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/*
*
* Authors:
* MenTaLguY <mental@rydia.net>
* Marco Cecchetti <mrcekets at gmail.com>
*
* Copyright 2007-2008 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/curve.h>
#include <2geom/ord.h>
namespace Geom
{
int CurveHelpers::root_winding(Curve const &c, Point p) {
std::vector<double> ts = c.roots(p[Y], Y);
if(ts.empty()) return 0;
double const fudge = 0.01; //fudge factor used on first and last
std::sort(ts.begin(), ts.end());
// winding determined by crossings at roots
int wind=0;
// previous time
double pt = ts.front() - fudge;
for ( std::vector<double>::iterator ti = ts.begin()
; ti != ts.end()
; ++ti )
{
double t = *ti;
if ( t <= 0. || t >= 1. ) continue; //skip endpoint roots
if ( c.valueAt(t, X) > p[X] ) { // root is ray intersection
// Get t of next:
std::vector<double>::iterator next = ti;
next++;
double nt;
if(next == ts.end()) nt = t + fudge; else nt = *next;
// Check before in time and after in time for positions
// Currently we're using the average times between next and previous segs
Cmp after_to_ray = cmp(c.valueAt((t + nt) / 2, Y), p[Y]);
Cmp before_to_ray = cmp(c.valueAt((t + pt) / 2, Y), p[Y]);
// if y is included, these will have opposite values, giving order.
Cmp dt = cmp(after_to_ray, before_to_ray);
if(dt != EQUAL_TO) //Should always be true, but yah never know..
wind += dt;
pt = t;
}
}
return wind;
}
} // end namespace Geom
/*
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:encoding=utf-8:textwidth=99 :
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