Added old abandoned KDE3 version of koffice

git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/applications/koffice@1077364 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 1112 insertions, 0 deletions

diff --git a/karbon/core/vsegment.cc b/karbon/core/vsegment.cc
new file mode 100644
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--- /dev/null
+++ b/karbon/core/vsegment.cc
@@ -0,0 +1,1112 @@
+/* This file is part of the KDE project
+   Copyright (C) 2001, 2002, 2003 The Karbon Developers
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public License
+   along with this library; see the file COPYING.LIB.  If not, write to
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+*/
+
+#include <math.h>
+
+#include <qdom.h>
+
+#include "vpainter.h"
+#include "vpath.h"
+#include "vsegment.h"
+
+#include <kdebug.h>
+
+VSegment::VSegment( unsigned short deg )
+{
+	m_degree = deg;
+
+	m_nodes = new VNodeData[ degree() ];
+
+	for( unsigned short i = 0; i < degree(); ++i )
+		selectPoint( i );
+
+	m_state = normal;
+
+	m_prev = 0L;
+	m_next = 0L;
+}
+
+VSegment::VSegment( const VSegment& segment )
+{
+	m_degree = segment.degree();
+
+	m_nodes = new VNodeData[ degree() ];
+
+	m_state = segment.m_state;
+
+	// Copying the pointers m_prev/m_next has some advantages (see VSegment::length()).
+	// Inserting a segment into a path overwrites these anyway.
+	m_prev = segment.m_prev;
+	m_next = segment.m_next;
+
+	// Copy points.
+	for( unsigned short i = 0; i < degree(); i++ )
+	{
+		setPoint( i, segment.point( i ) );
+		selectPoint( i, segment.pointIsSelected( i ) );
+	}
+}
+
+VSegment::~VSegment()
+{
+	delete[]( m_nodes );
+}
+
+void
+VSegment::setDegree( unsigned short deg )
+{
+	// Do nothing if old and new degrees are identical.
+	if( degree() == deg )
+		return;
+
+	// TODO : this code is fishy, please make it sane
+
+	// Remember old nodes.
+	VNodeData* oldNodes = m_nodes;
+	KoPoint oldKnot = knot();
+
+	// Allocate new node data.
+	m_nodes = new VNodeData[ deg ];
+
+	if( deg == 1 )
+		m_nodes[ 0 ].m_vector = oldKnot;
+	else
+	{
+		// Copy old node data (from the knot "backwards".
+		unsigned short offset = kMax( 0, deg - m_degree );
+
+		for( unsigned short i = offset; i < deg; ++i )
+		{
+			m_nodes[ i ].m_vector = oldNodes[ i - offset ].m_vector;
+		}
+
+		// Fill with "zeros" if necessary.
+		for( unsigned short i = 0; i < offset; ++i )
+		{
+			m_nodes[ i ].m_vector = KoPoint( 0.0, 0.0 );
+		}
+	}
+
+	// Set new degree.
+	m_degree = deg;
+
+	// Delete old nodes.
+	delete[]( oldNodes );
+}
+
+void
+VSegment::draw( VPainter* painter ) const
+{
+	// Don't draw a deleted segment.
+	if( state() == deleted )
+		return;
+
+
+	if( prev() )
+	{
+		if( degree() == 3 )
+		{
+			painter->curveTo( point( 0 ), point( 1 ), point( 2 ) );
+		}
+		else
+		{
+			painter->lineTo( knot() );
+		}
+	}
+	else
+	{
+		painter->moveTo( knot() );
+	}
+}
+
+bool
+VSegment::isFlat( double flatness ) const
+{
+	// Lines and "begin" segments are flat.
+	if(
+		!prev() ||
+		degree() == 1 )
+	{
+		return true;
+	}
+
+
+	// Iterate over control points.
