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/*
**************************************************************************
description
--------------------
copyright : (C) 2002 by Andreas Zehender
email : zehender@kde.org
**************************************************************************
**************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
**************************************************************************/
#ifndef PMSPLINESEGMENT_H
#define PMSPLINESEGMENT_H
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "pmvector.h"
#include <tqvaluelist.h>
/**
* Helper class for splines
*
* Each instance of this class represents one spline segment. A point
* on the segment is given by the equation
*
* fi(t) = A[i] * t^3 + B[i] * t^2 + C[i] * t + D[i]
*
* with t ranging from 0 to 1.
*/
class PMSplineSegment
{
public:
/**
* Standard constructor
*/
PMSplineSegment( )
{
m_a[0] = m_b[0] = m_c[0] = m_d[0] = 0.0;
m_a[1] = m_b[1] = m_c[1] = m_d[1] = 0.0;
}
/**
* Copy constructor
*/
PMSplineSegment( const PMSplineSegment& s )
{
int i;
for( i = 0; i < 2; i++ )
{
m_a[i] = s.m_a[i];
m_b[i] = s.m_b[i];
m_c[i] = s.m_c[i];
m_d[i] = s.m_d[i];
}
}
/**
* Assigns s to the segment
*/
PMSplineSegment& operator= ( const PMSplineSegment& s )
{
int i;
for( i = 0; i < 2; i++ )
{
m_a[i] = s.m_a[i];
m_b[i] = s.m_b[i];
m_c[i] = s.m_c[i];
m_d[i] = s.m_d[i];
}
return *this;
}
/**
* Returns a 2D vector with the point on the spline segment
*/
PMVector point( double t ) const;
/**
* Returns the gradient on the spline
*/
PMVector gradient( double t ) const;
/**
* Calculates the spline parameters for the linear spline type
*/
void calculateLinear( const PMVector& p1, const PMVector& p2 );
/**
* Calculates the spline parameters for the quadratic spline type
*/
void calculateQuadratic( const PMVector& p1, const PMVector& p2,
const PMVector& p3 );
/**
* Calculates the spline parameters for the cubic spline type
*/
void calculateCubic( const PMVector& p1, const PMVector& p2,
const PMVector& p3, const PMVector& p4 );
/**
* Calculates the spline parameters for the bezier spline type
*/
void calculateBezier( const PMVector& p1, const PMVector& p2,
const PMVector& p3, const PMVector& p4 );
/**
* Calculates the spline parameters for the quadric bezier
*/
void calculateQuadricBezier( const PMVector& p1, const PMVector& p2,
const PMVector& p3 );
private:
double m_a[2], m_b[2], m_c[2], m_d[2];
};
typedef TQValueList<PMSplineSegment> PMSegmentList;
typedef TQValueList<PMSegmentList> PMSegmentListList;
#endif
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