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/**
* \file
* \brief Infinite straight ray
*//*
* Copyright 2008 Marco Cecchetti <mrcekets at gmail.com>
*
* 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.
*/
#ifndef LIB2GEOM_SEEN_RAY_H
#define LIB2GEOM_SEEN_RAY_H
#include <vector>
#include <2geom/point.h>
#include <2geom/bezier-curve.h> // for LineSegment
#include <2geom/exception.h>
#include <2geom/math-utils.h>
#include <2geom/transforms.h>
#include <2geom/angle.h>
namespace Geom
{
/**
* @brief Straight ray from a specific point to infinity.
*
* Rays are "half-lines" - they begin at some specific point and extend in a straight line
* to infinity.
*
* @ingroup Primitives
*/
class Ray {
private:
Point _origin;
Point _vector;
public:
Ray() : _origin(0,0), _vector(1,0) {}
Ray(Point const& origin, Coord angle)
: _origin(origin)
{
sincos(angle, _vector[Y], _vector[X]);
}
Ray(Point const& A, Point const& B) {
setPoints(A, B);
}
Point origin() const { return _origin; }
Point vector() const { return _vector; }
Point versor() const { return _vector.normalized(); }
void setOrigin(Point const &o) { _origin = o; }
void setVector(Point const& v) { _vector = v; }
Coord angle() const { return std::atan2(_vector[Y], _vector[X]); }
void setAngle(Coord a) { sincos(a, _vector[Y], _vector[X]); }
void setPoints(Point const &a, Point const &b) {
_origin = a;
_vector = b - a;
if (are_near(_vector, Point(0,0)) )
_vector = Point(0,0);
else
_vector.normalize();
}
bool isDegenerate() const {
return ( _vector[X] == 0 && _vector[Y] == 0 );
}
Point pointAt(Coord t) const {
return _origin + _vector * t;
}
Coord valueAt(Coord t, Dim2 d) const {
return _origin[d] + _vector[d] * t;
}
std::vector<Coord> roots(Coord v, Dim2 d) const {
std::vector<Coord> result;
if ( _vector[d] != 0 ) {
double t = (v - _origin[d]) / _vector[d];
if (t >= 0) result.push_back(t);
} else if (_vector[(d+1)%2] == v) {
THROW_INFINITESOLUTIONS();
}
return result;
}
Coord nearestTime(Point const& point) const {
if ( isDegenerate() ) return 0;
double t = dot(point - _origin, _vector);
if (t < 0) t = 0;
return t;
}
Ray reverse() const {
Ray result;
result.setOrigin(_origin);
result.setVector(-_vector);
return result;
}
Curve *portion(Coord f, Coord t) const {
return new LineSegment(pointAt(f), pointAt(t));
}
LineSegment segment(Coord f, Coord t) const {
return LineSegment(pointAt(f), pointAt(t));
}
Ray transformed(Affine const& m) const {
return Ray(_origin * m, (_origin + _vector) * m);
}
}; // end class Ray
inline
double distance(Point const& _point, Ray const& _ray) {
double t = _ray.nearestTime(_point);
return ::Geom::distance(_point, _ray.pointAt(t));
}
inline
bool are_near(Point const& _point, Ray const& _ray, double eps = EPSILON) {
return are_near(distance(_point, _ray), 0, eps);
}
inline
bool are_same(Ray const& r1, Ray const& r2, double eps = EPSILON) {
return are_near(r1.vector(), r2.vector(), eps)
&& are_near(r1.origin(), r2.origin(), eps);
}
// evaluate the angle between r1 and r2 rotating r1 in cw or ccw direction on r2
// the returned value is an angle in the interval [0, 2PI[
inline
double angle_between(Ray const& r1, Ray const& r2, bool cw = true) {
double angle = angle_between(r1.vector(), r2.vector());
if (angle < 0) angle += 2*M_PI;
if (!cw) angle = 2*M_PI - angle;
return angle;
}
/**
* @brief Returns the angle bisector for the two given rays.
*
* @a r1 is rotated half the way to @a r2 in either clockwise or counter-clockwise direction.
*
* @pre Both passed rays must have the same origin.
*
* @remarks If the versors of both given rays point in the same direction, the direction of the
* angle bisector ray depends on the third parameter:
* - If @a cw is set to @c true, the returned ray will equal the passed rays @a r1 and @a r2.
* - If @a cw is set to @c false, the returned ray will go in the opposite direction.
*
* @throws RangeError if the given rays do not have the same origins
*/
inline
Ray make_angle_bisector_ray(Ray const& r1, Ray const& r2, bool cw = true)
{
if ( !are_near(r1.origin(), r2.origin()) )
{
THROW_RANGEERROR("passed rays do not have the same origin");
}
Ray bisector(r1.origin(), r1.origin() + r1.vector() * Rotate(angle_between(r1, r2) / 2.0));
return (cw ? bisector : bisector.reverse());
}
} // end namespace Geom
#endif // LIB2GEOM_SEEN_RAY_H
/*
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:fileencoding=utf-8:textwidth=99 :
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