Base class for spline interpolations providing a first order parametric continuity ( C1 ) between adjoing curves. More...

#include <qwt_spline.h>

Inheritance diagram for QwtSplineC1:

[legend]

List of all members.

Public Member Functions
virtual QVector< QLineF >	bezierControlLines (const QPolygonF &) const
	Interpolate a curve with Bezier curves.
virtual QPolygonF	equidistantPolygon (const QPolygonF &, double distance, bool withNodes) const
	Find an interpolated polygon with "equidistant" points.
virtual QPainterPath	painterPath (const QPolygonF &) const
	Calculate an interpolated painter path.
virtual QVector < QwtSplinePolynomial >	polynomials (const QPolygonF &) const
	Calculate the interpolating polynomials for a non parametric spline.
	QwtSplineC1 ()
	Constructor.
virtual double	slopeAtBeginning (const QPolygonF &, double slopeNext) const
virtual double	slopeAtEnd (const QPolygonF &, double slopeBefore) const
virtual QVector< double >	slopes (const QPolygonF &) const =0
	Find the first derivative at the control points.
virtual	~QwtSplineC1 ()
	Destructor.

Detailed Description

Base class for spline interpolations providing a first order parametric continuity ( C1 ) between adjoing curves.

All interpolations with C1 continuity are based on rules for finding the 1. derivate at some control points.

In case of non parametric splines those points are the curve points, while for parametric splines the calculation is done twice using a parameter value t.

See also:: QwtSplineParametrization

Definition at line 230 of file qwt_spline.h.

Constructor & Destructor Documentation

QwtSplineC1::QwtSplineC1 ( )

Constructor.

The default setting is a non closing spline with no parametrization ( QwtSplineParametrization::ParameterX ).

See also:: QwtSpline::setParametrization(), QwtSpline::setBoundaryType()

Definition at line 960 of file qwt_spline.cpp.

QwtSplineC1::~QwtSplineC1 ( ) [virtual]

Destructor.

Definition at line 966 of file qwt_spline.cpp.

Member Function Documentation

QVector< QLineF > QwtSplineC1::bezierControlLines ( const QPolygonF & points ) const [virtual]

Interpolate a curve with Bezier curves.

Interpolates a polygon piecewise with cubic Bezier curves and returns the 2 control points of each curve as QLineF.

Parameters:

points Control points

Returns:: Control points of the interpolating Bezier curves

Implements QwtSplineInterpolating.

Reimplemented in QwtSplineC2, QwtSplineLocal, and QwtSplineCubic.

Definition at line 1099 of file qwt_spline.cpp.

QPolygonF QwtSplineC1::equidistantPolygon	(	const QPolygonF &	points,
		double	distance,
		bool	withNodes
	)		const `[virtual]`

Find an interpolated polygon with "equidistant" points.

The implementation is optimzed for non parametric curves ( QwtSplineParametrization::ParameterX ) and falls back to QwtSpline::equidistantPolygon() otherwise.

Parameters:

points	Control nodes of the spline
distance	Distance between 2 points according to the parametrization
withNodes	When true, also add the control nodes ( even if not being equidistant )

Returns:: Interpolating polygon

See also:: QwtSpline::equidistantPolygon()

Reimplemented from QwtSplineInterpolating.

Reimplemented in QwtSplineC2.

Definition at line 1165 of file qwt_spline.cpp.

QPainterPath QwtSplineC1::painterPath ( const QPolygonF & points ) const [virtual]

Calculate an interpolated painter path.

Interpolates a polygon piecewise into cubic Bezier curves and returns them as QPainterPath.

The implementation calculates the slopes at the control points and converts them into painter path elements in an additional loop.

Parameters:

points Control points

Returns:: QPainterPath Painter path, that can be rendered by QPainter

Note:: Derived spline classes might overload painterPath() to avoid the extra loops for converting results into a QPainterPath

Reimplemented from QwtSplineInterpolating.

Reimplemented in QwtSplineC2, QwtSplineLocal, and QwtSplineCubic.

Definition at line 1041 of file qwt_spline.cpp.

QVector< QwtSplinePolynomial > QwtSplineC1::polynomials ( const QPolygonF & points ) const [virtual]

Calculate the interpolating polynomials for a non parametric spline.

C1 spline interpolations are based on finding values for the first derivates at the control points. The interpolating polynomials can be calculated from the the first derivates using QwtSplinePolynomial::fromSlopes().

The default implementation is a two pass calculation. In derived classes it might be overloaded by a one pass implementation.

Parameters:

points Control points

Returns:: Interpolating polynomials

Note:: The x coordinates need to be increasing or decreasing

Reimplemented in QwtSplineC2, QwtSplineLocal, and QwtSplineCubic.

Definition at line 1199 of file qwt_spline.cpp.

double QwtSplineC1::slopeAtBeginning	(	const QPolygonF &	points,
		double	slopeNext
	)		const `[virtual]`

Parameters:

points	Control points
slopeNext	Value of the first derivative at the second point

Returns:: value of the first derivative at the first point

See also:: slopeAtEnd(), QwtSpline::boundaryCondition(), QwtSpline::boundaryValue()

Definition at line 977 of file qwt_spline.cpp.

double QwtSplineC1::slopeAtEnd	(	const QPolygonF &	points,
		double	slopeBefore
	)		const `[virtual]`

Parameters:

points	Control points
slopeBefore	Value of the first derivative at the point before the last one

Returns:: value of the first derivative at the last point

See also:: slopeAtBeginning(), QwtSpline::boundaryCondition(), QwtSpline::boundaryValue()

Definition at line 995 of file qwt_spline.cpp.

QVector< double > QwtSplineC1::slopes ( const QPolygonF & points ) const [pure virtual]

Find the first derivative at the control points.

Parameters:

points Control nodes of the spline

Returns:: Vector with the values of the 2nd derivate at the control points

Note:: The x coordinates need to be increasing or decreasing

Implemented in QwtSplineC2, QwtSplineLocal, and QwtSplineCubic.

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation