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107 lines
3.8 KiB
107 lines
3.8 KiB
/*
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**************************************************************************
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description
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--------------------
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copyright : (C) 2002 by Andreas Zehender
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email : zehender@kde.org
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**************************************************************************
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**************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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**************************************************************************/
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#include "pmsplinesegment.h"
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PMVector PMSplineSegment::point( double t ) const
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{
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double t2 = t * t;
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double t3 = t2 * t;
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return PMVector( m_a[0]*t3 + m_b[0]*t2 + m_c[0]*t + m_d[0],
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m_a[1]*t3 + m_b[1]*t2 + m_c[1]*t + m_d[1] );
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}
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PMVector PMSplineSegment::gradient( double t ) const
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{
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double t2 = t * t;
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return PMVector( 3*m_a[0]*t2 + 2*m_b[0]*t + m_c[0],
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3*m_a[1]*t2 + 2*m_b[1]*t + m_c[1] );
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}
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void PMSplineSegment::calculateLinear( const PMVector& p1, const PMVector& p2 )
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{
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m_a[0] = 0.0;
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m_b[0] = 0.0;
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m_c[0] = -1.0 * p1[0] + 1.0 * p2[0];
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m_d[0] = 1.0 * p1[0];
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m_a[1] = 0.0;
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m_b[1] = 0.0;
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m_c[1] = -1.0 * p1[1] + 1.0 * p2[1];
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m_d[1] = 1.0 * p1[1];
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}
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void PMSplineSegment::calculateQuadratic( const PMVector& p1,
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const PMVector& p2,
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const PMVector& p3 )
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{
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m_a[0] = 0.0;
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m_b[0] = 0.5 * p1[0] - 1.0 * p2[0] + 0.5 * p3[0];
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m_c[0] = -0.5 * p1[0] + 0.5 * p3[0];
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m_d[0] = 1.0 * p2[0];
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m_a[1] = 0.0;
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m_b[1] = 0.5 * p1[1] - 1.0 * p2[1] + 0.5 * p3[1];
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m_c[1] = -0.5 * p1[1] + 0.5 * p3[1];
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m_d[1] = 1.0 * p2[1];
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}
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void PMSplineSegment::calculateCubic( const PMVector& p1, const PMVector& p2,
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const PMVector& p3, const PMVector& p4 )
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{
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m_a[0] = -0.5 * p1[0] + 1.5 * p2[0] - 1.5 * p3[0] + 0.5 * p4[0];
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m_b[0] = p1[0] - 2.5 * p2[0] + 2.0 * p3[0] - 0.5 * p4[0];
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m_c[0] = -0.5 * p1[0] + 0.5 * p3[0];
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m_d[0] = p2[0];
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m_a[1] = -0.5 * p1[1] + 1.5 * p2[1] - 1.5 * p3[1] + 0.5 * p4[1];
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m_b[1] = p1[1] - 2.5 * p2[1] + 2.0 * p3[1] - 0.5 * p4[1];
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m_c[1] = -0.5 * p1[1] + 0.5 * p3[1];
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m_d[1] = p2[1];
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}
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void PMSplineSegment::calculateBezier( const PMVector& p1, const PMVector& p2,
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const PMVector& p3, const PMVector& p4 )
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{
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m_a[0] = - p1[0] + 3.0 * p2[0] - 3.0 * p3[0] + p4[0];
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m_b[0] = 3.0 * p1[0] - 6.0 * p2[0] + 3.0 * p3[0];
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m_c[0] = -3.0 * p1[0] + 3.0 * p2[0];
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m_d[0] = p1[0];
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m_a[1] = - p1[1] + 3.0 * p2[1] - 3.0 * p3[1] + p4[1];
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m_b[1] = 3.0 * p1[1] - 6.0 * p2[1] + 3.0 * p3[1];
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m_c[1] = -3.0 * p1[1] + 3.0 * p2[1];
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m_d[1] = p1[1];
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}
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void PMSplineSegment::calculateQuadricBezier( const PMVector& p1,
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const PMVector& p2,
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const PMVector& p3 )
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{
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m_a[0] = 0;
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m_b[0] = p1[0] - 2.0 * p2[0] + p3[0];
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m_c[0] = -2.0 * p1[0] + 2.0 * p2[0];
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m_d[0] = p1[0];
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m_a[1] = 0;
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m_b[1] = p1[1] - 2.0 * p2[1] + p3[1];
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m_c[1] = -2.0 * p1[1] + 2.0 * p2[1];
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m_d[1] = p1[1];
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}
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