+	for( unsigned short i = 0; i < degree() - 1; ++i )
+	{
+		if(
+			height( prev()->knot(), point( i ), knot() ) / chordLength()
+			>= flatness )
+		{
+			return false;
+		}
+	}
+
+	return true;
+}
+
+KoPoint
+VSegment::pointAt( double t ) const
+{
+	KoPoint p;
+
+	pointDerivativesAt( t, &p );
+
+	return p;
+}
+
+void
+VSegment::pointDerivativesAt( double t, KoPoint* p,
+							  KoPoint* d1, KoPoint* d2 ) const
+{
+	if( !prev() )
+		return;
+
+
+	// Optimise the line case.
+	if( degree() == 1 )
+	{
+		const KoPoint diff = knot() - prev()->knot();
+
+		if( p )
+			*p = prev()->knot() + diff * t;
+
+		if( d1 )
+			*d1 = diff;
+
+		if( d2 )
+			*d2 = KoPoint( 0.0, 0.0 );
+
+		return;
+	}
+
+
+	// Beziers.
+
+	// Copy points.
+	KoPoint* q = new KoPoint[ degree() + 1 ];
+
+	q[ 0 ] = prev()->knot();
+
+	for( unsigned short i = 0; i < degree(); ++i )
+	{
+		q[ i + 1 ] = point( i );
+	}
+
+
+	// The De Casteljau algorithm.
+	for( unsigned short j = 1; j <= degree(); j++ )
+	{
+		for( unsigned short i = 0; i <= degree() - j; i++ )
+		{
+			q[ i ] = ( 1.0 - t ) * q[ i ] + t * q[ i + 1 ];
+		}
+
+		// Save second derivative now that we have it.
+		if( j == degree() - 2 )
+		{
+			if( d2 )
+				*d2 = degree() * ( degree() - 1 )
+					  * ( q[ 2 ] - 2 * q[ 1 ] + q[ 0 ] );
+		}
+
+		// Save first derivative now that we have it.
+		else if( j == degree() - 1 )
+		{
+			if( d1 )
+				*d1 = degree() * ( q[ 1 ] - q[ 0 ] );
+		}
+	}
+
+	// Save point.
+	if( p )
+		*p = q[ 0 ];
+
+	delete[]( q );
+
+
+	return;
+}
+
+KoPoint
+VSegment::tangentAt( double t ) const
+{
+	KoPoint tangent;
+
+	pointTangentNormalAt( t, 0L, &tangent );
+
+	return tangent;
+}
+
+void
+VSegment::pointTangentNormalAt( double t, KoPoint* p,
+								KoPoint* tn, KoPoint* n ) const
+{
+	// Calculate derivative if necessary.
+	KoPoint d;
+
+	pointDerivativesAt( t, p, tn || n ? &d : 0L );
+
+
+	// Normalize derivative.
+	if( tn || n )
+	{
+		const double norm =
+			sqrt( d.x() * d.x() + d.y() * d.y() );
+
+		d = norm ? d * ( 1.0 / norm ) : KoPoint( 0.0, 0.0 );
+	}
+
+	// Assign tangent vector.
+	if( tn )
+		*tn = d;
+
+	// Calculate normal vector.
+	if( n )
+	{
+		// Calculate vector product of "binormal" x tangent
+		// (0,0,1) x (dx,dy,0), which is simply (dy,-dx,0).
+		n->setX( d.y() );
+		n->setY( -d.x() );
+	}
+}
+
+double
+VSegment::length( double t ) const
+{
+	if( !prev() || t == 0.0 )
+	{
+		return 0.0;
+	}
+
+
+	// Optimise the line case.
+	if( degree() == 1 )
+	{
+		return
+			t * chordLength();
+	}
+
+
+	/* This algortihm is by Jens Gravesen <gravesen AT mat DOT dth DOT dk>.
+	 * We calculate the chord length "chord"=|P0P3| and the length of the control point
+	 * polygon "poly"=|P0P1|+|P1P2|+|P2P3|. The approximation for the bezier length is
+	 * 0.5 * poly + 0.5 * chord. "poly - chord" is a measure for the error.
+	 * We subdivide each segment until the error is smaller than a given tolerance
+	 * and add up the subresults.
+	 */
+
+	// "Copy segment" splitted at t into a path.
+	VSubpath path( 0L );
+	path.moveTo( prev()->knot() );
+
+	// Optimize a bit: most of the time we'll need the
+	// length of the whole segment.
+	if( t == 1.0 )
+		path.append( this->clone() );
+	else
+	{
+		VSegment* copy = this->clone();
+		path.append( copy->splitAt( t ) );
+		delete copy;
+	}
+
+
+	double chord;
+	double poly;
+
+	double length = 0.0;
+
+	while( path.current() )
+	{
+		chord = path.current()->chordLength();
+		poly = path.current()->polyLength();
+
+		if(
+			poly &&
+			( poly - chord ) / poly > VGlobal::lengthTolerance )
+		{
+			// Split at midpoint.
+			path.insert(
+				path.current()->splitAt( 0.5 ) );
+		}
+		else
+		{
+			length += 0.5 * poly + 0.5 * chord;
+			path.next();
+		}
+	}
+
+
+	return length;
+}
+
+double
+VSegment::chordLength() const
+{
+	if( !prev() )
+		return 0.0;
+
+
+	KoPoint d = knot() - prev()->knot();
+
+	return sqrt( d * d );
+}
+
+double
+VSegment::polyLength() const
+{
+	if( !prev() )
+		return 0.0;
+
+
+	// Start with distance |first point - previous knot|.
+	KoPoint d = point( 0 ) - prev()->knot();
+
+	double length = sqrt( d * d );
+
+	// Iterate over remaining points.
+	for( unsigned short i = 1; i < degree(); ++i )
+	{
+		d = point( i ) - point( i - 1 );
+		length += sqrt( d * d );
+	}
+
+
+	return length;
+}
+
+double
+VSegment::lengthParam( double len ) const
+{
+	if(
+		!prev() ||
+		len == 0.0 )		// We divide by len below.
+	{
+		return 0.0;
+	}
+
+
+	// Optimise the line case.
+	if( degree() == 1 )
+	{
+		return
+			len / chordLength();
+	}
+
+
+	// Perform a successive interval bisection.
+	double param1 = 0.0;
+	double paramMid = 0.5;
+	double param2 = 1.0;
+
+	double lengthMid = length( paramMid );
+
+	while( QABS( lengthMid - len ) / len > VGlobal::paramLengthTolerance )
+	{
+		if( lengthMid < len )
+			param1 = paramMid;
+		else
+			param2 = paramMid;
+
+		paramMid = 0.5 * ( param2 + param1 );
+
+		lengthMid = length( paramMid );
+	}
+
+	return paramMid;
+}
+
+double
+VSegment::nearestPointParam( const KoPoint& p ) const
+{
+	if( !prev() )
+	{
+		return 1.0;
+	}
+
+
+	/* This function solves the "nearest point on curve" problem. That means, it
+	 * calculates the point q (to be precise: it's parameter t) on this segment, which
+	 * is located nearest to the input point P.
+	 * The basic idea is best described (because it is freely available) in "Phoenix:
+	 * An Interactive Curve Design System Based on the Automatic Fitting of
+	 * Hand-Sketched Curves", Philip J. Schneider (Master thesis, University of
+	 * Washington).
+	 *
+	 * For the nearest point q = C(t) on this segment, the first derivative is
+	 * orthogonal to the distance vector "C(t) - P". In other words we are looking for
+	 * solutions of f(t) = ( C(t) - P ) * C'(t) = 0.
+	 * ( C(t) - P ) is a nth degree curve, C'(t) a n-1th degree curve => f(t) is a
+	 * (2n - 1)th degree curve and thus has up to 2n - 1 distinct solutions.
+	 * We solve the problem f(t) = 0 by using something called "Approximate Inversion Method".
+	 * Let's write f(t) explicitly (with c_i = p_i - P and d_j = p_{j+1} - p_j):
+	 *
+	 *         n                     n-1
+	 * f(t) = SUM c_i * B^n_i(t)  *  SUM d_j * B^{n-1}_j(t)
+	 *        i=0                    j=0
+	 *
+	 *         n  n-1
+	 *      = SUM SUM w_{ij} * B^{2n-1}_{i+j}(t)
+	 *        i=0 j=0
+	 *
+	 * with w_{ij} = c_i * d_j * z_{ij} and
+	 *
+	 *          BinomialCoeff( n, i ) * BinomialCoeff( n - i ,j )
+	 * z_{ij} = -----------------------------------------------
+	 *                   BinomialCoeff( 2n - 1, i + j )
+	 *
+	 * This Bernstein-Bezier polynom representation can now be solved for it's roots.
+	 */
+
+
+	// Calculate the c_i = point( i ) - P.
+	KoPoint* c = new KoPoint[ degree() + 1 ];
+
+	c[ 0 ] = prev()->knot() - p;
+
+	for( unsigned short i = 1; i <= degree(); ++i )
+	{
+		c[ i ] = point( i - 1 ) - p;
+	}
+
+
+	// Calculate the d_j = point( j + 1 ) - point( j ).
+	KoPoint* d = new KoPoint[ degree() ];
+
+	d[ 0 ] = point( 0 ) - prev()->knot();
+
+	for( unsigned short j = 1; j <= degree() - 1; ++j )
+	{
+		d[ j ] = 3.0 * ( point( j ) - point( j - 1 ) );
+	}
+
+
+	// Calculate the z_{ij}.
+	double* z = new double[ degree() * ( degree() + 1 ) ];
+
+	for( unsigned short j = 0; j <= degree() - 1; ++j )
+	{
+		for( unsigned short i = 0; i <= degree(); ++i )
+		{
+			z[ j * ( degree() + 1 ) + i ] =
+				static_cast<double>(
+					VGlobal::binomialCoeff( degree(), i ) *
+					VGlobal::binomialCoeff( degree() - i, j ) )
+				/
+				static_cast<double>(
+					VGlobal::binomialCoeff( 2 * degree() - 1, i + j ) );
+		}
+	}
+
+
+	// Calculate the dot products of c_i and d_i.
+	double* products = new double[ degree() * ( degree() + 1 ) ];
+
+	for( unsigned short j = 0; j <= degree() - 1; ++j )
+	{
+		for( unsigned short i = 0; i <= degree(); ++i )
+		{
+			products[ j * ( degree() + 1 ) + i ] =
+				d[ j ] * c[ i ];
+		}
+	}
+
+	// We don't need the c_i and d_i anymore.
+	delete[]( d );
+	delete[]( c );
+
+
+	// Calculate the control points of the new 2n-1th degree curve.
+	VSubpath newCurve( 0L );
+	newCurve.append( new VSegment( 2 * degree() - 1 ) );
+
+	// Set up control points in the ( u, f(u) )-plane.
+	for( unsigned short u = 0; u <= 2 * degree() - 1; ++u )
+	{
+		newCurve.current()->setP(
+			u,
+			KoPoint(
+				static_cast<double>( u ) / static_cast<double>( 2 * degree() - 1 ),
+				0.0 ) );
+	}
+
+
+	// Set f(u)-values.
+	for( unsigned short k = 0; k <= 2 * degree() - 1; ++k )
+	{
+		unsigned short min = kMin( k, degree() );
+
+		for(
+			unsigned short i = kMax( 0, k - ( degree() - 1 ) );
+			i <= min;
+			++i )
+		{
+			unsigned short j = k - i;
+
+			// p_k += products[j][i] * z[j][i].
+			newCurve.getLast()->setP(
+				k,
+				KoPoint(
+					newCurve.getLast()->p( k ).x(),
+					newCurve.getLast()->p( k ).y() +
+						products[ j * ( degree() + 1 ) + i ] *
+							z[ j * ( degree() + 1 ) + i ] ) );
+		}
+	}
+
+	// We don't need the c_i/d_i dot products and the z_{ij} anymore.
+	delete[]( products );
+	delete[]( z );
+
+kdDebug(38000) << "results" << endl;
+for( int i = 0; i <= 2 * degree() - 1; ++i )
+{
+kdDebug(38000) << newCurve.getLast()->p( i ).x() << " "
+<< newCurve.getLast()->p( i ).y() << endl;
+}
+kdDebug(38000) << endl;
+
+	// Find roots.
+	QValueList<double> params;
+
+	newCurve.getLast()->rootParams( params );
+
+
+	// Now compare the distances of the candidate points.
+	double resultParam;
+	double distanceSquared;
+	double oldDistanceSquared;
+	KoPoint dist;
+
+	// First candidate is the previous knot.
+	dist = prev()->knot() - p;
+	distanceSquared = dist * dist;
+	resultParam = 0.0;
+
+	// Iterate over the found candidate params.
+	for( QValueListConstIterator<double> itr = params.begin(); itr != params.end(); ++itr )
+	{
+		pointDerivativesAt( *itr, &dist );
+		dist -= p;
+		oldDistanceSquared = distanceSquared;
+		distanceSquared = dist * dist;
+
+		if( distanceSquared < oldDistanceSquared )
+			resultParam = *itr;
+	}
+
+	// Last candidate is the knot.
+	dist = knot() - p;
+	oldDistanceSquared = distanceSquared;
+	distanceSquared = dist * dist;
+
+	if( distanceSquared < oldDistanceSquared )
+		resultParam = 1.0;
+
+
+	return resultParam;
+}
+
+void
+VSegment::rootParams( QValueList<double>& params ) const
+{
+	if( !prev() )
+	{
+		return;
+	}
+
+
+	// Calculate how often the control polygon crosses the x-axis
+	// This is the upper limit for the number of roots.
+	switch( controlPolygonZeros() )
+	{
+		// No solutions.
+		case 0:
+			return;
+		// Exactly one solution.
+		case 1:
+			if( isFlat( VGlobal::flatnessTolerance / chordLength() ) )
+			{
+				// Calculate intersection of chord with x-axis.
+				KoPoint chord = knot() - prev()->knot();
+
+kdDebug(38000) << prev()->knot().x()  << " " << prev()->knot().y()
+<< knot().x() << " " << knot().y() << " ---> "
+<< ( chord.x() * prev()->knot().y() - chord.y() * prev()->knot().x() ) / - chord.y() << endl;
+				params.append(
+					( chord.x() * prev()->knot().y() - chord.y() * prev()->knot().x() )
+					/ - chord.y() );
+
+				return;
+			}
+			break;
+	}
+
+	// Many solutions. Do recursive midpoint subdivision.
+	VSubpath path( *this );
+	path.insert( path.current()->splitAt( 0.5 ) );
+
+	path.current()->rootParams( params );
+	path.next()->rootParams( params );
+}
+
+int
+VSegment::controlPolygonZeros() const
+{
+	if( !prev() )
+	{
+		return 0;
+	}
+
+
+	int signChanges = 0;
+
+	int sign = VGlobal::sign( prev()->knot().y() );
+	int oldSign;
+
+	for( unsigned short i = 0; i < degree(); ++i )
+	{
+		oldSign = sign;
+		sign = VGlobal::sign( point( i ).y() );
+
+		if( sign != oldSign )
+		{
+			++signChanges;
+		}
+	}
+
+
+	return signChanges;
+}
+
+bool
+VSegment::isSmooth( const VSegment& next ) const
+{
+	// Return false if this segment is a "begin".
+	if( !prev() )
+		return false;
+
+
+	// Calculate tangents.
