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tdegraphics/ksvg/plugin/backends/agg/BezierPathAgg.cpp

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/*
Copyright (C) 2003 Nikolas Zimmermann <wildfox@kde.org>
This file is part of the KDE project
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
aint 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 "Point.h"
#include "BezierPathAgg.h"
#include <kdebug.h>
#include <agg_basics.h>
#include <agg_bounding_rect.h>
using namespace T2P;
double BezierPathAgg::length(double t)
{
if(m_length < 0.0)
{
double total = 0.0;
double x = 0.0, y = 0.0;
double x2, y2;
unsigned cmd;
unsigned int id = 0;
m_curved_trans.rewind(id);
while(!agg::is_stop(cmd = m_curved_trans.vertex(&x2, &y2)))
{
if(agg::is_move_to(cmd))
{
x = x2;
y = y2;
}
else if(agg::is_line_to(cmd))
{
double dx = x, dy = y;
dx = x2 - dx;
dy = y2 - dy;
total += sqrt(pow(dx, 2) + pow(dy, 2));
x = x2;
y = y2;
}
}
return total * t;
}
else
return m_length * t;
}
void BezierPathAgg::pointTangentNormalAt(double t, Point *p, Point *tn, Point *n)
{
double totallen = length(t);
double total = 0.0;
double x = 0.0, y = 0.0;
double x2, y2;
unsigned cmd;
unsigned int id = 0;
m_curved_trans.rewind(id);
while(!agg::is_stop(cmd = m_curved_trans.vertex(&x2, &y2)))
{
if(agg::is_move_to(cmd))
{
x = x2;
y = y2;
}
else if(agg::is_line_to(cmd))
{
double dx = x, dy = y;
x = x2;
y = y2;
dx = x - dx;
dy = y - dy;
double seg_len = sqrt(pow(dx, 2) + pow(dy, 2));
total += seg_len;
if(total >= totallen)
{
double fract = 1 - (totallen - (total - seg_len)) / seg_len;
if(p)
{
p->setX(x - dx * fract);
p->setY(y - dy * fract);
}
if(tn)
{
//kdDebug() << k_funcinfo << "dx : " << dx << endl;
//kdDebug() << k_funcinfo << "dy : " << dy << endl;
tn->setX(dx);
tn->setY(dy);
}
if(n)
{
// Calculate vector product of "binormal" x tangent
// (0,0,1) x (dx,dy,0), which is simply (dy,-dx,0).
n->setX(dy);
n->setY(-dx);
}
return;
}
}
}
}
void BezierPathAgg::boundingBox(Point *topLeft, Point *bottomRight)
{
double x1, y1, x2, y2;
agg::bounding_rect(m_curved, *this, 0, 1, &x1, &y1, &x2, &y2);
*topLeft = Point(x1, y1);
*bottomRight = Point(x2, y2);
}
// vim:ts=4:noet