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circle.cpp
/*
 * Circle Curve
 *
 * Authors:
 *      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/circle.h>
#include <2geom/ellipse.h>
#include <2geom/svg-elliptical-arc.h>
#include <2geom/numeric/fitting-tool.h>
#include <2geom/numeric/fitting-model.h>



namespace Geom
{

void Circle::set(double A, double B, double C, double D)
{
    if (A == 0)
    {
        THROW_RANGEERROR("square term coefficient == 0");
    }

    //std::cerr << "B = " << B << "  C = " << C << "  D = " << D << std::endl;

    double b = B / A;
    double c = C / A;
    double d = D / A;

    m_centre[X] = -b/2;
    m_centre[Y] = -c/2;
    double r2 = m_centre[X] * m_centre[X] + m_centre[Y] * m_centre[Y] - d;

    if (r2 < 0)
    {
        THROW_RANGEERROR("ray^2 < 0");
    }

    m_ray = std::sqrt(r2);
}


void Circle::set(std::vector<Point> const& points)
{
    size_t sz = points.size();
    if (sz < 3)
    {
        THROW_RANGEERROR("fitting error: too few points passed");
    }
    NL::LFMCircle model;
    NL::least_squeares_fitter<NL::LFMCircle> fitter(model, sz);

    for (size_t i = 0; i < sz; ++i)
    {
        fitter.append(points[i]);
    }
    fitter.update();

    NL::Vector z(sz, 0.0);
    model.instance(*this, fitter.result(z));
}


SVGEllipticalArc
Circle::arc(Point const& initial, Point const& inner, Point const& final,
             bool _svg_compliant)
{
    Ellipse e(center(X), center(Y), ray(), ray(), 0);
    return e.arc(initial, inner, final, _svg_compliant);
}


}  // 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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