119 lines
3.1 KiB
C++
119 lines
3.1 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
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#define BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
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#include <boost/range.hpp>
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#include <boost/geometry/core/point_type.hpp>
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#include <boost/geometry/views/detail/points_view.hpp>
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#include <boost/geometry/algorithms/assign.hpp>
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namespace boost { namespace geometry
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{
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/*!
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\brief Makes a box behave like a ring or a range
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\details Adapts a box to the Boost.Range concept, enabling the user to iterating
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box corners. The box_view is registered as a Ring Concept
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\tparam Box \tparam_geometry{Box}
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\tparam Clockwise If true, walks in clockwise direction, otherwise
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it walks in counterclockwise direction
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\ingroup views
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\qbk{before.synopsis,
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[heading Model of]
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[link geometry.reference.concepts.concept_ring Ring Concept]
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}
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\qbk{[include reference/views/box_view.qbk]}
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*/
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template <typename Box, bool Clockwise = true>
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struct box_view
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: public detail::points_view
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<
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typename geometry::point_type<Box>::type,
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5
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>
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{
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typedef typename geometry::point_type<Box>::type point_type;
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/// Constructor accepting the box to adapt
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explicit box_view(Box const& box)
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: detail::points_view<point_type, 5>(copy_policy(box))
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{}
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private :
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class copy_policy
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{
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public :
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inline copy_policy(Box const& box)
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: m_box(box)
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{}
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inline void apply(point_type* points) const
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{
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// assign_box_corners_oriented requires a range
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// an alternative for this workaround would be to pass a range here,
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// e.g. use boost::array in points_view instead of c-array
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std::pair<point_type*, point_type*> rng = std::make_pair(points, points + 5);
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detail::assign_box_corners_oriented<!Clockwise>(m_box, rng);
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points[4] = points[0];
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}
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private :
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Box const& m_box;
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};
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};
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#ifndef DOXYGEN_NO_TRAITS_SPECIALIZATIONS
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// All views on boxes are handled as rings
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namespace traits
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{
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template<typename Box, bool Clockwise>
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struct tag<box_view<Box, Clockwise> >
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{
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typedef ring_tag type;
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};
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template<typename Box>
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struct point_order<box_view<Box, false> >
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{
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static order_selector const value = counterclockwise;
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};
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template<typename Box>
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struct point_order<box_view<Box, true> >
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{
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static order_selector const value = clockwise;
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};
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}
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#endif // DOXYGEN_NO_TRAITS_SPECIALIZATIONS
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
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