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// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2014-2015, Oracle and/or its affiliates.
// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
// Licensed under the Boost Software License version 1.0.
// http://www.boost.org/users/license.html
#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_IS_ACCEPTABLE_TURN_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_IS_ACCEPTABLE_TURN_HPP
#include <boost/range.hpp>
#include <boost/geometry/core/point_order.hpp>
#include <boost/geometry/core/tag.hpp>
#include <boost/geometry/core/tags.hpp>
#include <boost/geometry/algorithms/detail/overlay/turn_info.hpp>
namespace boost { namespace geometry
{
#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace is_valid
{
template
<
typename Geometry,
order_selector Order = geometry::point_order<Geometry>::value,
typename Tag = typename tag<Geometry>::type
>
struct acceptable_operation
{};
template <typename Polygon>
struct acceptable_operation<Polygon, counterclockwise, polygon_tag>
{
static const detail::overlay::operation_type value =
detail::overlay::operation_union;
};
template <typename Polygon>
struct acceptable_operation<Polygon, clockwise, polygon_tag>
{
static const detail::overlay::operation_type value =
detail::overlay::operation_intersection;
};
template <typename MultiPolygon>
struct acceptable_operation<MultiPolygon, counterclockwise, multi_polygon_tag>
{
static const detail::overlay::operation_type value =
detail::overlay::operation_intersection;
};
template <typename MultiPolygon>
struct acceptable_operation<MultiPolygon, clockwise, multi_polygon_tag>
{
static const detail::overlay::operation_type value =
detail::overlay::operation_union;
};
template <typename Geometry, typename Tag = typename tag<Geometry>::type>
struct is_acceptable_turn
{};
template <typename Ring>
struct is_acceptable_turn<Ring, ring_tag>
{
template <typename Turn>
static inline bool apply(Turn const&)
{
return false;
}
};
template <typename Polygon>
class is_acceptable_turn<Polygon, polygon_tag>
{
protected:
template <typename Turn, typename Method, typename Operation>
static inline bool check_turn(Turn const& turn,
Method method,
Operation operation)
{
return turn.method == method
&& turn.operations[0].operation == operation
&& turn.operations[1].operation == operation;
}
public:
template <typename Turn>
static inline bool apply(Turn const& turn)
{
using namespace detail::overlay;
if ( turn.operations[0].seg_id.ring_index
== turn.operations[1].seg_id.ring_index )
{
return false;
}
operation_type const op = acceptable_operation<Polygon>::value;
return check_turn(turn, method_touch_interior, op)
|| check_turn(turn, method_touch, op)
;
}
};
template <typename MultiPolygon>
class is_acceptable_turn<MultiPolygon, multi_polygon_tag>
: is_acceptable_turn<typename boost::range_value<MultiPolygon>::type>
{
private:
typedef typename boost::range_value<MultiPolygon>::type polygon;
typedef is_acceptable_turn<polygon> base;
public:
template <typename Turn>
static inline bool apply(Turn const& turn)
{
using namespace detail::overlay;
if ( turn.operations[0].seg_id.multi_index
== turn.operations[1].seg_id.multi_index )
{
return base::apply(turn);
}
operation_type const op = acceptable_operation<MultiPolygon>::value;
if ( base::check_turn(turn, method_touch_interior, op)
|| base::check_turn(turn, method_touch, op))
{
return true;
}
// Turn is acceptable only in case of a touch(interior) and both lines
// (polygons) do not cross
return (turn.method == method_touch
|| turn.method == method_touch_interior)
&& turn.touch_only;
}
};
}} // namespace detail::is_valid
#endif // DOXYGEN_NO_DETAIL
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_IS_ACCEPTABLE_TURN_HPP
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