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/**
* \file
* \brief Intersection utilities
*//*
* Authors:
* Krzysztof Kosiński <tweenk.pl@gmail.com>
*
* Copyright 2015 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.
*/
#ifndef SEEN_LIB2GEOM_INTERSECTION_H
#define SEEN_LIB2GEOM_INTERSECTION_H
#include <2geom/coord.h>
#include <2geom/point.h>
namespace Geom {
/** @brief Intersection between two shapes.
*/
template <typename TimeA = Coord, typename TimeB = TimeA>
class Intersection
: boost::totally_ordered< Intersection<TimeA, TimeB> >
{
public:
/** @brief Construct from shape references and time values.
* By default, the intersection point will be halfway between the evaluated
* points on the two shapes. */
template <typename TA, typename TB>
Intersection(TA const &sa, TB const &sb, TimeA const &ta, TimeB const &tb)
: first(ta)
, second(tb)
, _point(lerp(0.5, sa.pointAt(ta), sb.pointAt(tb)))
{}
/// Additionally report the intersection point.
Intersection(TimeA const &ta, TimeB const &tb, Point const &p)
: first(ta)
, second(tb)
, _point(p)
{}
/// Intersection point, as calculated by the intersection algorithm.
Point point() const {
return _point;
}
/// Implicit conversion to Point.
operator Point() const {
return _point;
}
friend inline void swap(Intersection &a, Intersection &b) {
using std::swap;
swap(a.first, b.first);
swap(a.second, b.second);
swap(a._point, b._point);
}
bool operator==(Intersection const &other) const {
if (first != other.first) return false;
if (second != other.second) return false;
return true;
}
bool operator<(Intersection const &other) const {
if (first < other.first) return true;
if (first == other.first && second < other.second) return true;
return false;
}
public:
/// First shape and time value.
TimeA first;
/// Second shape and time value.
TimeB second;
private:
// Recalculation of the intersection point from the time values is in many cases
// less precise than the value obtained directly from the intersection algorithm,
// so we need to store it.
Point _point;
};
// TODO: move into new header?
template <typename T>
struct ShapeTraits {
typedef Coord TimeType;
typedef Interval IntervalType;
typedef T AffineClosureType;
typedef Intersection<> IntersectionType;
};
template <typename A, typename B> inline
std::vector< Intersection<A, B> > transpose(std::vector< Intersection<B, A> > const &in) {
std::vector< Intersection<A, B> > result;
for (std::size_t i = 0; i < in.size(); ++i) {
result.push_back(Intersection<A, B>(in[i].second, in[i].first, in[i].point()));
}
return result;
}
template <typename T> inline
void transpose_in_place(std::vector< Intersection<T, T> > &xs) {
for (std::size_t i = 0; i < xs.size(); ++i) {
std::swap(xs[i].first, xs[i].second);
}
}
typedef Intersection<> ShapeIntersection;
} // namespace Geom
#endif // SEEN_LIB2GEOM_INTERSECTION_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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