1 /*
2 * Elliptical Arc - implementation of the svg elliptical arc path element
3 *
4 * Authors:
5 * MenTaLguY <mental@rydia.net>
6 * Marco Cecchetti <mrcekets at gmail.com>
7 *
8 * Copyright 2007-2008 authors
9 *
10 * This library is free software; you can redistribute it and/or
11 * modify it either under the terms of the GNU Lesser General Public
12 * License version 2.1 as published by the Free Software Foundation
13 * (the "LGPL") or, at your option, under the terms of the Mozilla
14 * Public License Version 1.1 (the "MPL"). If you do not alter this
15 * notice, a recipient may use your version of this file under either
16 * the MPL or the LGPL.
17 *
18 * You should have received a copy of the LGPL along with this library
19 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * You should have received a copy of the MPL along with this library
22 * in the file COPYING-MPL-1.1
23 *
24 * The contents of this file are subject to the Mozilla Public License
25 * Version 1.1 (the "License"); you may not use this file except in
26 * compliance with the License. You may obtain a copy of the License at
27 * http://www.mozilla.org/MPL/
28 *
29 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
30 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
31 * the specific language governing rights and limitations.
32 */
35 #ifndef _2GEOM_SVG_ELLIPTICAL_ARC_H_
36 #define _2GEOM_SVG_ELLIPTICAL_ARC_H_
39 #include <2geom/curve.h>
40 #include <2geom/angle.h>
41 #include <2geom/utils.h>
42 #include <2geom/bezier-curve.h>
43 #include <2geom/sbasis-curve.h> // for non-native methods
44 #include <2geom/numeric/vector.h>
45 #include <2geom/numeric/fitting-tool.h>
46 #include <2geom/numeric/fitting-model.h>
49 #include <algorithm>
53 namespace Geom
54 {
56 class SVGEllipticalArc : public Curve
57 {
58 public:
59 SVGEllipticalArc(bool _svg_compliant = true)
60 : m_initial_point(Point(0,0)), m_final_point(Point(0,0)),
61 m_rx(0), m_ry(0), m_rot_angle(0),
62 m_large_arc(true), m_sweep(true),
63 m_svg_compliant(_svg_compliant)
64 {
65 m_start_angle = m_end_angle = 0;
66 m_center = Point(0,0);
67 }
69 SVGEllipticalArc( Point _initial_point, double _rx, double _ry,
70 double _rot_angle, bool _large_arc, bool _sweep,
71 Point _final_point,
72 bool _svg_compliant = true
73 )
74 : m_initial_point(_initial_point), m_final_point(_final_point),
75 m_rx(_rx), m_ry(_ry), m_rot_angle(_rot_angle),
76 m_large_arc(_large_arc), m_sweep(_sweep),
77 m_svg_compliant(_svg_compliant)
78 {
79 calculate_center_and_extreme_angles();
80 }
82 void set( Point _initial_point, double _rx, double _ry,
83 double _rot_angle, bool _large_arc, bool _sweep,
84 Point _final_point
85 )
86 {
87 m_initial_point = _initial_point;
88 m_final_point = _final_point;
89 m_rx = _rx;
90 m_ry = _ry;
91 m_rot_angle = _rot_angle;
92 m_large_arc = _large_arc;
93 m_sweep = _sweep;
94 calculate_center_and_extreme_angles();
95 }
97 Curve* duplicate() const
98 {
99 return new SVGEllipticalArc(*this);
100 }
102 double center(unsigned int i) const
103 {
104 return m_center[i];
105 }
107 Point center() const
108 {
109 return m_center;
110 }
112 Point initialPoint() const
113 {
114 return m_initial_point;
115 }
117 Point finalPoint() const
118 {
119 return m_final_point;
120 }
122 double start_angle() const
123 {
124 return m_start_angle;
125 }
127 double end_angle() const
128 {
129 return m_end_angle;
130 }
132 double ray(unsigned int i) const
133 {
134 return (i == 0) ? m_rx : m_ry;
135 }
