 0.f
	)

Sets the control points of the curve.

Internally the curve's parameters are calculated from these control points.

Parameters:

curveLength

the length of the curve segment, whose parameter range range is mapped to [0;1]. The segment is centered around the control points. If no length is supplied, the segment runs from the first to the last control point (these points are only approximated, since this is a least-squares-fit)

Returns:

true, if parameter calculation was successful