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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /graphics/epix/circle.cc
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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 <rot 13 nujnat at zngupf dot ubylpebff dot rqh>
+ * 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.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 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