+	KoPoint t1;
+	KoPoint t2;
+
+	pointTangentNormalAt( 1.0, 0L, &t1 );
+
+	next.pointTangentNormalAt( 0.0, 0L, &t2 );
+
+
+	// Dot product.
+	if( t1 * t2 >= VGlobal::parallelTolerance )
+		return true;
+
+	return false;
+}
+
+KoRect
+VSegment::boundingBox() const
+{
+	// Initialize with knot.
+	KoRect rect( knot(), knot() );
+
+	// Add p0, if it exists.
+	if( prev() )
+	{
+		if( prev()->knot().x() < rect.left() )
+			rect.setLeft( prev()->knot().x() );
+
+		if( prev()->knot().x() > rect.right() )
+			rect.setRight( prev()->knot().x() );
+
+		if( prev()->knot().y() < rect.top() )
+			rect.setTop( prev()->knot().y() );
+
+		if( prev()->knot().y() > rect.bottom() )
+			rect.setBottom( prev()->knot().y() );
+	}
+
+	if( degree() == 3 )
+	{
+		/* 
+		The basic idea for calculating the axis aligned bounding box (AABB) for bezier segments
+		was found in comp.graphics.algorithms:
+		
+		Both the x coordinate and the y coordinate are polynomial. Newton told 
+ 		us that at a maximum or minimum the derivative will be zero. Take all 
+ 		those points, and take the ends; their AABB will be that of the curve. 
+		
+		We have a helpful trick for the derivatives: use the curve defined by 
+ 		differences of successive control points. 
+		This is a quadratic Bezier curve:
+				
+				2
+		r(t) = Sum Bi,2(t) *Pi = B0,2(t) * P0 + B1,2(t) * P1 + B2,2(t) * P2
+			   i=0
+
+		r(t) = (1-t)^2 * P0 + 2t(1-t) * P1 + t^2 * P2
+
+		r(t) = (P2 - 2*P1 + P0) * t^2 + (2*P1 - 2*P0) * t + P0
+
+		Setting r(t) to zero and using the x and y coordinates of differences of
+		successive control points lets us find the paramters t, where the original 
+		bezier curve has a minimum or a maximum.
+		*/
+		double t[4];
+	
+		// calcualting the differnces between successive control points
+		KoPoint x0 = p(1)-p(0);
+		KoPoint x1 = p(2)-p(1);
+		KoPoint x2 = p(3)-p(2);
+
+		// calculating the coefficents
+		KoPoint a = x2 - 2.0*x1 + x0;
+		KoPoint b = 2.0*x1 - 2.0*x0;
+		KoPoint c = x0;
+
+		// calculating parameter t at minimum/maximum in x-direction
+		if( a.x() == 0.0 )
+		{
+			t[0] = - c.x() / b.x();
+			t[1] = -1.0;
+		}
+		else
+		{
+			double rx = b.x()*b.x() - 4.0*a.x()*c.x();
+			if( rx < 0.0 )
+				rx = 0.0;
+			t[0] = ( -b.x() + sqrt( rx ) ) / (2.0*a.x());
+			t[1] = ( -b.x() - sqrt( rx ) ) / (2.0*a.x());
+		}
+
+		// calculating parameter t at minimum/maximum in y-direction
+		if( a.y() == 0.0 )
+		{
+			t[2] = - c.y() / b.y();
+			t[3] = -1.0;
+		}
+		else
+		{
+			double ry = b.y()*b.y() - 4.0*a.y()*c.y();
+			if( ry < 0.0 )
+				ry = 0.0;
+			t[2] = ( -b.y() + sqrt( ry ) ) / (2.0*a.y());
+			t[3] = ( -b.y() - sqrt( ry ) ) / (2.0*a.y());