137 bool large_arc_flag() const
138 {
139 return m_large_arc;
140 }
142 bool sweep_flag() const
143 {
144 return m_sweep;
145 }
147 double rotation_angle() const
148 {
149 return m_rot_angle;
150 }
152 void setInitial( const Point _point)
153 {
154 m_initial_point = _point;
155 calculate_center_and_extreme_angles();
156 }
158 void setFinal( const Point _point)
159 {
160 m_final_point = _point;
161 calculate_center_and_extreme_angles();
162 }
164 void setExtremes( const Point& _initial_point, const Point& _final_point )
165 {
166 m_initial_point = _initial_point;
167 m_final_point = _final_point;
168 calculate_center_and_extreme_angles();
169 }
171 bool isDegenerate() const
172 {
173 return ( are_near(ray(X), 0) || are_near(ray(Y), 0) );
174 }
176 bool is_svg_compliant() const
177 {
178 return m_svg_compliant;
179 }
181 Rect boundsFast() const
182 {
183 return boundsExact();
184 }
186 Rect boundsExact() const;
188 // TODO: native implementation of the following methods
189 Rect boundsLocal(Interval i, unsigned int deg) const
190 {
191 if (isDegenerate() && is_svg_compliant())
192 return chord().boundsLocal(i, deg);
193 else
194 return SBasisCurve(toSBasis()).boundsLocal(i, deg);
195 }
197 std::vector<double> roots(double v, Dim2 d) const;
199 std::vector<double>
200 allNearestPoints( Point const& p, double from = 0, double to = 1 ) const;
202 double nearestPoint( Point const& p, double from = 0, double to = 1 ) const
203 {
204 if ( are_near(ray(X), ray(Y)) && are_near(center(), p) )
205 {
206 return from;
207 }
208 return allNearestPoints(p, from, to).front();
209 }
211 // TODO: native implementation of the following methods
212 int winding(Point p) const
213 {
214 if (isDegenerate() && is_svg_compliant())
215 return chord().winding(p);
216 else
217 return SBasisCurve(toSBasis()).winding(p);
218 }
220 Curve *derivative() const;
222 Curve *transformed(Matrix const &m) const;
224 std::vector<Point> pointAndDerivatives(Coord t, unsigned int n) const;
226 D2<SBasis> toSBasis() const;
228 bool containsAngle(Coord angle) const;
230 double valueAtAngle(Coord t, Dim2 d) const;
232 Point pointAtAngle(Coord t) const
233 {
234 double sin_rot_angle = std::sin(rotation_angle());
235 double cos_rot_angle = std::cos(rotation_angle());
236 Matrix m( ray(X) * cos_rot_angle, ray(X) * sin_rot_angle,
237 -ray(Y) * sin_rot_angle, ray(Y) * cos_rot_angle,
238 center(X), center(Y) );
239 Point p( std::cos(t), std::sin(t) );
240 return p * m;
241 }
243 double valueAt(Coord t, Dim2 d) const
244 {
245 if (isDegenerate() && is_svg_compliant())
246 return chord().valueAt(t, d);
248 Coord tt = map_to_02PI(t);
249 return valueAtAngle(tt, d);
250 }
252 Point pointAt(Coord t) const
253 {
254 if (isDegenerate() && is_svg_compliant())
255 return chord().pointAt(t);
257 Coord tt = map_to_02PI(t);
258 return pointAtAngle(tt);
259 }
261 std::pair<SVGEllipticalArc, SVGEllipticalArc>
262 subdivide(Coord t) const
263 {
264 SVGEllipticalArc* arc1 = static_cast<SVGEllipticalArc*>(portion(0, t));
265 SVGEllipticalArc* arc2 = static_cast<SVGEllipticalArc*>(portion(t, 1));
266 assert( arc1 != NULL && arc2 != NULL);
267 std::pair<SVGEllipticalArc, SVGEllipticalArc> arc_pair(*arc1, *arc2);
268 delete arc1;
269 delete arc2;
270 return arc_pair;
271 }
273 Curve* portion(double f, double t) const;
275 // the arc is the same but traversed in the opposite direction
276 Curve* reverse() const
277 {
278 SVGEllipticalArc* rarc = new SVGEllipticalArc( *this );
