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/*
* Nearest Points Toy
*
* Authors:
* Nathan Hurst <njh at njhurst.com>
* Marco Cecchetti <mrcekets at gmail.com>
*
* Copyright 2008 authors
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*/
#include <2geom/d2.h>
#include <2geom/sbasis.h>
#include <2geom/path.h>
#include <2geom/bezier-to-sbasis.h>
#include <toys/path-cairo.h>
#include <toys/toy-framework.h>
using namespace Geom;
class np_finder
{
public:
np_finder(cairo_t* _cr, D2<SBasis> const& _c1, D2<SBasis> const& _c2)
: cr(_cr), c1(_c1), c2(_c2)
{
dc1 = derivative(c1);
dc2 = derivative(c2);
cd1 = dot(c1,dc1);
cd2 = dot(c2,dc2);
dsq = 10e30;
}
void operator() ()
{
nearest_times_impl(0.5, 0, 1);
d = sqrt(dsq);
}
Point firstPoint() const
{
return p1;
}
Point secondPoint() const
{
return p2;
}
double firstValue() const
{
return t1;
}
double secondValue() const
{
return t2;
}
double distance() const
{
return d;
}
private:
void nearest_times_impl( double t, double from = 0, double to = 1 )
{
//std::cerr << "[" << from << "," << to << "] t: " << t << std::endl;
double st = t, et = t;
std::pair<double, double> npc = loc_nearest_times(t, from, to);
//std::cerr << "(" << npc.first << "," << npc.second << ")" << std::endl;
if ( npc.second != -1 && dsq > L2sq(c1(npc.first) - c2(npc.second)) )
{
t1 = npc.first;
t2 = npc.second;
p1 = c1(t1);
p2 = c2(t2);
dsq = L2sq(p1 - p2);
}
if (npc.first < t)
st = npc.first;
else
et = npc.first;
//std::cerr << "[" << st << "," << et << "]" << std::endl;
double d1 = std::fabs(st - from);
double d2 = std::fabs(to - et);
if ( d1 > EPSILON )
nearest_times_impl(from + d1/2, from, st);
if ( d2 > EPSILON )
nearest_times_impl(et + d2/2, et, to);
}
std::pair<double, double>
loc_nearest_times( double t, double from = 0, double to = 1 )
{
unsigned int i = 0;
std::pair<double, double> np(-1,-1);
std::pair<double, double> npf(from, -1);
std::pair<double, double> npt(to, -1);
double ct = t;
double pt = -1;
double s;
//cairo_set_source_rgba(cr, 1/(t+1), t*t, t, 1.0);
//cairo_move_to(cr, c1(t));
while( !are_near(ct, pt) )
{
++i;
pt = ct;
s = nearest_time(c1(ct), c2, dc2, cd2);
//std::cerr << "s: " << s << std::endl;
//cairo_line_to(cr, c2(s));
ct = nearest_time(c2(s), c1, dc1, cd1, from, to);
//std::cerr << "t: " << t1 << std::endl;
//cairo_line_to(cr, c1(ct));
if ( ct < from ) return npf;
if ( ct > to ) return npt;
}
//std::cerr << "\n \n";
//std::cerr << "iterations: " << i << std::endl;
cairo_stroke(cr);
np.first = ct;
np.second = s;
return np;
}
double nearest_time( Point const& p, D2<SBasis> const&c, D2<SBasis> const& dc, SBasis const& cd, double from = 0, double to = 1 )
{
D2<SBasis> sbc = c - p;
SBasis dd = cd - dotp(p, dc);
std::vector<double> zeros = roots(dd);
double closest = from;
double distsq = L2sq(sbc(from));
for ( unsigned int i = 0; i < zeros.size(); ++i )
{
if ( distsq > L2sq(sbc(zeros[i])) )
{
closest = zeros[i];
distsq = L2sq(sbc(closest));
}
}
if ( distsq > L2sq(sbc(to)) )
closest = to;
return closest;
}
SBasis dotp(Point const& p, D2<SBasis> const& c)
{
SBasis d;
d.resize(c[X].size());
for ( unsigned int i = 0; i < c[0].size(); ++i )
{
for( unsigned int j = 0; j < 2; ++j )
d[i][j] = p[X] * c[X][i][j] + p[Y] * c[Y][i][j];
}
return d;
}
private:
static const Coord EPSILON = 10e-3;
cairo_t* cr;
D2<SBasis> const& c1, c2;
D2<SBasis> dc1, dc2;
SBasis cd1, cd2;
double t1, t2, d, dsq;
Point p1, p2;
};
class NearestPoints : public Toy
{
private:
void draw( cairo_t *cr, std::ostringstream *notify,
int width, int height, bool save, std::ostringstream *timer_stream)
{
cairo_set_line_width (cr, 0.2);
D2<SBasis> A = handles_to_sbasis(handles.begin(), A_bez_ord-1);
cairo_d2_sb(cr, A);
D2<SBasis> B = handles_to_sbasis(handles.begin()+A_bez_ord, B_bez_ord-1);
cairo_d2_sb(cr, B);
np_finder np(cr, A, B);
np();
cairo_move_to(cr, np.firstPoint());
cairo_line_to(cr, np.secondPoint());
cairo_stroke(cr);
//std::cerr << "np: (" << np.firstValue() << "," << np.secondValue() << ")" << std::endl;
Toy::draw(cr, notify, width, height, save,timer_stream);
}
public:
NearestPoints(unsigned int _A_bez_ord, unsigned int _B_bez_ord)
: A_bez_ord(_A_bez_ord), B_bez_ord(_B_bez_ord)
{
unsigned int total_handles = A_bez_ord + B_bez_ord;
for ( unsigned int i = 0; i < total_handles; ++i )
handles.push_back(Geom::Point(uniform()*400, uniform()*400));
}
private:
unsigned int A_bez_ord;
unsigned int B_bez_ord;
};
int main(int argc, char **argv)
{
unsigned int A_bez_ord=8;
unsigned int B_bez_ord=5;
if(argc > 2)
sscanf(argv[2], "%d", &B_bez_ord);
if(argc > 1)
sscanf(argv[1], "%d", &A_bez_ord);
init( argc, argv, new NearestPoints(A_bez_ord, B_bez_ord));
return 0;
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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