+		}
+
+		// calculate points at found minimum/maximum and update bounding box
+		for( int i = 0; i < 4; ++i ) 
+		{
+			if( t[i] >= 0.0 && t[i] <= 1.0 )
+			{
+				KoPoint p = pointAt( t[i] );
+	
+				if( p.x() < rect.left() )
+					rect.setLeft( p.x() );
+		
+				if( p.x() > rect.right() )
+					rect.setRight( p.x() );
+
+				if( p.y() < rect.top() )
+					rect.setTop( p.y() );
+		
+				if( p.y() > rect.bottom() )
+					rect.setBottom( p.y() );
+			}
+		}
+	
+		return rect;
+	}
+
+	for( unsigned short i = 0; i < degree() - 1; ++i )
+	{
+		if( point( i ).x() < rect.left() )
+			rect.setLeft( point( i ).x() );
+
+		if( point( i ).x() > rect.right() )
+			rect.setRight( point( i ).x() );
+
+		if( point( i ).y() < rect.top() )
+			rect.setTop( point( i ).y() );
+
+		if( point( i ).y() > rect.bottom() )
+			rect.setBottom( point( i ).y() );
+	}
+
+
+	return rect;
+}
+
+VSegment*
+VSegment::splitAt( double t )
+{
+	if( !prev() )
+	{
+		return 0L;
+	}
+
+
+	// Create new segment.
+	VSegment* segment = new VSegment( degree() );
+
+	// Set segment state.
+	segment->m_state = m_state;
+
+
+	// Lines are easy: no need to modify the current segment.
+	if( degree() == 1 )
+	{
+		segment->setKnot(
+			prev()->knot() +
+			( knot() - prev()->knot() ) * t );
+
+		return segment;
+	}
+
+
+	// Beziers.
+
+	// Copy points.
+	KoPoint* q = new KoPoint[ degree() + 1 ];
+
+	q[ 0 ] = prev()->knot();
+
+	for( unsigned short i = 0; i < degree(); ++i )
+	{
+		q[ i + 1 ] = point( i );
+	}
+
+
+	// The De Casteljau algorithm.
+	for( unsigned short j = 1; j <= degree(); ++j )
+	{
+		for( unsigned short i = 0; i <= degree() - j; ++i )
+		{
+			q[ i ] = ( 1.0 - t ) * q[ i ] + t * q[ i + 1 ];
+		}
+
+		// Modify the new segment.
+		segment->setPoint( j - 1, q[ 0 ] );
+	}
+
+	// Modify the current segment (no need to modify the knot though).
+	for( unsigned short i = 1; i < degree(); ++i )
+	{
+		setPoint( i - 1, q[ i ] );
+	}
+
+
+	delete[]( q );
+
+
+	return segment;
+}
+
+double
+VSegment::height(
+	const KoPoint& a,
+	const KoPoint& p,
+	const KoPoint& b )
+{
+	// Calculate determinant of AP and AB to obtain projection of vector AP to
+	// the orthogonal vector of AB.
+	const double det =
+		p.x() * a.y() + b.x() * p.y() - p.x() * b.y() -
+		a.x() * p.y() + a.x() * b.y() - b.x() * a.y();
+
+	// Calculate norm = length(AB).
+	const KoPoint ab = b - a;
+	const double norm = sqrt( ab * ab );
+
+	// If norm is very small, simply use distance AP.
+	if( norm < VGlobal::verySmallNumber )
+		return
+			sqrt(
+				( p.x() - a.x() ) * ( p.x() - a.x() ) +
+				( p.y() - a.y() ) * ( p.y() - a.y() ) );
+
+	// Normalize.
