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Diffstat (limited to 'boost/geometry/algorithms/touches.hpp')
| -rw-r--r-- | boost/geometry/algorithms/touches.hpp | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/boost/geometry/algorithms/touches.hpp b/boost/geometry/algorithms/touches.hpp new file mode 100644 index 0000000000..7d424af428 --- /dev/null +++ b/boost/geometry/algorithms/touches.hpp @@ -0,0 +1,181 @@ +// Boost.Geometry (aka GGL, Generic Geometry Library) + +// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands. +// Copyright (c) 2008-2012 Bruno Lalande, Paris, France. +// Copyright (c) 2009-2012 Mateusz Loskot, London, UK. + +// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library +// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. + +// Use, modification and distribution is subject to the Boost Software License, +// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) + +#ifndef BOOST_GEOMETRY_ALGORITHMS_TOUCHES_HPP +#define BOOST_GEOMETRY_ALGORITHMS_TOUCHES_HPP + + +#include <deque> + +#include <boost/geometry/geometries/concepts/check.hpp> +#include <boost/geometry/algorithms/detail/overlay/self_turn_points.hpp> +#include <boost/geometry/algorithms/detail/overlay/get_turns.hpp> +#include <boost/geometry/algorithms/disjoint.hpp> +#include <boost/geometry/algorithms/intersects.hpp> +#include <boost/geometry/algorithms/num_geometries.hpp> + + +namespace boost { namespace geometry +{ + +namespace detail { namespace touches +{ + +template <typename Turn> +inline bool ok_for_touch(Turn const& turn) +{ + return turn.both(detail::overlay::operation_union) + || turn.both(detail::overlay::operation_blocked) + || turn.combination(detail::overlay::operation_union, detail::overlay::operation_blocked) + ; +} + +template <typename Turns> +inline bool has_only_turns(Turns const& turns) +{ + bool has_touch = false; + typedef typename boost::range_iterator<Turns const>::type iterator_type; + for (iterator_type it = boost::begin(turns); it != boost::end(turns); ++it) + { + if (it->has(detail::overlay::operation_intersection)) + { + return false; + } + + switch(it->method) + { + case detail::overlay::method_crosses: + return false; + case detail::overlay::method_equal: + // Segment spatially equal means: at the right side + // the polygon internally overlaps. So return false. + return false; + case detail::overlay::method_touch: + case detail::overlay::method_touch_interior: + case detail::overlay::method_collinear: + if (ok_for_touch(*it)) + { + has_touch = true; + } + else + { + return false; + } + break; + case detail::overlay::method_none : + case detail::overlay::method_disjoint : + case detail::overlay::method_error : + break; + } + } + return has_touch; +} + +}} + +/*! +\brief \brief_check{has at least one touching point (self-tangency)} +\note This function can be called for one geometry (self-tangency) and + also for two geometries (touch) +\ingroup touches +\tparam Geometry \tparam_geometry +\param geometry \param_geometry +\return \return_check{is self-touching} + +\qbk{distinguish,one geometry} +\qbk{[def __one_parameter__]} +\qbk{[include reference/algorithms/touches.qbk]} +*/ +template <typename Geometry> +inline bool touches(Geometry const& geometry) +{ + concept::check<Geometry const>(); + + typedef detail::overlay::turn_info + < + typename geometry::point_type<Geometry>::type + > turn_info; + + typedef detail::overlay::get_turn_info + < + typename point_type<Geometry>::type, + typename point_type<Geometry>::type, + turn_info, + detail::overlay::assign_null_policy + > policy_type; + + std::deque<turn_info> turns; + detail::self_get_turn_points::no_interrupt_policy policy; + detail::self_get_turn_points::get_turns + < + Geometry, + std::deque<turn_info>, + policy_type, + detail::self_get_turn_points::no_interrupt_policy + >::apply(geometry, turns, policy); + + return detail::touches::has_only_turns(turns); +} + + +/*! +\brief \brief_check2{have at least one touching point (tangent - non overlapping)} +\ingroup touches +\tparam Geometry1 \tparam_geometry +\tparam Geometry2 \tparam_geometry +\param geometry1 \param_geometry +\param geometry2 \param_geometry +\return \return_check2{touch each other} + +\qbk{distinguish,two geometries} +\qbk{[include reference/algorithms/touches.qbk]} + */ +template <typename Geometry1, typename Geometry2> +inline bool touches(Geometry1 const& geometry1, Geometry2 const& geometry2) +{ + concept::check<Geometry1 const>(); + concept::check<Geometry2 const>(); + + + typedef detail::overlay::turn_info + < + typename geometry::point_type<Geometry1>::type + > turn_info; + + typedef detail::overlay::get_turn_info + < + typename point_type<Geometry1>::type, + typename point_type<Geometry2>::type, + turn_info, + detail::overlay::assign_null_policy + > policy_type; + + std::deque<turn_info> turns; + detail::get_turns::no_interrupt_policy policy; + boost::geometry::get_turns + < + false, false, + detail::overlay::assign_null_policy + >(geometry1, geometry2, turns, policy); + + return detail::touches::has_only_turns(turns) + && ! geometry::detail::disjoint::rings_containing(geometry1, geometry2) + && ! geometry::detail::disjoint::rings_containing(geometry2, geometry1) + ; +} + + + +}} // namespace boost::geometry + +#endif // BOOST_GEOMETRY_ALGORITHMS_TOUCHES_HPP |