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// 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.
// This file was modified by Oracle on 2014.
// Modifications copyright (c) 2014 Oracle and/or its affiliates.
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
// 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_CORE_POINT_ORDER_HPP
#define BOOST_GEOMETRY_CORE_POINT_ORDER_HPP
#include <boost/mpl/assert.hpp>
#include <boost/range/value_type.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <boost/geometry/core/ring_type.hpp>
#include <boost/geometry/core/tag.hpp>
#include <boost/geometry/core/tags.hpp>
namespace boost { namespace geometry
{
/*!
\brief Enumerates options for the order of points within polygons
\ingroup enum
\details The enumeration order_selector describes options for the order of
points within a polygon. Polygons can be ordered either clockwise or
counterclockwise. The specific order of a polygon type is defined by the
point_order metafunction. The point_order metafunction defines a value,
which is one of the values enumerated in the order_selector
\qbk{
[heading See also]
[link geometry.reference.core.point_order The point_order metafunction]
}
*/
enum order_selector
{
/// Points are ordered clockwise
clockwise = 1,
/// Points are ordered counter clockwise
counterclockwise = 2,
/// Points might be stored in any order, algorithms will determine it on the
/// fly (not yet supported)
order_undetermined = 0
};
namespace traits
{
/*!
\brief Traits class indicating the order of contained points within a
ring or (multi)polygon, clockwise, counter clockwise or not known.
\ingroup traits
\tparam Ring ring
*/
template <typename Ring>
struct point_order
{
static const order_selector value = clockwise;
};
} // namespace traits
#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace point_order
{
struct clockwise
{
static const order_selector value = geometry::clockwise;
};
}} // namespace detail::point_order
#endif // DOXYGEN_NO_DETAIL
#ifndef DOXYGEN_NO_DISPATCH
namespace core_dispatch
{
template <typename Tag, typename Geometry>
struct point_order
{
BOOST_MPL_ASSERT_MSG
(
false, NOT_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE
, (types<Geometry>)
);
};
template <typename Point>
struct point_order<point_tag, Point>
: public detail::point_order::clockwise {};
template <typename Segment>
struct point_order<segment_tag, Segment>
: public detail::point_order::clockwise {};
template <typename Box>
struct point_order<box_tag, Box>
: public detail::point_order::clockwise {};
template <typename LineString>
struct point_order<linestring_tag, LineString>
: public detail::point_order::clockwise {};
template <typename Ring>
struct point_order<ring_tag, Ring>
{
static const order_selector value
= geometry::traits::point_order<Ring>::value;
};
// Specialization for polygon: the order is the order of its rings
template <typename Polygon>
struct point_order<polygon_tag, Polygon>
{
static const order_selector value = core_dispatch::point_order
<
ring_tag,
typename ring_type<polygon_tag, Polygon>::type
>::value ;
};
template <typename MultiPoint>
struct point_order<multi_point_tag, MultiPoint>
: public detail::point_order::clockwise {};
template <typename MultiLinestring>
struct point_order<multi_linestring_tag, MultiLinestring>
: public detail::point_order::clockwise {};
// Specialization for multi_polygon: the order is the order of its polygons
template <typename MultiPolygon>
struct point_order<multi_polygon_tag, MultiPolygon>
{
static const order_selector value = core_dispatch::point_order
<
polygon_tag,
typename boost::range_value<MultiPolygon>::type
>::value ;
};
} // namespace core_dispatch
#endif // DOXYGEN_NO_DISPATCH
/*!
\brief \brief_meta{value, point order (clockwise\, counterclockwise),
\meta_geometry_type}
\tparam Geometry \tparam_geometry
\ingroup core
\qbk{[include reference/core/point_order.qbk]}
*/
template <typename Geometry>
struct point_order
{
static const order_selector value = core_dispatch::point_order
<
typename tag<Geometry>::type,
typename util::bare_type<Geometry>::type
>::value;
};
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_CORE_POINT_ORDER_HPP
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