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/*
* circle.cc -- ePiX::Circle class
*
* This file is part of ePiX, a C++ library for creating high-quality
* figures in LaTeX
*
* Version 1.1.9
* Last Change: July 30, 2007
*/
/*
* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
* Andrew D. Hwang <ahwang -at- holycross -dot- edu>
* Department of Mathematics and Computer Science
* College of the Holy Cross
* Worcester, MA, 01610-2395, USA
*/
/*
* ePiX is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* ePiX 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 General Public
* License for more details.
*
* You should have received a copy of the GNU General Public License
* along with ePiX; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <cmath>
#include "errors.h"
#include "constants.h"
#include "triples.h"
#include "state.h"
#include "segment.h"
#include "frame.h"
#include "camera.h"
#include "path.h"
#include "paint_style.h"
#include "intersections.h"
#include "circle.h"
namespace ePiX {
static const double EPS(EPIX_EPSILON);
Circle::Circle(const P& ctr, const double rad, const P& perp)
: m_center(ctr), m_radius(rad), m_perp(perp), m_malformed(false)
{
double temp(norm(perp));
if (temp < EPS)
{
epix_warning("Degenerate circle normal, using (0,0,1)");
m_perp=E_3;
}
else
m_perp *= (1.0/temp); // normalize
}
// point-and-center constructor -- parallel to (x1,x2,0)-plane
Circle::Circle(const P& ctr, const P& pt)
: m_center(ctr), m_radius(norm(pt - ctr)), m_perp(E_3), m_malformed(false)
{
if (fabs(E_3|(pt - ctr)) > EPS)
epix_warning("Circle requested with point not in (x,y) plane");
}
// three-point circle constructor
Circle::Circle(const P& pt1, const P& pt2, const P& pt3)
: m_malformed(false)
{
P D21(pt2-pt1), D31(pt3-pt1), D32(pt3-pt2), N(D21*D31);
if (norm(D21) < EPS ||
norm(D31) < EPS ||
norm(D32) < EPS ||
norm(N) < EPS)
{
epix_warning("Collinear points in Circle constructor");
m_malformed = true;
}
else
{
m_perp = (1.0/norm(N))*N;
P q2(0.5*(pt1+pt2));
P dir2(m_perp*(q2-pt1));
P q3(0.5*(pt1+pt3));
P dir3(m_perp*(q3-pt1));
m_center = Segment(q2, q2+dir2)*Segment(q3, q3+dir3);
m_radius = norm(m_center - pt1);
}
}
Circle::Circle(bool tag) : m_malformed(true) { }
P Circle::center() const
{
return m_center;
}
double Circle::radius() const
{
return m_radius;
}
P Circle::perp() const
{
return m_perp;
}
bool Circle::malformed() const
{
return m_malformed;
}
// translation
Circle& Circle::shift(const P& arg)
{
if (!m_malformed)
m_center += arg;
return *this;
}
Circle& Circle::move_to(const P& arg)
{
if (!m_malformed)
m_center = arg;
return *this;
}
// scale radius
Circle& Circle::scale(const double c)
{
if (!m_malformed)
m_radius *= c;
return *this;
}
// project to screen by camera
void Circle::draw() const
{
if (m_malformed)
return;
// else
double r(m_radius);
P N(m_perp);
frame axes; // standard basis
if (EPS <= norm(N*E_3))
axes = frame(E_3*N, E_3, N);
path data(m_center, r*(axes.sea()), r*(axes.sky()), 0, full_turn());
data.close().fill(the_paint_style().fill_flag());
data.draw();
}
//// global functions ////
void circle(const P& ctr, const double rad, const P& perp)
{
Circle C(ctr, rad, perp);
C.draw();
}
void circle(const P& ctr, const P& pt)
{
Circle C(ctr, pt);
C.draw();
}
void circle(const P& pt1, const P& pt2, const P& pt3)
{
Circle C(pt1, pt2, pt3);
C.draw();
}
} // end of namespace
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