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koffice/karbon/core/vsegment.cc

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/* 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 );
}