+	return QABS( det ) / norm;
+}
+
+bool
+VSegment::linesIntersect(
+	const KoPoint& a0,
+	const KoPoint& a1,
+	const KoPoint& b0,
+	const KoPoint& b1 )
+{
+	const KoPoint delta_a = a1 - a0;
+	const double det_a = a1.x() * a0.y() - a1.y() * a0.x();
+
+	const double r_b0 = delta_a.y() * b0.x() - delta_a.x() * b0.y() + det_a;
+	const double r_b1 = delta_a.y() * b1.x() - delta_a.x() * b1.y() + det_a;
+
+	if( r_b0 != 0.0 && r_b1 != 0.0 && r_b0 * r_b1 > 0.0 )
+		return false;
+
+	const KoPoint delta_b = b1 - b0;
+
+	const double det_b = b1.x() * b0.y() - b1.y() * b0.x();
+
+	const double r_a0 = delta_b.y() * a0.x() - delta_b.x() * a0.y() + det_b;
+	const double r_a1 = delta_b.y() * a1.x() - delta_b.x() * a1.y() + det_b;
+
+	if( r_a0 != 0.0 && r_a1 != 0.0 && r_a0 * r_a1 > 0.0 )
+		return false;
+
+	return true;
+}
+
+bool
+VSegment::intersects( const VSegment& segment ) const
+{
+	if(
+		!prev() ||
+		!segment.prev() )
+	{
+		return false;
+	}
+
+
+	//TODO: this just dumbs down beziers to lines!
+	return linesIntersect( segment.prev()->knot(), segment.knot(), prev()->knot(), knot() );
+}
+
+// TODO: Move this function into "userland"
+uint
+VSegment::nodeNear( const KoPoint& p, double isNearRange ) const
+{
+	int index = 0;
+
+	for( unsigned short i = 0; i < degree(); ++i )
+	{
+		if( point( 0 ).isNear( p, isNearRange ) )
+		{
+			index = i + 1;
+			break;
+		}
+	}
+
+	return index;
+}
+
+VSegment*
+VSegment::revert() const
+{
+	if( !prev() )
+		return 0L;
+
+	// Create new segment.
+	VSegment* segment = new VSegment( degree() );
+
+	segment->m_state = m_state;
+
+
+	// Swap points.
+	for( unsigned short i = 0; i < degree() - 1; ++i )
+	{
+		segment->setPoint( i, point( degree() - 2 - i ) );
+	}
+
+	segment->setKnot( prev()->knot() );
+
+
+	// TODO swap node attributes (selected)
+
+	return segment;
+}
+
+VSegment*
+VSegment::prev() const
+{
+	VSegment* segment = m_prev;
+
+	while( segment && segment->state() == deleted )
+	{
+		segment = segment->m_prev;
+	}
+
+	return segment;
+}
+
+VSegment*
+VSegment::next() const
+{
+	VSegment* segment = m_next;
+
+	while( segment && segment->state() == deleted )
+	{
+		segment = segment->m_next;
+	}
+
+	return segment;
+}
+
+// TODO: remove this backward compatibility function after koffice 1.3.x
+void
+VSegment::load( const QDomElement& element )
+{
+	if( element.tagName() == "CURVE" )
+	{
+		setDegree( 3 );
+
+		setPoint(
+			0,
+			KoPoint(
+				element.attribute( "x1" ).toDouble(),
+				element.attribute( "y1" ).toDouble() ) );
+
+		setPoint(
+			1,
+			KoPoint(
+				element.attribute( "x2" ).toDouble(),
+				element.attribute( "y2" ).toDouble() ) );
+
+		setKnot(
+			KoPoint(
+				element.attribute( "x3" ).toDouble(),
+				element.attribute( "y3" ).toDouble() ) );
+	}
+	else if( element.tagName() == "LINE" )
+	{
+		setDegree( 1 );
+
+		setKnot(
+			KoPoint(
+				element.attribute( "x" ).toDouble(),
+				element.attribute( "y" ).toDouble() ) );
+	}
+	else if( element.tagName() == "MOVE" )
+	{
+		setDegree( 1 );
+
+		setKnot(
+			KoPoint(
+				element.attribute( "x" ).toDouble(),
+				element.attribute( "y" ).toDouble() ) );
+	}
+}
+
+VSegment*
+VSegment::clone() const
+{
+	return new VSegment( *this );
+}
+