279 rarc->m_sweep = !m_sweep;
280 rarc->m_initial_point = m_final_point;
281 rarc->m_final_point = m_initial_point;
282 rarc->m_start_angle = m_end_angle;
283 rarc->m_end_angle = m_start_angle;
284 return rarc;
285 }
287 double sweep_angle() const
288 {
289 Coord d = end_angle() - start_angle();
290 if ( !sweep_flag() ) d = -d;
291 if ( d < 0 )
292 d += 2*M_PI;
293 return d;
294 }
296 LineSegment chord() const
297 {
298 return LineSegment(initialPoint(), finalPoint());
299 }
301 private:
302 Coord map_to_02PI(Coord t) const;
303 Coord map_to_01(Coord angle) const;
304 void calculate_center_and_extreme_angles();
306 private:
307 Point m_initial_point, m_final_point;
308 double m_rx, m_ry, m_rot_angle;
309 bool m_large_arc, m_sweep;
310 double m_start_angle, m_end_angle;
311 Point m_center;
312 bool m_svg_compliant;
314 }; // end class SVGEllipticalArc
316 template< class charT >
317 inline
318 std::basic_ostream<charT> &
319 operator<< (std::basic_ostream<charT> & os, const SVGEllipticalArc & ea)
320 {
321 os << "{ cx: " << ea.center(X) << ", cy: " << ea.center(Y)
322 << ", rx: " << ea.ray(X) << ", ry: " << ea.ray(Y)
323 << ", rot angle: " << decimal_round(rad_to_deg(ea.rotation_angle()),2)
324 << ", start angle: " << decimal_round(rad_to_deg(ea.start_angle()),2)
325 << ", end angle: " << decimal_round(rad_to_deg(ea.end_angle()),2)
326 << " }";
328 return os;
329 }
334 namespace detail
335 {
336 struct ellipse_equation;
337 }
340 class make_elliptical_arc
341 {
342 public:
343 typedef D2<SBasis> curve_type;
345 make_elliptical_arc( SVGEllipticalArc& _ea,
346 curve_type const& _curve,
347 unsigned int _total_samples,
348 double _tolerance );
350 private:
351 bool bound_exceeded( unsigned int k, detail::ellipse_equation const & ee,
352 double e1x, double e1y, double e2 );
354 bool check_bound(double A, double B, double C, double D, double E, double F);
356 void fit();
358 bool make_elliptiarc();
360 void print_bound_error(unsigned int k)
361 {
362 std::cerr
363 << "tolerance error" << std::endl
364 << "at point: " << k << std::endl
365 << "error value: "<< dist_err << std::endl
366 << "bound: " << dist_bound << std::endl
367 << "angle error: " << angle_err
368 << " (" << angle_tol << ")" << std::endl;
369 }
371 public:
372 bool operator()()
373 {
374 const NL::Vector & coeff = fitter.result();
375 fit();
376 if ( !check_bound(1, coeff[0], coeff[1], coeff[2], coeff[3], coeff[4]) )
377 return false;
378 if ( !(make_elliptiarc()) ) return false;
379 return true;
380 }
382 bool svg_compliant_flag() const
383 {
384 return svg_compliant;
385 }
387 void svg_compliant_flag(bool _svg_compliant)
388 {
389 svg_compliant = _svg_compliant;
390 }
392 private:
393 SVGEllipticalArc& ea;
394 const curve_type & curve;
395 Piecewise<D2<SBasis> > dcurve;
396 NL::LFMEllipse model;
397 NL::least_squeares_fitter<NL::LFMEllipse> fitter;
398 double tolerance, tol_at_extr, tol_at_center, angle_tol;
399 Point initial_point, final_point;
400 unsigned int N;
401 unsigned int last; // N-1
402 double partitions; // N-1
403 std::vector<Point> p; // sample points
404 double dist_err, dist_bound, angle_err;
405 bool svg_compliant;
406 };
409 } // end namespace Geom
414 #endif /* _2GEOM_SVG_ELLIPTICAL_ARC_H_ */
416 /*
417 Local Variables:
418 mode:c++
419 c-file-style:"stroustrup"
420 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
421 indent-tabs-mode:nil
422 fill-column:99
423 End:
424 */
425 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :